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<br />. <br /> <br />. <br /> <br />. <br /> <br />Drainage Basin <br /> <br />The drainage basin above the Schwartzwalder Mine extends <br />into Gilpin County and has its headwaters in Arapahoe National <br />Forest. The terrain ranges from rolling, grassy meadows <br />surrounded by forest, to extremely steep and rugged mountains. <br />The highest elevation is at 10,540 feet located on top <br />of Thorodin MoUntain. other high points which rim the basin <br />are Mt. Tom (9,735), Centralia (9,740), Black Hawk (9,840), <br />Tremont (10,388), Miramonte, and' Blue (9,400) Mountains. <br /> <br />Much of Golden Gate Canyon State Park is located in the <br />upper Ralston Creek basin which is outlined on the following <br />map. <br /> <br />The drainage area above the study reach is approximately <br />41 square miles determined from a review of USGS 7~ minute <br />series 'maps 'of the Ralston Buttes, Black Hawk, Tungsten, <br />and Central City Quadrangles. <br /> <br />The Ralston Creek basin is a watershed for the Denver <br />Water Board which stores water in Ralston Reservoir downstream <br />of the study reach. <br /> <br />Mapping <br /> <br />A detailed topographic base map for the study reach was <br />obtained from the "Pre-Mining and Mining Plan Map" filed by <br />the operators of the mine with the Colorado Mined Land <br />Reclamation Board (File No. 77/300 HR). The map is a black <br />line print of a pencil manuscript prepared in September 1975 <br />by Kuchera & Associates under contract to Cotter Corporation. <br />The date of photography was August 8, 1975. The map scale <br />is 1 inch equals 120 feet and the contour interval is five feet. <br />___The area of map coverage is shown on the location ~~p. <br /> <br />The map accuracy and datum used were not indicated on <br />this map. Some difficulty in following contours in the <br />vicinity of the channel was experienced but this was not found <br />to be a major limitation. <br /> <br />-3- <br />