Maps, Models, and Mystery: Interconnected Groundwater and the Public Trust

American Bar Association (ABA) | August 10th, 2019

Walk into the office of any water law practitioner, anywhere, and you might think you made a wrong turn and walked into the office of your local cartographer. We are a p

Walk into the office of any water law practitioner, anywhere, and you might think you made a wrong turn and walked into the office of your local cartographer. We are a profession that depends on, and you might even say reveres, a good map. Rights to water flowing in surface streams are fundamentally defined by geography, and maps have long been a requirement of appropriation and essential evidence of riparian ownership. In turn, injury to a surface water right is determined by physics, as the topography of the land establishes the linear relation of impacts from other diversions, whether it be upstream (cause), or downstream (affected). In homage to these principles, some hydrologists will orient their maps top-to-bottom as upstream to downstream, rather than north to south. In our practice, gravity is our compass. Upending the convenient simplicity of rivers and streams flowing from mountaintop to ocean are alluvial and glacial valleys, in which unconsolidated sediment serve as giant sponges and blocks of fractured rock contain hidden stores of oftentimes ancient waters. Through these geologic features, hidden beneath the surface, water percolates, flows, and moves across the landscape. These subsurface waterbodies interconnect with surface streams and changes in the groundwater basin, whether due to drought or artificial extractions, and influence surface flow on a time scale ranging from minutes to centuries. To understand the relationship with any hope of precision, we need much more than a map; we need a hydrogeologist and a whole lot of data. All of this is by way of introducing two themes of emerging law in California that stand to influence trends beyond the state: (1) the legal relevance of interconnected groundwater to surface flows in protecting instream uses, and (2) recognition in the law of the need to understand and manage these interconnected waters.

May Revision Trailer Bill Proposals on the Delta Conveyance Project and Water Quality Control Plans

Legislative Analyst's Office (LAO) | May 27th, 2025

LAO Bottom Line: We recommend deferring action on both proposals, without prejudice. These policy issues do not have budget implications. Deferring action would allow the

LAO Bottom Line: We recommend deferring action on both proposals, without prejudice. These policy issues do not have budget implications. Deferring action would allow the Legislature more time and capacity for sufficient consideration of the potential benefits, implications, and trade-offs. Below, we describe the proposals and note some key issues for the Legislature to keep in mind when it considers these proposals.

Memo: Issues Related to Overlap between Pre-1914 and Riparian Water Right Claims in the Delta

California State Water Resources Control Board (SWRCB) | December 15th, 2017

To: Michael Patrick George, Delta Watermaster From: Micah Green, Water Rights Analyst Re: Issues Related to Overlap between Pre-1914 and Riparian Water Right Claims in

To: Michael Patrick George, Delta Watermaster From: Micah Green, Water Rights Analyst Re: Issues Related to Overlap between Pre-1914 and Riparian Water Right Claims in the Delta Date: December 15, 2017 Pursuant to your request, I have researched an issue raised in the course of my review of responses to the Division of Water Rights’ 2015 Information Order submitted by water right claimants within the Legal Delta. I. Question Presented Under California water law and within the Legal Delta, are there any circumstances under which riparian and appropriative rights can “overlap” becoming indistinguishable or inseparable such that either or both may be lawfully exercised at the election of the holder? II. Short Answer It is possible to perfect both riparian and appropriative water rights for beneficial use on the same parcel. However, riparian and appropriative rights are distinct property interests that must be separately established. There is no California precedent recognizing “overlapping” or “intertwined” water rights, and water laws against hoarding and non-use operate to preclude the duplicative exercise of water rights.

Methodology for Flow and Salinity Estimates in the Sacramento-San Joaquin Delta and Suisun Marsh

California Department of Water Resources (DWR) | June 1st, 2017

This is the 38th annual progress report of the California Department of Water Resources’ San Francisco Bay-Delta Evaluation Program, which is carried out by t

This is the 38th annual progress report of the California Department of Water Resources’ San Francisco Bay-Delta Evaluation Program, which is carried out by the Delta Modeling Section. This report is submitted annually by the section to the State Water Resources Control Board pursuant to its Water Right Decision D-1485, Term 9, which is still active pursuant to its Water Right Decision D-1641, Term 8. This report documents progress in the development and enhancement of computer models for the Delta Modeling Section of the Bay-Delta Office. It also reports the latest findings of studies conducted as part of the program. This report was compiled under the direction of Tara Smith, Program Manager for the Bay-Delta Evaluation Program.

Mono Lake Basin Water Right Decision 1631

California State Water Resources Control Board (SWRCB) | September 28th, 1994

Decision and Order Amending Water Right Licenses to Establish Fishery Protection Flows in Streams Tributary to Mono Lake and to Protect Public Trust Resources at Mono Lak

Decision and Order Amending Water Right Licenses to Establish Fishery Protection Flows in Streams Tributary to Mono Lake and to Protect Public Trust Resources at Mono Lake and in the Mono Lake Basin (Water Right Licenses 10191 and 10192, Applications 8042 and 8043, City of Los Angeles, Licensee)  

Mono Lake Committee request for an emergency action to protect Mono Lake and its public trust resources

California State Water Resources Control Board (SWRCB) | December 16th, 2022

Mono Lake Kutzadika’a Tribe support for Emergency Action at Mono Lake Due to Low Lake Level

California State Water Resources Control Board (SWRCB) | December 22nd, 2022

Mono Lake: background, Decision 1631, current conditions, ongoing developments

California State Water Resources Control Board (SWRCB) | January 1st, 2023

Near-term Colorado River Operations Draft Supplemental Environmental Impact Statement

U.S. Bureau of Reclamation (USBR) | April 11th, 2023

Reclamation is proposing revising the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year (beginning O

Reclamation is proposing revising the 2007 Interim Guidelines for the near-term operation of Glen Canyon and Hoover Dams beginning in the 2024 operating year (beginning October 1, 2023) to address the potential for continued low-runoff conditions in the Basin.

Necessity for Comprehensive Adjudication of Water Rights on the Sacramento and San Joaquin Rivers in Aid of the Central Valley Project

U.S. Government Publishing Office (GPO) | November 30th, 1942