A storm with a uniform depth of 1 in. falls on a 25-acre watershed. Determine the total volume of rainfall in acre-feet and cubic feet. If all of the water were collected in a storage basin having vertical walls and a floor area of 25,000 ft2, how deep of a basin would be needed?

Compute the diameter (cm) of the outfall required to drain storm water from the watershed described in figure below. Use rainfall intensity = 4 cm/hr. Average velocity of flow is 1 m/s. Other data are for: Area 1: C=0.5, area=0.005 km2. Area 2: C=0.4, area =0.01 km2. Area 3: C=0.7, area=0.015 km2.

Solve the problem using the NRCS method for a watershed located right outside New York City, New York for a 50 year storm event. Assume the soil hydrologic group B (65%), C (25%) and D (10%). Given Am-1.29 sm. Impervious = 6.6 acres, Woods =819 acres. Overland flow: L=100 ft, s=4%, fair; Shallow Concentrated Flow: unpaved L= 2300 ft, s=2.7%, stream flow L=9000 ft, s= 3.4% The Time of Concentration is 20¹ 12¹ n = 0.035

You are asked to design a rectangular clarifier for a wastewater treatment plant. The clarifier is designed to settle 2,000 m3/day with an overflow rate of 32m3/m2-day. If the tank is 2.4 m deep and 4.0 m wide, what should the length and detention time be?