Orono Community Management Plan 2020-2040

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City of Orono Surface Water Management Plan February 2019 2 1.3 LAND USE OVERVIEW AND PHILOSOPHY Orono, located within the Central Hardwood Forest region of Minnesota, was originally covered with hardwood forest vegetation intermixed with prairie, lakes, streams and wetlands. The “Big Woods,” as this region is often called, consists primarily of maple, basswood, American elm, and oak trees. Between 1850 and 1880, the forests were extensively cleared for agricultural use. ORONO IS FORMED The City of Orono was created from parts of Medina and Excelsior townships and included a number of settlements which grew up along the railway lines such as Crystal Bay, Navarre, and Ferndale, as well as others that served the farming or summer home communities such as Tamarack (which later became the City of Long Lake) and Saga Hill. The open areas between these settlements developed in two distinct fashions: the shores of Lake Minnetonka in southern Orono became dotted with summer homes, and the areas away from the lake in central and northern Orono supported cash crop and dairy agriculture and truck farming. DEVELOPMENT AND INFRASTRUCTURE A local/county road network was developed to serve these diverse communities, and U.S. Highway 12 provided a regional transportation link as it crossed northern Orono. To support agriculture, early development and road construction, county drainage systems were developed, including ditches that connected many of Orono’s large wetlands and marshes to the nearby creeks flowing to Lake Minnetonka. After WWII, full-year homes began to fill in much of the Lake’s shoreline, and a scattering of residential subdivisions developed in the more rural areas away from the Lake. As lakeshore development expanded, point source pollution from inadequate septic systems was recognized as not only a health risk but as a factor in the deteriorating water quality of the Lake. Municipal sewer lines were extended along Orono’s developed lakeshore starting in the 1960's. The city’s municipal sewage treatment plant was one of seven constructed to serve the cities within the Lake Minnetonka watershed. However, these plants were relatively inefficient in phosphorus removal, and each ultimately discharged back into the Lake. IMPACT ON ECOLOGY The ecology of the Lake makes it extremely susceptible to pollution. Due to its many bays (connected by restricted channels), a relatively small watershed area, and its primary source of hydrology being precipitation within the watershed, the Lake has an extremely long 25-year flush out period for a complete water change. Pollutants entering the lake remain for a long time and are not easily diluted. Lake Minnetonka has historically suffered from two problems that affect its environmental health and its value as a public amenity. The first is deterioration in water quality due to eutrophication, the natural aging process by which lakes are enriched with nutrients that stimulate excessive plant growth. This process has been artificially accelerated as a result of development in the Lake’s watershed. The second problem is hydrologic instability. With precipitation as the primary water source, water levels have fluctuated widely depending on rainfall. In more recent years, increasing urbanization of the watershed has resulted in increased amounts of stormwater runoff and, in turn, higher water levels that affect low-lying properties. THE PROBLEM WITH PHOSPHORUS Studies in the 1960s and 70s led to the conclusion that phosphorus is the key nutrient in the ecology of Lake Minnetonka. An overabundance of phosphorus results in excessive algae and weeds, reducing water