<p>When left to flow unrestricted from Lake Minnetonka in years past, the Minnehaha Creek was a gushing waterway that powered mills and could flood large areas. Today, the Minnehaha Creek Watershed District (MCWD) moderates the lake and creek with the Gray’s Bay Dam, an outlet on the lake’s east end. </p><p>Operating the dam is a delicate give-and-take. The MCWD must balance water between the lake and creek to limit flooding on both, while also keeping water levels high enough for a healthy ecosystem and recreational access. </p><p>The state Department of Natural Resources dictates how to operate the dam using a formula that considers water levels and time of year. The dam typically closes for the winter in November and doesn’t open again until ice-out in the spring. To protect the dam’s three gates from ice damage during the winter months, the District places metal “stop logs” in front of the gates. </p><p>When the ice recedes in the spring, the dam is usually opened only part way to keep Minnehaha Creek from flooding. Around mid-June the gates are opened wider to maintain optimum water levels in Lake Minnetonka, prevent erosion and build capacity for the following spring’s snow melt. Throughout the open water season, MCWD staff also adjusts the gates in anticipation of heavy rains to prevent flash flooding in the creek. </p><p>The dam does more than control flooding. Regulating water flow in Minnehaha Creek prevents damage to the creek bed caused by drying, protects wildlife habitat, and enhances recreational enjoyment of the area. And the dam itself is a destination — improvements over the years include a paved parking lot, picnic facilities, restrooms, bike racks, educational signage and a canoe landing. </p>