APPLICATION OF THE DEVELOPED (WQMIS) AS A DECISION SUPPORT TOOL FOR LAKE MANAGEMENT - Integrating GIS, Remote Sensing, and Mathematical Modelling for Surface Water Quality Management - page 193

C. Reduction of phosphorous Loads from Barseek drain to the Lake

Since most of the fisheries are located around Barseek drain it is expected that high levels of nutrients
and wastes concentrations reaches the lake directly as non point sources from this location. A scenario
is developed to reduce the phosphorous concentrations at Barseek drain boundaries by 10% and 30%
reductions, as shown in Figure (9-3) .

Figure (9-3): The effect of reduction of (PO4) at Barseek drain on the CHL-a concentrations
at mid lake location

The reduction of PO4 at only at barseek drain outlet to the lake does not lower the CHL-
aconcentration more than 10%, but reduction of nutrients from all input sources to the lake seems to be
the reasonable scenario for reduction of primary production of algae in the lake. The scenarios results
also show that the limiting factor to the CHL-a in the lake is both the phosphorous and nitrogen
compounds. These results indicates that the management scenarios for the reduction of nutrients loads
to the lake needs intensive reduction of nutrients in the watershed upstream and the 10% reduction of
loads at drains inlets to the lake is a the starting management control action. Further research and
analysis should be done on spatial and temporal variation of CHL-a concentrations based on the
reduction scenarios to select the best management scenario taking into consideration all the
surrounding factors.