California is one of the most hydrologically altered landscapes in the world. As water becomes ever more scarce and the human population continues to grow, that vast engineered system strains to meet the needs of people let alone the needs of nature. 

Water rights allocations far exceed actual surface water supply, and millions of wells tap groundwater to meet the increasing demands of farms and communities. As groundwater reservoirs are depleted they can in turn reduce surface flows – exacerbating a vicious cycle in which people and nature both lose. Rivers, wetlands and groundwater-dependent ecosystems are caught in this struggle for an increasingly limited resource. Nearly half of California’s roughly 4,000 freshwater species are considered vulnerable to extinction. Of the taxa that are found nowhere but California – our endemic freshwater biodiversity – 90 percent are at risk.

But there is hope. While it is impossible to return natural flows to most of California’s rivers and streams, we can – through science, technology, and innovative market tools – endeavor to deliver water when and where nature needs it most.

Groundwater

In a normal year, groundwater accounts for 40 percent of California’s water supply. That…>>

Surface Flows

Californians have fundamentally altered many of the state’s rivers and streams with dams,…>>

Science in Action

Freshwater | Terrestrial | Science

Rewilding the San Joaquin Valley

40 years of science sets the course for the largest recovery of species in U.S. history

Freshwater | Terrestrial | Marine | Science

Research for Impact

How do we design scientific research to have impact in the world?

2021 | Freshwater | Terrestrial | Planning | Technology | Science | Publications & Reports

Planting Stormwater Solutions: A methodology for siting nature-based solutions for pollution capture, habitat enhancement, and multiple health benefits

Kelsey Jessup, Sophie S. Parker, John M. Randall, Brian S. Cohen, Rowan Roderick-Jones, Shona Ganguly, Jill Sourial

This paper presents results from Planting Stormwater Solutions, part of TNC’s Urban Conservation work in Los Angeles. The authors develop a methodology to prioritize siting of vegetated…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Biological responses to stream nutrients: A Synthesis of Science From Experimental Forests and Ranges

Kristen Wilson, Dale W. Johnson, Douglas F. Ryan, ed.

Authored by TNC staff and colleague, Chapter 8 of this report synthesizes environmental monitoring and studies performed at Sagehen Experimental Forest that are relevant to water quality regulatory…

2021 | Freshwater | Terrestrial | Marine | Planning | Publications & Reports

Coastal Adaptation Vision for Naval Base Ventura County Point Mugu: Technical Report

Environmental Science Associates (ESA) for The Nature Conservancy and Naval Base Ventura County


2021 | Freshwater | Terrestrial | Marine | Planning | Science | Video

StoryMap: Restoring coastal wetlands for climate resilience: A case study at Naval Base Ventura County Point Mugu

Charlotte Stanley, Alyssa Mann, Walter Heady

The United States operates thousands of military installations in the U.S. and worldwide, worth about $1.2 trillion. These facilities are where personnel train and test weaponry, with…

2021 | Freshwater | Terrestrial | Marine | Planning | Science | Publications & Reports

Restoring coastal wetlands for climate resilience: A case study at Naval Base Ventura County, Pt. Mugu

Walter Heady, Alyssa Mann, Stacey Solie, Bob Battalio, James Jackson, Kendall Lousen, and Bob Barnes

The U.S. Congress and the Department of Defense (DoD) have determined that climate change is a threat to national security and have required military installations to develop plans to improve the…

2021 | Freshwater | Terrestrial | Marine | Planning | Science | Publications & Reports

Coastal Adaptation with the U.S. Navy at Point Mugu

Alyssa Mann, Walter Heady, Charlotte Stanley

TNC and the United States Navy partnered together to prepare for the impacts of climate change on Naval Base Ventura County (NBVC), Point Mugu in California. NBVC is a critical and strategic asset of…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Cannabis farms in California rely on wells outside of regulated groundwater basins

Christopher Dillis, Van Butsic, Jennifer Carah, Samuel Zipper, Theodore Grantham

Water management practices for cannabis farming in California are not well understood. This study examined permit reporting data and found that the vast majority (>75%) of permitted cannabis farms…

2021 | Freshwater | Planning | Science | Publications & Reports

Mind the Gaps: The Case for Truly Comprehensive Sustainable Groundwater Management

Barton H. Thompson, Jr., Melissa M. Rohde, Jeanette K. Howard, Sandi Matsumoto

In 2014, California’s landmark Sustainable Groundwater Management Act (SGMA) promised comprehensive management of California’s groundwater. This report, Mind the Gaps: The Case for Truly…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Shifting geographies of legal cannabis production in California

Christopher Dillis, Eric Biber, Hekia Bodwitch, Van Butsic, Jennifer Carah, Phoebe Parker-Shames, Michael Polson, and Theodore Grantham

This study used permitting and GIS data to explore geographic characteristics of legal cannabis farms in California. The study found two divergent paths of development - one characterized by numerous,…

2021 | Freshwater | Science | Maps & Webmaps

California Natural Flows Webapp

Julie K.H. Zimmerman, Daren M. Carlisle, Jason T. May, Kirk R. Klausmeyer, Theodore E. Grantham, Larry R. Brown, Jeanette K. Howard, Nathaniel Rindlaub, Falk Schuetzenmeister

Water is essential for California’s people, economy, and environment. Centuries of water management through dams and diversion have altered the flows in many streams and rivers, which can harm…

2021 | Freshwater | Terrestrial | Planning | Technology | Science | Data

Natural Communities Commonly Associated with Groundwater Version 2.0 (NCCAG 2.0)

Kirk Klausmeyer, Jeanette Howard, Melissa Rohde, Charlotte Stanley

The first step to sustainably manage groundwater dependent ecosystems (GDEs) is to identify where they are. The Nature Conservancy developed a statewide spatial database that provides locations of…

2021 | Freshwater | Planning | Maps & Webmaps

ICONS: Interconnected Surface Water in the Central Valley

Charlotte Stanley, Kirk Klausmeyer

This dataset categorizes the rivers and streams in the Central Valley on the likelihood that they are interconnected surface water (ISW) -- surface water hydraulically connected to groundwater. The…

2021 | Freshwater | Planning | Science | Publications & Reports

Managing Groundwater to Ensure Ecosystem Function

Laurel Saito, Bill Christian, Jennifer Diffley, Holly Richter, Melissa M. Rohde, Scott A. Morrison

In this paper, we describe minimum provisions for planning, managing, and monitoring groundwater in a manner that collectively can lower the risk of harm to groundwater-dependent ecosystems and…

2021 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Rewilding Agricultural Landscapes: A California Study in Rebalancing the Needs of People and Nature

H. Scott Butterfield, T. Rodd Kelsey, and Abigail K. Hart, Editors

As the world population grows, so does the demand for food, putting unprecedented pressure on agricultural lands. At the same time, climate change, soil degradation, and water scarcity mean that…

2021 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Predicting shorebird distributions in managed wetland habitats to inform where to implement habitat programs

Erin Conlisk, Gregory H. Golet, Mark D. Reynolds, Blake Barbaree, Kristin Sesser, Kristen Byrd, Sam Veloz, Matthew E. Reiter

Highly mobile species, such as migratory birds, respond to seasonal and yearly changes in resource availability by moving among habitats. Understanding how they select among habitats is important for…

2020 | Freshwater | Terrestrial | Marine | Planning | Technology | Science | Publications & Reports

Nature-Based Climate Solutions: A Roadmap to Accelerate Action in California

Sydney J. Chamberlin, Michelle Passero, Ashley Conrad-Saydah, Tanushree Biswas, Charlotte K. Stanley

California’s natural and working lands – its forests, grasslands, wetlands, farmlands, rangeland, and urban green spaces – provide Californians with numerous environmental, social,…

2020 | Freshwater | Planning | Technology | Economics | Science | Publications & Reports

Base of fresh water, groundwater salinity and well distribution across California

Mary Kang, Debra Perrone, Ziming Wang, Scott Jasechko, Melissa M. Rohde

To ensure that California’s groundwater is sustainably managed in the future and over the long-term, current state definitions of what constitutes groundwater may need to be revised, according…

2020 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

Conservation of Mojave Desert springs and associated biota: status, threats, and policy opportunities

Sophie S. Parker, Andy Zdon, William T. Christian, Brian S. Cohen, Maura Palacios Mejia, Naomi S. Fraga, Emily E. Curd, Kiumars Edalati, Mark A. Renshaw

This paper presents results from the Mojave Desert Springs research project, and discusses why the conservation of these groundwater-dependent ecosystems is so critical to biodiversity. The authors…

2020 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2020 Annual Report

Brynn Pewtherer, Scott Morrison

The Nature Conservancy deploys science to help overcome major challenges facing people and nature. In today’s fast-paced world, turning threats to nature into opportunities for conservation…