October 2009 - South Tahoe Public Utility District

Section 9: Recycled Water Infrastructure Projects
The following Master Plan projects reflect ideas and modifications to the existing recycled water
system designed to enhance the utility of the recycled water distribution system, increase the
reliability and regulatory compliance associated with the storage and distribution of recycled
water resources, and to reduce or eliminate potential operational constraints. All projects
discussed in this section pertain to recycled water infrastructure. The purpose and need
statement(s) satisfied by the project, as well as the aspects of the project, are listed. There are
10 recycled water projects detailed in this section of which six are recommended for
implementation in the near future while the other four are projects whose implementation is
contingent on various factors described for each.
9.1 Project No. 1 - Recycled Water Irrigation Fields on Diamond
Valley Ranch
This project addresses the purpose and need statements:
PN-5. Adequate emergency disposal facility for recycled water and options are currently
unavailable for recycled water.
PN-10. Recycled water systems are needed to improve operational flexibility.
This project entails construction of irrigation fields on the District‟s Diamond Valley Ranch
property. The project includes a total of seven irrigation fields. Five of the irrigation fields,
totaling approximately 344 acres are planned to utilize an aerial irrigation system using center
pivot irrigation equipment. Two of the irrigation fields totaling approximately 49 acres, will utilize
gravity surface (flood) irrigation. The remaining 511 acres of water righted land will continue to
be irrigated with freshwater. The irrigation fields utilizing surface irrigation methods will serve a
dual purpose including service as an irrigation site for the majority of the time and service as an
temporary storage facility for recycled water in the event of an emergency which generally
would be a flood event. The combined temporary storage volume of the flood irrigated irrigation
fields is approximately 294 acre feet.
An evaluation of the existing recycled water emergency disposal facility (On-Farm) illustrated a
need for a new facility that would be utilized in a variety of scenarios and hydrologic conditions.
The key requirement for determining the size and location of this new facility is its proximity to
Harvey Place Reservoir. The proposed location on the Diamond Valley Ranch allows for the
release of recycled water from Harvey Place Reservoir into the irrigation fields for temporary
storage and return pumping back to Harvey Place Reservoir, or the delivery of the impounded
water directly into the Diamond Ditch system.
The design concept is to allow surface and aerial irrigation, useable in all seasons. Initially the
facility will be irrigated with existing freshwater rights diverted from the West Fork of the Carson
River. As the potential need for recycled application area grows in response to potential
development of existing application areas, recycled water would be used to irrigate the irrigation
fields upon securing a permit for recycled water application (Project No. 12, page 10-77).
In practice the flood irrigated irrigation fields would temporarily hold recycled water in times of
emergency. During normal operations the irrigation fields would provide alternative uses. To
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 9-61