you dont brother god luck
Yes, the amount of precipitation required by a lake to increase the water content by 2 feet, can be understood in scientific way.
We know that lake water content depends on some factors such as amount of precipitation, amount of evaporation, the dimensions and size of the lake, the depth of lake, speed of the water flow. Therefore, if we know exact figures about all such factors, or if we measure such factors, it will give a more proper answer in a scientific and logical way.
Hope it helps :)