On June 6, 2018, the Delta Watermaster formally released a memorandum (Overlap Memo) drafted several months earlier, rejecting the theory of overlapping pre-1914 and riparian water rights in the Delta and stating the position that these water rights cannot be duplicative and must be separately established.  The Delta Watermaster’s position in the Overlap Memo will affect how water users report their water use each year and could potentially affect some Delta water users’ claim of right.

The Delta Watermaster evaluated the theory of overlapping pre-1914 and riparian water rights as a result of responses to the State Water Resources Control Board’s 2015 Informational Order.  The Informational Order required claimants of pre-1914 and riparian water rights to submit documentation supporting each claim of right, as well as an accounting of water diverted under each right.  Some claimants responded with the assertion that their pre-1914 and riparian water rights are overlapping and that it would be impossible to separate the rights, absent an adjudication.

The Overlap Memo concludes that different elements are necessary to establish pre-1914 water rights versus riparian water rights.  Although it is possible to perfect both types of rights on the same parcel of land, the claimant would have to separately and independently establish the elements of each claim.  Further, each water right has specific limitations that the claimant must observe.  For example, riparian water rights authorize diversions of natural flow, and water diverted under a riparian right cannot be held in storage.  Pre-1914 appropriative rights, on the other hand, authorize diversions of water to storage and use on non-riparian parcels.

The Overlap Memo is not intended to have a regulatory effect, but rather represents the Delta Watermaster’s understanding of current law.  However, the Overlap Memo is intended to “guide” water users in preparing annual statements of diversion and use.  If the State Water Resources Control Board were to bring an enforcement action based on the positions described in the Overlap Memo, at that point the subject of the enforcement would be able to challenge the Overlap Memo’s legal conclusions.

For more information, please contact Brittany K. Johnson at bjohnson@somachlaw.com.

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