9377 - Laserfiche WebLink

Home Browse Search

~ . Since 1979, Reclamation and the Service have been working cooperatively to study the fishes and their habitats under the auspices of the Colorado River Fishery Project, the Colorado River Fishery Monitoring Program, and now the broad-based Recovery Implementation Program which is being directed by John Hamill at our Denver office. Over the years it has also become clear that small tributary impoundments or depletions although cumulatively harmful, are not as detrimental to occupied habitat as are the large, mainstem CRSP impoundments. For this reason much of our focus has been on the operation of the larger mainstem CRSP facilities, such as Glen Canyon, Flaming Gorge, Aspinall and Navajo. Storage of high stream flows for late season release and use alters the natural flow patterns in which these fish evolved. In general, we believe that a more natural hydrograph that follows Ilnormal" seasonal changes has greater potential for meeting the fishes biological and ecological requirements. In those areas where flows fluctuate daily as well as seasonally, which is typical of load-following power operations, research has been focused on changes in individual backwaters or mi"crohabitats and how those physical changes affect all life stages of target fishes that inhabit them. As you would expect this type of field research is expensive, time consuming, and requires several years of continuous' field data to eliminate extraneous variables that ,confound each years' findings. Nonetheless, a pattern has slowly developed and each year we are better equipped to make informed adjustments as to the fishes needs.