According to the nature of pump storage dams, always a definite volume of water dislocate between upstream and downstream reservoirs. The important issues related to water resource planning in water filling and operation periods of such projects can be generally as follows:
1- Water filling period:
In this period generally the upstream reservoir is filled up to the maximum operation level and it is necessary to fill the downstream reservoir to the minimum operation level. Also the water rights and environmental issues of the mentioned reservoir downstream should be considered.
2- Operation period
In this period, parts of daily outflow of the river which is surplus to the upstream reservoir profitable volume, would be used in power generation system and other parts would be released for the minimum needed water rights of downstream area in the river. Also in downstream reservoirs, releasing the compulsory surplus water which is from upstream reservoir and releasing the inflow of downstream reservoir water from two rivers of Garmrudbar and Chalus for keeping the reservoir at the minimum operation level and preserving needed empty volume of reservoir are among the important issues.
According to the considerable volume of water surplus, which is evacuated daily through the bottom outlet of downstream reservoir, some arrangements can be considered such as turbine installation in the exit of bottom outlet for optimum use of water.