8089 - Laserfiche WebLink

Home Browse Search

4-inch openings between bars. The secondary screening device also consists of a rack of vertical steel bars; however, the opening between these bars - will only be 114-inch wide. No "take" of endangered species is anticipated by the construction and operation of the fish passageway. The screening devices located at the fish passageway entrance prevent fish from entering the structure and being drawn into the city of Grand Junction's pumping plant intake. The location of the fish passageway on the inside of a major river bend (away from deeper and faster flows) and the perpendicular orientation of the fish passageway entrance to the flow of the river also prevent "take. " The status of endangered fish in the Gunnison River under present conditions has been clarified. Historical accounts by early settlers along the Gunnison River indicate the Colorado squawfish and razorback sucker were common in this area. The numbers have declined to the point that both are very rare as indicated in the text. The only razorback suckers known to occur in the river upstream from the Redlands Diversion are fish stocked by the Service in 1994. A small remnant population of Colorado squawfish are present upstream but no recruitment of young has been documented in this reach. During 2 years of extensive surveys in 1992-1993 only 5 squawfish were found upstream from the diversion. Non-native fish present in the Gunnison River include the smallmouth bass, channel catfish, carp, sand shiner, fathead minnow, white sucker, black bullhead, killifish, largemouth bass, green sunfish, northern pike, and brown trout. A higher percentage of native fish occurs upstream of the diversion dam and in this area a few non-natives such as the channel catfish are veryuncommon. The fish passageway will be operated to keep additional non-native fish from moving upstream. The passageway is designed to do this; it is recognized that this may not be 100 percent effective, but it is considered a practical measure. It should be noted that it is much easier to keep the fish from moving upstream than it would be to keep them from moving downstream. It is desirable to reduce or not introduce non-natives, such as channel catfish, in the Gunnison River as they compete with the native fish, especially in warm backwater areas that are very important for successful reproduction of native fish. The 300 cfs flow recommendation below the Redlands is preliminary and based on maintaining water depth for fish to move upstream between the Colorado River and the passageway. River cross-sections were taken in the 2.3 mile reach of the Gunnison River at several flow levels and depth versus flow relationships were developed. Included in the 300 ifs is 100 cfs necessary to operate the passageway. During the period of the interim agreement, these flows and their effect on habitat will be monitored to provide data for final recommendations. Critical habitat on the Gunnison River has been designated as occurring between the Colorado River and the Gunnison's confluence with the Uncompahgre River. Radio telemetry data indicates that the fish have moved a few miles upstream past the Uncompahgre confluence. Upstream from Delta the river is restricted by a diversion dam--the Hartland Diversion Dam-- and also colder water released from the Aspinall Unit may have changed habitat conditions to the point that they are unsuitable for some of the native fish. 53