Civil UPSC ESE Exam Solution 2021
UPSC ESE Exam Solution 2021 for Civil Engineering UPSC ESE 2021 GS Paper 1 download exam paper from telegram https://telegram.me/civil_experiences
A lake has an area of 15 km2. Observation of hydrological variables during a certain year has shown as follows:
Precipitation = 700 mm/year,
Average inflow Qin = 1.4 m2/s;
Average outflow Qout = 1.6 m/s
Assume that there is no net water exchange between the lake and the groundwater. What is the evaporation during this year?
ANSWER= [B] 280 mm
Detailed Solution for Civil Engineering Exam
Precipitation (P) = 700 mm/yr
Avg inflow (Qin) = 1.4 m 3/sec
Avg Outflow (Qout) = 1.6 3/sec
lake area = 15 km2
Assuming no chance in storage in a year, we have
Inflow – Outflow = 0
Inflow = Outflow
(700 * 10-3 * 15 * 106) + (1.4 * 365 * 24 * 60 * 60) = (1.6 * 365 * 24 * 60 * 60) + (E * 10-3 * 15 * 106)
(where E = evaporation in mm/yr)
solving we get
E = 279.52 mm/yr
E = 280 mm/yr
