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<br />!!il17i11 <br />v....,--. '.). <br /> <br />Wetland Mitigation <br /> <br />A- 12 <br /> <br />A.3.4 <br /> <br />Indirect Impact Mitigation Plan <br /> <br />The Corps has indicated that it is not acceptable, from an impact mitigation perspective, <br />to assume that new wetlands will be naturally regenerated on the channel margins (See <br />Section III.I above). The applicants suggested a "contingent" mitigation plan that would <br />be ready to implement if and when adverse impacts were observed. Ultimately, the <br />Corps determined that it wanted to see all indirect widening impacts mitigated in advance <br />of project operation. To the extent the impacts are ephemeral as predicted by the <br />Wetland Consultants, then a substantial benefit to system wetlands will have been <br />realized. However, to the extent such beneficial predictions are not realized, then the <br />project will have mitigated, in advance for all wetlands impacts regardless. <br /> <br />The Applicants have agreed to accept this proposal. Following are details: <br /> <br />A.3.4.1 Site acreage, identification and locations <br /> <br />The total erosive impact of project operation is predicted to be 36, 45.6 or 56.1 acres of <br />wetlands (750, 850 or 950--cfs project). Of this amount, 6.6 acres will be compensated <br />for at the Wetlands Mitigation Site, leaving a potential requirement for 29.4, 39, or 49.5 <br />acres of additional indirect mitigation. Prior to commencement of project construction, <br />Sponsors will identify specific, indirect impact mitigation sites that total this 29.4, 39 or <br />49.5 acres. Sponsors will attempt to spread these sites across at least 7 of the 15 <br />Oreystone-identified reaches, so that mitigation is performed within one reach of any <br />impact2. <br /> <br />In addition.to the specific mitigation sites, Sponsors will attempt to replace lost <br />cottonwoods and woody/riparian vegetation as close to the impact as possible. In most <br />cases, this should mean replacement within a few hundred feet of the impact. Sponsors' <br />ability to do this exactly on-site will, however, be influenced by landowner permission <br />and site-specific limitations. If precise, on-site mitigation is not practicable, then woody <br />species replacement will occur at the next closest indirect impact mitigation site. <br /> <br />A.3.4.2 Site design and implementation <br /> <br />Monitoring (See Section 11.4 of this plan document) will indicate if and when a net <br />adverse effect to wetland and riparian resources has occurred. The analysis associated <br />with the monitoring effort will also determine the wetland functions that have been lost, <br />using HOM, HEP, WET or a similar Corps-approved methodology. Upon recognition of <br />a net loss, the Applicants will notify the Corps. If the Corps determines that additional <br /> <br />Greystone's reach boundaries were based largely on watershed features, such as diversions and stream <br />confluences. The wetland types found along the river are relatively uniform, and do not exhibit <br />significant reach-to-reach changes. Mitigating in a reach adjacent to the impact should still preserve <br />the potentially lost function. <br /> <br />AS Laterai Hydropower Project <br /> <br />JUly 2000 <br /> <br />, .' <br /> <br />. <br /> <br />L.',! <br />. k"'C'.... . "'k,\i <br /> <br />"" <br /> <br />.&' ~ ' <br />