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<br />1'I1'!>~l.'(\9 <br />l')~J..... U .I <.. <br /> <br />Wetland Mitigation <br /> <br />A- 10 <br /> <br />A.3.2 On-Site Mitigation of Direct Impacts <br /> <br />A.3.2.1 Hard points <br /> <br />Hard points are very effective at controlling erosion, while at the same time minimizing <br />the impact on existing wetlands and riparian vegetation. Adverse effects of hard points <br />will be limited to the footprint of the structure itself. Typical spacing of hard points for <br />this project is about 50 feet on center. Assuming a 10-foot lateral footprint, this means <br />that 80% of the protected bank area is not directly impacted by rock placement. Between <br />the hard points, vegetation will be left alone. By controlling erosion at the bends, <br />wetlands in spaces between hard points can actually improve, as the erosive power of the <br />water is controlled and converted to slower eddies. <br /> <br />The total footprint of proposed hard points in wetlands is 0.14 acres. The Sponsors will <br />allow and encourage vegetation to grow through the hard points as they accumulate fine <br />sediment from the river. This will provide partial mitigation at the point of impact. <br /> <br />In addition, the 0.14 acres of direct impact will be mitigated, on a I-for-l basis, at the <br />Wetlands Mitigation Site discussed below. <br /> <br />A.3.2.2 Revetment sites <br /> <br />Revetments are more intrusive on wetlands than are hard points, since they will blanket <br />the entire bank being stabilized. However, this does not necessarily mean that the <br />underlying wetland will be lost. If revetment stones are mixed with soil, and vegetation <br />allowed to grow through the riprap, the bank can retain many wetland values. Indeed, <br />many sites that Greystone delineated as wetlands were riprapped in the past, yet over the <br />years have re-established wetlands functions and values as vegetation took hold. <br /> <br />Wherever riprap affects existing wetlands, the Sponsors plan to encourage wetland re- <br />growth by mixing rock with soil as or before it is placed, and where necessary, spreading <br />a layer of topsoil over the rocks. These areas will then be seeded and sprigged, and <br />allowed to regrow naturally. This will provide a certain amount of "on-site" mitigation, <br />and will minimize the overall impact. <br /> <br />Revetment impacts on wetlands will also be mitigated, on a I-for-l basis, in the Wetland <br />Mitigation Site. The total wetland impact of all proposed revetment sites is 0.81 acres. <br /> <br />A.3.2.3 Monitor sites <br /> <br />The impacts of potential stabilization at Monitor sites, as well as the amount of on-site <br />mitigation, will be determined by the type of stabilization that is ultimately installed. On- <br />site mitigation of wetland impacts will follow the same procedures discussed above for <br />revetment and hard point sites. <br /> <br />AS Lateral Hydropower Project <br /> <br />July 2000 <br /> <br />