Agenda - Parks and Recreation Commission - 11/18/2004

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APPENDE~ A The Geotog3, of MississipPi West Anoka County's geologic history is rich in glacial activit-y. The most important glacial movement to the present landscape formation of/~fississippi West Regional Park was the Grantsburg subtobe (USDA, 1977). The Grantsburg sublobe exzended to the northwest from the southerly expanding Des Moines lobe. As thc glacier proc~ded it blocked the original Mississippi River channel, which caused the river to floTM into the St. Croix River Valley. Eventually, the river began to shift southwesterly until it finally arrived at its present course. The Mississippi River d~osited sands and gravel across the landscape as its course m/gated. Mississippi West Regional Park is located on these river-depos/ted sands.. The Five Soil Forming and Community Type Factors Parent material The parent material is the mineral base that exists .upon which the soils form and the vegetation flourishes. The parent material of the soils at Mississippi West is °utwash sands. In general, this parent- material ~ves these soils a very low available water hOlding capacity, and natural fertility. These sandy outwash soils are highly susceptible to wind.and water erosion if they are unvegetated. Climate The climate influences the development of the soils m many ways including depth'of leaching due to excess precipitation. Vegetative types in this area can only thrive with a certain temperature and/or rainfall patterns. The climate of Anoka County mists of hot summers.and cold'wmters. The mean wirrmr temperature is 13.3°F and the mean summer temperature is 67.6°F. Precipitation is the greatest m the summer where 21.5 roches is the average. This accoums'for about 75% of Anoka County's ann.ual precipitation. Biolog3' All of the organisms that live in or on the soil influence ~ development. Veg.~ta. tion ~rongty affb~ the fommtio'n of soil throu~ subsoil to surface nument transport, lea on the surface as residues or near d~e ~uface as roots. The native vegetation of the mainland is pnmarity roll prairie grasses, oak sa,,zmmahs, and oak Woodlands. The native vegetar_ic~ on the islands and the shoreiine is deciduous 33