Page 25 - Beaumont Basin Watermaster

BEAUMONT BASIN WATERMASTER

MEMORANDUM NO. 19-03

Date: February 6, 2019

From: Hannibal Blandon, ALDA Inc.

Subject: Status Report on the Development of a Return Flow Methodology
for the Beaumont Basin

Recommendation: None – For Information Purposes Only

The purpose of this Technical Memorandum is to provide an update on the work
conducted under Task No. 17 to develop a Return Flow Accounting Methodology.

In consideration of the fact that irrigation return flow contributes to the Safe Yield of the
Beaumont Basin, the Beaumont Basin Watermaster Board directed ALDA/Thomas
Harder & Co. (ALDA/TH&Co) to develop a methodology to account for the return flow that
occurs overlying each Appropriator service area. The work was begun in October 2018.
To date, we have conducted the following work:

▪ Obtained 2017 water delivery records from the Beaumont-Cherry Valley Water
District (BCVWD), City of Banning, and Yucaipa Valley Water District.

▪ Correlated water account addresses to Assessor’s Parcel Numbers (APNs) for
BCVWD and the City of Banning

▪ Began developing a return flow accounting methodology based on a review of the
available water delivery records from the Appropriators.

It is noted that our scope of work assumed that the Appropriators would provide records
correlated to APNs. However, as BCVWD and the City of Banning did not have the
resources to conduct this work, it was necessary for ALDA/TH&Co to correlate the water
delivery accounts to APNs. This work was out of scope.

The following work remains to be conducted;

▪ Reconcile approximately 100 unidentified accounts for BCVWD

▪ Finish correlating City of Banning water delivery accounts to APNs (90 percent
complete)
▪ Finalize the return flow analysis methodology

▪ Prepare the seepage lag analysis
▪ Prepare the Technical Memorandum documenting study

Beaumont Basin Watermaster - February 6, 2019 - Page 25 of 29