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<br />Wetland mitigation targets a constructed to excavated ratio of 1.5:1 for project duration. <br />Constructed wetlands at the reclaimed site will consist of about 16.5 acres, more than 1.6 times <br />the pre-mining wetland acreage of 9.8 acres. Constructed wetland environments are designed to <br />replace functions and habitat of lost wetlands. <br />3.1 Type of Habitat to be Created/Enhanced/Restared <br />Constructed wetlands will consist of free water surface systems with bench substrate hydraulically <br />connected with river groundwater. Bench elevation will be placed approximately 2 feet below <br />river groundwater elevation based on adjacent river surface during ordinary river stages. These <br />stage elevations vary across the site and correspond with river gradient, approximately 7.7 feet <br />per mile in reach adjacent to site. Average river water-table elevation is assumed to equal <br />bankfull elevation minus 6 feet based on observed site-specific conditions. Bench placement <br />within this water regime will help ensure wetland hydrology for sustaining functional systems. <br />Bench surface will slope approximately at a 1% grade from mid-point upward towards shore and <br />downward towards the toe (Appendix B, DS-2). The sloping surface will provide a wider range <br />in bench elevations where the saturated water regime can be intercepted. This low-gradient <br />surface is typical of emergent wetland basins and will increase diversity of vegetation growing <br />along this transitional zone, from a wet meadow groundwater habitat (water table 0 to 1 foot <br />below surface) to an emergent habitat (water surface 0 to 1 foot). <br />Excavated pit will be opened to the river upon completion of the pit (Appendix B, RP-1). The <br />river inlet will be a Texas Crossing, designed for backwater fishery enhancement by creating <br />flooded bottomland and riverine habitat. Water will pass through structure for the duration of <br />high water flow during the spring. This structure will also function as a diversion channel during <br />flood events and help dissipate floodwater in a localized area. The outlet will consist of 5 <br />channels (see Appendix B, DS-2). <br />3.2 Function and Values of Habitat to be Created/Enhanced/Restored <br />Constructed wetland habitat is designed to replace value of lost natural wetlands. Placement of <br />these systems into the proper hydrologic regime could actually increase wetland value above that <br />of replaced indigenous wetlands. Constructed wetland functions include wildlife habitat, <br />storage/conveyance of flood waters, and filtering of sediment and contaminants from runoff prior <br />to discharging into river. <br />3-1 <br />