Upper Los Pinos Water Quality Report

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quality system. Because of the connection bet`s-een the upper and lower watersheds, a lvatershed plan is needed to understand these inten-elationshipswrth respect to the water-quality needs of the people and communities within the watershed. Several states have enacted regulations requiring watershed plans. In Colorado, Senate Bill 02-087 was adopted by the 2002 Colorado General Assembly and establishes the Colorado Watershed Protection Fund. The legislative declaration states: The general assembly hereby finds and declares that the natural heritage and quality of life in Colorado are of fundamental importance to the citizens of the state, and the protection of this natural heritage and quality of life are essential to sustain economic development in the state. Watershed plans consist of the evaluation of available data in awatershed--surface water, ground water, physical, biological, and chemical. These data maybe compared to standards, such as water-quality standards. or the data mav be compiled and presented to the public for a description of watershed health. Watershed plans begin with the identification of the hydrologic unit codes that comprise the watershed. Hydrologic unit codes in Los Pinos River «,atershed include 1408010113, 1408010114, 140801011, 1408010116, and 1408010117 (fig. 1). These hydrologic unit codes consist of subbasins or drainage basins that drain into conunon tributaries or reaches of the river. Frequently, the slopes, soil ripes, and vegetation cover may be similar within a hydrologic unit code. The watershed plan for the Los Pinos River ~yatershed as a ~yhole will be addressed through incremental efforts. First, this report compiles data for development of a ~yatershed plan for the upper Los Pinos River watershed (upper basin). The upper basin includes the communities of the Vallecito Reservoir area, the forest lands, and wilderness areas. The lower Los Pinos River ~yatershed may be addressed in future efforts to include agricultural communities, housing developments, energy ei-traction areas, quid the Southern Ute Reservation. All of the communities are connected through the iliteractions of Los Pinos River watershed. Purpose and Scope The purpose of this report is to compile water- qualit<--data for the upper Los Pinos River watershed and provide limited interpretations. Characteristics and trends ofiyater-quality data are described. and certain parameters that eiceed ~yater-quality standards are described. Suggestions are made for continued moiutoring and for the development of a «atershed plan. No new data. were collected related to the hydrology or water qualit<- of the watershed. This work was done as part of an effort by the San Juan Resource Conservation and Development Council (San Juan RC&D) to assist local communities «ith natural resources projects. The work was funded by a grant from the Colorado Watershed Protection Fund. Compilation of available data began in October 2004 and was completed in December 2004. Report «riting «as completed in January 200. Electronic files of the data base, digital maps, and copies of this report are available at the San Juan RC&D office, 31 Suttle St., Durango, Colorado, 81303, (970) 2~9-3287. PHYSICAL SETTING, CLIMATE, AND HYDROLOGY The upper Los Pinos River watershed encompasses 70 min of rugged mountainous terrain in the Sa« Juan Mountains of southwestern Colorado. Altitudes range from 7,600 ft below the Vallecito Dam to 14,082 ft at the summit of Windom Peale ili the Weminuche Wilderness (fig. 2). Land o~yneiship in the Los Pinos River watershed is diverse. Land ownership includes the Federally owned San Juan National Forest and Bureau of Land Management lands, Bureau of Reclamation land near the reservoir-. and the Weminuche Wilderness. State lands include land o~~ned by the Colorado State Land Board ("State Sections") which are reserved for wildlife habitat. Private lands include agricultural land, to«7iships, and housing developments. The Southern Ute reservation encompasses much of the lower watershed. There are private inholdings within the reservation that include agricultural lands, townships, and housing developments. Energy- production (mostly coal-bed methane eitraction) occurs throughout the lo~yer ~yatershed related to the coal beds of the Sale Juan Basin. The climate of the area is typical of the margins of semi-arid enviromnents bordering large mountain chains. Annual precipitation at Vallecito Reservoir averages 26.2 inches; the average sno~yfall at the reservoir is 118 inches. although sno~yfall in the moun- tains can be much greater (for ezarnple, annual snow- fall in Silverton, Colorado. averages 154 inches). Mean monthly temperatures range from 27°F in whiter to 58°F in summer (Western Regional Climate Center, http://~~~~--w.wrcc.dri.edu/, accessed January 20, 2005). ~' ~ SouthwestHydro-Logic 3