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.. r • <br />United States Natural Resources <br />Department of Conservation <br />Agriculture Service <br />----------------------------------- <br />August 17, 1995 <br />Mr. John Ungefug, P.E. <br />Southway Construction Co., Inc. <br />117 White Pine Drive <br />Alamosa, CO 81101 <br />Dear Mr. Ungefug: <br />USDA Service Center <br />2295 State Avenue <br />Alamosa, CD 81191 <br />R~t^.F~vF~ <br />~Cj ~ ~ 1995 <br />D\v`5\ol\ p1 \Vanet°" a AGO o~.7 <br />On July 18, 1995 I examined the proposed site for the fill soil <br />borrow area located in the NE1/4NW1/4 Section 8-T37N-R10E, Alamosa <br />County. The site is currently rangeland with greasewood, inland <br />saltgrass, alkali sacaton and other traces of (orbs and grasses. The <br />dominant soil is a Corlett-Hooper Complex, undulating. Slope varies <br />from 9-15 percent. The Corlett soil occurs on the sand dunes which may <br />be 15-29 feet in height while the Hooper soil occurs between the <br />dunes. The surface texture ranges from loamy sand to clay loam. Both <br />the Corlett and Hooper sails have strong alkaline characteristics. <br />To prevent groundwater contamination I first recommend you <br />determine the groundwater elevation prior to mining operations to <br />ensure excavation will remain two feet above the groundwater table. As <br />you are aware the bottom of the existing borrow pit is fringed with <br />perennial hydrophytic vegetation, i.e. Baltic rush and arrowgrass, <br />which suggests that future excavations should not go as deep. Drilling <br />core samples when the groundwater table is at its highest will help <br />you determine the depth to water. <br />Secondly, when borrow pit operations begin, wind erosion <br />potential is very high. This can pose a safety hazard for Highway 160, <br />one-half mile north of the site, and health problems to nearby <br />residents. Some preventive measures to reduce wind erosion include: <br />1> erecting snowfences on the south and west borders of the exposed <br />area to decrease the unsheltered distance and reduce the soil from <br />blowing off the site; and 2) reduce the mined strips from 10 acres to <br />5 acres with revegetation occurring immediately following the opening <br />of a new strip. <br />Third, to successfully re-establish vegetation on this site, <br />stockpile a minimum of six inches of clean topsoil (the Alamosa County <br />Soil Survey indicates Corlett and Hooper series have topsoil in the <br />top seven inches). The topsoil must have sufficient depth and <br />potential fertility to support the new grass seeding. The site needs <br />to be reclaimed to 3:1 slopes or flatter. The topsoil should be spread <br />evenly back over the site and drilled to grass between November 1 and <br />April 15. <br />