Please, help

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wanderbeg
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Posts: 20
Joined: Mon Mar 18, 2019 3:21 am
Vensim version: PLE

Please, help

Post by wanderbeg »

Hi, guys

I'm simulating a water balance of a reservoir. Its total capacity is 411 million m³. In the early years of the historical series, the reservoir level was always above 95% of its capacity, when I applied the management tools, accumulated more water in the reservoir, but it is already at its limit that is 411 million m³, but the water level is rising, 450, 490 .... This can disrupt the reservoir level when applying the management tools in low water supply.
I would like to know how to apply the management tools, and keep the reservoir level at its maximum limit (411), for those years of high water levels.

Is there a conditional function that will solve my problem?

Best regards,
tomfid
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Posts: 3804
Joined: Wed May 24, 2006 4:54 am

Re: Please, help

Post by tomfid »

Presumably you have a stock of water in the reservoir, with an inflow (river flow or rainfall or something, presumably exogenous) and an outflow (discharge).

I would guess that there's a mechanism something like the following:

water in reservoir = INTEG( inflow - discharge, initial water )
inflow = ...
discharge = MAX( discharge for consumption, discharge for safety )
discharge for consumption = { some function of demand for irrigation or hydropower or whatever }
water capacity = 411e6 ~ m^3
desired safety margin = .02
desired max water = (1-desired safety margin)*water capacity
discharge for safety = MAX(0, water in reservoir-desired max water)/min discharge time
min discharge time = {something small, but not smaller than TIME STEP}
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