Section 4: Soil and Water Conservation Engineering
Watershed Management
Subtopic: Water budgeting in watershed
Question Statement:
In a watershed annual water budget analysis, annual precipitation is $P = 650\text{ mm}$, total measured stream runoff is $Q = 120\text{ mm}$, and total evapotranspiration loss is $ET = 480\text{ mm}$. The net change in catchment water storage ($\Delta S = P - Q - ET$) in $\text{mm}$ is ________ (answer in integer).
Answer Key:
50
Step-by-Step Solution & Explanation
From the watershed hydrologic balance:
$\Delta S = P - Q - ET$
$\Delta S = 650 - 120 - 480 = 650 - 600 = 50\text{ mm}$