The annual storage in Broad River watershed is 0 cm/y. Annual precipitation is 100 cm/y and evapotranspiration is 50 cm/y. The s
andy loam soil in the watershed has an infiltration rate of 5 × 10-7 cm/s. The area of the watershed is 40 km2. Calculate the annual flow at the outlet of Broad River. What is the runoff coefficient for this watershed?
2 answers:
Answer:
The annual flow at the outlet of Broad River is 13688480 m³
The runoff coefficient for the watershed is 0.342212
Explanation:
Here, we have
The annual storage in the watershed = 0 cm/y
Annual precipitation = 100 cm/y
Annual evapotranspiration = 50 cm/y
infiltration rate = 5 × 10-7 cm/s
Watershed area = 40 km²
From the question, annual infiltration rate is given by
Annual infiltration rate = 5 × 10-7 cm/s × 31557600 s/year = 15.7788 cm/y
Therefore, annual flow =
Annual precipitation - Annual evapotranspiration - Annual infiltration rate - Annual storage in the watershed
Annual flow = 100 cm/y - 50 cm/y - 15.7788 cm/y - 0 cm/y = 34.2212 cm/y
The area of the watershed = 40 km²
Therefore, the volume of the annual flow is given by;
Height of annual flow × area of the watershed
Volume of annual flow = 34.2212 cm × 40 km² = 1368.848 cm·km²
= 13688480 m³
The runoff coefficient = =
The amount of precipitation received is given by
100 cm × 40 km² = 4000 cm·km² = 40000000 m³
Runoff coefficient = = 0.342212.
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