A lake is stricken due to phosphorus excess leading to eutrophication and low dissolved oxygen. The target P concentration in the lake is <0.025 mg/l
The currect P inputs are as follows:
Creek A: Q=315 L/s, P=0.045 mg/l
Creek B Q=20L/s, P=0.048 mg/l
Creek C Q=28L/s, P=0.053 mg/l
Other non point sources: P in =221 kg/yr
Loading from an internal lake sediments P in =2158 kg/yr
Settling rate within the lake P out = 2030 kg/yr
A) calculate the steady state P concentration in the lake
B)Creek A has been identified as the easiest to control. What would the P concentration have to be reduced to in Creek A, in order to reduce the concentration in the lake below 0.025 mg/l?