Water
Evaluation and Planning System (WEAP)
Description:
WEAP is a practical tool for water resources planning. Its
capabilities go a step beyond conventional supply-oriented
simulation models and allow the user to incorporate a broad
spectrum of variables including environmental impacts and
policies into simulations.
WEAP's applications are broad, and encompass municipal and agricultural systems, as well as natural watersheds ranging from single subbasins or complex river systems. It can be used to address issues including sectoral demand analyses, water conservation, water rights, polluction tracking, hydropower generation, and project cost-benefit analyses.
It is intended to assist in the planning and management of water systems, rather than to simply simulate scenarios for different designs, though it can be used for this purpose as well.
Capabilities:
WEAP can simulate nearly all aspects of just about any water
system, and will produce reports on how various modifications
and management practices will impact each area. WEAP can process
user-input information on such things as:
• Demand sites (neighborhoods, farms, golf courses,
etc)
• Catchments, rivers, diversions, and river nodes
• Groundwater and other water supplies, transmission
links, runoff and infiltration links, and return flow links
• Wastewater treatment plants
• Priorities for water allocation (policies for water
allocation, environmental regulations)
Limitations:
WEAP is not intended for use in the design of new
water systems. It is a tool to aid in the ongoing analysis
and management of existing water systems and water resources.
It offers the user an opportunity to see the potential effects
of different changes made to a system, and to optimize the
decision-making process. If your goal is to redesign a system
or do 3-D modeling of watershed infiltration and runoff, WEAP
may not be the best choice (try SWMM,
WaterCAD, or HEC-GeoHMS).
If policies and regulations factor into your analysis, WEAP
will prove useful, but consider using one of the other programs
to design your reference system prior to defining your study
in WEAP.
Basic Inputs:
WEAP has a user-friendly Windows-based interface, and allows
the user an opportunity to describe nearly any water system
by accepting an extensive set parameters.
• Details of the water system being studied (economic,
demographic, hydrological, and technological trends).
• Future assumptions and potential policy changes (environmental
regulations, meteorological factors, changes in population,
advances in technology, etc).
Basic Output:
The outputs produced by WEAP are intended to aid in the user
in decision-making regarding the planning and management of
a particular water system. WEAP runs its simulation with a
time-interval of one month and reports projections on all
aspects of the system. The simulations are each compared to
a reference run (which should be the current system with no
modifications). Effects of different system configurations
can be viewed in the 'Results View' tab (water availability,
pollution tracking, hydropower generation, economic impacts,
etc)
How to Run the Model:
There are several steps common to most applications
of WEAP. They are:
• Define the study (set the timeframe, spatial
boundary of the area in question, system components and configuration)
• Input scenario parameters (actual water demand, pollution
loads, resources and supplies for the system). This will be
your reference scenario against which other simulations will
be compared.
• Define future assumptions (policies, costs, technological
development, and other factors affecting demand, pollution,
supply, and hydrology.
• Construct scenarios with different combinations of
assumptions and policies to answer "what if" questions
(What if a water-recycling program is implemented? What if
climate change alters the hydrology? etc)
• Click on the 'Results View.' Evaluate the scenarios
with respect to their effects on water sufficiency, costs
and benefits, compatibility with environmental targets, and
sensitivity to uncertainty in key variables. Develop an understanding
of the effects of different development choices.
Developer: Water Evaluation and Planning Sytem (WEAP) was developed by the Stockholm Environment Institute in collaboration with the Tellus Institute.
Faculty Contact:
Application:
