Agenda - Council - 02/12/2002 - Laserfiche WebLink

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Potential Environmental Effects '1) Effects on Wet/ands Wetlands serve a variety of functions, including flood control, water purification, shoreline stabilization and erosion control. They also support a diverse array of fish, waterfowl, and other wildlife. Despite their value, wetlands continue to face threats such as drainage for agriculture; filling for roads or other development; and discharge of pesticides, herbicides, and nutrients from domestic sewage. Between the 1780s and the 1980s, Minnesota lost 42 % of its wetlands (Dahl 1990). The City of Ramsey, however, is fortunate to possess wetlands as a dominant feature of the city's landscape. The citizens of Ramsey place a high value on these wetlands and wish to ensure their protection as the city grows. Increased lawn runoff from The Ponds could jeopardize the health of our wetlands by altedng the pH and nutrient balance. The Ponds proposes to add 307 new units to an 60+ acre area adjacent to DNR Wetland 114P. We are concerned that fertilizers, herbicides, and other lawn care chemicals will enter surrounding wetlands through runoff and change the pH or nutrient balance. The pH of water in an aquatic ecosystem greatly influences the distribution and abundance of organisms. Species diversity typically decreases in acid waters by disrupting osmoregulation, increasing toxic heavy metal concentrations, and by reducing the quality and range of food sources available (Begon et al. 1990). Productivity in aquatic ecosystems is primarily limited by the availability of nutrients, especially nitrogen and phosphorus (Begon et al. 1990). Nitrogen and Phosphorus also are commonly found-in lawn care products. If these products enter DNR 114P via runoff, they could easily cause large increases in algae and compromise water quality. Increases in the volume and/or rate of runoff could cause area flooding. The addition of 307 family units to the area will certainly increase runoff in the area. Rate of flow can be controlled through detention ponds and manipulating pipe diameter. Volume of runoff, however,-is much more difficult to control; eventually the water must enter the watershed. A higher volume of runoff could lead to flooding in an area where the City of Ramsey already has a concem for this issue. In January, 2001, the City was investigating maintenance on a' drainage ditch that flows into DNR Wetlands 114P (Strommen 2001). This situation has not yet been resolved, and floods could potentially be made worse by increased runoff from The Ponds. -183-