1. Steven Burian and Erfan Goharian Hydroinformatics Fall 2013
Modeling with WEAP
Steven Burian and Erfan Goharian
Hydroinformatics
Fall 2013

2. Learning Objectives Describe priority-based water allocations
Draw a system schematic (that includes water sources, demand sites, and return flows)
Calculate the streamflow from a watershed using rainfall-runoff methods
Calculate allocations given available water and delivery priorities
Use the WEAP system to set up a schematic, enter data, obtain results, and define + analyze scenarios

3. Why a IWRM model?
Allocation of limited water resources
concerns regarding environmental quality
planning under climate variability and uncertainty
need to develop and implement sustainable water use strategies
A systematic process for linking water and water-related policy, objectives, and uses to improve decision making in:
operation and management of natural
resources and environmental systems;
design and implementation of programs and policies.
A coordinating framework for integrating sectoral needs, water and water-related policy, resource allocation, and management within the context of social, economic, and environmental development objectives.
The integration is over several dimensions: between demand and supply, between water quantity and quality, and between economic development objectives and environmental constraints.

4. Water Allocation Modeling
All resources are not available for each user
Also reach gains/losses, reservoir storage, consumptive use, return flows, groundwater, soil moisture, etc. must be considered
Priorities
Appropriation doctrine (first in time, first in right)
By purpose (e.g.: urban demands before environmental)
By location (e.g.: upstream, then downstream, or reverse)
Change in time and locations (spatial and temporal changes)
All the factors should be modeled in order to track water
Key model development steps
Draw the system schematic
Identify model approach and data for system components
Enter data and run the model

5. System Definition Include major components
Subsystems
Identify based on project objectives and requirements
Identify connections between components
Relationships or real connections
System boundaries
Create drawing
Labeling components
Arrowed lines
As straight forward as possible
Questions for students:
What are the major system components and linkages?
Water sources (surface and groundwater)
Demand sites (agricultural, urban, etc..)
Source connections to demand sites
Outflows from demand sites after use

6. Why WEAP? software tool for integrated water resources planning
user-friendly framework for planning and policy analysis
Water balance database: WEAP provides a system for maintaining water demand and supply information
Scenario generation tool: WEAP simulates water demand, supply, runoff, streamflows, storage, pollution generation, treatment and discharge and instream water quality
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.
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.

7. Questions WEAP can answer
What if population growth and economic development patterns change?
What if reservoir operating rules are altered?
What if groundwater is more fully exploited?
What if water conservation is introduced?
What if ecosystem requirements are tightened?
What if a conjunctive use program is established to store excess surface water in underground aquifers?
What if a water recycling program is implemented?
What if a more efficient irrigation technique is implemented?
What if the mix of agricultural crops changes?
What if climate change alters demand and supplies?
How does pollution upstream affect downstream water quality?
How will land use changes affect runoff?
etc
Selecting some of them based on relation to our work

8. Using WEAP Design the schematic Select Methods Data Results
Scenario Explorer
Notes
Today: introduce user interface
Tuesday: automate use through Application Programming Interface
Next Thursday: Finalize homework and analyses
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.
The Data view allows you to create variables and relationships, enter assumptions and projections using mathematical expressions, and dynamically link to Excel.
The Results view allows detailed and flexible display of all model outputs, in charts and tables, and on the Schematic.
You can highlight key data and results in your system for quick viewing.
The Notes view provides a place to document your data and assumptions.

9. Schematic
Objects: Rivers, demand nodes, reservoirs, diversion and etc.
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

10. Hydrologic Module of WEAP
(1) the Rainfall Runoff method (2) Irrigation (FAO Crop Requirements Approach) (3) Soil Moisture Method (4) the MABIA Method

11. Calculate Allocation Mass Balance Equation
More demand sites, water sources like reservoirs and return flows make more complex data requirements and allocation calculations
Integrated Water Resource Management
Hydroinformatics and computer modeling can really help!
P + Gin – (ET + Q + Gout) = ∆S

12. WEAP Allocation Method
In each time step, WEAP solves a small linear program
Maximize Demand Satisfaction
Meet supply priorities
Obey demand site preferences
Mass balance
Other constraints
Embed the LP in a time-series simulation (psuedo code)

13. Data Enter data for each schematic component
Rivers: Headflows for each month of the simulation
Reaches: Reach gains for each month of the simulation
Diversions: Minimum flow requirements as reach losses
Demand sites: activity levels, use rates, losses, consumption, demand priority (1=highest; 99=lowest)
Transmission links: Max flows, supply preference
Return flows: routing (percent returned)
Reservoirs: storage capacity, initial storage, volume-elevation curve, evaporation, pool definitions, buffer coefficients, priority
Enter data or read from input file

14. Identify data for system components
Determine water availability
Sources
Return flows
Identify delivery for demand sites (demands)
Allocate water based on priorities to demand sites (delivery preferences)
Allocate remaining available water to meet delivery target of highest priority demand site
Repeat Steps 4 and 5 for next highest priority site

15. Example
Parley’s Creek supplies water to part of the city and for an agricultural district. Before going to the city, the water should go to Parley’s Water Treatment Plant (40mgd capacity). 15% of the city’s withdrawals are directly going to the Jordan River and the rest of that collected, treated, returned to the river, and will be available for Jordan River use by the agricultural district.
Draw the schematic of the system:
Erfan – I do not understand this…

16. Calculate Allocations Example
Parleys Creek can supply part of Salt Lake City and a downstream agricultural district. 70% of the city’s withdrawals are collected, treated, discharged, and available for downstream use by the agricultural district. 70 ac-ft is available in the river this year. The table shows demand site priorities and delivery targets.
Demand Site
Priority [rank]
Delivery Target [ac-ft/yr]
City
2 (lower) 30
Agricultural
1 (high) 60
What water volume is allocated to each demand site?

17. Example
What kind of data we need?
Hydrologic model
System model

18. Precipitation Input

19. Results Click the Results icon and recalculate (all scenarios)
Choose results from schematic or dropdown lists
Numerous options to view, tabulate, and export

20. Next Session
Define and manage scenarios from the Data module and enter input data
Use Scenario Explorer icon to open scenario dashboard
Automate inputting data
Use Scripting in WEAP