October 2009 - South Tahoe Public Utility District

13.2 Recycled Water Production Triggered Project
Implementation
Data provided in Section 5 indicate an increase in recycled water production in the next 20
years. The following summarizes recycled water volumes, the acreage required for direct
application to land, and the corresponding surplus or deficiency for the years 2008 and 2028.
Year 2008
• Harvey Place Reservoir Release: 4,738 Acre-feet
• Acreage Required for Direct Land Application: 1,458 Acres
• Application Land Deficiency: 3 Acres (based on a 3.25 acre-feet/acre/year recycled
water application rate
Year 2028
• Harvey Place Reservoir Release: 5,848 Acre-feet
• Acreage Required for Direct Land Application: 1,799 Acres
• Application Land Deficiency: 344 Acres (this stated deficiency does not include the
potential acreage for irrigation with recycled water at the Diamond Valley Ranch
The annual peak recycled water outflow from Harvey Place Reservoir was 4,738 acre-feet in
2007 and is estimated to increase to 5,848 acre-feet by 2028 (See Tables 13.1 and 13.2, page
13-93). Using a planning application rate of 3.25 acre-feet per acre per year, 1,458 acres are
required for recycled water application in the year 2008 while 1,799 acres are required in the
year 2028.
Currently (2008) recycled water is being applied to 1,455 acres of 1,883 permitted acres.
Sufficient application acreage is not currently available (1,455 acres actual versus 1,458 acres
needed); the direct land application deficiency is projected to increase by 2028 (1,455 acres
actual versus 1,799 acres needed). Sufficient application acreage is available in 2028 if
additional permitted acreage is utilized (1,883 acres permitted versus 1,799 acres needed),
however, utilization of additional permitted acreage may be difficult due to topographical land
constraints.
To determine application volumes for the blended water irrigators Bruns, Gansberg and
Neddenriep, an estimate was made of the delivery of the ranchers‟ water rights on the West
Fork of the Carson River. The available water supply from the West Fork was estimated using
data from the USGS gauging station at Woodfords (Appendix C), and compared to the
cumulative West Fork water right allotments (Appendix G). Ranchers whose water rights fall
below average river flow matches of the cumulative column for a given month of the irrigation
season do not receive water for that month. The delivery volumes are summarized in Appendix
G.
The above evaluation does not account for application of blended water or the 20% additional
capacity desired by the District.
Four ranches currently blend fresh water with recycled water which increases the amount of
recycled water runoff. A summary of blending practices per ranch is shown in Table 13.3 (page
13-94). An estimate of the average amount of fresh water available to the four ranches is 2,643
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 13-91