October 2009 - South Tahoe Public Utility District

5.2.4 Groundwater Monitoring
The District has maintained a groundwater monitoring program in Alpine County with a total of
16 separate monitoring points including 9 groundwater monitoring wells installed in 1988 in
response to a Lahontan Regional Water Quality Control Board order issued in 1984. The
purpose of the groundwater monitoring program is to verify that the District‟s recycled water
operations do not have a negative impact on the groundwater resources of Alpine County. The
groundwater monitoring program is a requirement of the District‟s discharge permit issued by
Lahontan Regional Water Quality Control Board. As of this writing the Alpine County Board of
County Supervisors has contracted with the Alisto Engineering Group of Walnut Creek,
California to conduct an evaluation of the District‟s groundwater monitoring program. The scope
of work generally includes the following.
• Survey existing monitoring sites to establish consistent location and elevation data.
• Gather water table elevations on a quarterly basis to establish groundwater table
contours.
• Evaluate the 16 existing groundwater monitoring sites to verify their suitability. Some of
the locations are private wells that may not accurately measure shallow water table
elevations while others may be negatively affected by private septic tank and leach field
wastewater management and disposal systems.
• Evaluate groundwater table contours to develop recommendations for changes to the
groundwater monitoring program to improve its effectiveness.
The evaluation intends to determine the effectiveness of the District‟s groundwater monitoring
program and recommend additional groundwork monitoring well sites. A final report of the
evaluation is scheduled for completion in November, 2008. The findings of the study may be
used to modify the groundwater monitoring program of the District‟s discharge permit with the
Lahontan Regional Water Quality Control Board.
The additional well sites will most likely include additional monitoring wells on the Diamond
Valley Ranch property. It is anticipated the installation of the additional groundwater monitoring
wells will occur in late 2008 and early 2009.
South Tahoe Public Utility District
Recycled Water Facilities Master Plan - October 2009 Page 5-39