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JUL-28-94 THU 15:03 • FAX N0, 303 9~ 4775 P, 03 DRAFT down gradient. The Rock Creek area is considered a crown jewel habitat for numerous species. The wtiqueness and diversity of habitats found in this area are unpazalleled. Information supplied to date from WAI is insufficient in detailing how WAI intends to preclude alteration of these habitats. Substantial additional information shall be required regarding the hydrology and the flow of water through the pediment. The wetlands that exist along the colluvial slopes are the result of a shallow aquifer drainage from the R~acky Flats Alluvium. Water stored in the alluvium does not penetrate the underlying claysU~ne bedrock. At this contact, the alluvium water moves horizontally and discharges to the sut~face along preferential flow paths. In other areas sandstone lenses may subcrop below the Rock}' Flats Alluvium, These bedrock sandstone lenses may be rechazged from the Rocky Flats Alluvium and have the potential to transmit water to Ute colluvial slopes in a similar manner. The resulting seeps produce wetlands along the colluvial slopes. Removal of the Rocky Flats Alluvium as part of the WAI mining expansion has the potential to dewater the wetlands that exist along the colluvial slopes by removing the subsurface flow paths. In order to fully understand the impacts that mining might have on wetlands located along the colluvial slopes in Rock Creek, WAI should be required to thoroughly investigate the hydraulic conne~.tion between the seeps and the alluvium. The investigation should me es to e gYo~ri~wa r ydrology as a nfu~o f season, heterogeneity of the substrate, and geomorphology. In addition, background sites for Rocky Flats environmental monitoring need to be maintained for 3 - 5 }ears until the Environmental Protection Agency and the Colorado Department of Health approve data collected and added samples can be obtained to fill gaps in the data. Western Aggregates and the Department of Energy at Rocky Flats will be holding a joint meeting with hydrologists and concemed/interested parties sometime during the week of August 1, 1994. The propose of this meeting is the presentation and discussion of the serious hydrologic concerns and patenUal impacts. Highly Sensitive Iiabituts The Rock Creek area comprises a unique interspersion of riparian, wetland and shrub habitats. It is anticipated that the collapse of any one of these habitats will have a rippling~t on the others. Interruption of the ground water flows could destroy the wetlands in Rock Creek, and has the potential to reduce or stop the ground water fed base flow of the entire creek. It is imperative that the hydrology of the azea be maintained either natwally o~manually. Wetland Banking should be a tradeoff considered at the time of reclamation. In addition, Western Aggregates should consult with the Color~~~ F~~ti ~^~ ~~t~~~fe to conduct studie;s under the Endangered Species Act. This act is designed to protect plant and animal resoun:es from adverse effects resulting from development. The act provtdes protection not only to individual plant and animal species but also to the ecosystems on which they depend. Peregrine falcons from two different aeries use the proposed area for forage. The bald eagles that winter at Standley Lake may use Rock Creek as well. There is a significant population of a candidate species, Preble's Meadow Jumping Mouse, known to exist in the Rock Creek area. The propo<.;ed action may trigger a Biological Assessment to consider the impact to this species. In addition, the Ecology Staff has supervised surveys, as required by U.S. Fish and Wildlrfe on the Ute Ladies'-tresses. The initial phase of the survey work will be completed in 1994, but surveys are required at three year intervals after 1994.