Page 32 - Beaumont Basin Watermaster - DRAFT 2016 Annual Report

Section 3
Status of the Basin and Administration of the Judgment

Groundwater flow within the Beaumont Basin generally depends on location with respect to a
groundwater flow divide which occurs in the center of the basin approximately coincident with
the Noble Creek drainage. West of the Noble Creek drainage, groundwater generally flows
to the northwest and ultimately towards San Timoteo Wash. East of the Noble Creek
drainage, groundwater flows to the southeast towards the City of Banning. The groundwater
flow directions did not change significantly between 2015 and 2016 except near the Noble
Creek Recharge Facility where a localized mount can be seen in 2016.

Basin-wide groundwater level trends in the Beaumont Basin were evaluated based on
hydrographs from eights key wells and the groundwater level change map developed by
subtracting the 2015 groundwater surface from the 2016 groundwater surface (See Figures
3-7 and 3-8). In the northwest portion of the basin (YVWD 34 and Singleton Ranch 7),
groundwater levels remained stable or increased between November 2015 and November
2016. At Tukwet Canyon Golf Club C, groundwater levels continued a steady decline in
2016 that has been observed since 2003. When evaluated on a long-term basis,
groundwater levels in wells in the western portion of the basin have shown a general long-
term decline since approximately 2005.

As shown on Figure 3-8, groundwater levels in the north central portion of the basin rose as
much as 40 ft in 2016 as a result of renewed recharge at the Noble Creek Artificial Recharge
facility. Conversely, groundwater levels in TW-1, located on the northeast corner of the
recharge facility continued a decline that had started in 2014. This well is perforated in the
lower aquifer and typically shows a delayed response to groundwater recharge relative to
wells perforated in the upper aquifer.

In the south-central portion of the basin, groundwater levels at Oak Valley No. 1 increased in
2016 by over 10 feet. At BCVWD Well No. 2, groundwater levels rose in March 2016 to the
highest levels in eleven years, declined in the summer, and have been rising since
September. At Banning Well C-4 (southeast Beaumont Basin), groundwater levels were
rising in April, declined in the summer, and began increasing in October.

The variability of groundwater levels at BCVWD Well No. 2 and Banning Well C4 are likely
due to seasonal pumping patterns in these areas. Groundwater levels in the northeast
portion of the basin (335714116565002) have been trending upward since 2010 and have
remained mostly stable in 2016.

3.6.2 Analysis of Change in Groundwater Storage
Basin-wide change in groundwater storage between Fall 2015 and Fall 2016 was analyzed
as a function of the difference in groundwater levels across the basin and the specific yield of
the aquifer sediments. Groundwater level change across the basin was analyzed using the
following procedure:

1. The Fall 2014 and Fall 2015 model-generated groundwater contour maps were each
converted into three-dimensional raster surfaces.

2. The basin was discretized into 100-ft by 100-ft grid cells.

Beaumont Basin Watermaster 2016 Annual Report – DRAFT – August 2017 3-11