Welcome to WEAP's Website WEAP
WEAP is an initiative of the Stockholm Environment Institute.


About WEAP

Home
Why WEAP?
Features
What's New?
Sample Screens
Demonstration
Publications
History and Credits

Using WEAP
Download
Licensing
User Guide
Tutorial
Videos (YouTube)

User Forum
Discussions
Members List
Edit Profile

Additional Support
Training
University Courses
Collaboration

About Us
SEI-US Water Resources Program
Please Contact Us

Environmental News
Ocean microplastics: First global view shows seasonal changes and sour...
An estimated 8 million tons of plastic trash enters the ocean each year, and most of it is battered by sun and waves int...

Cause, scope determined for deadly winter debris flow in Uttarakhand,...
The Uttarakhand region of India experienced a humanitarian tragedy on Feb. 7, 2021, when a wall of debris and water barr...

World-first discovery could fuel the new green ammonia economy
Scientists have developed a new technique using phosphonium salts that can help drive the future production of green amm...
Source: Science Daily
LEAP
Interested in Energy?
Read about LEAP: SEI's software for energy planning.

Link WEAP and LEAP for combined Water-Energy planning.
Watch a video demo!
   

User Forum

All Topics | Topic "Reservoir Calculation (Top of Inactive, Evaporation, Allocation)"
Log in to post new messages or reply to existing messages.
 
Author Message
Ms. Claudia Drebing

Subject: Reservoir Calculation (Top of Inactive, Evaporation, Allocation)   
Posted: 12/9/2020 Viewed: 809 times
Hello,
I've created a WEAP-model and have problems understanding some of its results regarding the reservoir. The reservoir has specific values for Top of Inaction, Top of Buffer and max. Storage Volume (=Top of Conservation).

1)The Inactive Zone of a reservoir can only loose water due to evaporation, according to the help guide. And for each time step the previous storage volume will loose or gain Netto-Evaporation and gain Inflow. The result is called Storage for Operation. If the Storage for Operation is higher than the Top of Inactive, Transmission Links will deliver water to demand sites. In my projekt the Storage for Operation ist below Top of Inactive, but the demand site, which has to be allocated water first, still receives up to 20 % of its water demand. Could you point out, if I misunderstood the help guides explanation or if there is special calculation rule that is not mentioned in the help guide?

2)The reservoir looses water due to evaporation or gains water due to direct rain (so the Netto Evaporation is negative or positive). If the reservoir reaches his max. storage in the previous time step, WEAP models no direct rain in the current time step. Could you explain, why upstream inflow creates outflow, but direct rain does not?

3)The reservoir has three demand sites. Each one has its own demand priority. During one time step there is water scarcity. The first demand site can't fullfill its demand, that's why the other other demand sites should receive no water. But the reservoir still deliveres a tiny portion of water (<1% of the demand sites water demand) to the third demand site. Does this error occur because WEAP uses a distribution on a percentage basis for the allocation calculation?

Best regards
Deleted User

Subject: Re: Reservoir Calculation (Top of Inactive, Evaporation, Allocation)   
Posted: 12/14/2020 Viewed: 796 times
"Check the priority for the demand sites."
have you checked base flow?
if you want exact solution send me the model(compressed file)
Mail: nagaraj116011@gmail.com

Ms. Anne Hereford

Subject: Re: Reservoir Calculation (Top of Inactive, Evaporation, Allocation)   
Posted: 1/6/2021 Viewed: 720 times
Due to numerical instability issues in the LP solver, very small amounts of water (usually <1 cubic meter per timestep) are sometimes alotted to lower priority demand sites even when higher priority sites are not receiving 100% of their demand. This prevents the solver from reporting infeasibility in later iterations. (Thanks to Jack Sieber for this explanation).
Topic "Reservoir Calculation (Top of Inactive, Evaporation, Allocation)"