Upper Los Pinos Watershed Report

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Rainfall Runoff, Flood Hazards, and Water-Quality Data for the Upper Los Pinos River Watershed, Southwestern Colorado, 2006 By Winfield G. Wright Certified Professional Hydrologist INTRODUCTION The upper Los Pinos River watershed (Figure 1) appears to be remote and isolated from any harm. The forests, streams, and lakes that are cherished by hikers, boaters, fishermen, and hunters seem permanent and irreplaceable. Views of the San Juan Mountains from Vallecito Reservoir rival the views of scenic mountain chains in the world (see cover photo). The watershed, however, is experiencing environmental stresses due to wildfires, recreational use, housing developments, and atmospheric deposition. The Missionary Ridge wildfire of July 2002 burned over 70,000 acres of forest and destroyed 56 homes in the areas between Durango and Vallecito Lalce. Following the wildfire, flash floods and debris flows impacted the Vallecito Lake community where homes, businesses, and roads received measurable damage (Figure 2). The Bear Creek wildfire occurred during August 2003 in the upper Vallecito Creek watershed, a maj or branch of the Los Pinos River watershed. Managed as a "Wildland Fire Use" that allowed the fire to burn naturally, more than 1,800 acres of wilderness were scorched. The burned terrain consisted mostly of steep slopes above 9,000 ft elevation in the Weminuche Wilderness. During August 2003 following the wildfires, there was a fish kill in Vallecito Reservoir when 1,000's of kokanee salmon and trout were found floating dead in the lake. Low dissolved oxygen (DO) concentrations in the lake were blamed for the fish kill, but there was no monitoring of lake water quality occurring at the time to indicate whether it was low DO, high metals, or something else. Housing developments crowd Vallecito Creels along its banks north of the reservoir. During October 6-7, 2006, rain fell on an early snowpack, and the high flows in Vallecito Creek almost caused severe damage to houses and property (Figure 2). Almost, that is, because if the rain had continued for a few more hours, there might have been severe flood damage to houses and roads in the Vallecito Creek community. Before the wildfires occurred, the State of Colorado had been compiling data for mercury in fish tissue in Vallecito Reservoir. Slowly over the years, the mercury concentrations in predatory sport fish (northern pike and walleye) had increased to the point of issuing a warning to the public. In early summer 2006, the Colorado Department of Public Health and Environment issued a press release that warned of fish consumption from the lake due to high mercury concentrations. Signs were posted around the lake, and public meetings were held. The citizens of the Vallecito community were understandably upset. Concerns were voiced that the mercury might be sourced from coal-fired power plants located in northwestern New Mexico. To quote Jay Powell, Chairman of the Vallecito Lake Community Council, "we moved here for clean air and clean water, and it's all falling down around us." The community at Vallecito Lake consists of people who are concerned about the upper Los Pinos River watershed. Since 1997, the Volunteer S ~~.