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Lorertcim Canvon Mine -Surface Water Technical ReDOrr • Statistical Data Reduction Methodology The analytical results and field parameters were plotted to determine water types. Mean, median, and standard deviation values were generated to determine the accuracy and precision of the data. Major cations and anions were plotted on trilinear (Piper, 1944) and Stiff diagrams for comparative analyses of water types. SECTION 3 -RESULTS AND DISCUSSION The Lorencito Canyon Mine is located on tributaries south of the Purgatove River, 2.7 mites east of Weston, Colorado. The headwaters of the Purgatoire are located eighteen miles west of the permit area, and the river is draining 403.7 square miles of watershed at its confluence with Lorencito Canyon. The Purgatoire is a tributary of the Arkansas River. Watershed Delineation and Drainage Basin Characteristics Watersheds in the area display dendritic drainage patterns characteristic of flow through relatively flat-lying, generally uniform geologic features (Leet, et al., 1982). Eleven drainage basins are within the permit boundary or received drainage from within the permit boundary. All of these • drainages are included in the Purgatoire River drainage. The watersheds contain both forested and open slopes. Drainage basins identified in the study area range from 0.9 m~ to 403.7 mi'-. Drainage basins within the permit boundary range from 0.9 miz to 3.2 miZ for Jeff Canyon and Cow Canyon, respectively. Within the study area, Cow Canyon and Lorencito Canyon are the principal drainages. Although several small side drainages exist, Cow Canyon is a fully enclosed basin, and receives no waters from outside the basin or from contributing drainages. Lorencito Canyon is the principal drainage in the permit area and receives waters from Jeff, Chimney, Puertecito, Little Pine, Bonita, Alamosa, and Little Alamosa Canyons. All of these drainages eventually empty into the Purgatoire River. The lower reaches of Cow Canyon and all of Lorencito can be described as mature channels formed in alluvial valleys. The remaining drainages can be described as generally young channels, characterized by steep sides, with "V" shaped valleys with steep gradients (Lett, et al. 1982). Characteristics of the major drainages connected to and within the project area are detailed in Table SW-4. • sw.475\Deccm6er 4, 1996 11