October 2009 - South Tahoe Public Utility District

11.3.1 Project Description
The alignment of Indian Creek directly below Harvey Place Reservoir Dam is planned to be
modified to provide for phosphorus sedimentation and biological nutrient assimilation in a 20-
acre treatment wetland. The objective of this design is to provide hydraulic retention time of the
high phosphorus water. A series of pools, emergent vegetation, and plug-flow wetlands provide
wetland area for the separation of phosphorus from the source water. The wetland should be
sized to pass the maximum released flow from Indian Creek Reservoir, yet function at optimum
treatment potential near 5 cfs, the mean annual release rate. This provides enhanced treatment
throughout most of the year and minor but beneficial treatment during high flow periods.
Treatment wetlands construction costs vary greatly throughout the region. The conceptual cost
for the treatment wetlands project is $0.9 million.
11.3.2 Project Considerations
Wetland maintenance and success criteria are the key to a successful treatment wetland. Plant
selection and substrate quality affect the rates of phosphorus absorption but the long-term
maintenance of the wetland should ensure success. This maintenance involves annual grubbing
and flow path work, burning, and periodic replanting.
11.4 Project No. 17 - Diversion Ditch for Stormwater Flow Away
From Harvey Place Reservoir and to Indian Creek
Reservoir
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 Indian Creek Reservoir and the Harvey Place Reservoir were both strategically located to
minimize the amount of surface water flow, stormwater runoff, and snowmelt into them because
of their original design function of storing recycled water. There is one unnamed canyon located
near the southeast corner of the Harvey Place Reservoir that flows to Harvey Place Reservoir.
This project would construct the infrastructure necessary to capture this surface water flow and
direct it to the Indian Creek Reservoir.
Implementation of this project is contingent upon the required recycled water storage volume in
the Harvey Place Reservoir. If the total volume of recycled water increases, or the lands
receiving recycled water for irrigation decreases, then additional storage may be required in the
Harvey Place Reservoir. Additionally, projections indicate that in the year 2028 the Harvey
Place Reservoir will be near its capacity limits.
11.4.1 Project Description
This project involves constructing an intercepting ditch near the southeast corner of the Harvey
Place Reservoir to intercept stormwater and drainage flows that currently flow into the Harvey
Place Reservoir and divert them to the Indian Creek Reservoir. The purpose of this project
would be to reduce stormwater flow into the Harvey Place Reservoir thereby increasing the
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 11-84