Surface water commonly is hydraulically connected to ground water, but the interactions are difficult to observe and measure and have largely been ignored in water-management considerations and policies. However, the Sustainable Groundwater Management Act (SGMA), passed in 2014, is California’s first statewide law that explicitly reflects the fact that surface water and groundwater are frequently interconnected and that groundwater management can impact groundwater-dependent ecosystems, surface water flows, and the beneficial uses of those flows. The challenge of quantifying these interactions has led to the development of several techniques.
At the 2019 Western Groundwater Congress, Gilbert Barth, PhD is an Associate and Senior Hydrologist with S.S. Papadopulos & Associates in their Boulder office, gave an overview of groundwater-surface water interactions and discussed some of the tools and techniques that he has helped develop. Dr. Barth provides quantitative assessments of groundwater resources to address questions associated with water planning, and specializes in model development and calibration with a focus on quantifying changes between surface water and groundwater systems. He’s developed and applied models throughout the Western US for regional, interstate, and international deliberations.
Sierra Ryan is a water resources planner with the County of Santa Cruz. In this presentation from the Groundwater Resources Association‘s 2019 Western Groundwater Congress, Ms. Ryan tells the story of how the Santa Cruz Mid-County Groundwater Agency balanced the various perspectives, authorities, and interpretations of the DWR regulations in writing the portion of their Groundwater Sustainability Plan that pertained to the depletion of interconnected surface water (sustainability indicator or undesirable result #6). “I promise you that it was not as simple as we thought it was to begin with, so for those of you in the medium and high priority basins that have the 2022 deadlines, I hope you’re thinking about this now,” Ms. Ryan advised. Click here to read this article at Maven’s Notebook.
“In 2014 California introduced the Sustainable Groundwater Management Act (SGMA) into state law to help manage the conflict between ground and surface water. But updating legal structures to accommodate evolving scientific knowledge involves far more than simply rewriting statutes, according to researchers in the US.
“Understanding the interconnections between groundwater and surface water doesn’t make those conflicts go away,” says Dave Owen of University of California, Hastings. “But at least acknowledging those interconnections in law puts legal decision-makers in a position to start managing conflicts, rather than just letting them play out without any legal oversight.” … ”
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.
The Sustainable Groundwater Management Act (SGMA), passed in 2014, is California’s first statewide law that explicitly reflects the fact that surface water and groundwater are frequently interconnected and that groundwater management can impact groundwater-dependent ecosystems, surface water flows, and the beneficial uses of those flows.
SGMA requires groundwater sustainability agencies (GSAs) to manage groundwater to avoid six undesirable results, one of which is significant and unreasonable adverse impacts on beneficial uses of surface water. While this aspect of SGMA is clearly important, significant uncertainties exist regarding how GSAs will actually define and achieve this goal. At the 2019 California Water Law Symposium, a panel of experts discussed the structure of SGMA and how it addresses these water connections, particularly in relation to fisheries and the public trust doctrine.
Seated on the panel:
Rick Frank:Rick Frank is a professor of law at the UC Davis Law School. For many years, he was with the California Attorney General’s office and litigated a number of very important water and environmental cases.
Letty Belin: Letty Belin is an attorney who specializes in tribal water rights, water law, and other natural resource issues. Letty served as counsel to the Deputy Secretary of the Interior in Washington DC, most recently a visiting fellow at Stanford’s Water in the West program.
That requirement is an important step towards rationalizing California water management, which has long treated groundwater and surface water as separate resources. The requirement also is part of a larger story about evolving science and policy in a changing world. … “
“When the California Legislature created the “modern” water rights regulatory system more than a century ago, it focused exclusively on surface water, exempting groundwater from the permitting system. Yet in most watersheds, surface water and groundwater are closely linked. Actions that change one often have an impact on the other. The arbitrary legal divide has made it harder to manage the state’s water. But a recent law and a new court decision have done a better job of connecting surface water and groundwater.
When rain falls or snow melts in the foothills and mountains of California, water follows several pathways downhill and into rivers and streams. Some water moves across the land or through deep soils and weathered bedrock, arriving in rivers hours to weeks after rain or snowmelt. And some percolates deep into the ground, becoming groundwater. … “
A Guidebook for using California’s Sustainable Groundwater Management Act to protect fisheries
From the Center on Urban Environmental Law at Golden Gate University:
“In California, surface waters have historically been regulated as if they were unconnected to groundwater. Yet, in reality, surface waters and groundwater are often hydrologically connected. Many of the rivers that support fisheries such as salmon and trout are hydrologically dependent on tributary groundwater to maintain instream flow. This means that when there is intensive pumping of tributary groundwater the result can be reductions in instream flow and damage to fisheries.
For this reason, stakeholders concerned about adequate instream flows for fisheries in California’s rivers, streams and creeks need to be effectively engaged in the implementation of California’s Sustainable Groundwater Management Act (SGMA). …
Each SGMA Groundwater Plan must detail how the groundwater basin will be managed to avoid overdraft conditions and, importantly for fisheries, to avoid adverse impacts on hydrologically connected surface waters.
Although groundwater sustainability agencies and fishery stakeholders recognize that the groundwater-surface water connection needs to be addressed in SGMA Groundwater Plans, at present there is limited guidance on how to do this. That is, what are the specific types of information, modeling, monitoring, and pumping provisions that should be included in SGMA Groundwater Plans to ensure that groundwater extraction does not cause significant adverse impacts on fisheries? The purpose of this guidebook is to provide such guidance.”