Adrainage basin bordering the sea has an area of 7500 km2 . the average precipitation for this drainage basin is 900 mm year-1 . the average surface water flow at the outlet of the drainage basin equals 22.5 × 108 m3 year-1 . the average groundwater flow to the sea is 100 mm year-1 . the averages are determined for 30 hydrological years. determine the average actual evaporation in mm year-1 and m3 year-1.

Explanation:

Given data:

Basin Area = 7500 km^2

average precipitation

average surface flow

average ground flow

total time period for averages = 30 hydrological year

Volume = height * area ,

here, height of precipitation

total precipitation over the surface

volume of flow of Groundwater to sea

Average surface flow

The evaporation volume is given as

* Precipitation = Evaporation + surface  flow + groundwater flow.

therefore, we have

Evaporation = Precipitation - (surface water flow + groundwater flow)

putting all value in above equation to get evaporation value

Evaporation

obtained height of water by dividing above calculated volume of evaporation by total area