to the tutorial
WEAP
Water Evaluation And Planning System
Tutorial
A collection of stand-alone modules to aid in learning
the WEAP software
August 2015
WEAP
Water Evaluation And Planning System
Tutorial Modules
Tutorial Overview .......................................................5
WEAP in One Hour ............................................... 15
Basic Tools ............................................................... 41
Scenarios ................................................................... 51
Refining the Demand Analysis............................... 73
Refining the Supply ................................................. 95
Data, Results and Formatting............................... 115
Reservoirs and Power Production ....................... 135
Water Quality ......................................................... 149
The WEAP/ QUAL2K Interface ....................... 173
Hydrology ............................................................... 181
Financial Analysis................................................... 199
Linking WEAP to MODFLOW .......................... 211
Linking WEAP to LEAP ...................................... 239
WEAP
Water Evaluation And Planning System
Tutorial Overview
Introduction ............................................................... 6
Background ............................................................... 6
WEAP Development ................................................ 7
The WEAP Approach ............................................. 7
Program Structure ...................................................... 8
The Tutorial Structure ............................................. 11
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Tutorial Overview
Introduction
WEAP© is a microcomputer tool for integrated water resources planning. It
provides a comprehensive, flexible and user-friendly framework for policy analysis.
A growing number of water professionals are finding WEAP to be a useful
addition to their toolbox of models, databases, spreadsheets and other
software.
This overview summarizes WEAP’s purpose, approach and structure. The
contents of the WEAP tutorial are also introduced; the tutorial is
constructed as a series of modules that takes you through all aspects of
WEAP modeling capabilities. Although the tutorial itself is built on very
simple examples, it covers most aspects of WEAP. A more complex model
presenting those aspects in the context of a real situation is included with
WEAP under the name “Weeping River Basin." A detailed technical
description is also available in a separate publication, the WEAP User Guide.
Background
Many regions are facing formidable freshwater management challenges.
Allocation of limited water resources, environmental quality, and policies for
sustainable water use are issues of increasing concern. Conventional supplyoriented simulation models are not always adequate. Over the last decade, an
integrated approach to water development has emerged that places water
supply projects in the context of demand-side issues, water quality and
ecosystem preservation.
WEAP aims to incorporate these values into a practical tool for water
resources planning. WEAP is distinguished by its integrated approach to
simulating water systems and by its policy orientation. WEAP places the
demand side of the equation - water use patterns, equipment efficiencies, reuse, prices and allocation - on an equal footing with the supply side streamflow, groundwater, reservoirs and water transfers. WEAP is a
laboratory for examining alternative water development and management
strategies.
WEAP is comprehensive, straightforward, and easy-to-use, and attempts to
assist rather than substitute for the skilled planner. As a database, WEAP
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WEAP Tutorial
WEAP Development
7
provides a system for maintaining water demand and supply information. As a
forecasting tool, WEAP simulates water demand, supply, flows, and storage,
and pollution generation, treatment and discharge. As a policy analysis tool,
WEAP evaluates a full range of water development and management options,
and takes account of multiple and competing uses of water systems.
WEAP Development
The Stockholm Environment Institute provided primary support for the
development of WEAP. The Hydrologic Engineering Center of the US Army
Corps of Engineers funded significant enhancements. A number of agencies,
including the World Bank, USAID and the Global Infrastructure Fund of
Japan have provided project support. WEAP has been applied in water
assessments in over one hundred countries.
The WEAP Approach
Operating on the basic principle of a water balance, WEAP is applicable to
municipal and agricultural systems, single catchments or complex
transboundary river systems. Moreover, WEAP can address a wide range of
issues, e.g., sectoral demand analyses, water conservation, water rights and
allocation priorities, groundwater and streamflow simulations, reservoir
operations, hydropower generation, pollution tracking, ecosystem
requirements, vulnerability assessments, and project benefit-cost analyses.
The analyst represents the system in terms of its various supply sources (e.g.,
rivers, creeks, groundwater, reservoirs, and desalination plants); withdrawal,
transmission and wastewater treatment facilities; ecosystem requirements,
water demands and pollution generation. The data structure and level of detail
may be easily customized to meet the requirements of a particular analysis, and
to reflect the limits imposed by restricted data.
WEAP applications generally include several steps. The study definition sets up
the time frame, spatial boundary, system components and configuration of the
problem. The Current Accounts, which can be viewed as a calibration step in the
development of an application, provide a snapshot of actual water demand,
pollution loads, resources and supplies for the system. Key assumptions may
be built into the Current Accounts to represent policies, costs and factors that
affect demand, pollution, supply and hydrology. Scenarios build on the Current
Accounts and allow one to explore the impact of alternative assumptions or
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August 2015
8
Tutorial Overview
policies on future water availability and use. Finally, the scenarios are evaluated
with regard to water sufficiency, costs and benefits, compatibility with
environmental targets, and sensitivity to uncertainty in key variables.
Program Structure
WEAP consists of five main views: Schematic, Data, Results, Scenario
Explorer and Notes. These five views are presented below.
Schematic:
This view contains GIS-based tools for easy configuration of your system.
Objects (e.g., demand nodes, reservoirs) can be created and positioned within
the system by dragging and dropping items from a menu. ArcView or other
standard GIS vector or raster files can be added as background layers. You
can quickly access data and results for any node by clicking on the object of
interest.
Data:
The Data view allows you to create variables and relationships, enter
assumptions and projections using mathematical expressions, and dynamically
link to Excel.
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WEAP Tutorial
Program Structure
9
Results:
The Results view allows detailed and flexible display of all model outputs, in
charts and tables, and on the Schematic.
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Tutorial Overview
Scenario Explorer:
You can highlight key data and results in your system for quick viewing.
Notes:
The Notes view provides a place to document your data and assumptions.
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WEAP Tutorial
The Tutorial Structure
11
The Tutorial Structure
This complete tutorial guides you through the wide range of applications
that can be covered with WEAP. The first three modules (WEAP in one
hour, Basic Tools and Scenarios) present the essential elements needed for
any WEAP modeling effort. The other modules present refinements that
may or may not apply to your situation.
Aside from the three basic modules, the tutorial modules can be completed
in any order and independently, as you see fit. They all start with the same
model that you will create after completing the first three modules.
Below is a list of all modules, starting with the three basic modules; the
bulleted points indicate the aspects covered in each module.
WEAP in One Hour

Creating a New, Blank Study Area

Setting General Parameters

Entering Elements into the Schematic

Getting First Results
Basic Tools

Creating and Using Key Assumptions

Using the Expression Builder
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Tutorial Overview
Scenarios

Preparing the Ground for Scenarios

Creating the Reference Scenario

Creating and Running Scenarios

Using the Water Year Method
Refining the Demand Analysis

Disaggregating Demand

Modeling Demand Side Management, Losses and Reuse

Setting Demand Allocation Priorities
Refining the Supply

Changing Supply Priorities

Modeling Reservoir Supply

Adding Flow Requirements

Modeling Groundwater Resources
Data, Results and Formatting

Exchanging Data

Importing Time Series

Working with Results

Formatting
Reservoirs and Power Production

Modeling Reservoir Operation

Adding Hydropower Computation

Modeling Run-of-River Power Plants
Water Quality
August 2015

Setting up Quality Modeling

Entering Water Quality Data

Using Water Quality Inflow Constraints for a Demand Site

Entering Pollution Generating Activity for Demand Sites

Modeling a Wastewater Treatment Plant
WEAP Tutorial
The Tutorial Structure
13
The WEAP/ QUAL2K Interface

Linking to QUAL2K

Running Scenarios
Hydrology

Modeling Catchments: the Simplified Coefficient Method

Modeling Catchments: the Soil Moisture Model

Simulating Surface Water-Groundwater Interaction
Financial Analysis

Setting up the Cost and Benefit Model

Modeling Cost

Modeling Benefits
Linking WEAP to MODFLOW

Linking to MODFLOW

Running MODFLOW and Viewing Results

Scenario: Increased Population

Scenario: Irrigation

Scenario: Artificial Recharge
Linking WEAP to LEAP

Linking WEAP and LEAP

Scenario: Hydropower Generation from WEAP

Scenario: Demand for Cooling Water from LEAP

Scenario: Electricity Demand from WEAP
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August 2015
WEAP
Water Evaluation And Planning System
WEAP in One Hour
A TUTORIAL ON
Creating a New, Blank Study Area ......................... 16
Setting General Parameters ...................................... 20
Entering Elements into the Schematic ....................... 23
Getting First Results ................................................ 36
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WEAP in One Hour
Creating a New, Blank Study Area
1.
Establish a New, Blank Area.
You are now going to practice creating a new, blank area. When you open
WEAP for the first time, a project area called “Weaping River Basin” will
appear. Use the Area, Create Area menu option to make a new, blank area.
A window, as shown below, will appear in which you should click on the
“Initially Blank” option. In the next steps, you will be defining this area for
a specific geographic area of the world - so you can name the area based on
this selection if you like (e.g., My_Ghana_Area). You can also save it as
another version of model under construction, in the event you wanted
multiple versions. Note that you can choose whether to have it password
protected.
After clicking “OK” you may be prompted to save changes to the Weaping
River Basin. After clicking yes or no, you will get the following screen:
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WEAP Tutorial
Creating a New, Blank Study Area
17
Click “OK” again. In the next screen, you will select the geographic area for
your project from the world map that appears. Use your cursor to draw a
rectangle around the area that your project will represent. The boundaries
will appear as a green rectangle.
You can then use the slider bar on the lower left of the window to zoom
into this selected area.
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WEAP in One Hour
You can redraw you green rectangle to best capture the area you want in
this view. Click on “OK” when you are satisfied with your area boundaries.
Note that you can modify these boundaries later by choosing “Set Area
Boundaries” on the pull-down menu under Schematic on the top menu bar.
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WEAP Tutorial
Creating a New, Blank Study Area
19
In WEAP, models are called “areas."
Areas are limited by boundaries, which define the extent of the project area. If you create a
new area by copying an existing one, the boundary is kept identical to that of the existing
area. To modify boundaries once you have established a New Area, go to Schematic on the
menu, and choose “Set Area Boundaries.”
Note that if you want to start with a “blank” area, you can use the steps above to select a
geographic area over one of the oceans instead of a land mass.
2.
Add a GIS layer to the Area
You can add GIS-based Raster and Vector maps to your project area - these
maps can help you to orient and construct your system and refine area
boundaries. To add a Raster or Vector layer, right click in the middle
window to the left of the Schematic and select “Add a Raster Layer” or
“Add a Vector Layer."
A window will appear in which you can input the name of this file and
where WEAP can find it on your computer or on the internet. For now,
close the window by pressing the “Cancel” button.
Background vector data can be added by clicking “Add Vector Layer." WEAP reads vector
information in the SHAPEFILE format. This format can be created by most GIS software.
A large amount of georeferenced data (both in vector and raster format) is available on the
Internet, sometimes for free. Beware that some of the downloadable data might need GIS
processing before being usable in WEAP, especially to adapt the projection and/or
coordinate system.
3.
Saving an Area
If you want to save this Area for your own use later, Use the “Area”,
“Save…” menu or press Ctrl+S.
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WEAP in One Hour
Setting General Parameters
We are now going to proceed with learning how to navigate through WEAP
and its functionalities. For the remaining exercises in this tutorial we will be
using a pre-defined Area called “Tutorial."
To open this Area, on the Main Menu, go to Area and select “Open." You
should see a list of Areas that includes “Tutorial”—select this Area. You
should now see the Schematic as shown below—with blue lines for rivers
and a yellow polygon for the city.
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WEAP Tutorial
Setting General Parameters
21
If you do not see this, go to the Area Menu, select “Revert to Version” and
choose the version named “Starting Point for ‘WEAP in One Hour’ module”
(it will have a date and time before the title).
4.
Set the General Parameters
Once the Area opens, use the “General” menu to set Years and Time Steps.
Set the Current Accounts Year to 2000 and the Last Year of Scenarios to 2005.
Set the Time Steps per year to 12. Set the Time Step Boundary to “Based on
calendar month” and starting in January (see below) Keep the default (SI units) for
now.
Under “General”, the units also be set. We will leave them in the default (SI
units) for now.
The year 2000 will serve as the “Current Accounts” year for this project. The Current
Accounts year is chosen to serve as the base year for the model, and all system information
(e.g., demand, supply data) is input into the Current Accounts. The Current Accounts is the
dataset from which scenarios are built. Scenarios explore possible changes to the system in
future years after the Current Accounts year. A default scenario, the “Reference Scenario”
carries forward the Current Accounts data into the entire project period specified (here, 2000
to 2005) and serves as a point of comparison for other scenarios in which changes may be
made to the system data. There will be a more detailed discussion of scenarios in an
upcoming module.
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WEAP in One Hour
The time steps should be chosen to reflect the level of precision of the data available. A
shorter time step will increase the calculation time, especially when several scenarios have to
be calculated.
5.
Save a version of your Area
Select “Save Version” under the “Area” menu. A window will appear asking
for a comment to describe this version. Type “general parameters set."
As with any other program, it is usually a good idea to regularly save your work in WEAP.
WEAP manages all the files pertaining to an area for you. Saving a new area will
automatically save the related files. The files are saved in the WEAP program installation
folder. You can manage the areas, export and import them, back them up and send them per
email using the Area…, Manage Areas menu.
WEAP also has a very convenient versioning feature that allow saving versions of a model
within the same area. Use the “Area”, “Save Version…:” menu to save a version, and the
“Area”, “Revert to Version” to switch to another version. You can switch between recent and
older versions without losing data. WEAP will automatically create versions of your model
every time you save. It is however better to manually create a version of a status you really
want to keep since WEAP will eventually delete old automatic versions to save disk space,
keeping only a few.
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WEAP Tutorial
Entering Elements into the Schematic
23
Entering Elements into the Schematic
6.
Draw a River
Click on the “River” symbol in the Element window and hold the click as
you drag the symbol over to the map. Release the click when you have
positioned the cursor over the upper left starting point of the main section
of the river. Move the cursor, and you will notice a line being generated
from that starting point.
The direction of drawing matters: the first point you draw will be the head of the river from
where water will flow. You can edit the river course later on by simply clicking-moving any
part of the river to create a new point, or right-clicking any point to delete it.
Follow the main river, drawing from the upstream (upper left) to the downstream
(lower right), clicking once to end each segment that you draw. You can follow the
line of the river as closely as you like, or you can draw a less detailed representation
(below). Note though, that how closely you follow the actual course of the river will
have implications for the performance of certain functionalities in WEAP. For
example, if you plan to model water quality parameters along the river, it would be
advantageous to construct the river element as closely as possible to the actual river
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WEAP in One Hour
course, because WEAP will need to calculate residence times in the river (a function
of reach lengths) to perform water quality simulations. Zooming in on the river
(using the zooming bar in the lower schematic window) can help if you want to
follow the rivers path more closely. You do not need to draw a river on the branch
coming horizontally from the left. You can also adjust the river later if you want to
add more detail.
When you double click to finish drawing the river, a dialog box appears for
naming the river (see below).
Name the river "Main River."
You may also enter an optional label for the schematic presentation (a
shorter label can help to keep the schematic from becoming cluttered).
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WEAP Tutorial
Entering Elements into the Schematic
25
You can move the river label to another location by right clicking anywhere
on the river and selecting "Move Label." The label will follow the cursor single click when the label is in the desired location.
7.
Enter Data for the Main River
There are two ways to navigate to the data entry section of WEAP to enter
data for the Main River.
1) Right-click on the Main River and select Edit data and any item in the
list.
2) Switch to the Data view by clicking on the Data symbol on the left of
the main screen. Select: Supply and Resources/ River /Main River in the Data
tree. You may have to click on the “plus sign” icon beside the Supply
and Resources branch in order to view all of the additional branches
below it in the tree.
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WEAP in One Hour
Alternatively, you can use the Tree pull-down menu and select “Expand All”
to view all branches.
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WEAP Tutorial
Entering Elements into the Schematic
27
The "Inflows and Outflows" window should be open - if it isn't, click on
the appropriate button. Click on the "Headflow" tab. Click on the area just
beneath the bar labeled “2000” in the data input window to view a pulldown menu icon. Select the “Monthly Time-Series Wizard” from the drop-down menu.
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WEAP in One Hour
Use the Monthly Time Series Wizard to enter the following data series:
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Flow (CMS)
12
7
11
17
80
136
45
32
38
18
9
7
Note that as you enter each data point, the data is shown graphically also.
Do not input or change any other data yet. Push Finish to close the wizard.
WEAP divides up rivers into reaches (segments). Originally your river has only one reach; as
you add withdrawal and return points, WEAP will automatically create new reaches.
8.
Create an Urban Demand Site and Enter the Related Data
Creating a demand node is similar to the process you used to create a river.
Return to the Schematic view and pull a demand node symbol onto the
schematic from the Element window, releasing the click when you have
positioned the node on the left bank of the river (facing downstream) in the
yellow area that marks the city’s extent.
Enter the name of this demand node as "Big City" in the dialog box, and set the
demand priority to 1.
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WEAP Tutorial
Entering Elements into the Schematic
29
Right click on the Big City demand site and select "Edit data" and "Annual
Activity Level." This is the alternative way to edit data, rather than clicking
on the "Data" view icon on the side bar menu and searching through the
data tree.
The Demand Priority represents the level of priority for allocation of constrained resources
among multiple demand sites. WEAP will attempt to supply all demand sites with highest
Demand Priority, then moving to lower priority sites until all of the demand is met or all of
the resources are used, whichever happens first
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WEAP in One Hour
You must first select the units before entering data. Click on the “N/A”
under Unit in the Annual Activity level tab. Pull down the arrow that
appears, select "People”, and click “OK."
In the space under the field labeled”2000”, enter the Annual Activity Level as
800,000.
Next, click on the "Annual Water Use Rate" tab and enter 300 under the year
2000.
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WEAP Tutorial
Entering Elements into the Schematic
31
The monthly variation is expressed as a percentage of the yearly value. The values for all of
the months have to sum up to 100% over the full year. If you don’t specify monthly variation,
WEAP will prescribe a monthly variation based on the number of days in each month.
We will not edit these values for the city demand, but we will edit them later for the
agricultural demand.
Finally, click on the "Consumption" tab and enter 15. Note that the units are preset to "percent."
9.
Create an Agriculture Demand Site
Pull another demand node symbol into the project area and position it on
the other side of the Main River opposite and downstream of Big City.
Name this demand node "Agriculture", and set the demand priority to 1.
Consumption represents the amount of water that is actually consumed (i.e. is not returned
in the form of wastewater).
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WEAP in One Hour
In the same manner as for Big City, enter the Annual Activity Level and
Annual Water Use Rate in the Data View for the Agriculture demand site
after first selecting "hectares" as the units (you may have to click on the
“plus” sign to the left in the tree in order to see all of the options for area
units).
Annual Activity Level
Annual Water Use rate
100,000 hectares
3,500 m3/hectare
Select the Monthly Variation tab and the Monthly Time Series Wizard to
enter the data below for the monthly variation in the water use rate.
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WEAP Tutorial
Entering Elements into the Schematic
33
Monthly Variation:
- 5% in April
- 10% in May and June
- 20% in July
- 30% in August
- 25% in September
- 0% for the rest of the year
Finally, click on the Consumption tab and enter 90.
You could have created one single demand site integrating both urban and agriculture
demand. However, we will see later that this removes some of the flexibility in the water
supply priorities allocation.
10.
Connect the Demand with a Supply
You now need to tell WEAP how demand is satisfied; this is accomplished
by connecting a supply resource to each demand site. Return to the
Schematic view and create a Transmission Link from the Main River to Big
City and to Agriculture. Do this by dragging the Transmission Link first to
a position on the river, releasing the click, then pulling the link to Big City
and double clicking on this demand node. Do the same for Agriculture, but
start the Transmission Link downstream of the one created for Big City.
Select a Supply Preference of 1 for each Transmission Link.
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WEAP in One Hour
The Supply Preference parameter allows you to define which source should be used in
priority to supply water to this Demand Site. WEAP will attempt to supply all of the demand
with sources having the highest preference level, only using lower-level sources if the highlevel sources do not have sufficient supply.
11.
Create Return Flow Links
Now create a Return Flow from Big City to the Main River. Do the same
for Agriculture to the Main River. Follow the same "drag and release"
procedure as for the Transmission Links.
The return flow for the urban demand site should be positioned downstream of the
agriculture withdrawal point. In the flow direction, the sequence should be:
withdrawal for Big City, withdrawal for Agriculture, return from Big City, return
from Agriculture.
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WEAP Tutorial
Entering Elements into the Schematic
35
Next, set the Return Flow Routing for the Big City Return Flow. Do this by
right-clicking on each Return Flow and selecting "edit data" and "Return
Flow Routing" or by going to the Data view\Supply and Resources\Return
Flows\from Big City.
Set the Return Flow Routing to 100%.
Do the same for the Agriculture Return Flow.
Return Flow Routing is the percent of total outflow from a demand site that is directed
through a Return Flow Link. If only one Return Flow Link is created for a demand node,
then the Return Flow Routing for that link must be 100%. Likewise, if multiple Return Flow
links are created for a demand node, then Routing factors for all of the links must sum to
100%. Losses within the Return Flow Links are specified separately.
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12.
WEAP in One Hour
Check your Model
At this point, your model should look similar to the figure below.
Getting First Results
13.
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Run the Model
Click on the “Results” view to start the computation. When asked whether
to recalculate, click yes. This will compute the entire model for the
WEAP Tutorial
Getting First Results
37
Reference Scenario - the default scenario that is generated using Current
Accounts information for the period of time specified for the project (here,
2000 to 2005). When the computation is complete, the Results view will
appear.
14.
Check your Results
Click on the “Table” tab and select “Demand” and “Water Demand” from
the primary variable pull-down menu in the upper center of the window
(see below).
Also, click the “Annual Total” Box.
If you have entered all data as listed in previous steps, you should obtain the
following annual demand values for each year (2000 to 2005) of the
Reference scenario:
Annual Demand for Agriculture
Annual Demand for Urban Area
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350 M m3
240 M m3
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WEAP in One Hour
If you do not obtain those values go back to the “Data” view and check your inputs.
If you obtain an error or warning message read it carefully as it might reveal where in your
inputs is the discrepancy, or which step you skipped.
15.
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Look at Additional Results
Now, look at the monthly Demand Coverage rates in graphical form. Click
on the “Chart” tab. Select “Coverage” from the primary variable pull-down
menu in the upper center of the window. Right now the Demand variables
are shown at the top of the menu, since Demand is checked below. If you
were in another variable subsection, such as Supply and Resources, you
would have to go into Demand to find the Coverage variable.
WEAP Tutorial
Getting First Results
39
Format the graph by selecting the 3-D option on the right side-bar menu,
and ensure that “All months” is selected in the pull-down menu above the
graph (also keep the “Monthly Average” option checked). Note that the 3D option allows the viewer to see both data sets even while they overlap.
The graph should like the one below.
During the months of December and February, which have little flow in the river,
Big City lacks water, and therefore demands go unmet. We modeled agriculture to
only require water March-September, so it registers 100% coverage in the DecemberFebruary shortage because it has no water demand. Agriculture only has a shortfall
in supply in the month of August and September, when the plants require the most
water. Note that because Agriculture and Big City both have a supply preference of
1, when there is water shortage they will have equal percentages of unmet demand,
assuming they are both demanding water at that time.
You can fully customize the way WEAP charts are displayed, as well as print or copy graphs
to the clipboard using the toolbox located to the right of the graph.
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WEAP
Water Evaluation And Planning System
Basic Tools
A TUTORIAL ON
Creating and Using Key Assumptions ...................... 42
Using the Expression Builder ................................... 45
August 2015
Note:
For this module you will need to have completed the previous module (“WEAP in
one hour”) or have a basic knowledge of WEAP (creating an area, drawing a model,
entering basic data, obtaining first results). To begin this module, go to the Main
Menu, select “Revert to Version” and choose the version named “Starting Point for
‘Basic Tools’ module.”
42
Basic Tools
Creating and Using Key Assumptions
1.
Using Key Assumptions
Key Assumptions are pieces of data that may be useful to apply across
multiple elements. The use of key assumptions is especially worthwhile
when the model has a large number of similar objects, for example demand
sites, and when performing scenario analyses. In this case, you can easily set
all your demand sites to have the same unit domestic consumption. Then,
you can create scenarios to vary this consumption without having to edit
each and every demand site – simply by changing the key assumption value.
Key Assumptions are created by going to the Data view and right-clicking
on the Key Assumptions branch of the Data Tree. Select “Add” - this will
create a new Key Assumption variable below the Key Assumption branch.
After clicking Add, you can name your Key assumptions in the Data Tree.
Name them and enter the data as follows: (be sure to select the appropriate
units from the Units pull-down menu. Cubic meters will be found under
“Volume,”):
Unit Domestic Water Use
Unit Irrigation Water Needs
August 2015
300 m3
3,500 m3
WEAP Tutorial
Creating and Using Key Assumptions
43
With Key Assumptions, it is important to ensure that the units designated in
a Key Assumption variable match the units indicated for the variable as it
occurs elsewhere in the data tree. In this case, the 300 m3 domestic water
use matches the 300 m3/person use specified in Big City/Water
Use/Annual Use Rate. Similarly, the key assumption Unit Irrigation Water
Needs matches the units in Agriculture/Water Use/Annual Water Use Rate.
Create one more Key Assumption, Domestic Variation, that is unitless (“No
Unit”), and use the Monthly Time Series Wizard to populate it with values:
Domestic Variation
- Jan to Feb & Nov. to Dec.:
- Mar. to May & Sept. to Oct.
- June
- Jul, Aug
2.
0.9
1.0
1.1
1.15
Creating References to Key Assumption
Create a Key Assumption reference for “Big City Annual Water Use." Do
this by going to the “Annual Water Use Rate” window for Big City in the
Data view. Click on the Expression Builder pull-down menu in the space
where you entered the “Annual Water Use Rate” (300 m3) previously.
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Basic Tools
In the Expression Builder window, delete the value of 300 from the text
field at the bottom of the Expression Builder window, click on the
“Branches” tab towards the bottom left of the screen, then click on the
“Unit Domestic Water Rate” under Key Assumption (you may have to
expand the data tree to see all of the branches) in the Data tree field and
drag it down to the text field so it shows up as Key\Unit Domestic
Use[m^3]. Click on “Finish."
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Using the Expression Builder
45
Repeat this procedure to replace the 3500 m3/ha water use rate for the
“Agriculture” Demand Site with the newly created “Unit Irrigation Water
Needs” Key Assumption.
If you check the results now by re-recalculating, you should have the same annual
total values for demand as obtained in the WEAP in One Hour module:
- Annual Demand for Agriculture
350 M m3
- Annual Demand for Urban Area
240 M m3
Using the same process, references to other objects’ data can also be created. This can be
helpful in certain cases. Upon dragging and dropping the object to be referenced from the
tree to the expression builder’s text field, a list of all available variables appears.
Using the Expression Builder
3.
Creating Mathematical Expressions
You will now alter the monthly variation in water demand for Big City using
a mathematical expression. In the Data view, click on the Big City demand
site, then “Water Use” and the “Monthly Variation” tab and select the
Expression Builder from the pull-down menu in the data entry bar.
Create the following expression by pulling down the “Domestic Variation”
Key Assumption and typing in the modifying terms:
Key\Domestic Variation * 100 / 12
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Basic Tools
Note that if you had made a mistake in typing the expression, such as entering a space
instead of a division sign, an error message would have appeared after clicking “Finish."
You would then be given the opportunity to review and correct the expression. After the
correction of an error, you must click “Verify” before “Finish."
View the new results for “Demand Site Coverage” after making these
changes. Click on the Results view and click on “Yes” to recalculate. The
results should appear as below:
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Using the Expression Builder
47
Note that there is no longer unmet demand in December for Big City
because the fraction of demand in December decreased from 8.5%
(originally based on the number of days in the month) to 7.5% (now based
on the expression using the “Domestic Variation” Key Assumption). You
can review the numerical values calculated from the “Monthly Variation”
expression by selecting the “Table” tab in the data review panel at the
bottom of the data window. Remember it is calculated from the original
data we entered in the Key Assumptions/Domestic Variation, subjected to
the equation we entered in the Expression Builder.
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4.
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Basic Tools
Using Built-In Functions
We will assume that the current population of Big City (2000) is not known,
but we know its population during the last census and the growth estimate.
We can use the built-in “GrowthFrom” function to compute the current
population of Big City. Do this by selecting the Expression Builder from
the pull-down menu in the year 2000 data input field within the “Annual
Activity Level” window for Big City. Delete the present value of 800000,
click on the “Function” tab rather than the “Branch” tab and drag down
into the text field the “GrowthFrom” expression selected from the list of
built in expressions.
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Using the Expression Builder
49
Input the following data into the “GrowthFrom” expression, using the
format indicated in the description window next to the expression list.
Date of last Census
Population at last census
Estimated growth rate
1990
733,530
1.75%
This results in the following format for the expression:
GrowthFrom(1.75%, 1990, 733530)
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Basic Tools
The Expression Builder is only a simple way of entering expressions and functions. Savvy
users can by-pass it and enter functions, references and mathematical expressions directly in
the main Expression window.
August 2015
WEAP Tutorial
WEAP
Water Evaluation And Planning System
Scenarios
A TUTORIAL ON
Preparing the Ground for Scenarios .......................... 52
Creating the Reference Scenario ................................. 53
Creating and Running Scenarios ............................... 58
Using the Water Year Method ................................. 61
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Scenarios
Note:
For this module you will need to have completed the previous modules (WEAP in
One Hour and Basic Tools) or have a fair knowledge of WEAP (data structure, Key
Assumptions, Expression Builder). To begin this module, go to the Main Menu,
select “Revert to Version” and choose the version named “Starting Point for
‘Scenarios' module."
Preparing the Ground for Scenarios
1.
Understand the Structure of Scenarios in WEAP
In WEAP the typical scenario modeling effort consists of three steps. First,
a “Current Accounts” year is chosen to serve as the base year of the model;
Current Accounts has been what you have been adding data to in the
previous modules. A “Reference” scenario is established from the Current
Accounts to simulate likely evolution of the system without intervention.
Finally, “what-if” scenarios can be created to alter the “Reference Scenario”
and evaluate the effects of changes in policies and/or technologies.
Read the “Scenarios” help topic (under the Data subheading in the Help Contents)
for a more detailed description of the WEAP approach.
2.
Change the Time Horizon for the Area
In the Data or Schematic view, under the General\Years and Time Steps
menu, change the “Time Horizon” of the Area.
Current Accounts Year
Last Year of Scenarios
3.
2000 (unchanged)
2015
Create an Additional Key Assumption
Create the following key assumption:
Population Growth Rate
2.2
There is no unit for this Key Assumption, but remember to change the
“Scale” field to Percent.
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Creating the Reference Scenario
53
Creating the Reference Scenario
4.
Describe the Reference Scenario
The “Reference” Scenario always exists. Change its description in the
Area\Manage Scenarios menu to reflect its actual role. Note that you must
be in the Data View or Schematic view to have access to the “Manage
Scenarios” option in the Area menu.
For example, “Base Case Scenario with population growth continuing at the 19601995 rate and slight irrigation technology improvement."
5.
Change the Unit Irrigation Water Use
In the Data View, change the “Unit Irrigation Water Needs” Key
Assumption to reflect a new annual pattern for the period (2001-2015) after
the Current Accounts year. To make the change, you will need to select the
“Reference” scenario from the drop-down menu at the top of the screen.
Use the “Yearly Time-Series Wizard” to construct the time series.
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Scenarios
First, select the function "Linear Interpolation" by clicking on it, then click "Next."
Click on "Enter Data" in the next window, click "Next", then click "Add"
to add the following data to the time series:
Enter Time-Series Data:
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Linear Interpolation
WEAP Tutorial
Creating the Reference Scenario
55
Data:
2000 3500
2005 3300
2010 3200
2015 3150
Growth after last year: 0%
Note that the first data point, for the year 2000, should already be listed in
the data input window because it was input when the “Unit Irrigation Water
Needs” Key Assumption was created in the Current Accounts (see Exercise
1 under Creating and Using Key Assumptions, Basic Tools Module).
As you can see while running the Yearly Time Series Wizard, WEAP offers a wide range of
techniques to build time series, including importing from Excel files, creating step
functions, using forecasting equations etc.
The Yearly Time Series Wizard helps you create expressions. You can also simply type or
edit the expression (in this case, “Interp( 2000,3300, 2005,3300, 2010,3200, 2015,3150 )”
without running the wizard, either directly or through the Expression Builder.
6.
Set the Population Growth
Change the population of Big City to grow by the rate defined by the
“Population Growth Rate” Key Assumption defined in an earlier step. Here
again you will have to select the “Reference” scenario in the drop-down
menu at the top of the Data view.
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Scenarios
Make sure you have the Big City Demand Site and its Annual Activity Level tab
selected. Delete the current expression and select the “Growth” function in the
Expression Builder in the pull-down menu below the 2001-2015 field (Note that
the present expression in this field is the same as that for the Current Accounts
year). Then click on the “Branch” tab above the text field. Either double click on
the "Population Growth Rate" Key Assumption in the Data Tree, or drag it down
into the expression window. Your final function should read
“Growth(Key\Population Growth Rate/100)”
Note that you have to divide the “Population Growth Rate” by 100 in order for
WEAP to recognize the value of 2.2 in the Key Assumption as 0.022 in the
calculation.
The same effect could have been modeled without creating a Key Assumption in the first
place. We will see however that doing so provides more flexibility when adding other
scenarios.
Any value for which no time series is defined for the “Reference” scenario is assumed to
remain constant. In our case for example, the Agriculture demand will remain constant until
2015 unless we change this variable as well.
7.
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Run the Reference Scenario
Run the Reference Scenario by clicking the “Results” view. Look at a 3-D
graph of “Unmet Demand” (select “Annual Total”) for both demand sites.
It should be similar to the figure below. Think about the following points.
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Creating the Reference Scenario
57
How does the demand evolve compared to the unmet demand?
Why is the total unmet demand decreasing at first and then increasing?
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Scenarios
Creating and Running Scenarios
8.
Create a New Scenario to Model High Population Growth
Create a new scenario to evaluate the impact of a population growth rate for
Big City higher than 2.2% for the period 2001-2015.
For this you will have to return to the Data View or the Schematic View.. Choose
the menu “Area”, “Manage Scenario”, right-click the “Reference” scenario and
select “Add." Name this scenario “High Population Growth” and add the
description “This scenario looks at the impact of increasing the population growth
rate for Big City from a value of 2.2% to 5.0%.”
9.
Enter the Data for this Scenario
Make the following changes in the Data view after having chosen your new
scenario in the drop-down menu at the top of the screen:
Select the “Population Growth Rate” Key Assumption and change the value under
the 2001-2015 field to 5.0. Note that the color of the data field changes to red after
the change - this occurs for any values that are changed to deviate from the
“Reference” scenario value.
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Creating and Running Scenarios
10.
59
Compare Results for the Reference and Higher Population Growth
Scenarios
Compare, graphically, the results for the two scenarios we have established
so far (Reference and Higher Population Growth).
For example, select “Water Demand” from the primary variable pull-down menu.
Click in the drop-down menu to the right of the chart area (above the graph legend),
and select “All Scenarios." Choose to show only Big City demand by selecting it
from the pull-down list in the upper left pull-down menu of the Results window.
Your graph should be similar to the one below.
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Scenarios
Note the higher Water Demand for Big City in the “Higher Population
Growth” scenario, as expected.
Next, compare “Unmet Demand” for the two scenarios. Use the primary
variable pull-down menu to select “Unmet Demand."
Again, note the higher Unmet Demand for the Higher Population Growth
scenario.
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Using the Water Year Method
61
When creating many scenarios in the same area, the computation can become lengthy. In
this case you can exclude some of the scenarios from the calculation by unchecking the
“Show results for this scenario” box in the scenario manager for those scenarios.
Using the Water Year Method
11.
Create the Water Year Definitions
The previous exercise only varied demand, not supply. In this step we now want
to see how natural variation in climate data (stream flow, rainfall etc.) can be
taken into account in WEAP through scenario analyses. We will use the
“Water Year Method” as an example. The Water Year Method is a simple
means to represent variation in climate data such as streamflow, rainfall, and
groundwater recharge. The method first involves defining how different
climate regimes (e.g., very dry, dry, very wet) compare relative to a normal
year, which is given a value of 1. Dry years have a value less than 1, very wet
years have a value larger than 1.
With the “Reference” scenario selected, go into the data view and click on
the "Water Year Method" branch under "Hydrology" in the Data tree.
Select the "Definitions" tab and expand the window, if necessary, to see all
five defitions. Enter the following data:
Very Dry
Dry
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0.7
0.8
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Scenarios
Normal
Wet
Very wet
1.0
1.3
1.45
Monthly variations can be entered with the Water Year Monthly Fluctuation Wizard in the
drop down menu.
12.
Create the Water Year Sequence
The next step in using the “Water Year Method” is to create the sequence
of climatic variation for the scenario period. Each year of the period is
assigned one of the climate categories (e.g., wet). , select the "Sequence" tab
under the "Water Year Method" branch.
Set the Current Account as Normal
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Using the Water Year Method
63
Then, select the “Reference” scenario and input the following sequence.
2001-2003
2004
2005
2006-2008
2009-2010
2011
2012
2013
2014
2015
normal
very dry
wet
normal
dry
very wet
normal
wet
normal
dry
To input this sequence
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Scenarios
In order to let the inflows to the model (in our case, the headflow of the main river) vary in
time, WEAP offers two strategies. If detailed forecasts are available, those can be read using
the ReadFromFile function (refer to the Tutorial module on Format and Data for more
details). Another method, which is the one presented here, is the “Water Year Method."
Under this method every year in the model’s duration can be defined as normal, wet, very
wet, dry or very dry. Different scenarios can then alter the chosen sequence of dry and wet
years to assess the impact of natural variation on water resources management.
13.
Set up the Model to Use the Water Year Method
In the Data tree, change the “Headflow” for the Main River in the
“Reference” scenario to use the “Water Year Method." Note that before,
the monthly values of Headflow were the same for the period 2001-2015 as
for 2000, the Current Accounts year.
Use the drop down menu in the “Get Values from” to select this method. You may
have to scroll left in this window to get the “Get Values from” field to appear
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WEAP Tutorial
Using the Water Year Method
14.
65
Re-run the Model
Run the model again and compare “Unmet Demand” for the “Reference”
and “Higher Population Growth” scenarios, as before (of course, “Water
Demand” will not have changed after altering the supply side of the model
with the Water Year Method).
Note that Big City “Unmet Demand” for both scenarios is much more
erratic using the Water Year Method than assuming a constant headflow to
the Main River, as observed in the previous exercise. In the present case,
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Scenarios
Unmet Demand varies as the future climate varies. During years wetter or
much wetter than normal (2000, the Current Accounts year), Unmet
Demand is actually lower than in 2000 for both scenarios, even with the
increase in Water Demand from population growth (2.2% for the Reference
and 5.0% for the Higher Population Growth scenarios). The increased
precipitation, and headflow to the river, mitigates this increased demand in
the wetter years.
The opposite occurs in the dry to very dry years, where the population
growth is exacerbated by the lower precipitation and headflow in the river in
these years. This leads to even higher Unmet Demand than is simulated
assuming a constant climate (as performed in the previous exercise).
Since unmet demand is the difference between a large demand and a large supply, even a
rather small change in the supply at nearly-constant demand can have a very large impact
on the unmet demand.
This model does not take any kind of inter-year storage into consideration (reservoirs,
groundwater). Therefore, there is no way that the shortage in a dry year can be alleviated by
using surplus from previous, wetter years. For more details on how to model storage, refer to
the “Refining the Supply” WEAP tutorial module.
If you had wanted to compare, in the same graph in WEAP, results for the
Water Year Method to that generated assuming a constant climate, you
could have created a new scenario that used the Water Year Method rather
than changing the data in the “Reference” scenario to accommodate the
Water Year Method. This new scenario would be inherited from the
“Reference” scenario, and the Scenario tree in the “Scenarios Manager
would look as follows:
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Note that in this case, both the “Reference” (constant climate) and “Water
Year Method” scenarios (variable climate) would use a Population Growth
Rate equal to 2.2% for Big City, since the “Water Year Method” scenario is
inherited from the “Reference” scenario.
If one wanted to compare, in the same WEAP graph, constant climate and
variable climate using a 5% Population Growth Rate, you could create
another new scenario inherited from the “Water Year Method” scenario and
change the “Population Growth Rate” Key Assumption in this scenario to
5%. The tree structure would look as follows:
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Scenarios
WEAP allows for unlimited versatility in the arrangement of scenarios. Note that you can
output results to Excel, which also facilitates results comparisons among scenarios. This
feature will be discussed in greater detail in the “Data, Results, and Formatting” module.
15.
Change Scenario Inheritance
The following example demonstrates the utility of changing scenario
inheritance within WEAP.
Create a new scenario inherited from the “Reference” scenario, and name it
“Extended Dry Climate Sequence." The scenario tree structure should look
as follows:
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Using the Water Year Method
69
Go to the Data view and select this new scenario for editing. Click on the
“Water Year Method” branch of the data tree (below Hydrology) to edit the
climate sequence as follows:
2001-2003
2004
2005-2008
2009-2010
2011
2012
2013
2014
2015
normal
wet
normal
very dry
normal
dry
normal
normal
dry
The results (shown below) indicate that Big City “Unmet Demand” for the
“Extended Dry Climate Sequence” (new climate sequence and a 2.2 %
Population Growth Rate) falls somewhat in between those for the
“Reference” scenario (original climate sequence and a 2.2 % Population
Growth Rate) and the “Higher Population Growth Rate” scenario (original
climate sequence, but a 5% Population Growth Rate).
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Scenarios
Now, we will change the Scenario Inheritance of the “Extended Dry
Climate Sequence” scenario, placing it under the “Higher Population
Growth Rate” scenario so that it inherits the 5% Population Growth Rate
of that scenario. In the Scenario Manager, select the “Extended Dry Climate
Sequence” scenario, click on the drop down list to the right (below the text
saying “Extended Dry Climate Sequence is based on:”) and select “Higher
Population Growth” as the new parent scenario.
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Now, recalculate the results and look again at “Unmet Demand” for Big
City.
What changes do you notice to the unmet demand for the “Extended Dry Climate
Sequence” scenario?
With the higher population growth rate and dryer climate, Unmet Demand increases
substantially.
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WEAP
Water Evaluation And Planning System
Refining the
Demand Analysis
A TUTORIAL ON
Disaggregating Demand ........................................... 74
Modeling Demand Side Management, Losses
and Reuse ................................................................ 81
Setting Demand Allocation Priorities........................ 91
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Refining the Demand Analysis
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for all modules after ‘Scenarios’ module.”
Disaggregating Demand
1.
Create a new Demand Site
In the Current Accounts, create a new demand site downstream of Big City
to simulate rural demand. Name this node “Rural” and give it a Demand
Priority = 1. Provide a Transmission Link from the Main River positioned
downstream of both the Big City and Agriculture Return Flows. The Supply
Preference should be set to 1. Also provide a Return Flow for Rural that is
positioned further downstream.
Your area should now look as follows:
2.
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Create the Data Structure for “Rural” demand node
In order to create a data structure, right-click the “Rural” demand site in the
data view tree, and select “Add” to implement the following structure (do
not enter any data yet):
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Disaggregating Demand
75
Note that “Showers”, “Toilets”, “Washing”, and “Others” are added as subbranches below “Single Family Houses."
3.
Enter the Annual Activity Level data
Enter the following data under the Rural Demand Site, Annual Activity
Level tab (You will have to click on Single Family House in the Data Tree):
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Refining the Demand Analysis
Rural
Single Family Houses
Showers
Toilets
Washing
Others
Apartment Buildings
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120,000 Households
70% Share
80% Saturation
90% Saturation
55% Saturation
35% Saturation
Remainder share (use the Expression
Builder)
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Disaggregating Demand
77
Share vs. Saturation: even though both types of percentages are treated mathematically the
same by WEAP, they are conceptually different. At a given level of the tree, shares should
always sum up to 100%. They also allow the use of the “remainder” function. Saturation
indicates the penetration rate for a particular device and is independent of the penetration
rate for other devices (i.e., saturation rates for all sub-branches within a given branch do not
have to sum to 100.
4.
Enter the Annual Water Use Rate data
Enter the following data under the “Rural” demand site, “Annual Water
Use Rate” tab.
Rural
Single Family Houses
Showers
Toilets
Washing
Others
Apartment Buildings
Consumption (in consumption tab)
80 m3/household
120 m3/household
60 m3/household
40 m3/household
220 m3/household
80%
Note that the “Consumption” value is entered for the entire Rural demand node,
and not the sub-branches.
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5.
Refining the Demand Analysis
Check the results
Recalculate your results. In the Results view, choose “Water Demand” as
the primary variable from the pull down menu. Select “All Branches” from
the pull-down menu directly above the graph legend. Select 3-D and bar
graph as the format using the pull-down menu for the “Chart Type” icon
on the vertical graphing toolbar (see first and second screen shot below).
Select the Rural demand node from the pull down menu above the graph
(see third screen shot below).
To see the results stacked, click on the bar icon in the far right menu, and
click the option “stacked.”
In order to view Water Demand results for all of the Rural sub-branches
(e.g., Single Family Houses\Showers; Apartment Buildings), toggle up to
Level 2 on the “Levels” selection field (directly above the center of the
graph). The resulting graph should look like the one below:
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Disaggregating Demand
79
Change the branch of demand to the Rural demand.
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Refining the Demand Analysis
Do you understand why the Rural demand varies along the year even though we
have not entered any variation?
The variation in Rural demand is due to the fact that WEAP assumes a constant daily
demand per day (no monthly demand was specified by the user), so months that have less
days (like February) have a lower demand than months that have more days (like January).
Now create a 3-D graph of “Demand Site Coverage” and select all demand
sites for presentation (the pull-down menu to do the latter is to the right of
the graph; see below).
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Modeling Demand Side Management, Losses and Reuse
81
Do you understand why Coverage is always 100% for Rural but not for Big City
and Agriculture, even though they all have the same demand priority level?
The Rural withdrawal point is downstream of the return flow point for the Big City, which
means there is an additional volume of water available in the river; this return flow can easily
cover the rather small Rural demand.
Modeling Demand Side Management, Losses and
Reuse
6.
Implement Demand Side Management - the disaggregated approach
We will now create a new scenario that explores a demand side management
strategy. Call this scenario “New Washing Machines DSM”; it is to be
inherited from the “Reference” scenario so it will have the same climate and
Big City population growth rate as the “Reference” scenario. We deleted the
scenarios we are not using by clicking the “delete” button. The scenario tree
in the Manage Scenarios window should look like this:
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Refining the Demand Analysis
We will assume that a new type of washing machines allows a 1/3 reduction
(33.3% less) in washing water consumption. This new scenario will evaluate
the impact of this Demand Side Management measure if 50% of the
households can be convinced to purchase the water-saving machine.
First, go back to Current Accounts in the Data view, where you will create
two new branches (Old Machines and New Machines) in the Rural data
structure. Effectively, you are disaggregating the “Washing” variable to now
include two new sub-categories. Note that you must return to Current Accounts
because all new data structures have to be entered in Current Accounts, even if the
variable is not to be activated (i.e., given non-zero activity levels) in the Current Accounts
and “Reference” scenario.
When you go to add the first sub-branch under Washing, you will get the
following message:
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Modeling Demand Side Management, Losses and Reuse
83
Click ”Yes,” and add the following structure:
Change the units for “Old Machines” and “New Machines” to “Shares." Under
Annual Water Use, reenter the Water Use Rate for Old Machines (60
m3/household), as was the value for the original higher level variable “Washing."
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Refining the Demand Analysis
Enter a value of 100% for the “Old Machines Annual Activity Level." Leave
blank the Annual Activity Level for “New Machines” - this is the same as
entering a zero. Remember, you are entering these in the Current Accounts, so you
want only the “Old Machines” to be active in the “Reference” scenario. This
recreates the same effect as having the aggregated variable “Washing” in the original
Current Accounts and “Reference” scenario. The “New Machines” variable will be
activated in the “New Washing Machines DSM” scenario (see below).
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85
Now, switch to the “New Washing Machines DSM” scenario.
Input a value of 50 for New Machines (50% of all washing machines will be this
new variety) and Remainder(100) for Old Machines (use the Expression Builder
for the latter).
You will have to input again the original Water Use Rate for the Old Machines
(60 m3/household) as well as the new Water Use Rate for the New Machines:
Old Machines
60 m3/household
New Machines
60*0.667 m3/household
View the data on as “Bar,” selected on the right hand side from the top icon.
(Note that you have to tell WEAP to make the chart a bar graph to see
those results)
Now compare the numerical Water Demand results for the Washing branch
of the Rural demand site for the “Reference” and “New Washing Machines
DSM” scenarios. In the Results view, click on the Table tab and select the
Water Demand variable. Also select “Annual Total” rather than “Monthly
Average” and choose 2001 (you can only view numerical results for one
individual year at a time when comparing scenarios in the Table view, but
this does not present a difficulty for this example, as we do not try to model
any growth with time for the Washing variable). Choose Demand
Sites\Rural\Washing\Single Family Houses\Washing from the upper left
pull-down menu and “All Branches” from the upper right pull-down menu.
Select the “Reference” and “New Washing Machines DSM” scenarios from
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the pull-down menu at the bottom of the window. The table should look
like the following:
Note that the use of the New Machines in 2001 (and all subsequent years in
the “New Washing Machines DSM” scenario period) results in about
460000 m3 less water demand than if only Old Machines are used
(Reference scenario).
Demand-side management (DSM) refers to measures that can be taken on the consumer’s
side of the meter to change the amount or timing of water consumption (as compared to the
utility company's, or supply, side of the meter).
Another way of modeling disaggregated DSM is to reduce the unit consumption for the
affected category (in this case washing). There is no right or wrong way to model DSM,
although some ways can show more information than others within WEAP.
7.
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Implement Demand Side Management - the aggregated approach
If disaggregated data is not available, an equivalent value of DSM can be
computed. In this example, assuming we had not disaggregated the Rural
water demand, we could come to the same result by using the “Demand
Management” option for this Demand Site in the Data view. In this case the
reduction would amount to:
WEAP Tutorial
Modeling Demand Side Management, Losses and Reuse
Original contribution of
washing to rural water use
Share of New Machines
Reduction of New Machines
Multiplying all of these percentages together =
87
2,772/26,316 10.5%
50%
66.6%
3.5%
This value could be entered in the “Demand Management/Demand Savings” tab
for the Rural branch of a Demand Side Management scenario.
Demand Side Management (DSM) measures are not taken into account in the demand
view. To see the effect of a DSM measure, look at the change in Supply Requirement rather
than Water Demand.
8.
Model Reuse
Another water conservation strategy that could be studied with scenarios is
water reuse. Create a new scenario inherited from the “Reference” scenario
and name it “Big City Reuse." Make sure you are in this new scenario and
click on the Big City branch. Click on the “Loss and Reuse” button and
click the “Reuse Rate” tab.
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Enter the following expression in the 2001-2015 field using the Expression
Builder:
Smooth(2001,5, 2005,18, 2015,25)
First, pull the “Smooth” function into the text field of the Expression
builder and select “Smooth Curve” from the options. Click “Next” and
enter the data values. You should get a plot like the one below. Note that
Reuse in the Current Accounts (2000) remains zero. Click “Finish."
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In the Results View, compare Unmet Demand for Big City before
(Reference) and after (Big City Reuse) instituting this conservation strategy.
You should get the graph below, which shows substantial reductions in Big
City Unmet Demand when the water reuse strategy is used.
9.
Model Losses
Re-edit the model to take into account the fact that there is a 20% loss rate
in the network of Big City. Make this change for the Current Accounts so
that it will be carried through the “Reference” scenario, and as a result of
the inheritance feature, throughout all scenarios.
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What happens to the unmet demand for the Big City, both in the “Reference”
scenario and the “Big City Reuse” scenario compared to the earlier exercise without
losses?
Losses can happen in Transmission Link, in the Demand Site itself or in the Return flow.
Losses in the Transmission Link will affect the supply to the Demand Site. Losses in the
Demand Site will affect the required Supply Requirements of this Demand Site. Losses in
the Return Flow will only affect the flow returned.
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Setting Demand Allocation Priorities
10.
Edit Demand Site Priority
Create a new scenario, inherited from the “Reference”, and name it
“Changing Demand Priorities." Change the Demand Priority of the
Agriculture Demand Site in the Data view by clicking on the Agriculture
branch and then clicking on the Priority button, or by clicking on the node
in the Schematic View and selecting "General Info."
Change the Demand Priority from 1 to 2.
A demand priority can be any whole number between 1 and 99 (1 is the default) and allows
the user to specify the order in which the water requirements of demand sites are satisfied.
WEAP will attempt to satisfy the water requirement of a demand site with a demand priority
of 1 before a demand site with a demand priority of 2 or greater. If two demand sites have
the same priority, WEAP will attempt to satisfy their water requirements equally. Absolute
values have no significance for the priority levels; only the relative order matters. For
example, if there are two demand sites, the same result will occur if demand priorities are
set to 1 and 2 or 1 and 99.
Demand Priorities allow the user to represent in WEAP water allocation as it actually occurs
in their system. For example, a downstream farmer may have historical water rights to river
water, even though another demand site positioned upstream could extract as much river
water as it desired, leaving the farmer with little water in the absence of such water rights.
The Demand Priority setting allows the user to set the farmer's priority for water above that
of the upstream demand site. Demand Priorities can also change with time or change in a
scenario - more advanced subject matter to be dealt with later in the tutorial.
You can also change the Demand Priority in the Data View\”Priority” screen\”Demand
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Priority” tab.
11.
Compare Results
Display graphically the Unmet Demand for Agriculture for the “Reference”
and “Changing Demand Priorities” scenarios. It should look like the graph
below”:
Notice that the Unmet Demand for Agriculture increases when its Demand
Priority is raised to 2. This is because Big City now has preference for
having its demand met first. Evidence of this can be observed by generating
a graph of the monthly average Demand Coverage for Big City and
Agriculture across all years of the Reference scenario.
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Now compare these results to the same graph generated for the “Changing
Demand Priorities” scenario.
Notice that in the “Reference” scenario, for April and August, both Big City
and Agriculture do not get full coverage of their demand because they both
compete equally for Main River flow. When Big City is given preference for
meeting demand (Changing Demand Priorities scenario), however, its
coverage improves relative to Agriculture. At times, coverage is 100% for
Agriculture, but not for Big City - that is because there is no Agriculture
demand (primarily observed for the winter months). Note that the Demand
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Coverage for the Rural demand site is always 100% - this is because the
return flows for Big City and Agriculture satisfy the water demand created
by the Rural demand site.
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Water Evaluation And Planning System
Refining the
Supply
A TUTORIAL ON
Changing Supply Priorities ....................................... 96
Modeling Reservoir Supply ....................................... 99
Adding Flow Requirements ....................................106
Modeling Groundwater Resources ...........................110
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Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting point for all modules after ‘Scenarios’ module.”
Changing Supply Priorities
1.
Create a new Transmission Link for water reuse
Create a new transmission link starting at the Big City Demand Site and
ending at the Agriculture Demand Site. This is a conceptual model of reuse
of urban wastewater for agriculture purposes. Set the Supply Preference on
this Transmission Link to 2.
Supply Preference
2
If water quality were a concern, a wastewater treatment plant could have been added to treat
the water from Big City before Agriculture received it. Having the treatment plant in the
schematic would make it possible to simulate the changes in water quality before and after
treatment.
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2.
97
Results when you change Supply Preferences
Try changing the Supply Preferences of the two links that now supply
Agriculture and look at the related results for Demand Site Coverage. To
change Supply Preferences, either right click on the Transmission Link in
the Schematic view or go to the Data view and click on the appropriate
Transmission link below Supply and Resources\Linking Demands and
Supply\Agriculture.
Try the following combinations:
Supply Preferences = 1 from the Main River, 2 from Big City
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Supply Preferences = 2 from the Main River, 1 from Big City
Supply Preferences = 1 from the Main River and 1 from Big City
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Do you understand why the differences in Demand Coverage occur when the Supply
Preferences change?
You can modify the display of preferences on the schematic by using the
“Schematic\Change the Priority View” menu. The “View Allocation Order” option will
display the actual priority order in which WEAP computes supply. This is a function of the
Supply Preference of the link as well as the Demand Priority of the demand site.
Note that you can study the impact of changing Supply Preferences, like Demand Priorities,
by creating alternative scenarios.
3.
Revert to original model
You can do this using the “Revert to Version” option under the Area menu.
Choose “Starting point for all modules after “Scenarios” module” as you
did at the beginning of this exercise.
Modeling Reservoir Supply
4.
Create a Reservoir and enter the related data
First, create a new scenario inherited from “Reference”, and name it
“Reservoir Added."
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While in Manage Scenarios, highlight the High Population Growth scenario
and uncheck the box “show results for this scenario.” This will enable
WEAP to make calculations faster.
Then add a reservoir object on the Main River upstream of Big City, and
name it "Main River Reservoir." Unclick the box where it asks if this object
is active in Current Accounts.
Leave the Demand Priority at 99 (default).
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Right click on Main River Reservoir and select "Edit Data." Select the
“Storage Capacity” variable to enter the Data view (Make sure you have the
“Reservoir Added” scenario selected). Once you are in the Data view, you
will first have to click on the “Startup Year” button before you can alter any
other parameters. Note: you may have to click on the data tree before the
year will save.
Choose 2002 as the startup year for Main River Reservoir
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Then click on the “Physical” button and change the following parameters:
Storage Capacity
70 M m3
Note that the Scale is set to "Million"
More details about reservoirs operation and hydropower production are provided in the
“Reservoirs and Power Production” module of the WEAP tutorial.
5.
Run the Model and Evaluate the Results
Compare the Demand Site Coverage for Agriculture in the “Reference” and
“Reservoir Added” scenarios.
- Demand Coverage: why does Agriculture have higher coverage with the Main
River Reservoir in place?
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- Reservoir Storage Volume: does the solution of building a reservoir appear to be
sustainable? Use the primary variable pull down menu to select Reservoir Storage
Volume (under Supply and Resources\Reservoir), and select “All Years” from the
pull down menu at the bottom of the graph.
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- Flow in the River: how does having the reservoir on the Main River change the
flow downstream compared to the Reference scenario? Select Streamflow (under
Supply and Resources\River) from the primary variable pull-down menu and
click on “Monthly Average."
- Choose the year 2002 from the “Selected Years” option on the bottom menu,
and choose the reach below Withdrawal Node 2 for comparison.
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You may want to switch to a logarithmic axis (the button is located on the
vertical toolbar on the far right) to see more clearly the differences in flow
upstream and downstream of the Main River Reservoir.
Now select the reach below Return Flow Node 1 for comparison. Why is streamflow
along this reach more similar for the two scenarios?
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The creation of a large reservoir allows storage of “excess” water during high flow periods to
cover water demand during low flow periods. The price to pay is, however, a potentially
large impact on the hydrological regime of the river downstream of the reservoir. The
Return Flows from Big City and Agriculture provide the flow in the Main River during the
spring and winter months. A reservoir’s operation variables and flow requirements can be
used to mitigate the reservoir’s downstream impact.
Adding Flow Requirements
6.
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Create a Flow Requirements
Create another new scenario: “Flow Requirement Added." This scenario is
inherited from the “Reservoir Added” scenario. The scenario tree should
look like the one below:
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Now add a “Flow Requirement” to the Schematic view below the
withdrawal node for the Big City, but upstream of the withdrawal node for
Agriculture.
Demand Priority
1 (default)
Right click on the Flow Requirement and select Edit Data\Minimum Flow
Requirement. Add the value below (make sure you still have the “Flow
Requirement Added” scenario selected):
Minimal Flow Requirement
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Refining the Supply
Run the Model and Evaluate the Results
Look at the results and think about the related questions.
- How does adding the flow requirement change streamflow in the reach below the
flow requirement?
Compare streamflow below the flow requirement for the “Reference”,
“Reservoir Added”, and “Flow Requirement Added” scenarios for the same
year (2002). You should obtain a graph like the one below:
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- What is the Flow Requirement coverage?
You can view these data by selecting "Instream Flow Requirement
Coverage" under Demand. (Switch off the logarithmic display for the y axis,
and select only the “Flow Requirement Added” scenario for viewing).
- Why has the coverage now changed for the Big City?
Select “Demand Coverage” from the primary variable pull-down menu,
select the Big City demand site, and select the “Reference”, “Reservoir
Added”, and “Flow Requirement Added” scenarios for viewing.
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- Assuming this flow requirement was more important than supplying the Big City, how
should the model be changed to ensure that the flow requirement is fulfilled?
The relative level of Demand Priority for Big City, Agriculture and the Flow Requirement
will determine which demand is covered first. To ensure that the Flow Requirement is
covered first, change the Demand Priority of Big City to a higher number (lower priority)
than for the Flow Requirement, since it is upstream of the Flow Requirement.
Modeling Groundwater Resources
8.
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Create a Groundwater Resource
Create a Groundwater node next to the City and name it "Big City
Groundwater." Also, make it active in Current Accounts.
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Give Big City Groundwater the following properties (make sure you are in
Current Accounts when entering these data - you will realize you are not if
there is no tab for Initial Storage):
Storage Capacity Unlimited (default, leave empty)
Initial Storage
100M m3
Natural Recharge (use the Monthly Time Series Wizard, accessed in the field under
"2000")
- Nov. to Feb. 0M m3/month
- Mar. to Oct. 10M m3/month
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Refining the Supply
Connect Big City Groundwater with Big City
Use a Transmission Link to connect Big City Groundwater to the Big City
demand site, and provide it with a Supply Preference of 2.
Your model should look similar to the figure below:
10.
Update the characteristics of the Transmission Link between the Main
River and Big City
Change the characteristics of the Transmission Link connecting the Main
The Maximum Flow Volume or Percent of Demand parameter represents restrictions in the
capacity of a resource (due, for example to equipment limits).
River (Withdrawal Node 1) and Big City (make sure you are in Current
Accounts):
Supply Preference
1 (default)
Maximum Flow Volume 6 m3/sec
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11.
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Run the Model and Evaluate the Results
Look at the following results and think about the related questions.
- Is the groundwater extraction required to meet demands under these conditions
sustainable?
To view these results, select “Groundwater Storage” from the pull-down
menu under “Supply and Resources\Groundwater."
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- How does the relative use of water from Big City Groundwater and the Main
River evolve at the Big City demand site?
To view these graphical results for Big City specifically, first select "Supply
Delivered" under Demand using the primary variable pull-down menu.
Then choose "All Sources" in the pull-down menu on the right side of the
window above the graph legend. Next, select Big City as the demand site to
view using the pull-down menu above the graph. Click on “Annual Total."
Groundwater recharge and interaction with rainfall and surface water can be modeled rather
that entered as inputs. Refer to the “Hydrological Modeling” tutorial for more details.
Other resources can be modeled using the “Other Supply” object, which is characterized by
a monthly “production” curve. This object can be used to simulate a desalination plant or
inter-basin transfers, for example.
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WEAP
Water Evaluation And Planning System
Data, Results and
Formatting
A TUTORIAL ON
Exchanging Data ..................................................116
Importing Time Series ............................................119
Working with Results ............................................123
Formatting ............................................................127
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Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting point for all modules after ‘Scenarios’ module.”
Exchanging Data
1.
Export Data to Excel
Export the entire model to Excel by going to the Data view and selecting
“Edit”, “Export Expressions to Excel."
Export all branches, and all variables of the “Current Accounts” only (don’t
export any of the scenarios for this example) to a new workbook. Keep other options
at default values.
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This instruction creates a new Excel workbook that contains all the variables that can be
changed in the “Data” view, using the same structure as in the Data tree. In large models,
you can choose to export only the current branch and/or variable.
2.
Use Excel’s Auto Filtering Option
In the Excel Spreadsheet that was created in the previous steps, filter the
content to display only the “Consumption” variable. You will probably
have to scroll over to the right to see the column in the view.
Use the arrow to the right of the “variable” header to unselect “select all” and the
scroll down to select the “Consumption” variable in the drop-down list.
Auto-filtering does not change or erase the data; it only hides the rows that are not of
interest. Multiple filters can be used.
3.
Modify Data
In the Excel spreadsheet that was created in the previous steps, make the
following changes in the yellow column (it may be good to hide a few of the
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columns so that you can see both the variable values and the Demand Sites
to which they belong in the same view):
Big City Consumption
Agriculture Consumption
5% (value was 15 originally)
5% (value was 90 originally)
The values entered are not meant to be representative of realistic values, just examples.
When creating a large model, a quick way to enter a lot of data is to use the Excel Import
and Export functions combined with the Excel lookup capabilities. This requires the user to
have set up the model in a consistent way (data structure, names), however.
4.
Import the Data from Excel
Re-import the modified data in Excel.
In WEAP, choose “Edit”, “Import Expressions from Excel…”
Check that the Consumption data have been changed in your model.
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WEAP always reads from the Excel file that had the focus last. If you have several Excel files
open, you should ensure that the appropriate Excel file is selected before beginning the
importation into WEAP.
When re-importing into Excel, all rows are read, even those that are filtered out through the
auto-filtering options.
Importing Time Series
5.
Create a Streamflow Gauge Object
Add a “Streamflow Gauge” object to the model.
Insert the Streamflow Gauge downstream of the Big City, below the return flow
nodes for Agriculture and Big City.
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Data, Results and Formatting
Import Text File Data
Import streamflow data from a comma-separated text file containing
approximately 100 years of streamflow measurements up to 2003. To
import the file, use the “ReadFromFile” function in the streamflow gauge’s
data tab in the “Supply and Resources\River\Streamflow Gauges” branch
of the Data tree.
Type in the following function, which will read the file from a directory called
“Additional Files” located in your area’s folder:
”ReadFromFile(Additional Files\River_Flow.csv)”
If WEAP cannot find the file, try searching for it using the
“ReadFromFile Wizard” in the dropdown menu.
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The ReadFromFile function can be used for any variable that requires a time series, monthly
or yearly, such as headflow, groundwater recharge, etc.
WEAP will automatically locate the correct year and month and only use that data. If you
change the years modeled, WEAP will automatically read the correct data.
More information about the syntax of this function and the format of the data file can be
found in the “Read from File” help topic.
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Data, Results and Formatting
Compare the Actual and Modeled Streamflow
Recalculate the results and compare the historical streamflow data with the
WEAP simulated streamflow. Do this by clicking on the “Chart” tab of the
Results view and selecting from the primary variable pull-down menu:
Supply and Resources\River\Streamflow Relative to Gauge (Absolute).
WEAP will compare the observed flow at the streamflow gauge to the nearest upstream
node. In the case for this example, that node is Return Flow 2 (the Return Flow for
Agriculture). Comparing observed and simulated streamflow is one means for the user to
assess if the model is representing the system accurately.
Choose the “Selected Years” option from the pull-down menu below the
chart and select only the years 2000, 2001, 2002, and 2003 (the Current
Accounts is 2000, and the data file contains no stream gauge data beyond
2003). If the results display both scenarios, change it to the reference
scenario only with the pull-down menu to the right of the chart above the
legend. To display the years in different colors, use the same pull-down
menu above the legend to select “Selected Years.”Choose the Reference
scenario. You should obtain the graph below:
Notice that the simulated streamflow is greater than the observed
streamflow in the Current Accounts year (2000) but is less than observed in
subsequent years.
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8.
Create a Favorite Graph
Create a graph of streamflow that shows both the actual flow as recorded at
the streamgauge and the simulated streamflow at the appropriate node
upstream of the streamgauge (in this example, Return Flow Node 2). First,
select “Streamflow” from the primary variable pull-down menu. Then select
“Streamgauge” and “Below Return Flow Node 2” from the list that appears
when you choose “Select Nodes and Reaches” from the drop-down menu
of the Supply and Resources\River\Streamflow chart above the graph
legend (see below). Finally, select the years 2000, 2001, 2002, and 2003 to be
represented in the graph using the pull-down menu at the bottom of the
window.
Save this graph as a favorite by using the “Favorite”, “Save Chart as
Favorite” option. Name the file "Simulated and Observed Streamflow
Comparison."
From this point forward, the chart will appear in the list of favorite charts of the Results
view.
You can also export the data to Excel or to the clipboard, change the format and the display
of figures and charts, calculate statistics, group series with the smallest values, etc. from the
toolbar located at the right of the “Results” view.
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Data, Results and Formatting
Create an Overview
An overview displays important charts in the Scenario View like a
dashboard. Create an “Overview” displaying the streamflow, inflow, and
outflow to area charts.
Select the “Scenario Explorer” view. Click“Manage.” In the window that appears,
select “Inflows to Area”, “Outflows from Area” and the Favorite graph created in
the previous step.
Overviews can be created from any combination of favorites, but the charts need to be
created in the “Results” view prior to their integration in an overview. The data underlying
overviews can also be displayed in tabular format (select the “Table” tab) and exported to
Excel.
10.
Use the Dynamic Map
Dynamic Results Maps are a quick way to obtain an overview of the results
in their temporal context. In the “Results” view, select the “Map” tab and
play with the time slider at the bottom of the display to see how the
displayed parameters change.
Try this by selecting the Main River’s streamflow.
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Note that as you pull the slider across the bar, an indicator appears in the
graph above the bar to indicate the data selected (for this example, the year
2004 annual total is selected). In the smaller schematic view at the top of the
window, the width of the river will increase and decrease with the changing
data, and numerical values appear for each of the reaches.
11.
Export Results to Excel
All results can be readily exported to Excel from the “Results” view. A new
workbook is created that contains the results in table format, with the same
structure as in WEAP.
Recall the favorite graph you have created a few steps before by selecting it in the
“Favorite” menu of the Results View. Export the related data to Excel by
switching to the “Table” tab and hitting the “Export Table to Excel” button (
to the right of the screen.
12.
)
Calculate Statistics
You can generate statistics in the Results view for any table. Under “Charts”,
display the Reference Scenario Streamflow (annual total) for all reaches of
the Main River for all years. Now click on the Table tab and then click on
the "Stat" icon on the right vertical menu bar.
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We are provided with statistical values of Min, Max, Mean, Standard
Deviation (SD) and Root Mean Square (RMS).
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13.
Change the Appearance of a Background Vector Layer
In the Schematic View, change the color of the polygon for Big City by
right-clicking the “Cities” layer in the box below the Element Selection box
(see example below), and selecting “Edit."
In the window that appears, click on the Appearances tab, then click on the
“Fill Color” field. A color palette will appear.
Change the Background color to orange.
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Background vector data can be added by clicking “Add Vector Layer." WEAP reads vector
information in the SHAPEFILE format. This format can be created by most GIS software.
A large amount of georeferenced data (both in vector and raster format) is available on the
Internet, sometimes for free; websites such as www.geographynetwork.com or
www.terraserver.com provide good starting points for a search. Keep in mind that some of
the downloadable data might need GIS processing before being usable in WEAP, especially
to adapt the projection and/or coordinate system.
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129
Label a Vector Layer
You can edit the labels for the layers - right click on the “Rivers Polygons”
layer in the box to the right of the schematic, select “Edit” and choose the
“Label” tab. You can also change the size of the labels in this tab by going
to the Size field at the bottom of the window.
You can also hide layers in the Schematic view by clicking in the small box
to the left of the layer name (this makes the check mark disappear also).
15.
Add a Raster Layer
In the Schematic view, add a background map of the Big City region by
right-clicking in the Layer window (see example below) and selecting “Add
Raster Layer”
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Select the file “Map.jpg” located in the “_Maps\Tutorial” subdirectory of the
WEAP directory (e.g., C:\Program Files\WEAP21\_Maps\Tutorial). Also
enter a descriptive name to appear in the Layer window.
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Your map may show up as the first item in the window, placing it the other vectors
and shapes.
We want to see the rivers and roads. You can also move various layers
above or below each other in the schematic. Do this by right clicking on a
layer and selecting "Move Up" or "Move Down."
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After you have moved your layars, your model should now look similar to the figure
below:
WEAP uses a “world file” to correctly position your raster file for a specific map projection.
Those files define the coordinate of one of the corners of the raster and the cell size. They
can be created by many standard GIS programs such as ArcView.
The world file must have the same name as the raster file with a “w” added to its extension
and be in the same directory. For example, the world file for the above file is called
“map.jgw."
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Move around Labels
Complete the formatting of your area by changing the node and label font
size and moving around labels.
Under the Schematic pull-down menu, the “Set WEAP Node Size” and “Set
WEAP Node Label Size” menu options can be used to change the size of symbols
and labels. For each of these actions, a window with a slider will appear for
increasing and decreasing the size of these elements.
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Data, Results and Formatting
Right-Click on any object and select “Move Label” to move its label.
If you don’t want a label to appear for a given object, just right-click that object, select
“General Info” and delete the optional label text.
You can copy your map to the clipboard for later use in reports and presentations by
selecting “Copy Schematic to Clipboard…” in the “Schematic” menu. The file size
indicated in the dialog box corresponds to an uncompressed format. It is usually safe to go
with the default level of detail.
August 2015
WEAP Tutorial
WEAP
Water Evaluation And Planning System
Reservoirs and
Power Production
A TUTORIAL ON
Modeling Reservoir Operation.................................136
Adding Hydropower Computation ..........................141
Modeling Run-of-River Power Plants ......................144
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Reservoirs and Power Production
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting point for all modules after ‘Scenarios’ module.”
Modeling Reservoir Operation
1.
Create a Reservoir
Create a Reservoir on the Lake located upstream of the Big City’s
withdrawal from Main River. Name it “Big City Reservoir" and leave it
active in Current Accounts.
Demand Priority
99 (default)
Entering a Demand Priority of 99 ensures that the reservoir will only fill if all other needs are
fulfilled, including downstream demand.
2.
Enter the Physical Data
Right click on Big City Reservoir to edit data. Enter the following data in
the “Physical” window (make sure you are in Current Accounts).
Storage Capacity
70 M m3
Initial Storage
25 M m3
Volume Elevation Curve
Volume
Elevation
3
Mm
m
0.0
190
30.0
210
70.0
216
Net Evaporation
25 mm/month (note that it defaults to monthly
measurements).
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Modeling Reservoir Operation
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The “Volume Elevation Curve” is used both to model the surface for evaporation and to
compute the head in case hydropower production is simulated. A cylindrical shape is
assumed in converting reservoir volume and elevation into reservoir area.
Area
Elevation
productio
n
{Volume}
Net evaporation needs to account for both rainfall and evaporation. It can therefore be a
positive or a negative number; monthly variations can be modeled using the “Monthly Time
Series Wizard."
3.
Enter the Operation Data
In the same view, enter the following data in the “Operation” window.
Top of Conservation
Top of Buffer
Top of Inactive
Buffer Coefficient
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60 M m3
40 M m3
5 M m3
1.0
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Modeling Reservoir Operation
139
As illustrated by the figure to the
left, WEAP allows the modeling of
advanced reservoir operation
through the definition of several
zones that have different
operational constraints.
More can be learned through the
Help file’s “Reservoir Zones and
Operation” screen or by clicking
on the help button when in the
Reservoir’s Operation tab.
4.
Understanding the Impact of the Buffer Coefficient
Now create a new scenario inherited from the “Reference” scenario. Name
this scenario “Buffer Coefficient Changes." Then go back to the Data view
(make sure that you are in the new scenario you just created) and change the
buffer coefficient to 0.1. Click on results to run the new model.
Compare, for the “Reference” and “Buffer Coefficient Changes” scenarios,
the results for “Reservoir Storage Volume”, found under the “Supply and
Resources\Reservoirs” branch of the primary variable pull-down menu.
Select “All Years” from the pull-down menu at the bottom of the graph,
and click on “Monthly Average” at the top of the graph. Choose the
“Reference” scenario and “Buffer Coefficient Changes” scenario for
viewing from the pull-down menu above the legend. You can choose “Big
City Reservoir” from the pull-down menu directly above the graph.
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Reservoirs and Power Production
Also compare results also for Demand Coverage (under the Demand
branch). Select the “Reference” and “Buffer Coefficient Changes”
scenarios from the pull-down menu above the graph legend. Select “Big
City” as the demand site for viewing from the remaining pull-down menu
directly above the graph.
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Adding Hydropower Computation
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The Buffer Coefficient provides a way to regulate water releases when the water level in the
reservoir is within the buffer zone (see figure in the information box of the previous step).
When this occurs, the monthly release cannot exceed the volume of water in the buffer zone
multiplied by this coefficient. In other words, the buffer coefficient is the fraction of the
water in the buffer zone available each month for release. Thus, a coefficient close to 1.0 will
cause demands to be met more fully while rapidly emptying the buffer zone, while a
coefficient close to 0 will leave demands unmet while preserving the storage in the buffer
zone. This is why lower Demand Site Coverage is observed for results in the “Buffer
Coefficient Changes” scenario above.
Adding Hydropower Computation
5.
Understanding the way WEAP models Power Production
WEAP can model Power Production in three different ways: through online reservoirs, through off-line reservoirs, and through run-of-river
hydropower plants. In a later module, we will also discuss linking WEAP
with a Long-range Energy Alternatives Planning system (LEAP) energy
modeling software.
Refer to the help for more information on each category.
6.
Add Power Production Capabilities to Big City Reservoir
In this example we will model an operating reservoir power plant. Enter the
following data under the “Hydropower” window for Big City Reservoir in
the Current Accounts.
Max Turbine Flow
Tailwater Elevation
Plant Factor
Generating Efficiency
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80 CMS
195m
100%
60%
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Look at the “Hydropower Calculations” help topic for more information about how WEAP
computes power production.
7.
Compute Hydropower Production and Understand the Results
Run the model and look at the results in the Reference scenario for power
production for the year 2000.
The results can be accessed under the Primary Variable pull-down menu under
“Supply and Resources/Reservoir/Hydropower."
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Adding Hydropower Computation
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Do you understand why production levels between May and June are so similar,
even though flow in Main River and downstream water release is much greater in
June? To confirm this, look at the results for “Streamflow” in the reach above Big
City Reservoir (Below Main River Headflow).
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The streamflow that can be processed by the turbine has been capped to 80CMS (see
previous step), meaning that even though there is a higher discharge in June, the excess
quantity flows downstream without going through the turbine. Hydropower in June would
be the same for May and June if not for the fact that the Storage Elevation in Big City
Reservoir was slightly lower at the end of April than it was at the end of May (look at the
Storage Elevation results to confirm this - these numbers represent the status at the end of
each month indicated). This effect was slightly offset by the fact that May has 31 days to
produce power, whereas June has 30 days, but June still ended up having slightly higher
total production.
Off-line, “local” reservoirs’ hydropower production can be modeled in the same way.
Modeling Run-of-River Power Plants
8.
Create a Run-of-River Hydro Object
Create a Run-of-River Hydro Object on the Main River upstream of the Big
City Reservoir created in the previous exercise. Name it “Big City Run of
River."
Enter the following data in the “Supply and Resources\River\Run of River
Hydro” branch of the Data tree in the Data View:
Max Turbine Flow
Plant Factor
Generating Efficiency
Fixed Head
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80 CMS
100%
60%
19.5 m
WEAP Tutorial
Modeling Run-of-River Power Plants
9.
145
Run and Compare Results
Run your model and create a graph comparing the power production for
the run-of-river and the reservoir power plants. Do this by selecting “All
Hydropower” from the pull-down menu above the legend.
What are the reasons for the differences between both curves?
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Note that the Run of River hydropower is slightly higher in May than June, in contrast to
Big City Reservoir power production. This is due to the additional day available in May
compared to June. Run of River hydropower production does not have Storage Elevation as
limiting effect, whereas the Reservoir was still filling in May, which decreased the Reservoir
production for that month compared to June.
How does the run-of-river plant influence the streamflow of the
river, when compared to the Big City Reservoir plant?
To view this on the chart, select “Streamflow” from the primary variable
pull-down menu and choose “Selected Main River Nodes and Reaches”
from the pull-down menu above the legend. Select the following reaches:
“0\Headflow”, “1\Big City Run of River”, “2\Reach”, “2\Big City
Reservoir”, and “4\Reach” from the list.
We view the results (below) on a logarithmic scale, accessed by clicking on
the “Log” icon on the bar on the right.
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A reservoir can store water during high flows and release during low flow, thus having a
smoothing effect. A run-of-river operation, however, processes whatever water flows in the
river at any given point in time. Therefore, it does not affect the shape of the streamflow
curve.
Stockholm Environment Institute
August 2015
WEAP
Water Evaluation And Planning System
Water Quality
A TUTORIAL ON
Setting up Quality Modeling ...................................150
Entering Water Quality Data................................152
Using Water Quality Inflow Constraints for a
Demand Site .........................................................158
Entering Pollution Generating Activity for
Demand Sites ........................................................160
Modeling a Wastewater Treatment Plant ................164
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Water Quality
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for all modules after ‘Scenarios’ module.”
Setting up Quality Modeling
1.
Understanding Water Quality Modeling in WEAP
WEAP can model both conservative and non-conservative pollutants.
Conservative pollutants are modeled through a simple mass balance. Several
models are offered for non-conservative pollutants.
Read the Water Quality "Getting Started" help topic for a more detailed
description of WEAP capabilities.
2.
Create a Set of Pollutants
Create a set of pollutants that will be modeled by going to the
“General\Water Quality Constituents” menu.
In the dialog box, choose “Temperature” to be calculated by temperature
modeled in WEAP, under the “Calculated By” down.
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Next, add “TSS” (Total Suspended Solids) and “Salt” to the list of
constituents (“BOD” and “DO” should also already be listed):
Name
Temperature
TSS
Salt
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Calculate by
Temperature (Modeled in WEAP)
First-order Decay
Conservative (No Decay)
Decay Rate
0.25 per day
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More details are provided on the different models used for BOD and DO models in the
“Dissolved Oxygen and Biochemical Oxygen Demand” help topic.
Entering Water Quality Data
3.
Enter River Water Quality data
In the Data view tree, select “Supply and Resources\River” and click on the
Main River. Then open the “Water Quality” screen and enter the following
data, which will represent water quality at the headflow of the river:
Model Water Quality?
Temperature
15°C
BOD concentration
DO Concentration
TSS concentration
Salt concentration
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YES (check the box)
5mg/l
8mg/l
20mg/l
2mg/l
WEAP Tutorial
Entering Water Quality Data
4.
153
Enter River Geometric Characteristics
River geometric characteristics are needed for the various water quality
models. They are mainly used to compute velocity/residence time of the
water along a reach. In the Data view, select the “Reaches” branch of the
Main River and enter the following information under the “Physical” tabs.
Headflow Distance Marker
Tailflow Distance Marker
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0 km
300 km
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Water Quality
Note: intermediate reach lengths will be estimated by WEAP based on the
schematic.
In the Flow Stage Width tab,use the Wizard by clicking on the drop-down arrow
for “Below Main River Headflow” to enter the following data:
Flow
Stage
Width
0
0.00
0.00
10
2.00
15.00
50
6.00
20.00
100
8.00
25.00
200
10.00
30.00
Your final formula should read:
FlowStageWidthCurve( 0, 0, 0, 10, 2, 15, 50, 6, 20, 100, 8, 25, 200, 10, 30 )
We will assume this section remains constant and leave other reaches empty.
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Entering Water Quality Data
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Water Quality
The “Reach Length” tab displayed under the “Inflows and Outflows” category is used only
for modeling surface water-groundwater interactions. It represents the length of the reach
connected to the groundwater, which may be less than the total length of that reach.
5.
Enter the Climatic Data
Climatic Data are needed to compute water temperature. Click on the
“Climate” button and again select the “Below Main River Headflow” reach.
Enter the following climate data (for air temperature, use the Monthly Time
Series Wizard):
Air Temperature
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Set
Oct
Nov
Dec
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Value (°C)
10
11
13
15
21
24
29
31
28
20
16
12
WEAP Tutorial
Entering Water Quality Data
Humidity
Wind
Cloudiness Fraction
Latitude
157
65%
1 m/s
1
30°
Note: you can enter these values for the first reach and leave the other reaches blank
if you want the value to apply to all reaches.
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Water Quality
Using Water Quality Inflow Constraints for a
Demand Site
6.
Enter Constraint Data
A demand site may require that its water supply meets certain quality criteria.
Create a new scenario inherited from the “Reference” scenario and name it
“Big City Water Quality Inflow Constraints." In the Data view (make sure
you are in this new scenario), select the Big City branch of the data tree, and
click on the “Water Quality” button. Under the “BOD Inflow” tab, enter
the following maximum allowed concentration of BOD:
BOD inflow
7.
2 mg/L
Compare Results
Note that you earlier entered a BOD concentration (5 mg/L) for the Main
River Headflow (under Current Accounts), so you can now run the results
and compare the output for Big City Demand Site Coverage, with and
without this inflow constraint for Big City. For the period 2000 and 2001, a
comparison of Big City Demand Site Coverage for the “Reference” and
“Big City Water Quality Inflow Constraints” scenarios should look like the
following:
Why does Big City Coverage drop to zero during June, 2001, in the Inflow Constraint
scenario?
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Using Water Quality Inflow Constraints for a Demand Site
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If you look at the BOD concentration (Water Quality, River Water Quality) in the “Below
Main River Headflow” reach (pictured below), you will see that BOD rises above the
constraint (2 mg/L) for Big City intake during the month of June for both 2000 and 2001.
Since the constraint is activated during the scenario period (starting in 2001), coverage for
Big City decreases during June, 2001, because this demand site will not accept water that
falls below the BOD constraint, and no other sources of water other than the Main River
have been designated as supplies for Big City.
The simulated temporal pattern of the BOD concentration along this reach of the Main
River is a function of degradation, the extent of which is controlled by the residence time of
the water in the “Headflow” reach. The longer the residence time in this reach, the more
degradation that occurs. The pattern for BOD thus mirrors that of the flow velocity, and
streamflow, for the reach (both pictured below).
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Water Quality
Entering Pollution Generating Activity for
Demand Sites
8.
August 2015
Entering Data
We will assume that we know the concentration of pollutants in the outflow
(Return Flow) for Big City. Hence, we will use the “Concentration” series of
tabs in the “Demand Sites\Big City” branch of the Data tree. Click on the
“Water Quality” button and enter the following data (in Current Accounts):
WEAP Tutorial
Entering Pollution Generating Activity for Demand Sites
Temperature
BOD Concentration
DO Concentration
TSS Concentration
Salt Concentration
161
16 °C
60 mg/l
3 mg/l
5 mg/l
10 mg/l
For the Agriculture demand site, we will admit that we do not know the
concentration at the outflow, but we do know the pollutant generation
intensity. Enter the following data:
BOD intensity
DO Intensity
TSS Intensity
Salt Intensity
Temperature
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50 kg/ha
30 kg/ha
20 kg/ha
2 kg/ha
15°C
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Water Quality
Pollution outflow from a demand site is only based on the each demand site’s pollutant
concentration or intensity data, not on the water quality of the inflow to the demand site.
Note that temperature data can change over time.
9.
Evaluate the Results
Run the model and look at the following results for various water quality
constituents for the year 2000. Select “Pollution Generation” from the
primary variable pull-down menu (under Water Quality):
Demand Site Pollution Generation
River Water Quality (here we switched the colors to “Mac” in the colors option on
the bar on the right of the screen)
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Entering Pollution Generating Activity for Demand Sites
163
Note that Pollution Generation for Agriculture is confined to the spring and
summer months when farming is active.
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Modeling a Wastewater Treatment Plant
10.
Create a Wastewater Treatment Plant
Create a new scenario named “Wastewater Treatment Plant Added”- this
scenario is inherited from the “Reference." Then, add a Wastewater
Treatment Plant for Big City, name it “Big City WWTP” and make it
inactive in Current Accounts, and create a Return Flow Link from the Big
City to the WWTP. Keep the existing Return Flow Link from Big City to
the river. Also create another return flow from the WWTP to the river.
Your model should look similar to the figure below:
You will have to set the “Return Flow Routing” variables for both links.
For the Return Flow from Big City to Main River (Return Flow Node 1), set the
Routing to 100% for the Current Accounts year and 0% for years 2001-2015 in
the “Wastewater Treatment Plant Added” scenario.
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For the Return Flow from Big City to the Big City WWTP, set the Return Flow
to 100% for the years 2001-2015 in the “Wastewater Treatment Plant Added”
scenario. Set the return flowto zero in the Current Accounts. Even though it does
not yet exist, WEAP will give you errors if the percentages don’t add up to 100%
between existing and non-existing infrastructure. See below.
Also set the Routing to 100% for the Return Flow from the Big City WWTP to
the Main River (Return Flow Node 3). (in Wastewater Treatment Plant Added
scenario)
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Water Quality
You also have the possibility to set removal rates in the various return flows. This would be
useful if, for example, a given pollutant is decomposed by bacteria in the sewer system.
These data can be entered under the “Water Quality\Pollutant Decrease in Return Flow”
branches for the appropriate return flows (see figure below for example).
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Modeling a Wastewater Treatment Plant
11.
167
Enter WWTP Data
First, enter the “Start Year” by clicking on the “Start Year” button under
the “Water Quality\Wastewater Treatment” branch of the data tree for Big
City WWTP. Make sure you hit the enter key after entering 2001.
Start Year
2001
Also enter the following data under the “Treatment” category (with the
“Wastewater Treatment Plant Added” scenario selected):
Consumption
Daily Capacity
BOD Removal
DO Concentration
TSS Removal
Salt Removal
Temperature
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5%
2M m3
90%
5mg/l
80%
20%
15°C
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If only part of the wastewater is treated through the WWTP, there are two modeling
possibilities. One is to limit the Daily Capacity to whatever amount can actually be treated.
In this case the wastewater in excess will be discharged without treatment. In this case, the
share of untreated wastewater is not constant, but depends on the total flow.
Another solution is to create an additional return flow going from the demand site straight
to the river, by-passing the WWTP. In this case, a constant share can be set to by-pass the
WWTP by setting the return flow routing shares accordingly. A combination of both
methods is also possible.
12.
Evaluate the Results
Run the model and look at the following results for BOD in the
“Wastewater Treatment Plant Added” scenario, comparing them with the
“Reference” scenario values (without a wastewater treatment plant).
-RiverWater Quality (BOD downstream of Big City’s outflow into the river).
To view these results, first select “River Water Quality” under “Water
Quality” in the primary variable pull-down menu. Then choose “Selected
Scenarios” under the pull-down menu above the chart legend and select the
“Reference” and “Wastewater Treatment Plant Added” scenarios.
Using the pull-down menu at the bottom of the chart, select the years 2000
and 2001 for viewing. Select “Below Return Flow Node 3” (Return Flow
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Node 3 is the return flow for the WWTP, so you will be looking at water
quality in the river just downstream of the outflow from the WWTP) as the
Main River reach to view. Select “BOD” as the water quality constituent
from the pull-down menu directly above the chart, and unclick the
“Monthly Average” button to the far right. Your screen should look like the
one below:
Note that BOD levels decrease substantially in 2001 compared to 2000 in the reach below the
return flow from the treatment plant because the plant becomes active that year.
-WEAP can also display water quality results from upstream to downstream.
From the bottom menu, choose “All Main River Nodes and Reaches” and
check “Represent true relative distance?” This will show all nodes and
reaches along the X-axis, with their spacing proportional to their distance
downstream (distances shown in parentheses). Select July, 2010, as the
month and year. For the chart type, select “Line."
The charts shows that BOD levels rise as BOD-laden return flows enter the
river, and decline as the BOD decays as it moves downstream. The effect
of the wastewater treatment plant can be clearly seen. Your chart should
look like this:
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Water Quality
-Wastewater Treatment Plant Inflows and Outflows.
To view these results, select the “Wastewater Treatment Plant Inflows and
Outflows” (under Water Quality) from the primary variable pull-down
menu. Also select the “Wastewater Treatment Plant Added” scenario from
the far upper left menu. View “All Months (12)” and in the second icon on
the menu bar, select to have the bars stacked.
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In this type of chart, the outflows are represented as negative values and inflows are positive
values. Note also that the “Lost in Treatment” category represents the flow that is
consumed - a consumption rate of 5% was input in the data view for the treatment plant.
Stockholm Environment Institute
August 2015
WEAP
Water Evaluation And Planning System
The WEAP/
QUAL2K Interface
A TUTORIAL ON
Linking to QUAL2K ..........................................174
Running Scenarios .................................................180
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The WEAP/ QUAL2K Interface
Note:
For this module you will need to have completed the previous modules (WEAP in
One Hour, Basic Tools, Scenarios, and Water Quality) or have a fair knowledge of
WEAP (data structure, Key Assumptions, Expression Builder, creating scenarios).
To begin this module, go to the Main Menu, select “Revert to Version” and choose
the version named “Starting point for ‘Water Quality with QUAL2K’.” This version
enacts necessary files to complete this module.
Linking to QUAL2K
1.
Using QUAL2K for Water Quality Modeling in WEAP
In addition to using WEAP’s in-built capacity for water quality modeling, it
is possible to use the US EPA QUAL2K modeling framework. This module
demonstrates how to use the WEAP/QUAL2K interface, taking the Water
Quality module as a starting point. This module is not an introduction to
QUAL2K, which requires specialized knowledge, but if you are already
using QUAL2K, you should be able to link your QUAL2K file to WEAP
after this module.
QUAL2K is a 1-dimensional, steady state, instream water quality model for well mixed
channels (laterally and vertically). Constituents modeled include: ammonia, nitrate, organic
and inorganic phosphorous, algae, sediment, pH and pathogens. QUAL2K was developed
by Dr. Steve Chapra and his grad students at Tufts University. This module is not an
introduction to QUAL2K. Considerable work is required outside of WEAP to calibrate and
prepare a QUAL2K file. Refer to the QUAL2K manual for more information. Visit
http://www.epa.gov/athens/wwqtsc/html/qual2k.html to download or for more
information.
2.
Differences Between QUAL2K and WEAP
QUAL2K and WEAP are compatible in their general approach to water
quality modeling, but they do some things differently. The important
differences are:
 QUAL2K measures distance along a reach from the tail of the reach,
while WEAP measures distance from the head.
 QUAL2K allows for diurnal variations in water quality and climate,
while WEAP applies the same value to all times of day.
 WEAP is more tolerant of zero or missing values than is QUAL2K.
 QUAL2K and WEAP use different climate parameters. For example,
QUAL2K uses dew point, while WEAP uses humidity.
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Linking to QUAL2K
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 QUAL2K models many more constituents in much more detail,
including two separate CBOD constituents, ammonia, nitrate, organic
and inorganic phosphorous, algae, sediment, pH and pathogens (see
http://www.epa.gov/athens/wwqtsc/html/qual2k.html for more
details).
QUAL2K and WEAP are similar in that each treats a river as a sequence of
reaches, not necessarily of equal lengths. However, the reach boundaries as
defined in QUAL2K and in WEAP need not match. Where reach
boundaries do not match, WEAP handles the task of mapping water quality
and climate variables, based on distance markers.
Reservoirs present special challenges for water quality modeling. WEAP
includes reservoirs, but not for water quality, while QUAL2K includes weirs,
but they are not operated. It is recommended that rivers with reservoirs not
be linked to QUAL2K, or that they be modeled in two sections—above the
reservoir and below the reservoir.
3.
Link Pollutants to QUAL2K
This module uses the final result from the previous Water Quality module
as a starting point. Open the WEAP tutorial (by selecting Area \ Open
\ Tutorial from the menu), then selecting Area \ Revert to Version
\Starting point for ‘Water Quality’ from the menu.
Once the file is ready, change the water quality constituents to point to
QUAL2K.
 From the menu, select “General | Water Quality Constituents."
 For all of the constituents except Salt, select “Modeled in QUAL2K”
in the “Calculated By” drop-down.
 Link each constituent in WEAP (except salt) to a corresponding
QUAL2K constituent: “Temperature”  “Temperature”, “BOD”
 “CBOD fast”, “DO”  “Dissolved Oxygen”, “TSS” 
“Inorganic Solids."
Salinity is not directly modeled in QUAL2K, so it is not linked to a
QUAL2K constituent in this example. QUAL2K instead models
conductivity, which is an easily measured indicator of salinity.
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The WEAP/ QUAL2K Interface
Next, search for a QUAL2K data file (a file ending in .q2k).
 Look for the new drop-down labeled “QUAL2K Data File (.q2k)”
that has appeared at the bottom left of the Water Quality
Constituents dialog.
 Select “< Copy file from another directory >” from the drop-down.
 Search the Tutorial\Additional Files for the file
“Main_River_Tutorial.q2k." If you want to view the QUAL2K file,
click the “View” button to open it in the QUAL2K-formatted Excel
spreadsheet.
The Water Quality Constituents Dialog should now look like the following:
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Linking to QUAL2K
177
The QUAL2K file must initially be developed and edited outside of WEAP. WEAP will then
modify some of the values, and extract values from QUAL2K after it is run. To view or edit
the QUAL2K file, click on the “View” button next to the “QUAL2K Data File (.q2k)” dropdown on the Water Quality Constituents dialog.
4.
Change Reach Distance Markers
For marking reach distances, QUAL2K assigns the tail of the river a
distance of 0, and distance increases upstream. WEAP can measure reach
distances either downstream or upstream, but in the previous module
distance was measured downstream, opposite the convention for QUAL2K,
so the reach distance markers must be changed when linking to QUAL2K.
To set the reach distance markers:
 Go to Data View
 Navigate to the branch “Supply and Resources\River\Main
River\Reaches\Below Main River Headflow."
 Click on the “Physical” button.
 Select the “Distance Marker” tab. (This will only show up in Current
Accounts: if you do not see it, switch to Current Accounts in the
drop-down at the top of the page.)
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The WEAP/ QUAL2K Interface
 Set the distance for “Below Main River Headflow” to 300 km, and
the distance for “Tailflow Point” to 0 km.
5.
Set Dew Point and Cloud Cover
QUAL2K and WEAP use different climate parameters, so some additional
climate parameters must be set for QUAL2K. When using QUAL2K for
water quality calculations, WEAP changes the list of climate parameters
automatically.
While each reach in QUAL2K can have a different climate, for most WEAP
applications it is reasonable to assume that the climate is the same on all
reaches. In this case, climate parameters only need to be set for the top
reach, since for downstream reaches, upstream values are used by default.
For this example, two climate parameters will be set: cloud cover and dew
point.
Cloud cover is not a climate parameter in WEAP, so there is no
corresponding value already in WEAP. For this example assume that
average cloud cover is 30% along the river. To set this:
 Navigate to the branch “Supply and Resources\River\Main
River\Reaches\Below Main River Headflow”, if you are not already
there.
 Click on the “Climate” button.
 Select the “Cloud Cover” tab.
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 Type “30” for the value.
Dew point is used by QUAL2K instead of WEAP’s relative humidity
parameter. Dew point, Td, can be calculated from the air temperature, T, and
relative humidity, hr doing the following calculation. First, instead of using
air temperature T directly, use x = T/237.7. Then calculate dew point using:
Td=237.7 [17.3 x + (1 + x) ln hr]/[17.3 – (1 + x) ln hr]
Using this formula, and the values for air temperature (which are different
for each month) and relative humidity (65% for every month) in the Water
Quality module file, it turns out that dew point is about 6.5C below air
temperature for all months. So, to set dew point:
 Navigate to the branch “Supply and Resources\River\Main
River\Reaches\Below Main River Headflow”, if you are not already
there.
 Click on the “Climate” button.
 Select the “Dew Point Temperature” tab.
 Either use the Expression Builder or directly type in the formula “Air
Temperature - 6.5”, and make sure the units are “C." Do not type in
the [C] as shown below – WEAP will populate that automatically.
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The WEAP/ QUAL2K Interface
Running Scenarios
6.
Run Scenarios
Run the scenario by going to Results View and answering “Yes” to the
dialog asking whether to recalculate.
Note that when using QUAL2K, running scenarios can take a long time. Consider
reducing the number of scenarios that you calculate at any time.
QUAL2K will not run for months in which streamflow is zero at any point
in the river. If this situation occurs in one or more scenarios, add a (small)
minimum flow requirement on reaches for which QUAL2K is used to force
a flow greater than zero. Here is the error message you might see:
“QUAL2K Error: Error Code 3. This error might be caused a streamflow of zero in
the river, which QUAL2K does not allow. Perhaps use a flow requirement below to force
a small flow at that point.” Add a flow requirement to the river immediately
upstream from the first return flow node (from Big City), and set the
minimum flow requirement in Current Accounts to be 0.1 CMS. Re-run
calculations.
7.
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Compare Results
When you have finished running your selected scenarios, compare the
results with the results from the previous module. They should be similar,
but not identical, because the built-in water quality calculations in WEAP
make slightly different assumptions and use different approximations than
QUAL2K.
WEAP Tutorial
WEAP
Water Evaluation And Planning System
Hydrology
A TUTORIAL ON
Modeling Catchments: the Simplified
Coefficient Method .................................................182
Modeling Catchments: the Soil Moisture
Model ....................................................................187
Simulating Surface Water-Groundwater
Interaction .............................................................192
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Hydrology
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, key assumptions, expression builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for all modules after ‘Scenarios’ module.”
Modeling Catchments: the Simplified Coefficient
Method
1.
Create a New Catchment
Create a “Catchment” object in the Schematic view to simulate headflow for
Main River. Do this by pulling over a Catchment node and locating it near
the starting point of the Main River. Name it “Main River Headflow." Set it
to be active in Current Accounts, and leave “Includes Irrigated Areas?”
unchecked.
Next draw a Runoff/Infiltration path (dashed blue line) starting from the
catchment into the beginning of the Main River.
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Modeling Catchments: the Simplified Coefficient Method
2.
183
Create an Appropriate Substructure in the Basin
The first time you right click on the Catchment or select it in the Data Tree,
you will get a window that asks you to select a model for the Catchment.
Select Rainfall Runoff (simplified coefficient method).
There is also the opportunity to change this selection later by clicking on the
“Advanced” tab in the Data view:
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In the Data View, select the new catchment under the “Demand Sites and
Catchments” branch of the data tree On the right, click on the “Land Use”
button and enter the following data:
Area
Effective Precipitation
Kc (Crop Coefficients)
data)
Sep to Feb
March
April
May
Jun to Aug
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10M ha (you will have to choose the units first)
98%
(use the Monthly Time Series Wizard to input these
0.9
1.0
1.1
1.4
1.1
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Note that if you had clicked “yes” when asked if irrigated areas were to be
included in this catchment (under General Info when creating catchment),
another button “Irrigation” would have appeared under the catchment in
the Data view. This button would have two tabs under it: (1) “Irrigated”,
where you would input either a “0” for not irrigated, or a “1” for irrigated
for a particular land class; and (2) “Irrigated fraction” where you would
specify the fraction of irrigation water supplied to the area that is available
for evapotranspiration.
The Rainfall Runoff method is a simple method that computes runoff as the difference
between precipitation and a plant’s evapotranspiration. A portion of the precipitation can be
set to bypass the evapotranspiration process and go straight into runoff to ensure a base flow
(through the “effective precipitation” parameter).
The evapotranspiration is estimated by first entering the reference evapotranspiration, then
defining crop coefficients for each type of land use (Kc’s) that multiply the reference evapotranspiration to reflect differences occurring from plant to plant.
More information about this method can be obtained from the FAO Irrigation and Drainage
Paper 56, called “Crop Evapotranspiration” and available from the FAO’s website
(www.fao.org).
Entering an effective precipitation other than 100% is one way of acknowledging the fact
that part of the rainfall is not submitted to evapotranspiration during high intensity rainfall
events, hence generating a minimal runoff to the river even when the rainfall is lower than
the potential evapotranspiration. Another solution is to move to more developed models
such as the 2-buckets soil moisture model coupled with Surface Water – Groundwater
interaction modeling, as presented later in this module.
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3.
Hydrology
Enter the Climatic Data
Climatic Data are entered at the catchment level (Main River Headflow).
Enter the following data under the “Climate” tab using the Monthly Time
Series Wizard :
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Precip.
21
37
56
78
141
114
116
85
69
36
22
13
ETref
42
47
78
86
131
122
158
140
104
79
43
37
If not available from on-site stations, precipitation data can sometimes be derived from
world-wide climate models such as the one developed by Tim Mitchell at the University of
East Anglia (http://www.cru.uea.ac.uk/~timm/data/index.html). The use of GIS software
to extract the appropriate data is required. Such models provide average data in opposition
to actual data, implying that the calibration is much more delicate.
The Reference Evapotranspiration can be determined from a set of climatic and
topographic parameters using the Penman-Monteith equation. More details are provided in
the FAO publication mentioned earlier. Also, there exist global models of monthly reference
evapotranspiration put together by the FAO, available from the FAO’s website.
4.
Look at the Results
Results for Catchments are located in the “Catchment” category in the
primary variable pull-down menu.
“Runoff from Precipitation” to the Main River should look similar to the graph
below. Select "Selected Scenarios" from the pull-down menu above the graph legend
and check off "Reference." Select “Main River Headflow” as the Demand
site/branch from the menu to the upper left of the graph, and the year 2000 from
the “Selected Years” option using the menu at the bottom of the graph. Make sure
it is for “All Months.”
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Modeling Catchments: the Soil Moisture Model
5.
Replace the Agriculture Demand Site with a Catchment
Delete the Agriculture demand site and create a Catchment in its place.
Name it “Agriculture Catchment” and set it Active in Current Accounts,
Includes Irrigated Areas, and Demand Priority 1 (the demand priority only
appears after you have selected “Includes Irrigated Areas”).
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6.
Hydrology
Connect the New Catchment
Draw a Runoff/Infiltration Link to the Main River below the Return flow
node from the Big City. Add a Transmission Link from the Main River
(same starting point as the former Agriculture demand site), with a Supply
Preference of 1. Your model should now look similar to the figure below:
The purpose of this transmission link is to allow supplying irrigated areas with water from
the river in case rainfall is insufficient.
7.
Create sub-structure in the Catchment
We will assume this catchment has three types of land use. In the Data View,
add the following branches to your new catchment by right-clicking it in the
data tree and selecting “Add." (If you select the catchment for editing by
right clicking on the node in the schematic view rather than going through
the Data view, you will be asked beforehand to choose a simulation method
- pick the “Rainfall Runoff (soil moisture model)” method). Add the
following branches:
Irrigated
Forest
Grasslands
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Modeling Catchments: the Soil Moisture Model
8.
189
Enter the Appropriate Land Use Data
Select the Agricultural Catchment in the Data view and pick the “Rainfall
Runoff (soil moisture model)” method by clicking on the “Advanced”
button (click to the right of “Rainfall Runoff (simplified coefficient method)”
and use the arrow to scroll down). Then enter the following data after
clicking on the “Land Use” button:
Total Land Area
Share of Land Area
300,000 ha (you will have to select units first)
Irrigated
Forest
Grasslands
33%
25%
Remainder(100)
Runoff Resistance Factor
Root Zone Conductivity
Preferred Flow Dir.
Initial Z1
Irrigated
3.6
60
0.15
50%
Forest
3.0
35
0.15
20%
Grasslands
1.7
45 mm/month
0.15
20%
The remaining variables are the same for all land classes in the catchment:
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Hydrology
Initial Z2
20%
Soil Water Capacity
900 mm
Deep Water Capacity
35,000 mm
Deep Conductivity
240 mm/month
Kc
Use the same values as input for the Main River Headflow
catchment in the previous exercise. You can simply copy and paste
that expression into the Kc field for the Agriculture Catchment
land classes.
The Rainfall Runoff (soil moisture model) method has been developed to provide a simple
yet realistic way of modeling hydrological processes with a semi-physical representation.
Details about the method and its parameters, as well as calibration procedures, can be found
in the appendix to this tutorial as well as in articles posted to the “publication” section of
WEAP’s website (www.weap21.org). The related WEAP help topic provides a description of
each parameter and an overview of the model as well. The parameter values displayed above
are for illustration purposes only.
9.
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Enter the Appropriate Climate Data
In the same view as in the previous step, select the “Climate” screen and
enter the following data:
Precipitation
Use the same precipitation values as input for the Main River
Headflow catchment in the previous exercise.
Temperature
MonthlyValues( Jan, 9, Feb, 12, Mar, 16, Apr, 21,
May, 24, Jun, 27, Jul, 29, Aug, 29, Sep, 27, Oct,
22, Nov, 16, Dec, 11 )
WEAP Tutorial
Modeling Catchments: the Soil Moisture Model
Humidity
Wind
Latitude
191
65%
1m/s
30°
Data about snow coverage are not needed if the basin is not exposed to snow. WEAP
determines the appearance of snow based on the temperature and the melting and freezing
points parameters. If the last two are left empty, no snow will be allowed to accumulate.
10.
Set up Irrigated Areas
In the same view as in the previous step, select the “Irrigation” screen and
enter the following data:
Irrigated Area
Lower Threshold
Upper Threshold
11.
Irrigated
100%
45%
55%
Forest
0%
N/A
N/A
Grasslands
0%
N/A
N/A
Look at Results
Look at the following results. Here again, the results are located in the
“Catchment” category of the “Results” view. Select “Land Class Inflows
and Outflows” under the primary variable pull-down menu. Click to view all
variables above the chart legend. To view the “Irrigated” segment of the
Agriculture catchment, select “Branch: Demand Sites and
Catchments\Agriculture Catchment\Irrigated” from the pull-down menu to
the upper left of the chart. Choose the year 2000 from the “Selected Years”
option using the pull-down menu at the bottom, and click on “Monthly
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Hydrology
Average” to the right of annual total (you may have to expand the screen to
see it).
“Land Class Inflows and Outflows” represents in a very detailed manner the water
balance for each land use class. You should obtain a graph similar to the figure
below for the “Irrigated” land class inflows and outflows graph:
Change the unit from Cubic Meter to mm. Depth units such as mm are typically
more useful when examining or validating results catchment results. Note: you
cannot change to a depth unit if “Monthly Average” is checked.
You can also look at other parameters, such as “Soil Moisture in the upper bucket”
(Relative Soil Moisture 1 (%)).
Simulating Surface Water-Groundwater
Interaction
12.
Create a Groundwater Object
Create a new “Groundwater” node.
Locate this Groundwater object next to the Agriculture Catchment that you created
in the previous exercise. Name it “Agriculture Groundwater.”
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13.
193
Connect the Groundwater Object to a Catchment
Create the following connections:
1) Transmission Link from Agriculture Groundwater to Agriculture Catchment
(Supply Preference 1)
2) Infiltration/Runoff Link from Agriculture Catchment to Agriculture
Groundwater.
Your model should look similar to the one below:
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Hydrology
You can also create the Infiltration/Runoff Link between the catchment and the
groundwater node by right-clicking the catchment in the Schematic View, selecting
“General Info” and then choosing the groundwater field in the “Infiltration to” drop-down
menu.
14.
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Enter the Appropriate Data
In the Data View, select Agriculture Groundwater, examine the “Physical”
screen and select the “Model GW-SW flows” method from the “Method”
tab.
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195
Switch to the “Water Quality” window and then back to the “Physical”
window for the change to take effect (you will now see several new tabs in
the “Physical” window. If these do not populate, make sure you are in
current accounts). Enter the following data (leave blank if nothing is
specified) under the appropriate tabs:
Initial storage
Hydraulic Conductivity
Specific Yield
Horizontal Distance
Wetted Depth
Storage at River Level
15.
50M m3
10m/day
0.1
260m (the extent of the aquifer perpendicular to
the river )
5m
50M m3
Select the Reaches that Interact with the Aquifer
In the Data View’s tree, expand all the reaches of the Main River by clicking
on the “+” icon next to it in the “Supply and Resources\River” branch.
Select the reach that is below the return flow node from Big City (Return
Flow Node 1; you might have to switch to the Schematic view and rightclick on the nodes to find the name of that node in your model). Then enter
the following data in the “Reach Length” tab for this reach:
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16.
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Hydrology
Groundwater
Select “Agriculture Groundwater”
Reach Length
30,000 m
Look at the Results
Look at the “Demand Site Inflows and Outflows” in Demand for the
Agriculture catchment, and select “All Sources and Destinations” for the
year 2000.
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Note that these results include “Inflow from Agriculture Groundwater” (due to the
designation of the Agriculture Groundwater node as a source to supply irrigation water for
the Agriculture Catchment) and “Outflow to Agriculture Groundwater” (due to the creation
of a runoff/infiltration link between the two nodes).
Look also at “Groundwater Inflows and Outflows” (under Supply and
Resources\Groundwater) for the year 2000.
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Hydrology
Note that the “Inflow from Upstream” category indicates infiltration of Main River water to
Agriculture Groundwater along the river reach you selected earlier. Likewise, “Outflow to
Downstream” represents groundwater seepage into the Main River.
Look also at the height of groundwater above the river stage. This can be
viewed by selecting “Supply and Resources\Groundwater\Height Above
River” from the primary variable pull-down menu. Choose “Agriculture
Groundwater” from the “Selected Aquifers” option in the pull-down menu
above the chart legend.
Note that in the month where groundwater seepage to the Main River occurs (February),
the groundwater elevation is higher than the wetted depth of the river as designated in the
data (i.e., the difference in elevations is positive). Likewise, when Main River infiltration to
groundwater is occurring, the elevation difference is negative.
August 2015
WEAP Tutorial
WEAP
Water Evaluation And Planning System
Financial
Analysis
A TUTORIAL ON
Setting up the Cost and Benefit Model ....................200
Modeling Cost .......................................................202
Modeling Benefits ...................................................209
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Financial Analysis
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for all modules after ‘Scenarios’ module.”
Setting up the Cost and Benefit Model
1.
Understanding Cost and Benefit Modeling in WEAP
WEAP models three types of costs: Capital Costs, Fixed Operation &
Maintenance (O&M) Costs, and Variable O&M Costs. It also models three
types of benefits: fixed benefits, variable benefits and electricity revenues.
Costs and Benefits can be assigned to any object (e.g., a demand site, river
reach, groundwater node, reservoir or hydropower plant).
For more information on Cost and Benefits, refer to the “Entering Item Cost and
Benefits” topic in Help.
2.
Setting the Discount Rate
In the “General”, “Units” menu, select the “Monetary” tab and enter the
Discount Rate.
Discount Rate
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Setting up the Cost and Benefit Model
201
The Discount Rate is used to compute net present value and accrue monetary quantities
over time. It is different from the interest rate, which must be entered manually for each loan
payment computation.
One needs to decide upfront whether the analysis will be done in real or in nominal dollars
(with or without considering inflation) since this will have an effect on the discount rate,
interest rates and cost & benefit growth.
Determination of the Discount Rate is an important matter in economic analyses.
Guidelines exist that are based on different methods such as the Weighted Average Cost of
Capital (WACC) or Capital Asset Pricing Model (CAP-M). The US government currently
recommends a discount rate of 7% for public sector projects (including inflation).
3.
Changing the Modeling Duration
Cost modeling makes sense mainly if a long time period is being considered.
Extend the time period being simulated in WEAP by opening the
“General”, “Years and Time Steps” dialog box. Change the “Last Year of
Scenarios” variable:
Last Year of Scenarios
2025
Changing the “Last Year of Scenarios” will not affect the “Current Accounts”, the base year
for all scenarios. It will only affect all the scenarios, including the “Reference” scenario. For
more details about WEAP and scenarios, refer to the “Scenarios” module of the tutorial.
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Financial Analysis
Modeling Cost
4.
Enter Demand Site Cost Data
For the Big City demand site, enter the following data (in Current Accounts)
in the “Demand Sites” branch of the data tree in the Data view. Click on
the “Cost” button and enter under the “Capital Costs” tab:
Capital Costs
a loan of 120M$, occurring in 2000, payback
period 15 years, interest rate 5%
Use the Expression Builder to select the built-in function “LoanPayment”; pull this
function into the expression window and type in the parameters 120000000, 2000,
15, 5% within the parentheses. The expression should look like:
“LoanPayment(120000000,2000,15, 5%)”
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Modeling Cost
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Variable Operating Costs
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Financial Analysis
Fixed Operating Costs
a yearly value of 5M$, growing at a 3%
rate starting in 1995
Use the Expression Builder again, selecting the built-in function “GrowthFrom”
and entering the corresponding parameters in the parentheses. The formula should
read: “GrowthFrom(3%,1995,5000000)”
5.
Enter System-Wide Cost Data
We’ll assume that there was a loan made in years earlier than the Current
Account (base) year which is still being paid back. We’ll assign this cost to
the entire system, rather than to a specific object. Enter the following data
in the “Supply and Resources” branch of the data tree in the Data view.
Capital Costs
a loan of 300M$, occurring in 1989, payback
period 20 years, interest rate 6%
Again, use the Expression Builder and the “LoanPayment” function. The formula
should read “LoanPayment(300000000,1989,20,6%)”
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Modeling Cost
6.
205
Evaluate Results
Run the model and look at the following results:
Financial/Net Cost:
What is the difference between real and discounted dollar values for the Big
City?
Select “Financial\Net Cost” from the primary variable pull-down menu and choose
Big City from the list of items in the menu to the upper left of the chart. Select
“Capital Cost” from the upper right menu. Make sure the “Reference” scenario is
selected from the menu above the chart legend. Toggle between the “Real” and
“Discounted” options using the menu just to the left of the unit menu (set at U.S.
dollars).
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WEAP Tutorial
Modeling Cost
207
While real dollar are actual dollar values, discounted dollar values have been brought back to
their present value using the discount rate. The further in the future the cost occurs, the
lower its present value.
Average Cost of Water
What makes the cost vary on a monthly basis? On an annual basis?
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Financial Analysis
Select “Financial\Average Cost of Water” from the primary variable pull-down
menu. Keep the “Reference” scenario selected and click on “Monthly Average." You
should have a chart like the one below:
Monthly variations in average cost of water occur because of the largely varying
consumption of water (especially in the Agriculture area), while fixed costs remain constant.
Annual variations are mainly driven by changes in the capital costs (loans are paid back,
new loans occur).
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Modeling Benefits
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Modeling Benefits
7.
Enter Demand Site Benefit
In the “Cost” screen of the Big City Demand Site (Data View), enter the
following data, which could, for example, correspond to the price water is
sold for.
Variable Benefit
0.26$/m3
When modeling hydropower reservoirs (refer to the “Reservoir and Hydropower” WEAP
tutorial module), one can also enter revenues from electricity generation. The related dataentry tab exists only when pertinent.
8.
Compare Net Present Cost and Benefit
Display the Net Present Value of the project.
How do the Net Present Value of the Costs compare to the Net Present Value of
the Benefits?
In Results View, select “Financial\Net Present Value” from the primary variable
pull-down menu, and choose Big City as the item for viewing. You should have a
chart like the one below:
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Financial Analysis
What does that comparison tell you?
The Net Present Value of the costs can be compared to that of the benefit to obtain a sense
of the economic viability of the system. If the NPV of the costs exceeds the NPV of the
benefits, then the system is returning a lower profit than average projects (as defined by the
discount rate). If the NPV of the benefits exceed that of the costs, then the systems is
generating a profit higher than average projects.
August 2015
WEAP Tutorial
WEAP
Water Evaluation And Planning System
Linking WEAP to
MODFLOW
A TUTORIAL ON
Linking to MODFLOWError! Bookmark not defined.
Running MODFLOW and Viewing ResultsError! Bookmark no
Scenario: Increased PopulationError! Bookmark not defined.
Scenario: IrrigationError! Bookmark not defined.
Scenario: Artificial RechargeError! Bookmark not defined.
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Linking WEAP to MODFLOW
Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for 'Linking WEAP to MODFLOW module'.”
Linking to MODFLOW
1.
Using MODFLOW for Groundwater Modeling in WEAP
For situations where the built-in WEAP groundwater model is not
sufficiently complex, there is the option to link a WEAP model to a
MODFLOW model. MODFLOW is a three-dimensional finite-difference
groundwater model created by the U.S. Geological Survey (USGS). When
properly linked, data and results flow back and forth between WEAP and
MODFLOW for each calculation timestep. With this tight coupling
between the models, it is possible to study how changes in local
groundwater levels affect the overall system (e.g., groundwater-stream
interactions, pumping problems due to drawdown, lateral groundwater
recharge) and vice versa (e.g., infiltration and abstraction). However, be
advised that building and calibrating a MODFLOW model is not a simple
task. The version of MODFLOW that WEAP is designed to link to is
MODFLOW 2000.
This module is not an introduction to MODFLOW, which requires specialized knowledge,
but if you are already using MODFLOW, you should be able to link your MODFLOW
model to WEAP after this module. Considerable work is required outside of WEAP to
calibrate and prepare a MODFLOW model. Refer to the MODFLOW 2000 website for more
information: http://water.usgs.gov/nrp/gwsoftware/modflow2000/modflow2000.html.
The groundwater models in MODFLOW and WEAP are very different.
Whereas a WEAP groundwater node is represented as one large "bucket"
with no parameters to describe internal flows, MODFLOW represents
groundwater as a multilayered grid of independent cells, each with their own
flow parameters and equations that are used to model flows between cells,
and across the aquifer boundaries.
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Once you have WEAP and MODFLOW models linked, WEAP values for
groundwater infiltration (recharge) and abstraction (pumping), river stage,
and surface water runoff will be sent to MODFLOW as inputs for its
calculations, and MODFLOW results for groundwater level (head), lateral
flow between aquifers, and surface water-groundwater flows will come back
to WEAP as inputs for its calculations. This feedback between WEAP and
MODFLOW happens at each calculation timestep.
2.
Example WEAP model
The sample area used for this module differs from those in previous
modules. It includes a city whose supply comes entirely from groundwater,
rainfed agriculture, a spring-fed river that receives surface runoff from the
catchment and is hydraulically connected to groundwater. The catchment
includes forests and grassland, in addition to agriculture and the city.
Note that because WEAP does not spatially disaggregate catchments or
groundwater nodes, the one catchment node in this example represents the
entire area inside the red outline without any information about where in
the catchment the various land classes are. The one groundwater node
represents the entire aquifer, which extends over the same area as the
catchment, and does not include information about where the well field for
the city is (the red squares labeled Big City Wellfield). (For your own
applications, you are free to create multiple catchments and groundwater
nodes, and link them to different groups of MODFLOW cells.)
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3.
Linking WEAP to MODFLOW
Loading a MODFLOW model
To load a MODFLOW model, go to “Advanced\ MODFLOW Link
(Groundwater Flow)” on the Main menu. Check the "Link to
MODFLOW" checkbox and then type in or browse for the "MODFLOW
Name File." Typically the "Name" file has an extension of .NAM or .MFN.
For this example, all the MODFLOW files are contained in a subdirectory
named MODFLOW underneath the Tutorial area subdirectory. (Keeping
the MODFLOW files in a subdirectory of the WEAP area is a good
practice.) The name file for this example is called tutorial.mfn. After you
have specified the name file, WEAP will read in the MODFLOW model
and display information about it.
The name file lists the other files that contain data for the various aspects of
the MODFLOW model, such as recharge, pumping and river interactions.
These files are called "packages." Take a look at some of the packages for
this model—click on the "View/Edit Packages" button to and choose
"MODFLOW Name File: tutorial.mfn." You will see the list of
files/packages. Click the cancel button to close the name file and look at
another package, such as the "MODFLOW Discretization file: tutorial.dis."
The discretization file contains basic information about the model, such as
the number of layers, row and columns, and the width of each row and
column. As you can see in the screen above, WEAP has read in this
information already: 20 rows, 20 columns, 1 layer, and 1000 meters width
for both rows and columns.
Note that initially WEAP does not know how to link the MODFLOW
model to the WEAP model, as can be seen in the screen above, e.g.,
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"WARNING: Active cells linked to WEAP groundwater node: None
are linked" and "1 groundwater nodes (0 are linked to MODFLOW
cells)." The next step is to make this linkage.
4.
Linking WEAP elements (groundwater nodes, demand sites,
catchments, rivers) to MODFLOW cells
Each active MODFLOW cell is linked to one and only one WEAP
groundwater node. (For a given row and column, every layer will be linked
to the same groundwater node.) The linkage is established by a GIS shape
file (.shp) that relates MODFLOW cells (by row and column number) with
WEAP groundwater nodes (by name). The polygon shape file has one
rectangular feature for each MODFLOW cell (row, column) and must be
loaded as a background layer on the Schematic. For example, for a
MODFLOW model with 20 rows, 20 columns and 3 layers, there would be
400 features in the shape file. The shape file's attribute table file (.dbf) must
have fields for row number, column number and WEAP groundwater node
name. Other optional fields are described below. This shape file will also be
used to display MODFLOW results in WEAP.
To create this shape file, either use a GIS program such as ArcGIS, or
WEAP's built-in tool that can create a shape file corresponding to a
MODFLOW model as explained in the following section.
5.
Creating a new linkage shape file
On the Link to MODFLOW Groundwater Model screen (shown above),
click the "Choose shape file that has MODFLOW linkage
information" button. On the next window, for "Background Shape
File with MODFLOW Linkage Information" choose "< Create New
Shape File >" The following window will appear:
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WEAP automatically fills in the number of rows and columns, and the row
height and column width, which it read from the MODFLOW
discretization file. However, the MODFLOW model does not contain
information about the X,Y position (latitude and longitude) or the rotation
angle of the cells. Therefore, you will need to enter this information
yourself.
If you know the values for latitude, longitude and rotation, you can enter
the numbers directly. If you do not know the values, you can click on the
map to set the origin (lower left corner). You will see a purple box on the
map that indicates the area of all the cells. As long as you hold down the left
mouse key, the purple box will move with the mouse in the lower left
corner; release when the box is correctly positioned. You can zoom in on
the map (using the zoom slider below the inset map on the left, the mouse
wheel, or control-click and drag on the map) to help achieve greater
precision in placement of the area.
The File Name box contains the filename for the new shape file. Either
use the default filename ("MODFLOW Linkage.shp") or enter another
name. For now, enter “MODFLOW Created Linkage.shp” as the name.
Shape files always have a .shp extension.
Click the Create button to create it.
After the shape file has been created, WEAP will display it and allow you to
customize its appearance on the schematic. As you can see from the screen
below, the new shape file is a 20x20 grid of 400 cells.
The associated attribute table has fields for row, column, and for linking
various WEAP elements to each cell—GW, Catchment, Land_Use,
DemandSite and RiverReach. You table will need to be filled in, specifying
which cells are linked to which WEAP elements. For example, the name of
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the WEAP groundwater node (in the Tutorial, the node is named
"Groundwater") must be entered in the table in the column labeled GW for
each cell that corresponds to the WEAP groundwater node. For example,
in row 1, columns 6 through 17 correspond to the WEAP groundwater
node, so the table should have "Groundwater" in table column GW for
those cells.
Although you do not need to do it for this tutorial, you may edit this table in
several different ways. To edit inside WEAP, click the Edit button above
the lower right table and type the values directly into the table. You can
also edit the table in Microsoft Excel (the attribute table has the
extension .dbf, e.g., MODFLOW Linkage.dbf, make sure WEAP is not
open when you edit the attribute table file in Excel) or in any GIS program,
such as ArcGIS. If you do have access to GIS software, this will be the
easiest way to edit the table, but it can be done in WEAP. (WEAP can also
attempt to guess which MODFLOW cells the WEAP groundwater nodes,
demand sites and river reaches are linked to, based on proximity on the
Schematic. (This is described more below.)
After customizing its appearance, click the OK button. WEAP will add this
layer to your Schematic and return you to the "Choose shape file that has
MODFLOW linkage information" window.
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6.
Linking WEAP to MODFLOW
Use an existing shape file
Rather than spending the time now to fill in all the information in the
attribute table, we will use an existing shape file with all this information
already filled in. On the "Choose shape file that has MODFLOW
linkage information" window, select "< Add existing shape file as
new map layer >" for the "Background Shape File with MODFLOW
Linkage Information." A dialog box will appear, asking you to select the
ArcView Shape File to use. Choose “Linkage.shp” (in the Tutorial directory)
and click Open.
On the "Map Layer" screen, change the name to "MODFLOW Linkage."
On the "Label" tab, choose "R_C" for the Field and set the Size to 40%.
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Click OK. Now we need to specify which of the fields in the Linkage
attribute table will be used for the linkage, and to which MODFLOW and
WEAP items they correspond. The required fields are MODFLOW Cell
Row, MODFLOW Cell Column and Groundwater Name. Depending on
your model, you may or may not also match some or all of the following:
Catchment Name, Land Use Name, Demand Site Name and River Reach
Name. Based on the attribute file column names, WEAP will try to guess
which fields are used for what. For example, if it finds fields containing the
names "Row" and "Col", it will assume these contain the MODFLOW row
and column values. In this example, WEAP is able to correctly guess all the
fields:
If it didn't correctly guess, you would select the appropriate field for each
item (e.g., Groundwater Name Field). WEAP can also attempt to guess
which WEAP groundwater nodes, demand sites and river reaches
correspond to the MODFLOW groundwater, pumping, river and drain cells,
by clicking on the “Guess Groundwater Linkages” button, or the other
“Guess” buttons. Click OK to close this window.
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Note that WEAP now reports the linkage shape file and how many of the
WEAP and MODFLOW items are linked together, e.g., "1 groundwater
nodes (1 are linked to MODFLOW cells)" and "Active cells linked to
WEAP groundwater node: All are linked." Click Close to return to the
WEAP Schematic.
The layers "MODFLOW Linkage" and “MODFLOW Created Linkage” are
now in the list of background layers, ordered at the top. Note that WEAP
can only link to one MODFLOW layer at a time, so even though both are
shown, WEAP will only extract data from the layer specified in the
“Choose Shape File that has MODFLOW Linkage Information” window
(In Advanced/MODFLOW Link(Groundwater Flow)/Choose Shape file
that has MODFLOW linkage button). In this case, WEAP is linked to
linkage.shp, which is displayed in WEAP as MODFLOW Linkage.
If you want to change the order the layers in the element window, rightclick on the layer name and choose “Move Down.”
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Take a moment now to view the other information contained in this linkage
file. Right click on the name "MODFLOW linkage," choose "Set label to"
and choose one of the other fields, such as "LAND_CLASS." This will
show you which of the four land classes (Grassland, City, Forest, Farm)
each cell corresponds to. Choose the field "DEMANDSITE" to see from
which cells the Big City demand site will pump from. Choose the field
"GW_NODE" to see which MODFLOW cells are linked to the WEAP
groundwater node named "Groundwater." Finally, choose the field
"RIVERREACH" to see which cells are linked to the WEAP river "Blue
River."
7.
Set Pump Layer
One final step to link the WEAP model to the MODFLOW model is to
specify from which MODFLOW layer the Big City demand site will pump.
In general, a demand site or catchment node can pump from a single layer,
from many layers (in equal or different proportions), or have pumping be
handled as negative recharge in the MODFLOW recharge file.
Our MODFLOW Linkage has only one data layer (which you can verify by
going to Advanced/ MODFLOW Link (Groundwater Flow) to where it
says “MODFLOW” and then lists the numbers of rows, columns and
layers). Because there is only one layer, the pumping choices are from layer
1, or as negative recharge (enter pump layer = 0 for negative recharge). We
want to pump from layer 1. Go to the Data View, select "Big City" on the
data tree, then click on the "Pumping" category at the top and enter "1" for
the expression.
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You have now linked the WEAP model to the MODFLOW model.
Running MODFLOW and Viewing Results
8.
View Results
Click the Results button to calculate and view results. Notice that at each
calculation timestep, WEAP runs MODFLOW.
Results for MODFLOW are located in the “Supply and Resources /
Groundwater / MODFLOW” category in the pull-down menu just above
the chart.
Look at the results for Supply and Resources / Groundwater /
MODFLOW / Cell Head. This report shows the vertical head for each
MODFLOW cell. MODFLOW results utilize a 3-dimensional surface chart.
Make sure that "Surface" is selected as the chart type (the first icon in the
menu bar to the right of the screen), and that the "Y=0" button is not down.
The cell head for one timestep is shown. Experiment with the sliders below
the surface chart to rotate or tilt the surface. Click the "Rotate" button to
animate the chart. Click the "3-D" button to switch between 3-D surface
and 2-D plan views. You may also click on the 3-D surface and drag the
mouse to rotate the view.
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Can you see the impact of pumping from the Big City Wellfield? (This view
exaggerates the variation in head—click the "Y=0" button to see a more realistic
view. It is usually better to turn off Y=0 in order to see the differences clearly.)
Click on the Map tab to see the head values on the map, with a graph below.
When you click on a grid cell, its value over time will be graphed below the
map. Click on some of the cells at the Big City Wellfield to see how they
vary. There is a seasonal fluctuation in cell head (higher in winter, lower in
summer, due to increased pumping in the summer and lower rainfall in the
summer), and an overall trend downward from 2000 to 2010. You can click
and drag the mouse over many cells and the graph will update in real-time
as you move the mouse. This is a good way to get a quick understanding of
how cells in different areas of the model behave differently over time. Note
that the option to turn Y=0 off is now at the bottom right menu.
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Look at a few other MODFLOW results, such as Recharge, Pumping,
Drain Flow, and Leakage to River.
Scenario: Increased Population
Now that we have a MODFLOW model linked to our WEAP model, we
can create some WEAP scenarios and explore how they might affect
groundwater.
9.
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Create scenario
Switch to the Data View and create a new scenario underneath "Reference,"
call it "Increased Population" (Main menu: Area, Manage Scenarios).
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Under the Water Use tab, change the expression for the Annual Activity
Level for Big City from "Growth(1%)" to "Growth(5%)."
10.
Evaluate results
Go to Results and look for the impact of the increased pumping from Big
City on the groundwater levels. As you can see, the slow downward trend
of the Reference scenario has now accelerated in the Increased Population
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scenario. This is especially evident in the cells on or near the Big City
Wellfield.
but an effect, although smaller, can even be seen far away from the wellfield,
e.g., in Row 16, Column 6 (in the lower left corner of the model).
Scenario: Irrigation
The crops on this Farm are currently rainfed, but there is not enough
rainfall in the summer to meet their evapotranspirative demand. Look at
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the results for Catchments / ET shortfall for the Farm branch of the
catchment in the reference scenario
11.
Create scenario
Let's investigate the impact of adding irrigation from groundwater pumping,
both on the groundwater levels and on crop yields. Switch to the Schematic
View and go to Areas/Manage Scenarios. Create a new scenario underneath
"Reference," call it "Irrigation."
There are several steps to take to activate irrigation for the Farm land class
and for the MODFLOW cells associated with the Farm.
12.
Add transmission link
Add a transmission link from the groundwater node to the catchment, and
uncheck "Active in Base Year?" When you add this link, WEAP will
automatically set the catchment as having irrigation.
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You can leave the priority as 1.
13.
Set land class as irrigated
Go to the Data View and change "Irrigated" to 1 for the Farm, and
"Irrigation Fraction" to 50 (50% irrigation efficiency). Make sure that the
Irrigation scenario is selected in the "Data for" dropdown box at the top.
For the transmission link, set the Startup Year to 2003.
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Set MODFLOW layer for irrigation
We want MODFLOW to pump the irrigation water from layer 1. Click on
the "Catchment" branch in the data tree, then click on the "Irrigation"
category at the top and the “Pump Layer” variable tab. Enter a value of 1.
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15.
Linking WEAP to MODFLOW
Evaluate results
Go to the Results View. First, verify that irrigation begins in 2003, reducing
the ET Shortfall to zero. (The report can be found in the Catchments
category.)
What happens to crops yields, now that they receive all the water they need? Look
at the Catchment report for yields, comparing the yield across scenarios for 2003
and later
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Now look at the impact of irrigation on groundwater. View the
MODFLOW Cell Head Results on the Map tab. Click on a cell in the map
in the Farm to see the largest effect, or a cell far away from the Farm to see
the smaller effect.
Compare the pumping rates for the Farm and for Big City:
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Scenario: Artificial Recharge
For a final scenario, let's explore the impact of artificial recharge to
groundwater.
Artificial recharge, or "Aquifer Storage and Recovery" (ASR), involves injecting water into
an aquifer through wells or by surface spreading and infiltration and then pumping it out
when needed. The aquifer essentially functions as a water bank. Deposits are made in times
of surplus, typically during the rainy season, and withdrawals occur when available water
falls short of demand.
In this example, the water will come from outside the catchment area and
not vary seasonally.
16.
Create scenario
17.
Load shape file layer
Switch to the Schematic View and create a new scenario underneath
"Reference," call it "Artificial Recharge."
On the Main Menu, select Schematic, Add Vector Layer.
Choose the file artificial_recharge.shp. Give it the name "Artificial
Recharge", and change its appearance so that the Style is "Solid" and the
"Fill color" is light blue. Note that the cells are in column 6, rows 13-15.
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233
Edit linkage shape file
So that WEAP can tell MODFLOW which cells will receive the artificial
recharge, we need to edit the linkage shape file. In the Schematic View,
double-click on "MODFLOW Linkage", select the Table tab and click the
Edit button. Scroll down to find the artificial recharge cells: column 6, rows
13, 14 and 15. For these three cells, type into the field labeled
DEMANDSITE the name of the artificial recharge demand site: "Artificial
Recharge."
Return to the Schematic view and verify this new linkage information. Set
the label for the MODFLOW Linkage layer to DEMANDSITE. You
should see the artificial recharge cells labeled, as well as those for Big City
Wellfield:
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19.
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Create Other Supply and Demand Site
Create an "other supply" node called "Other Supply" in the upper right
corner. Create a new demand site—place it on top of one of the blue
artificial recharge cells. Call it "Artificial Recharge" and uncheck "Active in
Current Accounts?"
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Add a transmission link from Other Supply to Artificial Recharge. Then add
a Return Flow link from Artificial Recharge to the Groundwater node.
20.
Enter supply and demand data
Go to the Data View, select scenario "Artificial Recharge," and then click
on the branch for demand site Artificial Recharge in the tree. Set the Startup
Year to 2005.
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For Water Use, set the Annual Water Use Rate to 25 Million cubic meters
(the annual capacity of the injection wells) and the Consumption to 0%.
Click on the branch for the other supply, and then enter 1 CMS for the
inflow.
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Evaluate Results
Run the model and look at results for recharge depth and cell head.
Does the artificial recharge have much impact on groundwater levels at the recharge site?
Is there much of an impact closer to the Big City Wellfield or irrigation? Can you think
of another site for the artificial recharge that would better alleviate the drawdown from
pumping?
Groundwater levels at the recharge site are much higher than Reference:
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Groundwater levels by the Wellfield are almost the same as in Reference:
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WEAP
Water Evaluation And Planning System
Linking WEAP to
LEAP
A TUTORIAL ON
Linking WEAP and LEAP ...............................240
Scenario: Hydropower Generation from
WEAP ................................................................245
Scenario: Demand for Cooling Water from
LEAP .................................................................256
Scenario: Electricity Demand from WEAP ............262
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Note:
For this module you will need to have completed the previous modules (“WEAP in
One Hour, Basic Tools, and Scenarios) or have a fair knowledge of WEAP (data
structure, Key Assumptions, Expression Builder, creating scenarios). To begin this
module, go to the Main Menu, select “Revert to Version” and choose the version
named “Starting Point for 'Linking WEAP to LEAP’ module.”
Linking WEAP and LEAP
1.
Introduction to LEAP
LEAP, the Long-range Energy Alternatives Planning System, is a widelyused software tool for energy policy analysis and climate change mitigation
assessment developed at the Stockholm Environment Institute.
LEAP is an integrated modeling tool that can be used to track energy
consumption, production and resource extraction in all sectors of an
economy. It can be used to account for both energy sector and non-energy
sector greenhouse gas (GHG) emission sources and sinks. In addition to
tracking GHGs, LEAP can also be used to analyze emissions of local and
regional air pollutants, making it well-suited to studies of the climate cobenefits of local air pollution reduction.
For more information on LEAP and to download the software, visit
http://www.energycommunity.org.
2.
Coupled water-energy models in WEAP and LEAP
3.
WEAP Model
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We are going to examine a simple water-energy system; first the water side
of the system using WEAP, then the energy side using LEAP. Then we will
link the WEAP and LEAP models to examine the interaction between the
two sides and see how this interaction influences the results we obtain.
In the WEAP “Schematic” view there is a city situated near a river with its
own wastewater treatment plant. A reservoir harnesses hydropower from
the river. The demand for water comes from two sources: municipal
demand from the city, and demand for thermal cooling from a coal power
plant also situated near the river. The municipal demand has the first
demand priority (1) compared to the thermal cooling demand (2).
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Already we can see links between the water and energy systems in this
model. The reservoir and coal power plant utilize water to generate
electricity. On the other hand, the wastewater treatment plant uses energy in
its treatment process. Energy is also needed for processes like pumping for
transmission.
4.
View WEAP results
Switch to the “Results” view. Click the pull-down menu at the top left,
select “Supply and Resources” > “Reservoir” > “Hydropower Generation.”
This allows us to see the variation in hydropower generated by the reservoir
over time. Change the unit to Kilowatt-Hour. Remember that you can
change the chart type to a line or bar graph by clicking the “Chart Type”
button on the right hand side of the window.
You can also view the monthly average or the annual total hydropower
generated by checking the corresponding box at the top of the window.
From these options, we can see that hydropower generation peaks during
the summer, and varies from year to year.
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Monthly Average:
Annual Total:
5.
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LEAP Model
Now we will open the energy modeling program, LEAP, to see the current
sources of energy for Big City. Under the Area Menu, open the WEAPLEAP Tutorial and revert to version “Starting point for WEAP-LEAP
Tutorial.”
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Open the “Analysis” view in LEAP, which can be found on the left-hand
side of the window. This is similar to the “Data” view in WEAP. In the
“Scenario” pull-down window toward the top, make sure the “REF: No
WEAP Link” scenario is selected.
In the Data tree under “Transformation” > “Electricity” > “Processes,”
there are three processes that generate electricity: hydropower from the
reservoir, the coal steam power plant, and energy imports. If you select the
“Merit Order” tab, you can see that hydropower is dispatched first, followed
by energy from coal. Any remaining shortfalls are made up with imports,
which is last in the merit order.
The energy production capacities for these plants are under the “Exogenous
Capacity” tab.
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For each energy production process, the portion of maximum energy
production that is available can be found under the “Maximum Availability”
tab. In the “No WEAP Link” scenario, the maximum availability of the
hydropower plant has been entered as 100%. LEAP is assuming that all
water demand for hydropower will be met, as it has no information on the
amount of water available for hydropower generation.
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View LEAP results
Switch to the “Results” view, found under the “Analysis” button on the
left-hand side of the window. From the top pull-down window, select the
variable “Transformation: Average Power Dispatched.”
In 2014 (selected from the right dropdown menu or the bottom scroll bar),
almost a third of all electricity produced comes from hydropower, running
at its full rated capacity of 45 MW. This is unrealistic if there is insufficient
water to satisfy the demand for electricity.
Scenario: Hydropower Generation from WEAP
In order to have a more realistic representation of hydropower, we will now
link LEAP to WEAP, so that LEAP can read the hydropower results
calculated by WEAP. In this way, LEAP can determine how much
electricity could, in reality, be generated from hydropower.
7.
Create scenario in WEAP
In WEAP, choose the menu item Area, Manage Scenarios to create a new
scenario under the “No LEAP Link” scenario, and name it “Hydro Gen
from WEAP.”
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8.
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Linking WEAP to LEAP
Create scenario in LEAP
In LEAP, return to the Analysis View and click the “Scenarios” button
(with a blue S icon) toward the top of the window. Add a scenario by
clicking the green plus button in the upper left corner, and name the
scenario “Hydro Gen from WEAP.” In the “Based on” pull-down window
under the Inheritance tab, select “No WEAP Link.” This will ensure that
the new scenario inherits the characteristics of the “No WEAP Link”
scenario. Close the window.
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Linking WEAP and LEAP
In LEAP, go to the Analysis View and then, under the Advanced menu,
select “Link to WEAP Water Model.” The window that pops up is the link
manager. After checking the box in this window, you associate the LEAP
area with the correct WEAP area. It is also where you match LEAP and
WEAP scenarios and time steps.
Check the “Link to WEAP water model” box at the top. Where it says
<Select a WEAP Area >, choose “Tutorial.” When first linked, LEAP or
WEAP will attempt to match up the scenarios and timesteps from the two
models if they have the same name. The timesteps should all be
automatically matched, as well as the “Hydro Gen from WEAP” scenarios.
The “No WEAP Link” and “No LEAP Link” scenarios will not link (their
names are different), but this is correct—those two scenarios are not linked.
You can click the Error Check button to double-check for any errors. Then,
close the window.
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Now we shall follow the same steps for WEAP. In WEAP, under the
Advanced menu, select “Link to LEAP Energy Model.” A window just like
the LEAP link manager should pop up. Check the “Link to LEAP” box,
and verify that the LEAP Area, scenarios and timesteps are linked correctly.
Close the window.
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Scenario: Hydropower Generation from WEAP
10.
249
Time slices
In this example, the LEAP timeslices have already been set to monthly. But
when you create your own LEAP area, you will need to setup the timeslices
to match those in the WEAP area to be linked (typically, monthly). In the
LEAP Analysis view, go to the “General” menu at the top of the window
and select “Time Slices.” If this had been a new area, the default would be 8
seasonal day and night time slices. To change this, click “Setup.”
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In the “Setup Time Slices” window that appears, choose “Detailed” and
then OK.
Change “Main slices” to “12 Months.” Make sure “Daily slices” is “Whole
day” and “Weekly slices” is “Whole week.” To save these settings, click OK.
However, because the time slices are already monthly, you can just click
Cancel.
11.
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Reading WEAP Result into LEAP
In the LEAP “Analysis” view, open the Data tree to
“Transformation”>“Electricity”>”Processes.” Making sure that the new
“Hydro Gen From WEAP” scenario is selected, choose the “Maximum
Availability” tab. Select the Reservoir with Hydro branch and click on the
Expression Builder tab (shown with an orange E) further down on the
screen.
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Use the “Branch/Variable” button below the Expressions Builder tab to
enter branches from WEAP:
Choose the “Reservoir with Hydropower” branch and click Next.
Select the “Hydropower Generation” result variable (you may need to scroll
down) and click Finish. You might need to change the unit of
“Hydropower Generation” from GJ to MW by specifying in the expression,
as shown below.
Fill in the rest of the expression: put 100*Min(1, before the WEAPValue
function and )/Exogenous Capacity[MW]) after it. The completed expression
should be:
100*Min(1,WEAPValue(Supply and Resources\River\Green
River\Reservoirs\Reservoir with Hydropower:Hydropower
Generation[MW])/Exogenous Capacity[MW])
Click the “Submit” button at the top left corner of the Expression Builder.
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Note that you can also type this in. Spaces in names must be included for WEAP
and LEAP to recognize the expression.
The WEAPValue function tells LEAP to look at data or results calculated
by WEAP.
Run results in both WEAP and LEAP and then return to this Reservior
with Hydropower equation. The graph in the Chart tab below the
expressions shows that the hydropower maximum availability in 2011 and
2014, as calculated by WEAP, is actually much lower than 100%. This
restricts the amount of electricity LEAP can dispatch from hydropower.
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Scenario: Hydropower Generation from WEAP
12.
253
View LEAP Results
To see how hydropower results from WEAP affects the LEAP electricity
dispatch, switch to the “Results” view. Now that WEAP and LEAP are
linked and depend upon each other’s results, they will each need to make
sure that the other’s results are up to date. In the LEAP confirmation
dialog to run calculations, it notes that WEAP also needs to calculate and
gives you the option to do that too.
In this initial version of the linked WEAP-LEAP modeling system, the flow of calculations is
not fully automatic. In models which have links in both directions, the user is responsible
for running the models several times until the system converges, or recognizing the cases
where the results diverge or oscillate between two or more different states. We hope to
automate this process in future versions.
Note: Your results for this tutorial may not exactly match those shown here, depending on
how many times you iterate the calculations in LEAP and WEAP.
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Select the “Transformation: Average Power Dispatched” variable from the
pull-down window under the Chart tab. Select the “Hydro Gen from
WEAP” scenario from the “Scenario” pull-down window under that. Using
the pull-down windows at the right and bottom of the window, select “All
Branches” for the vertical axis of the chart, and “All Time Slices” for the
horizontal axis.
As we can see from the chart, there is much less hydropower and much
more coal steam in this scenario due to the restriction given by WEAP.
We can verify that the outputs generated by WEAP indeed match the inputs
to LEAP. Switching to the Table tab in the LEAP “Results” view, note that
for January 2014, the amount of hydropower generated by the reservoir is
6.55 MW. Note that you may have to change the decimal display by clicking
the button on the right. The units can be changed by clicking the vertical
Megawatts tab on the left.
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In WEAP, under the Table tab of the “Results” view, the value for January
2014 is also 6.55 MW (make sure the units displayed are MW by using the
dropdown menu in the upper right).
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Scenario: Demand for Cooling Water from LEAP
As mentioned before, the coal power plant downstream from the city uses
cooling water in its electricity generation process. The demand for water
from the coal plant is determined by how much electricity it generates in
LEAP.
13.
Create scenario
14.
Enter Water Use in WEAP
Create a new scenario in both WEAP and LEAP named “Cooling Water
Demand from LEAP.” The new scenario should inherit the properties of
the “Hydro Gen from WEAP” scenario. Check the link manager to ensure
that these new scenarios are linked to each other (“Advanced”>”Link to
WEAP” or “Link to LEAP” depending on whether you are in LEAP or
WEAP).
In the WEAP “Data” view, go to the Key Assumption for Cooling Water
Requirements per MHW \ Coal Steam on the Data tree, and enter 25000
gal (make sure the “Cooling Water Demand from LEAP” scenario is
selected):
Select Demand Sites \ Coal Power Plant on the tree. On the “Monthly
Demand” tab under “Water Use,” enter the following LEAP function:
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LEAPValue(Transformation\Electricity\Processes\Coal Steam:Average Power
Dispatched[MW]) * Days * 24 * Key\Cooling Water Requirements per
MWH\Coal Steam[m^3]
Note: You may use the “LEAP Branches” tab on WEAP’s Expression
Builder to help build the LEAPValue part of the expression. If you do, you
will need to change the unit from Kilowatt to MW:
Multiplying by Days * 24 converts power (MW) to energy (Megawatt-hours);
multiplying by the water requirement per MWH gives the volume of water
needed by the coal power plant to function.
The chart shows the variation in cooling water demand, depending on how
much electricity is generated by the coal power plant.
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Note: If LEAP has not yet calculated this scenario, you will not see any
results here.
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View WEAP results
In the “Results” view, select the “Reservoir Storage Volume and Zones”
variable in the top pull-down window (“Supply and
Resources”>”Reservoir”>“Storage Volume and Zones”). The graph shows
the storage volume (red) against the different reservoir zones. Look at it
first for Hydro Gen from WEAP for all years.
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Scenario: Demand for Cooling Water from LEAP
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Change the scenario to “Cooling water demand from WEAP.” Now we can
see that the reservoir level dropping lower over time due to the new
demand for cooling water.
If we view the “Demand Site Coverage” variable (Demand>Coverage), we
observe that demand coverage for the coal plant is less than 100% in several
month. This means that there is not enough water to satisfy the coal plant’s
demand.
[Results vary]
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16.
Linking WEAP to LEAP
Enter WEAP expression in LEAP
We will now see how this WEAP restriction affects the results in LEAP. Go
to the LEAP “Analysis” view and select the “Cooling Water Demand from
LEAP” scenario from the pull-down window. Under the “Maximum
Availability” tab, enter the following WEAP input expression for the Coal
Steam branch:
70 * WEAPValue(Demand Sites\Coal Power Plant:Coverage[%]) / 100
This is the demand coverage for the coal power plant. The chart shows that,
in months where the coverage is below 100%, the maximum availability will
be less than 70%.
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Scenario: Demand for Cooling Water from LEAP
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View Results in LEAP
Switching to the “Results” view, select the “Cooling Water Demand from
LEAP” scenario. In 2014, there is insufficient water to satisfy the cooling
water demand, which reduces the generating capacity of the coal plant. We
can see that at times, imports (in red) are now required to make up for the
lack in coverage by hydropower and coal steam.
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Scenario: Electricity Demand from WEAP
The water sector uses electricity to treat, pump and transmit water.
Depending on how much water is used and treated, the demand for
electricity changes accordingly.
18.
Create scenario in WEAP
In WEAP, create a new scenario called “Electricity Demand from WEAP,”
inheriting the characteristics of the “Cooling water demand from LEAP”
scenario. Here we are going to focus on two demands for electricity by the
water sector.
The first is the transmission link from the river to the city. In the Data tree,
open “Supply and Resources,” “Transmission Links” and “to City.”
You will create two new user-defined variables, “Electricity per Cubic Meter”
and “Total Electricity,” to model electricity used by water pumping and
treatment. Right click on an existing variable tab (e.g., Maximum Flow
Volume) and choose “Create.”
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First, create a new category named “Electricity”—select < Add New Category>
to add it.
Next, enter the following information and click Save:
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Once you have created the variable, enter data in the “Electricity Demand
from WEAP” scenario for the energy needed for pumping and treatment to
the City (1 kWH / cubic meter) and the Coal Power Plant (0.2 kWH / cubic
meter). Tip: just click on the transmission link in the lower left map to jump
to that branch in the tree.
Create another variable named “Total Electricity”:
Note: This variable will be a read-only calculated result--the default
expression you enter (Electricity per Cubic Meter * PrevTSValue(Flow) ) will
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Scenario: Electricity Demand from WEAP
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calculate the total electricity used by the transmission link in the previous
timestep. Because this is the default expression, it will be used for all
transmission links.
The second electricity demand in this model is from the Wastewater
Treatment Plant. Find this in the Data tree under “Water Quality” and
“Wastewater Treatment.” We will model it the same way as we did the
transmission links. Add two new user-defined variables: “Electricity per
Cubic Meter” and “Total Electricity,” with the following definitions:
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The default expression for the read-only result variable Total Electricity is
Electricity per Cubic Meter[kWH] * PrevTSValue(Wastewater Treatment Plant
Total Inflow[m^3])
Enter data in the “Electricity per Cubic Meter,” in the “Electricity Demand
from WEAP” scenario: 0.1 kWH / cubic meter.
19.
Add Key Assumption in WEAP
These two electricity demands can be summed up in one key assumption.
Add a new key assumption in the Data tree and name it “Electricity Use by
Water Sector.” (Right click on the “Key Assumptions” branch and choose
“Add,” and select Kilowatt-Hours for the unit.). Enter the following
expression in the Current Accounts:
(Supply and Resources\Transmission Links:Total Electricity[kWH] + Water
Quality\Wastewater Treatment:Total Electricity[kWH])
20.
Create scenario in LEAP
Open the “Analysis” view in LEAP and create a scenario named “Electricity
Demand from WEAP.” Go to the Link to WEAP screen and link this
scenario to the corresponding scenario in WEAP. In the Data tree, go to
branch Demand \ Water Sector. Enter this expression in “Final Energy
Intensity Time Sliced” (make sure the “Electricity Demand from WEAP”
scenario is selected):
WEAPValue(Key\Electricity Use by Water Sector[kWH])
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You will need to run calculations before you can see these results in the
Data View.
21.
View results and compare scenarios
In the “Results” view of LEAP, you can compare the energy demand across
scenarios. Choose the “Energy Demand Final Units” variable from the top
pull-down window, and “All Scenarios” for the legend. The “Electricity
Demand from WEAP” scenario should show a variation in demand, while
the other scenarios show straight lines because they do not take into
account the changing electricity demand from the water sector. You may
have to click the Y0 icon to the right to see the same view.
In WEAP, look at the results for Reservoir storage by scenario. You may
have to run them to or three times to see the following chart. Because of
the electricity demand from WEAP, LEAP must dispatch the coal plant
more, which increases the cooling water requirement, which further reduces
the reservoir level. Even in this simple example, you can see the complexity
that can be modeled by linking WEAP and LEAP.
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WEAP Tutorial
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