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·•~ 5.3 INVENTORY A1'ID AsSESSMENT OF WETLANDS <br />S .3. l Wetland Inventory <br />As stated earlier, the City's objective is to protect, enhance, and/or <br />restore wetlands that may be directly affected by runoff as development <br />and redevelopment occurs. Therefore, only those wetlands located <br />within 20 feet of a proposed or existing stormwater outlet pipe were <br />inventoried and mapped as part of the SWMP. This inventory also served <br />as the base of information for development of other parts of the wetland <br />management plan. <br />The wetlands inventoried for this SWMP are listed in Appendix I and are <br />shown on the SWMP System Map. <br />S .3 .2 Stormwater Susceptibility Assessment <br />The Guidance For Evaluating Urban Storm Water and Snowmelt Runoff <br />Impacts To Wetlands was the source material for rating a wetland's <br />susceptibility to runoff. Potential impacts associated with storm and <br />meltwater runoff include fluctuation in water levels (bounce) within the <br />wetland, the duration of inundation at the varying bounce elevations, <br />and the quality of the water being directed to the wetland. A given <br />wetland's susceptibility to runoff is dependent on the wetland type, and <br />the characteristics and quality of its plant community. <br />As an example, a sedge meadow, which likes a particular hydrologic <br />regime is much more susceptible than a floodplain forest, which depends <br />on fluctuating levels of water associated with seasonal flooding. Also, a <br />wet meadow with a variety of grasses and flowers is more sensitive than <br />one dominated by reed canary grass. The runoff susceptibility rating for <br />each of the evaluated wetlands is indicated by color-coding on the <br />system map. The ratings described in the guidance document are <br />❖ Highly Susceptible <br />❖ Moderately Susceptible <br />❖ Slightly Susceptible <br />❖ Least Susceptible. <br />·'·· <br />Further discussion on susceptibility and associated wetland community <br />descriptions, modified from the Guidance For Evaluating Urban Storm <br />Water and Snowmelt Runoff Impacts To Wetlands, is presented in <br />Appendix H. Each susceptibility rating cate·gory describes different <br />wetland types, including plant communities and hydrology. <br />City of Orono <br />c::,,,.,:..,,,,,.,,. IAI-"'--• .., _________ L ,.., <br />5-3