Projects by Discipline / Water Resources Planning and Management

Yampa River Basin Comprehensive Water Management Studies

The Yampa River has been identified by the Recovery Program for Threatened and Endangered Species of the Upper Colorado River Basin as containing some of the most extensive remaining natural habitat of four endangered Colorado River fish species. In 1990, the Colorado River Water Conservation District contracted with Hydrosphere to evaluate the water uses and needs in the Yampa River basin and to investigate the potential issues and effects associated with establishing a major instream flow program in the basin to assist in the recovery of the endangered fish species.

Hydrosphere completed this work in three phases. The first was a reconnaissance-level evaluation, supported by substantial public involvement, which included projection of future basin water needs, investigation of potential small reservoir sites off the mainstem of the river, development of a detailed computer model of basin hydrology and water management, and evaluation of a variety of water rights transfer and small reservoir development alternatives.

The second phase was a feasibility-level evaluation of the enlargement of the existing Elkhead Reservoir from a capacity of 13,700 acre-feet to 44,900 acre-feet. This included detailed engineering evaluations and preparation of preliminary Biological and Environmental Assessments of the enlargement project. Computer operations studies were carried out using the basin hydrology and water rights model to determine how the enlarged reservoir could best serve its water supply, recreation, and instream flow enhancement functions.

The third phase was an inventory and review of all diversion and water control structures in river reaches potentially occupied by the endangered fish species. These structures were evaluated for their effects on movement of endangered and other native fish species, on local benthic and riparian habitat conditions, and on recreational boating.