02-19-2002 Planning Packet - Laserfiche WebLink

Home Browse Search

In addition to the unnamed ditch that enters the property from the west, a single wetland (wooded, scrub-shrub swamp) was identified. This was located in the southwest quarter of the property and will be unavoidably impacted by the siting of the new fire station. The wetland identified on the property is dominated by mature black willow (SalLx nigra), red-osier dogwood {Comus stolonifera), and common buckthorn {Rhamnus cathartica). Fringe species include eastern cottonwood {Popitlus deltoides), tanarian honeysuckle {Lonicera japonica), prickly ash (Zxmthoxyium americanum) and common buckthorn. Herbaceous vegetation was sparse, but included reed canary grass {Phalaris arundinacea), an unidentified woodland sedge {Carex sp.), unidentified ferns, and ground ivy {Glechoma hederacea). Common buckthorn was a dominant plant throughout most of the upland and wetland areas. Soils in the wetland were composed of dense, black clay (2.5Y2.5/1). Some higher chroma inclusions were also observed and appeared to be the result of past disturbance. At approximately 14 inches, the soils changed to massive black clay (2.5/N) with no other colors being observed. Within the wetland areas, there were inclusions of disturbed soil (2.5Y4/4 and 2.5Y5/5) that displayed distinct mottling (7.5YR4/4) that may have been masked by the darker components. Organic content of the soils was very high within the wetland boundary. Heavy dark clays dominated upland soils. Higher chroma inclusions were also observed in the upland soils, but the frequency and contrast of mottling was less than in the wetland samples. Organic content was also less in the upland soil samples. The Hennepin County Soil Survey has mapped the site as Glencoe silty clay loam. Minnetoka silty clay loam, and Shorewood silty clay loam. The obser\'ed soil profiles were similar to the mapped soils, with the exception of the disturbed areas. Minnetonka and Glencoe silty clay loams are identified on the Hennepin County hydric soils list. Hydrology was not observed within the top 18 inches in either the wetland or upland samples. This may oe due to numerous factors including the abnormally dry fall or start of the winter season. Because of the time of year the delineation w as conducted, hydrology was assumed within the area of hydrophytic vegetation exhibiting hydric soil. Secondary hydrologic indicators including drainage patterns, and shallow and exposed roots suggest hydrologic conditions in the wetland area. The wetlands on the remainder of the site are restricted to the areas between the lop of the bank along the drainage ditch. This drainage ditch ha: a very shallow gradient and low banks on the west half of the property, but has become more deeply fissured as it flows east. The Minnehaha Creek Watershed District Permit Application City of Orono, Minnesota A-LONGL0204.00 Page 4