Consultant's Report - Minnesota State Legislature

Hydrological Characteristics
MINNESOTA DEPARTMENT OF NATURAL RESOURCES
Feasibility Study to Limit the Spread of Zebra Mussels from Ossawinnamakee Lake
Ossawinnamakee Lake has one main discharge point located in the southeastern portion of the
lake. One primary inflow point exists in the northwestern portion of the lake, Kimball Creek.
Under normal scenarios, Kimball Lake located to the north of Ossawinnamakee Lake, provides
the only direct inflow into the lake. Under this condition, flows exiting Kimball Lake enter
Kimball Creek, which MN DNR personnel indicate is a shallow creek of varying widths from
10.0 feet (3.0 meters) to 16.0 feet (4.9 meters). While water can flow from Kimball Lake to
Ossawinnamakee Lake, boat traffic between the two lakes is physically restricted and prohibited
by a County Board ordinance. A second potential inflow point exists, but according to MN DNR
has never accounted for flow into Ossawinnamakee Lake. In the rare event that Pelican Lake
elevations significantly rose, water could travel from Pelican Lake into Ossawinnamakee Lake
through an outlet stream in Pelican Lake located south of Ossawinnamakee Lake. Records
maintained by MN DNR since 1933 indicate that water has never exited Pelican Lake and
entered Ossawinnamakee Lake. The emergency outlet structure elevation for Pelican Lake is
1,207.1 feet (367.9 meters), which is 0.9. feet (0.3 meters) above the highest recorded
Ossawinnamakee Lake elevation of 1,206.8 feet (367.8 meters). Given these conditions, it is
highly unlikely that water will exit Ossawinnamakee Lake and enter Pelican Lake. Figure 111-2
displays the relationship of Ossawinnamakee Lake to Kimball Lake to the north and Pelican
Lake to the south.
The average water surface elevation Ossawinnamakee Lake is 1,205.5 feet (367.4 meters). The
highest recorded elevation outlined above was 1,206.8 feet (367.8 meters) while the lowest
recorded elevation was 1,205.0 feet (367.3 meters), which is an approximate 1.8 feet (0.55
meters) maximum elevation change. Under average conditions, the lake has a volume of 14,008
acre-feet (17,278,613 cubic meters) and a hydraulic residence time of six to seven years. The
surrounding watershed is approximately 9,296.0 acres (3,761.9 hectares), which results in a
watershed to lake surface areas ratio ofapproximately 14: 1.
III-3 Ossawinnamakee Lake and Pelican Brook Overview