Biological Opinions - Bureau of Reclamation

evaporation and seepage estimated at 17,000 acre-feet for the same period (Reclamation,
unpublished data).
Adult spawning principally occurs in Barnes Valley and Ben Hall Creeks. Access to these
creeks is believed to require a minimum surface elevation of about 4,805.00 ft (1,464.56 m)
during the February through May spawning period (USFWS 2008). Based on the POR (Table
7.11), lake levels are likely to provide access into spawning tributaries in all but the driest years.
Additionally, during very dry years both Barnes Valley and Ben Hall Creeks typically have low
spring flows that may not provide adequate upstream passage for spawning adults regardless of
lake elevations (Reclamation 2001a). Thus, low lake levels during the POR have not likely
impeded spawning.
Table 7.11 Gerber Reservoir elevation exceedances, February through May. POR = 1925-2012 (Reclamation
2012, Table 6-4).
Exceedance
(Percent)
95
February
(Feet)
4,804.88
(1,464.53 m)
March
(Feet)
4,809.12
(1,465.82 m)
April
(Feet)
4,810.01
(1,466.09 m)
May
(Feet)
4,809.55
(1,465.95 m)
90
4,807.68
(1,465.38 m)
4,813.37
(1,467.12 m)
4,815.94
(1,467.90 m)
4,816.35
(1,468.02 m)
85
4,810.75
(1,466.32 m)
4,815.16
(1,467.66 m)
4,818.85
(1,468.79 m)
4,817.76
(1,468.45 m)
80
4,812.72
(1,466.92 m)
4,817.63
(1,468.41 m)
4,820.27
(1,469.22 m)
4,819.15
(1,468.88 m)
75
4,814.48
(1,467.45 m)
4,818.76
(1,468.76 m)
4,821.41
(1,469.57 m)
4,820.27
(1,469.22 m)
70
4,815.82
(1,467.86 m)
4,820.14
(1,469.18 m)
4,822.45
(1,469.88 m)
4,820.94
(1,469.42 m)
65
4,817.11
(1,468.26 m)
4,821.56
(1,469.61 m)
4,824.41
(1,470.48 m)
4,822.58
(1,469.92 m)
60
4,817.78
(14,68.46 m)
4,822.64
(1,469.94 m)
4,825.28
(1,470.75 m)
4,823.55
(1,470.22 m)
55
4,818.15
(1,468.57 m)
4,824.02
(1,470.36 m)
4,826.90
(1,471.24 m)
4,825.17
(1,470.71 m)
50
4,820.02
(1,469.14 m)
4,824.89
(1,470.63 m)
4,827.70
(1,471.48 m)
4,826.56
(1,471.14 m)
108