Hearn Gulch Reservoir

Hearn Gulch Reservoir
Name	Hearn Gulch Reservoir
Location	San Juan County, Colorado, United States
Type	reservoir
Inflow	Hearn Gulch Creek
Outflow	Hearn Gulch Creek
Catchment	Uncompahgre Plateau
Area	45 ha
Volume	3,200,000 m3
Elevation	2,350 m

Hearn Gulch Reservoir is a high-altitude impoundment situated on Hearn Gulch Creek in San Juan County, Colorado, United States, created to store runoff for irrigation and municipal supply and to provide local flood control. The reservoir lies within a network of watersheds and mountain basins that connect to the San Juan River, the Colorado River Basin, and ultimately the Gulf of California, and it forms part of regional infrastructure that includes irrigation districts, federal land management, and conservation areas.

Introduction

Hearn Gulch Reservoir occupies a montane basin on the Uncompahgre Plateau and serves integrated purposes across water supply, habitat, and recreation; it interacts administratively with entities such as the Bureau of Reclamation, the Colorado Water Conservation Board, the San Juan County government, the U.S. Forest Service, and local irrigation companies. The site is proximal to communities and landmarks including the town of Silverton, the San Juan Mountains, the Continental Divide, Durango, and the Animas River watershed, and it is subject to water rights adjudication within the Colorado River Compact framework and oversight by state agencies such as the Colorado Division of Water Resources.

Geography and Hydrology

The reservoir sits at approximately 2,350 meters on a tributary network that feeds into the Animas and San Juan rivers, and its hydrology is influenced by snowmelt from the San Juan Mountains, seasonal monsoon patterns linked to the North American Monsoon, and long-term climatic forcing from phenomena like the El Niño–Southern Oscillation, the Pacific Decadal Oscillation, and Arctic Oscillation. Local geomorphology ties to the Uncompahgre Plateau, the San Juan volcanic field, the Laramide orogeny, and nearby drainage basins such as the Dolores River watershed and the Gunnison River system; hydrologic monitoring links to programs run by the U.S. Geological Survey, the National Weather Service, the Colorado River Basin Salinity Control Program, and academic groups at Colorado State University and the University of Colorado Boulder.

History and Construction

The reservoir was conceived in the context of late 19th and 20th century water development that involved mining camps, the Rio Grande Southern Railway, the Colorado Mining Association, the Reclamation Act, and regional irrigation needs driven by agricultural communities around Durango and Cortez. Construction phases engaged contractors and engineering practices influenced by standards from the U.S. Army Corps of Engineers, the Bureau of Reclamation, and design principles referenced in manuals from the American Society of Civil Engineers; project timelines intersect with events like the Dust Bowl era water policy shifts, New Deal programs under the Works Progress Administration, and later modifications prompted by federal environmental legislation such as the National Environmental Policy Act and the Endangered Species Act.

Ecology and Wildlife

The reservoir and its riparian zone support assemblages characteristic of montane and subalpine environments, including interactions among species listed or monitored by agencies like the U.S. Fish and Wildlife Service, Colorado Parks and Wildlife, The Nature Conservancy, and the Rocky Mountain Research Station. Vegetation communities include stands analogous to willows, cottonwoods, and montane meadows that provide habitat for mammals and birds associated with the San Juan Mountains, such as elk populations studied by Colorado State University biologists, mule deer herds, black bears, and raptor species tracked by Audubon Society chapters and partners in the North American Bird Conservation Initiative. Aquatic ecology considerations involve trout species valuable to anglers and researched by hatcheries, genetic studies comparable to those at the Colorado Division of Parks and Wildlife, and macroinvertebrate monitoring undertaken by university ecology labs and citizen science groups like Streamkeepers.

Recreational Use and Access

Recreation at the reservoir includes angling, hiking, birdwatching, and backcountry access that connect to trail networks managed by the U.S. Forest Service, the Bureau of Land Management, and county open-space programs; nearby recreational infrastructure relates to attractions such as the San Juan Skyway, the Rio Grande Southern corridor, and trail systems linking to wilderness areas like the Weminuche Wilderness. Visitor management and permit systems relate to state agencies and nonprofit partners such as Colorado Parks and Wildlife, the National Park Service for regional sites, and outdoor organizations including the Sierra Club and local outfitter associations that provide guiding services and safety briefings.

Management and Conservation

Management responsibilities are shared among local irrigation districts, San Juan County, the Colorado Water Conservation Board, federal agencies including the Bureau of Land Management and the U.S. Forest Service, and conservation NGOs such as The Nature Conservancy and the Trust for Public Land. Planning integrates water rights law rooted in priorities exemplified by the Colorado River Compact, state statutes administered by the Colorado Division of Water Resources, habitat conservation plans like those developed under the Endangered Species Act, and landscape-scale conservation strategies coordinated with academic centers at the University of Colorado and Colorado State University.

Environmental Issues and Impact Studies

Environmental assessments and impact studies have addressed concerns including sedimentation rates linked to historical mining in the San Juan Mountains, legacy heavy metal contamination from mining districts such as Sunnyside and Bonanza, altered flow regimes tied to upstream diversions resembling transbasin projects, and climate-driven hydrologic stress documented by the Intergovernmental Panel on Climate Change and regional climate assessments by the Western Water Assessment. Research collaborations among the U.S. Geological Survey, Colorado School of Mines, Colorado State University, and regional water authorities have produced monitoring data on water quality, aquatic biodiversity, reservoir sediment budgets, and adaptive management plans comparable to those implemented elsewhere in the Colorado River Basin.

Category:Reservoirs in Colorado Category:San Juan County, Colorado