The subwatershed is dominated by Lake Minnetonka with its complex configuration of bays and channels.

Table 5 and Table 6 below detail the physical and water quality characteristics of the lake.  The HHPLS modeled water quality and established goals for twenty-six of those bays.  An additional eight lakes had established goals in the 1997 plan but those goals were not modeled in the HHPLS.  Many of the bays are monitored as part of the District’s monitoring program.  Little or no water quality data is available for smaller lakes scattered throughout the subwatershed.    

The streams that drain the other subwatersheds in the upper watershed convey significant phosphorus and sediment loads to the lake, and are a major cause of the poor water quality in some of the bays.  In decades past, several sewage treatment plants operated in the upper watershed, and their discharges conveyed significant phosphorus loads to the lake.  Since those plants discontinued operation, the water quality in the Lake has improved considerably, but those old discharges may continue to influence water quality from phosphorus in the lake sediments.

Table 5.  Physical characteristics of lakes in the Lake Minnetonka subwatershed.

Source: Minnesota DNR

Table 6.  Selected water quality goals and current conditions of lakes in the Lake Minnetonka subwatershed.

 Table 7.  Selected water quality goals and current conditions in the minor Lake Minnetonka subwatershed and direct drainage lakes.

*10% reduction of the existing TP concentration provided it is above 25 μg/L; will require baseline data

**2003 data *** Clarity as estimated by the University of Minnesota using satellite imagery