11030 7TH AVE SE 2018-01-02 MF Import

IM R 2 H Charles Morgan Associates mx May 18, 1989 to H N Page " 2 HEH the dominant plant species of each vegetation strata are rated facultative or wetter, o x o indicating a prevalence of wetland vegetation. to H Soils in the area are a silt loam with organic material in the upper horizons. The A x 5 horizon is a black silt loam (7.5 YR 2/0) with about 25% organic matter. The B horizon o so is similar but contains slightly less organic matter. A dense glacial till was encountered at between 18 and 30 inures. The color and organic content of the soils classify them as hydric 0 H g N o or wetland soils. ZH The hydrology of the site clearly identifies the area as wetland. The wetland is a H H mosaic of small seeps and depressions. These small seeps surface at the north end of the o CAH wetland and flow in intermittent surface channels south and east towards North Creek. ot 1 ti Between these small channels, raised areas possessing slightly drier surface soils can be Rhh found. The eastern portion of the site may be inundated by flood flows of North Creek. y o ti Groundwater in the wetland is at or above the ground surface for much of the winter and early spring. Indications of standing water to about 4 inches were found in the numerous depressions within the wetland. Surface soil saturation during the summer is likely confined to these depressions, with higher areas of the wetland possessing groundwater at about one to two feet during the drier months. In conclusion, the wetland on the site is a well developed, complex forested system laced with numerous seeps and depressions. PROJECT IMPACTS The site plan dated April 17, 1989 shows the flagged wetland edge and the location of the proposed facilities. As designed, the project does not encroach into the wetland, and includes a 25 foot buffer between roads and structures and the wetland edge. As designed, this site plan follows the primary agency mandate of wetland preservation through .� avoidance, rather than encroachment and mitigation. In this respect, the project is consistent with the goal of wetland preservation. ` In order to ensure that the wetland continues to provide wildlife habitat and hydrologic benefits to North Creek, the following recommendations are given. Depending on the depth of the foundations necessary for the northern structure, some groundwater �� may be encountered during excavation. If this occurs, groundwater should be directed to the wetland and discharged in a dispersal system to imitate natural conditions and avoid interruption of water flow into the wetland. Quantities of water are anticipated to be low, I = as groundwater appears to move primarily from north to south and surface soils within the foundation area appear to be structural. Storm water should be routed through vegetated swales prior to discharge. Secondly, disturbance of soil or vegetation within the buffer should be kept to a minimum. Ideally, the buffer should be clearly identified and fenced prior to construction to avoid encroachment. If encroachment occurs, disturbed areas should be replanted with