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Grand River Park Project, M-2006-046 Response to Adequacy Letter of August 1, 2006 6 September 2006 Page 18 jurisdictional wetlands and the riparian fringe of the Colorado River. Based on recent detailed study of wetland and riparian resources on the site, for example, the Mining Plan Map and Reclamation Plan Map have both been revised to include additional setbacks from known resources. The current design of the proposed operation includes adequate safeguards to minimize impacts to Cottonwoods and wetlands that are not necessitated by the efficient recovery of sand and gravel. Jurisdictional wetland areas will be buffered by a no-mining setback at least 25 feet in width. Because the cone of depression during de-watering is too wide to allow for total buffering of groundwater effects without rendering aggregates economically unrecoverable, the applicant intends to recharge wetland areas by cycling clarified water through those wetlands proximate to mining. Martin and Wood Water Consultants, Inc., provided a special analysis of this recharge scheme and determined it to be feasible (see attached letter of April 13, 2006). The Division should note that this recharge plan will facilitate abest-case reclamation scenario but is not based on any known requirement of the Construction Materials Rules; the U.S. Army Corps of Engineers will typically have the final authority to determine appropriate mitigation for wetland impacts, if any jurisdictional impacts are found. Cottonwoods are not regulated as a threatened or endangered species and are not a species of concern in the state of Colorado. Cottonwood trees are not an important food source and have habitat value primarily as a perch for birds of prey, as well as general forest canopy. Snag Cottonwoods, to illustrate, have habitat value in the vicinity of the site, which benefit occurs regardless of the potential for some individual trees to succumb to stresses of various kinds throughout the lifecycle of the tree. And, while the Division notes anecdotal evidence that Cottonwoods are dependent on a shallow groundwater table for soil moisture, the rooting habit of the tree, according to other authorities, does not indicate such sensitivity to variations in soil moisture. According to plant expert Michael Dirr in the Manual of Woody Landscape Plants, the Cottonwood "prefers moist situations along waterways but tolerates dry soils." The applicant submits that the mining plan reasonably minimizes unnecessary impacts during the course of mining, and any impacts that are experienced will be addressed within the purview of the reclamation plan and the performance warranty required for release from permitting responsibilities. 26. The Division will estimate the cost to reclaim the site once the applicant addresses the concerns noted in this and subsequent letters. The Division will estimate a cost to reclaim fhe sife based on the information submitted in the application and responses to adequacy reviews.