Page 32 - Beaumont Basin Watermaster
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Section 3
Status of the Basin and Administration of the Judgment
It is emphasized that the OSY, as presented herein, is based on one year of data. When
evaluated on a long-term basis, this methodology can be used to estimate the long-term Safe
Yield of the basin, as defined in the Beaumont Basin Judgment. As required by the
Judgment, the Safe Yield of the basin was reevaluated in 2013.
It is also noted that there are a number of data limitations that could impact the OSY
estimate. These limitations include:
Accuracy of Overlyer Production Data – Production data from many of the Overlying
Parties is not metered but is estimated based on a water duty method (Wildermuth
Environmental, 2012). In addition to inherent limitations in this methodology, there are, in
some cases, discrepancies between groundwater production estimated using the water
duty method and production reported by individual parties to the California State Water
Resources Control Board. Resolution of Overlyer Production is anticipated to affect the
OSY (plus or minus) on the order of hundreds of ac-ft (not thousands). Further, potential
discrepancies in estimated production will no longer be an issue in the future as
production meters were installed in early 2014.
Change in Storage Calculation – Although groundwater storage change estimates will
always have inherent uncertainty, it is possible to develop more representative results
through collection and analysis of additional data. These data include:
9 Static groundwater levels from dedicated non-pumping wells. There is evidence
that groundwater levels measured in some wells had not recovered fully between
pumping cycles in the well and were not, therefore, representative of true static
conditions. This can be addressed by waiting longer after pumping to collect
groundwater levels or constructing/designating non-pumping groundwater
monitoring wells in strategic areas.
9 Measurement of surface water flow in selected drainages, hydrogeological data
near Noble Creek and San Timoteo Creek, and hydrogeological analysis of faults
in the basin to help achieve a better calibrated model, resulting in more accurate
groundwater head distributions. Bettering our understanding of the hydrogeology
of this area will help improve the accuracy of the model and its output.
Beaumont Basin Watermaster 2013 Annual Report – DRAFT August 2014 3-12
