What exactly is Tailwater elevation?

My understanding is, this is the level where turbines are installed in the reservoir. Let us assume that minimum reservoir level is 1300 ft AMSL, water level in reservoir is at 1350 ft AMSL and turbines are installed at 1310 ft AMSL. Should I use 1310 ft as tailwater level or 40 ft as tailwater level?

Rafique

Dear Ahmed,

Have a look at the topic Hydropower Calculations calculations in the Help menu. For reservoirs, the height that the water falls in the turbines is equal to the elevation at the beginning of the month minus the tailwater elevation.

Thus, in your example, you should use 1310 masl as the tailwater elevation. WEAP will calculate the "drop elevation" as the difference between the elevation of the water in the dam (determined by the volume elevation curve) and the tailwater elevation.

Hi Stephanie,

Thanks.

hi,

could you please tell me how to input Tailwater elevation into WEAP, because Tailwater elevation depend on discharge of reservoir through turbine.

i think, in WEAP has a function to describe that relationship

i hope will receive ASA from you

many Thanks

Dear Hung,

The tailwater elevation does not depend on the discharge of the reservoir through the turbine - the tailwater elevation stays constant in WEAP. It is the elevation that the water is released at (the elevation of the outlet of the reservoir).

You can enter the tailwater elevation under in the reservoir under the tab "Hydropower" and the sub-tab "Tailwater elevation."

Have a look at the topic Hydropower Calculations calculations in the Help menu to better understand how the reservoir is modeled.