Orono Community Management Plan 2020-2040

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City of Orono Surface Water Management Plan February 2019 7 ORONO – SURFACE WATER MANAGEMENT PLAN 2 Physical Environment This section describes the physical setting within Orono and includes climate, precipitation, geology and soils information. The Minnesota statute that prompts Cities to prepare local surface water management plans requires a land and water resources inventory section. The information presented here is intended to augment information provided by the watersheds in their own plans. 2.1 CLIMATE Orono has a Humid Continental Climate, typified by considerable seasonal temperature differences, hot and humid summers, and cold to extremely cold winters, and is located in USDA Plant Hardiness Zone 4b. Native vegetation has a seven month growing season (April to October) and crops have a five month growing season (May to September). Two-thirds of the precipitation occurs during the crop growing season, with a total of almost 31 inches annually. Refer to Table 2-1 for a 30 year average of temperature and precipitation Data. Refer to Point Precipitation Frequency Estimates provided by the National Oceanic and Atmospheric Administration (NOAA) Atlas 14 for estimated precipitation amounts for specific frequencies, durations, and locations at the link listed below. https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html?bkmrk=mn Table 2.1: 1981-2010 Monthly Climate Normals (MPLS Flying Cloud AP) Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Maximum Daily Temperature (°F) 23.6 29.1 40.6 57.4 69.7 78.7 83.1 80.6 71.5 58.5 41.3 27.1 55.2 Mean Daily Temperature (°F) 15.4 20.3 32.2 47.2 59.3 69.0 73.4 70.9 61.9 48.9 33.9 19.5 46.1 Minimum Daily Temperature (°F) 7.2 11.4 23.9 37.1 48.9 59.2 63.8 61.3 52.2 39.3 26.5 12.0 37.0 Average Precipitation (in.) 0.74 0.53 1.77 2.89 3.60 4.33 4.20 4.36 3.54 2.35 1.74 0.80 30.85 Source:National Oceanic and Atmospheric Administration 2.2 GEOLOGY The geology of the region surrounding Orono is the result of two different geologic processes: ·Warm, shallow seas covered the area and created conditions for the formation of sedimentary rocks. These formations are present as bedrock in the area. ·Glacial processes have resulted in the development of surficial geology, and therefore, the current landforms. The geology of the City can be generalized characterized as over 100 feet of glacial till/drift overlying sedimentary bedrock. BEDROCK GEOLOGY The bedrock units present beneath the City are marine sedimentary rocks primarily of the Upper Cambrian to Middle Ordovician ages (450 to 500± million years old). Ranging from deeper/older bedrock to relatively shallow/younger bedrock, the geologic units present include the St. Lawrence/Franconia formation, Jordan Sandstone, the Prairie du Chien group, and St. Peter Sandstone. SURFACE GEOLOGY Glacial influence on this area began around 2.5 million years ago and continued until about 10,000 years ago. However, the landscape seen today was almost entirely influenced by activity between 30,000 and