Answer:
The lake can withdraw a maximum of 
cubic feet per year to provide water supply for the Triangle area.
Explanation:
The maximum amount of water that can be withdrawn from the lake is represented by the following formula:
(Eq. 1)
Where:
- Available amount of water for water supply in the Triangle area, measured in cubic feet per year.
- Inflow amount of water, measured in cubic feet per year.
- Amount of water released for the benefit of fish and downstream water users, measured in cubic feet per year.
- Amount of water due to precipitation, measured in cubic feet per year.
- Amount of evaporated water, measured in cubic feet per year.
Then, we can expand this expression as follows:
(Eq. 2)
Where:
- Average watershed inflow, measured in cubic feet per second.
- Average flow to be released, measured in cubic feet per second.
- Yearly time, measured in seconds per year.
- Change in lake height due to precipitation, measured in feet per year.
- Change in lake height due to evaporation, measured in feet per year.
- Surface area of the lake, measured in square feet.
If we know that 
, 
, 
, 
, 
and 
, the available amount of water for supply purposes in the Triangle area is:
The lake can withdraw a maximum of cubic feet per year to provide water supply for the Triangle area.
