ESWR page - Endangered Species & Wetlands Report

feet [MAF] per year; 2000-2004 average: 5.719 MAF per year). 4 This increase continues
a long-term trend of increases in Delta water exports (Figure 4, top panel). During the
periods when delta smelt are vulnerable to entrainment, the relative increases in exports
have been even greater, with a 48% increase in winter exports (December-March, when
pre-spawning and spawning adults are in the Delta, Figure 4, middle panel) and a 28%
increase in spring exports (March-July, when larvae and small juveniles are in the Delta,
Figure 4, bottom panel).
Exports (SWP+CVP, million acre-feet)
6
5
4
3
2
1
0
2.5
2.0
1.5
1.0
0.5
0.0
2.5
2.0
1.5
1.0
0.5
0.0
Figure 4. Combined water exports (million acre-feet, MAF) of the Central Valley Project and the
State Water Project from 1967-2004. The upper panel shows total export volumes for each water
year. The middle panel shows exports for the winter period (December-March). The lower panel
shows springtime exports (March-July). Data source: California Department of Water Resources,
Dayflow.
Direct Impacts:
Annual (water year)
Winter (Dec-Mar)
Spring (Mar-July)
1970 1980 1990 2000
Delta smelt listed under ESA
The CDFG (2003) expressed concern that entrainment of delta smelt at the CVP and
SWP could be a major source of population impacts under certain conditions. Data from
the summer TNS show an almost complete disappearance of juvenile delta smelt in south
4 Exports are calculated as the combined annual total (using the water year calendar) for Central Valley
Project and State Water Project exports using data from Dayflow (California Department of Water
Resources).
15