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City of Orono <br />Surface Water Management Plan February 2019 9 <br />Group D – These soils have very slow infiltration rates ranging from 0 to 0.05 inches per hour when <br />thoroughly wetted. Group D soils are typically clay soils with high swelling potential, soils with high <br />permanent water table, soils with a clay layer at or near the surface, or shallow soils over nearly <br />impervious material. <br />Dual Hydrologic Soil Types – These include A/D, B/D, and C/D. These soils behave like D soils when <br />wet, and act like A, B, or C when dry. <br />The predominance of Type B soils in upland areas indicates moderate infiltration capacity. However, the <br />preponderance of Type D soils around wetlands and lakes indicates low infiltration capacity adjacent to <br />many of the City’s water bodies. For planning purposes, infiltration rates listed in the Minnesota <br />Stormwater Manual should be referenced. For design purposes, actual infiltration testing of site soils <br />should be performed to determine permeability rates. <br />2.4 SURFACE WATER RESOURCES <br />LAKE MINNETONKA <br />Surface water runoff from Orono drains to Minnehaha Creek’s upper watershed (the entire Lake <br />Minnetonka drainage area) and flows through parts of three MCWD subwatersheds: <br />1.Stubbs Bay Creek <br />2.Painters Creek <br />3.Long Lake Creek <br />Lake Minnetonka and its bays have a surface area of 22.6 square miles, and are listed as one of the <br />Minnesota Department of Natural Resources (DNR) Protected Waters. The lake drains an area of <br />approximately 126 square miles, has a maximum depth of 101 feet, and has an outlet/surface elevation of <br />approximately 930 feet. <br />WATER COURSES <br />There are six streams identified in Orono’s shoreland ordinance as protected waters within Orono. Five <br />of these streams are identified on the protected waters inventory for Hennepin County: Long Lake Creek, <br />“Wolsfeld” Creek, Tributary to “Wolsfeld” Creek, Stubbs Bay Creek and Painters Creek.Table 1.3 <br />identifies these streams and their locations.Figure 6 provides mapping of DNR Public Waters. <br />LAKES <br />There are 12 lakes identified in Orono’s shoreland ordinance as protected waters within Orono.Table 1.2 <br />identifies these lakes and their Public Classification, Ordinary High Water Level and Protected Waters <br />Identification Number. <br />These lakes are kettle lakes that were formed by large blocks of ice that became stationary while glacial <br />deposits settled around them. As the ice melted, they filled the “kettles” they had formed. As a result of <br />natural processes that have occurred since the end of glacial activity, mineral sediments and decomposing <br />plant materials were deposited in these lakes and have created their current configuration. They vary in <br />depth and shape, ranging from roundish to very irregular and from less than ten feet in depth to a deep <br />spot of 88 feet in Browns Bay on Lake Minnetonka. <br />WETLANDS <br />As stated above, a large percentage of the wetland basins in Orono developed in the depressions created <br />by glacial processes. Wetlands also occur in the nearly flat, sometimes extensive shoreline areas of Lake <br />Minnetonka. These are also considered depressional wetlands. According to Minnehaha Creek <br />Watershed District’s completed functional assessment of wetlands, the dominant wetland types within <br />Orono are shallow emergent marshes.