04-19-2004 Planning Packet - Laserfiche WebLink

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^ 5.2 Impacts to Wetlands with the passage of wetland protection legislation, ofxl cors^fuctjon of poods for runoff rnorxjgemenr. the rate of degradatlor from utxan development has been greatly slowed However, witn iotonsive land development, ogriculturol production, ond housekeeping practices m developed areos. degrodation of wetlonds ccntnues. TT'e focus of recent wetlord legislation, policy, ond practice hcs been to preserve the functions, values, and overoll qual*ty of wetlands by fnhirrizng poo- woter quality ond unmonaged quantities of runoff cssocicted w *h ac'o. uroon impacts. ^ 5.2.1 Water Quality Impacts Water quality plays a significant role in the overall quality of a wetland ^en the quality of incoming water declines, the plant comm jnty may degrode to fewer of spedes and retoin only species tcierort cf high nutrient and secflment ioods. A degraded plant commur^ty results o less valuoble ecosystem in terms of biodiversity, habitat, and aesthetes. There are two primoiy factors that effect the quality of runoff enterlnc wetlond. and therefore to overall woter quality within the wetand: 1. phosphorous, as the primary nutrient of concern 2. secHmentatioa resultir^g from erosion of soil. 5.2.2 Water Quantity Impacts Recent surface water management plans have protected wetlands from nutrients but not from fluctuotion of woter elevation (bounce) or du'crion of inundation, in fact, it was corrwDn to use wetlands to reduce floodina potential by sang pipes to maximize bounce and duration. The findings of the (State of Minnesota) Storm Water Advisory Group were published in a document called Gdoance For Fvahjot'ng U^n Sterm Water and Sryowrr^t Runoff Impacts To Wetlands (1994). The findings Indicated that there Is a broad range of toterar.ee to bounce and duration among different wetland types. And to a lesser extent, the ^ attributed to the characteristics and quality of Some wetlands (e.g.. bogs and fens) are sensitive to any disturbonce and vnll show sgns of degradation with even low-levei inputs of runoff Cc^verseiy. some wetlands (e g., floodplain forests) ore better adopit to handle fluctuating woter levels often associated with runoff aiyofarono