October 2009 - South Tahoe Public Utility District

Section 11: Fresh Water Infrastructure Projects
There are five freshwater infrastructure management projects described in this section. For all
five of these projects their implementation is contingent primarily on the District meeting its
requirements at the Indian Creek Reservoir.
The District is obligated to meet certain water quality goals (TMDLs) at the Indian Creek
Reservoir as well as providing sufficient water to meet minimum water surface elevation
requirements. Often there is insufficient fresh water in the West Fork of the Carson River for the
District to convey a sufficient amount of water to meet it‟s minimum water surface elevation
requirements. In these years the river is under “regulation” as discussed in Appendix G.
However, even in years when the river is not under regulation, the existing freshwater
conveyance infrastructure is often insufficient to convey existing and possible future Indian
Creek Reservoir freshwater storage rights to the reservoir.
11.1 Project No. 14 - Snowshoe Thompson No. 1 Conveyance
Capacity Improvements
This project addresses the purpose and need statement:
PN-9. Ability to meet Indian Creek Reservoir water quality requirements is impaired and
the District needs to meet TMDL requirements for the Indian Creek Reservoir.
The implementation of this project is contingent on two factors, one pertaining to water quality
and the other pertaining to water quantity. The District is currently implementing a Hypolimnetic
Oxygenation System project at the Indian Creek Reservoir. If this project is successful in
meeting the District‟s TMDL requirements, the water quality aspect of project implementation is
unnecessary. The other contingency factor is meeting the water surface elevation requirements
in the Indian Creek Reservoir. If not meeting the water surface elevation requirement due to
conveyance capacity limitations continues to be a problem, the freshwater conveyance
improvements of this project are needed.
Snowshoe Thompson No. 1 Ditch is the first conveyance ditch for freshwater to Indian Creek
Reservoir and for irrigation water to Diamond Valley pasturelands. Snowshoe Thompson No. 1
is an unlined ditch that has limited capacity for existing diversions. The limited capacity issues
combined with structural integrity concerns illustrate the need for improvements to this
conveyance.
11.1.1 Project Description
The Snowshoe Thompson Ditch No. 1 Ditch diverges from the south bank of the West Fork of
the Carson River about a half-mile above Woodfords. The proposed project is planned to pipe
portions of the ditch in its original alignment to improve capacity, integrity, and eliminate the
annual maintenance that is currently required.
The piped section of Snowshoe Thompson No. 1 Ditch is planned to start at the Millich Ditch
diversion structure. The Snowshoe Thompson No. 1 pipeline is planned to tie into the existing
concrete head works and sluice gate and extend along the hillside to a location near Hwy 89.
The need for a large conveyance volume to capture the full water right allocation necessitates a
large diameter pipe, perhaps as large as 36 inches. This large diameter allows the diversion of
approximately 40% of the allocated water right to be captured per month during the runoff
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 11-81