Under the Watershed Act, the Minnehaha Creek Watershed District exercises a series of powers to accomplish its statutory purposes. The legislature has recognized the public need to conserve natural resources through land utilization and flood control based upon sound scientific principles.

Land alteration affects the rate, volume, and quality of surface water runoff which ultimately must be accommodated by the existing surface water systems within the District. The watershed is large--180 square miles--and its outlet, Minnehaha Creek, has limited capacity to carry flows. Flooding problems already occur in the urbanized areas of the District along Minnehaha Creek, and on Lake Minnetonka shoreland.

Land alteration and utilization also can degrade the quality of runoff entering the streams and waterbodies of the District due to non-point source pollution. Sedimentation in lakes and streams from ongoing erosion processes and construction activities reduces the hydraulic capacity of waterbodies and degrades water quality. Water quality problems already exist in many of the lakes and streams throughout the District.

Projects which increase the rate of stormwater runoff can aggravate existing flooding problems and contribute to new ones. Projects which degrade runoff quality can aggravate existing water quality problems and contribute to new ones. Projects which fill floodplain or wetland areas can aggravate existing flooding by reducing flood storage and hydraulic capacity of waterbodies, and can degrade water quality by eliminating the filtering capacity of such areas. Dredging projects can also degrade water quality and eliminate the natural appearance of shoreland areas.