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approximately 5000 feet thick. It was formed when the area was submerged under a large inland sea <br />and was deposited with sediment from numerous tributaries. Many mazine fossils are found in the <br />shale deposits today. During Jurassic time, the area was uplifted forming the current Rocky Moun- <br />tains. The main river draining the area was the Colorado River, which has withstood many changes <br />to the surrounding environment over the past few million years. Floods of Pleistocene age formed <br />the gravel deposits which lie on the Mancos Shale around the permit area. The bed of the Colorado <br />Rivet is located on this Mancos Shale less than 1000 feet south of the permit area. On the south side <br />of the River, uplifted massive sandstones of the Dakota Sandstone, Morrison Formation and other <br />olderJutassic rocks are exposed. <br />3. Surface Hydrology <br />The permit area is located on the first shallow terrace above the Colorado River and is very flat (it <br />varies from 4490' and 4495' elevation). The River is approximately 4483' elevation and is located <br />approximately 400 feet southwest of the permit area at its closest point. According to FEMA <br />floodplain maps provided by Mesa County, over 60% of the permit area is within the 100 year <br />floodplain of the River. The floodplain is shown on Map B-1- Environntentai Resources. The sur- <br />face water discussion within the mining plan shows how the floodplain issue will not be a concern <br />for this operation. <br />There are no perennial or intermittent drainages within the permit area or its immediate vicinity. As <br />stated earlier, an abandoned irrigation channel of less than 18" depth is located immediately north of <br />the permit area. This irrigation ditch has been unused for decades and the landowners have no plans <br />to re-habilitate the system. The site naturally drains to the southwest, where a small pond is located <br />between the permit area and the River. This pond is approximately 2.5 acres in size and normally <br />has water, however, the drought of 2002 has left it a muddy depression with no water. Any overflow <br />from this pond goes duectly into the River, located immediately southwest of the pond. <br />The main drainage in the area is Adobe Creek, which is located 1400 feet northwest of the permit <br />area and drains a large area north to the Book Cliffs. It is isolated from the site and cannot be af- <br />fected by it. <br />19 Road Pit 10102 4 <br />