Final Programmatic Biological Opinion for Bureau of Reclamation's

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43300002500020000CFS150001000050000NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP OCTWET 1986 AVERAGE 1982 DRY 1989FIGURE 3. Baseline Flow condition in the Colorado River near Palisade below the GVIC Diversion as Modeled by CRDSS.
44Factors Affecting Species Environment within the Action AreaThe Service assumes that baseline flow conditions would provide improved habitat for theendangered fishes compared to existing flow conditions. However, even with baseline flowconditions, limiting factors for fishes exist under the environmental baseline. Under the modeledbaseline flow conditions today, competition and predation from nonnative fishes would be afactor. Also, under the modeled baseline flow conditions today it is likely that many floodplainhabitats would be diked off and bank stabilization would be in place. Impacts from dams such aschanges in temperatures and sediment loads, and barriers to fish movement would alter habitatconditions for endangered fishes.EFFECTS OF THE ACTIONThe effects of the Federal action described on page 1 are presented in this section.Factors to be ConsideredThe Service believes that water depletions are a major factor contributing to the reductions in thepopulations of the Colorado pikeminnow, humpback chub, bonytail, and razorback sucker. Othermajor factors include impacts of dams, competition from and predation by nonnative fishes,changes in flow and temperature regimes, and changes in river channel (which are also related towater depletions). These reductions in population and loss of habitat have caused the Service tolist these species as endangered and to implement programs to conserve the species.Implementation of the Recovery Actions outlined in the proposed action are designed to offsetdepletion impacts to the 15-Mile Reach and the Colorado River downstream to Lake Powell.Water depletions reduce the ability of the river to create and maintain important habitats andreduce the frequency and duration of availability of these habitats, as described below. Foodsupply, predation, and competition are important elements of the biological environment. Foodsupply is a function of nutrient supply and productivity; because high spring flows floodbottomland habitats increasing the nutrient supply and productivity of the river environment,reduction of high spring flows from water storage reservoirs that store water during spring peakflows may reduce food supply. Predation and competition from nonnative fish species have beenidentified as factors in the decline of the endangered fishes. Water depletions contribute toalterations in flow regimes that favor nonnative fishes, as described below. The Service concludesthat water depletions impact all four species of endangered fishes and the primary constituentelements of their critical habitat.There are a number of benefits associated with implementation of the Recovery Action Planelements that positively affect the Colorado River from Rifle to Lake Powell, including the15-Mile Reach. These benefits include: augmentation of late summer/fall base flows; spring peakenhancement; habitat restoration; fish passage; nonnative fish management; and propagation andstocking of endangered fishes.
Page 1 and 2: FINAL PROGRAMMATIC BIOLOGICAL OPINI
Page 3 and 4: INCIDENTAL TAKE ...................
Page 5 and 6: 2" Reclamation’s portion of 120,0
Page 7 and 8: On January 21-22, 1988, the Secreta
Page 9 and 10: funding component of the Recovery P
Page 11 and 12: 81. Habitat Protection ElementGener
Page 13 and 14: Also, the Service and the Colorado
Page 15 and 16: Table 1. The estimated benefits in
Page 17 and 18: through recovery efforts that will
Page 19 and 20: native fishes. Also, some species o
Page 21 and 22: “new” depletions. This would in
Page 23 and 24: Based on early fish collection reco
Page 25 and 26: infrequent pulsed recruitment make
Page 27 and 28: Area, in the Loma to Black Rocks re
Page 29 and 30: 26Figure 1. Distribution of adult C
Page 31 and 32: during high flows. Some of the pike
Page 33 and 34: In the Upper Basin, above Glen Cany
Page 35 and 36: 32Populations DynamicsThere are no
Page 37 and 38: in low velocity shorelines and back
Page 39 and 40: 36IMPORTANCE OF THE 15-MILE REACHTh
Page 41 and 42: occur in the 15-Mile Reach). Provid
Page 43 and 44: Applying the above regulations, the
Page 45: in a river basin. While the model i
Page 49 and 50: 46To determine conditions with wate
Page 51 and 52: 48140001200010000CFS800060004000200
Page 53 and 54: 50CFS240002200020000180001600014000
Page 55 and 56: 52CFS280002600024000220002000018000
Page 57 and 58: Release and protection of surplus H
Page 59 and 60: 56CFS500045004000350030002500200015
Page 61 and 62: The formation of a variety of chann
Page 63 and 64: options will be determined through
Page 65 and 66: Passage at the Price-Stubb Diversio
Page 67 and 68: species. Recent population estimate
Page 69 and 70: the endangered fishes. Ongoing Reco
Page 71 and 72: 68the Colorado pikeminnow, razorbac
Page 73 and 74: 70There are no current population e
Page 75 and 76: additional reasonable and prudent m
Page 77 and 78: The Recovery Action Plan is an adap
Page 79 and 80: 76actions have all been completed a
Page 81 and 82: 78LITERATURE CITEDAbbott, C. C. 186
Page 83 and 84: 80the Upper Colorado River Basin, P
Page 85 and 86: Kaeding, L. R., and D. B. Osmundson
Page 87 and 88: Minckley, W. L. 1983. Status of the
Page 89 and 90: Pitlick, J., and M. Van Steeter. 19
Page 91 and 92: Tyus, H. M., B. D. Burdick, R. A. V
Page 93: Wick, E. J. 1997. Physical processe

Final Programmatic Biological Opinion for Bureau of Reclamation's

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