October 2009 - South Tahoe Public Utility District

available storage volume of the Reservoir. Another benefit of this project will be to increase the
freshwater flushing flows to the Indian Creek Reservoir.
The length of Diversion Ditch would be approximately 2600 feet. The Diversion Ditch would
start at an existing culvert for the Airport road at the unnamed drainage. The alignment would
generally follow the airport road alignment to Indian Creek Reservoir. The ditch capacity would
be based on a detailed hydrological analysis of the tributary watershed.
The conceptual cost for the Diversion Ditch to divert stormwater away form Harvey Place
Reservoir to Indian Creek Reservoir is $0.4 million.
11.4.2 Project Considerations
A method of sediment control may be necessary to reduce sediment loading in the Indian Creek
Reservoir. The disadvantages of this project include capital cost expenditure and the District
would have additional operation and maintenance responsibilities.
Since the construction of Harvey Place Reservoir in 1988 only the flood of 1997 caused
significant concerns for the District. In that year the surface water flows into Harvey Place
Reservoir threatened the required storage capacity and created the potential for a spill from the
reservoir in the event of subsequent storms. To alleviate the situation, the District received
permission to land apply its recycled water outside of the irrigation season. Implementation of
this project would help the District in avoiding a spill from the Harvey Place Reservoir in a large
flood event.
11.5 Project No. 18 - Indian Creek Reservoir Spillway Channel
This project addresses the purpose and need statements:
PN-7. Operational control of the distribution system is insufficient.
PN-10. Recycled water system improvements are needed to improve operational
flexibility.
The implementation of this project is contingent with respect to the District‟s desire to reduce
operational constraints in the event of catastrophic floods.
The existing Harvey Place Reservoir infrastructure includes a spillway to comply with dam
safety regulations. The spillway prevents water from over-topping the dam.
11.5.1 Project Description
The Indian Creek Reservoir spillway originally discharged to Indian Creek. This was permissible
when the District utilized tertiary treatment at its wastewater treatment plant in South Lake
Tahoe. However, with the construction of Harvey Place Reservoir, the Indian Creek Reservoir
spillway configuration resulted in spillway discharge to Harvey Place Reservoir. This project
involves the construction of a spillway channel for Indian Creek Reservoir that conveys reservoir
spillage around Harvey Place Reservoir to Indian Creek. The project has an added benefit of
intercepting stormwater flow entering the east side of Harvey Place Reservoir.
The length of the channel would be approximately 6,000 feet. The capacity of the channel as
planned would match the existing capacity of the 24-inch diameter Indian Creek Reservoir outlet
pipeline. Alternatively a detailed hydrological study could identify the probable maximum flood
to establish the design capacity.
The conceptual cost for the Indian Creek Reservoir Spillway Channel is $0.9 million.
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 11-85