Subject: stream flow Posted: 3/25/2008 Viewed: 29300 times
stream flow Rasha Al-Graibeh eng_rasha firstname.lastname@example.org hello iwant to ask about stream flow to any one interset. if i have observed stream flow 4 millions cubic meter for wadi , in Weap result stream flow is in the last reach or i must sum the result in all reaches, also withdrawl nodes included in the resulting stream flow or not. thanks
Hope i can help, let me first discus the general idea of a stream, which is that rout which water pass through, and starting from a known point that is considered as headflow as a result of springs discharge or any other reason could start your simulation with amount of water (your case 4 MCM), and may it is connected with other features either by inflow nodes that add new volume of water to original stream, or by outflow (withdrawal) nodes that is taking off some water from stream flow to demand region, the rest of flow can be held by applying mass-balance equations, other things can be taken in the balance when you use GW recharge, and Losses (Evaporation), according to your water system.
WEAP can serve you to construct or simulate your case via its legend tools by using RIVER feature to draw the stream and put a value of its headflow, also you can add demand nodes to be connected later with your stream in a withdrawal nodes (the connection represented in WEAP by a tool called transmission link), after that WEAP is dealing your figure as the following:
- You have a stream with headflow of 4 MCM. - This volume of water will pass through its rout or flow into points down without changes (the stream is still carrying the same water volume from the headflow) unless you were assigning Rate of Evaporation or losses to GW as recharge (this can be found in WEAP Database). - Where the stream is connected with a demand nodes, then some water will leave out for providing a demand. Outflow to a demand is determined and controlled by demand requirement parameters which are built up in the WEAP Database view. - Finally WEAP will calculate the stream balance taking into consideration all boundary conditions you were using, through that WEAP is oriented to maximizing the demand coverage as a result of model optimization.
However, one thing is important here to understand, is that in stream tool structure called "REACH", WEAP is creating reach after particular event made by a stream (e.g. inflow or outflow nodes ... when the stream is connected with other river or by demand nodes), the functionality of reach in WEAP is as constraint or conditional rule which you can control a restricted volume of water to be held for a restricted use in that reach (by other words it is like volume of water that must be available in that reach from original water volume that passed through past reach), I think that definitely when you fill a reach by water volume or by value in WEAP database, so this will not add more amount of water to your streamflow.
Anyhow; may you can look at WEAP help and tutorials to find more explanation about it, also may through WEAP forum my colleagues can agree or modify my talk through this discussion.
All the Best,
Saleh T.MN. Al Qur'aan WERSC Research Assistant +962 777 965949
Subject: Re: inflow Posted: 3/26/2008 Viewed: 29292 times
Re: inflow Mehdi Mirzaee mmirzaee1 email@example.comHi Rasha, It's easy! WEAP calculate all inflow at each river reach. Thus it includes all inflows and outflows. If you get your last reach summary results, it is including all changes during processes which you define for your example or project. DO NOT make any SUMMATION!
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