TMDL Details Volney Site Description

Section 1.0 Background Information

1.1 Site Description

Lake Volney, located in Le Sueur County Minnesota is a small lake at only 277 acres; however, Lake Volney has a maximum depth of 65 feet and a mean depth of 22.7 feet making it one of the deepest lakes in southern Minnesota. Lake Volney is situated in a watershed that is comprised of moderate to steeply sloping hills that have been cleared primarily for agricultural purposes. The total acreage within the Lake Volney watershed is 2,017 acres; most of the watershed is dominated by agricultural land use. The watershed to lake ratio for Lake Volney is 7:1 (Table 1.1 A.). The stratification of this lake is highly beneficial to the water quality of this basin because a large percentage of the phosphorus load is retained within the hypolimnion (bottom layer of lake during stratification) during a majority of the open water season. The combination of a small watershed-to lake ratio and the thermal stratification of Lake Volney give this waterbody a better than average chance for restoration.

Fifty-four percent of Lake Volney has a depth greater than 15 feet; therefore, approximately 46% of the surface area is within the littoral zone (less than 15 feet deep) that is capable of supporting plant growth. Although curly-leaf pondweed (CLP) has been found in Lake Volney, the growth of this species has not become problematic. Moderately dense stands of CLP were found in a small percentage of the lake in 2009. The sediment within Lake Volney has been found to be non-conducive to supporting extremely dense stands of CLP (Pers. Comm. Steve McComas of Blue Water Science, 2008). The overall macrophyte community found in Lake Volney is extremely limited, with a total of three species found during the point intercept surveys conducted in 2009. The absence of macrophytes within Lake Volney may partially explain the high frequency by which algae blooms occur. The ample supply of nutrients in coordination with an absence of shading from macrophytes allows for algae to grow relatively uninhibited.