Question

3. [20] You have been conducting a water quality study of Lake Arjun, which has a surface area of 8.9 ×105 m2 . The average depth of the lake is 9 m. The lake is fed by a stream having a flow rate of 1.02 m3 /s and a phosphorus concentration of 0.023 mg/L. Runoff from the homes along the lake adds phosphorus at an average annual rate of 1.25 g/s. The river flows from the lake at a flow rate of 1.02 m3 /s. The average phosphorus concentration in the lake is 13.2 µg/L. Assume evaporation and precipitation negate each other. What is the calculated average settling rate of phosphorus?

Answer 1