REV106403 - Laserfiche WebLink

Home Browse Search

JUN-29-94 WED 15;24 CITY BOULDER OS/RE FAX N0, 3034429 P, 04 The present surface water hydrology plan is to retain all nmoff in the pit sites until the mined lands have been n:vegetated. The existing riparian azeas will not survive this disniption of their water regime. Sui.-face runoff should be not retained. Instead, it should be released at historic rates and locations aft+:r each storm event to support these riparian areas. Grou ndwater- With the present mining plan to excavate to the top of the bedrock (pierre shale), this will evaporate any groundwater or vadose water. (Augmentation water should be provided to replace this evaporated subsurface water.) The ripazian plants will not survive this undercutting of this water system. There are also existing wet areas, seeps, along all these valleys. Undercutting or dewatering by mining will destroy these seeps and their native ripazian areas. A plan to prevent the disruption of groundwater flow to the present riparian azeas should be developed prior to approval of this application. Groundwater Contamination Testing The application needs to update the available information concerning groundwater contamination in the application area. The application only referred to 1991 Rocky Flats Plant groundwater testing. No data was made available of these tests or other updated testing for our review. Proposed Reclamation Seed Mix The proposed seed mix is generally good, but we would request the following changes be made: Eliminate the forbs species from the seed mix until after grass has become established in the area. A noxious wed problem is already present; if herbicides are used, then the forb component is likely to be lost anyway. Forbs can always be added to the azea later. The one exception that might be considered is anitrogen-fixing native legume if soil 'N' is a problem. Eliminate Poa pratensis and Poa compressa from the seed mix. These are weedy species that will show up anyway. Substitute needleandthread, green needlegrass, mountain muhly, and junegrass, and boost the amount of western wheatgrass and little bluestem. We appreciate this opportunity to review the application material and provide to you our comments and concerns. ]3owever, the Boulder Open Space Staff will be recommending to the Open Space Board of Trustees and the Boulder City Council that we should oppose this mining application for the reasons outlined above. Sincerely, lenn D. Ca~rriere, P.E. Project Manager ce: Jim Crain, Director Delart: Wheeler, Deputy Director Tamar a Nauman Cindv Owsley, Boulder County Pazks and Open Space