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 number jumps to 60… >>

Surface Flows

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

Science in Action

Freshwater | Terrestrial | Marine | Science

Research for Impact

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

Freshwater | Science

Restoring California’s Largest River

How can we restore large rivers and floodplains to benefit nature and people?

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, and economic benefits, including greenhouse gas reductions (e.g., carbon sequestration). However, extreme heat events, droughts, floods, wildfires, development, and other anthropogenic impacts…


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 to this research published in PNAS. A research collaboration between McGill University, University of California Santa…


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 present results of a comprehensive survey of Mojave Desert springs including hydrological and ecological observations, and an…


2020 | Freshwater | Terrestrial | Science | Publications & Reports

A meta-analysis contrasting active versus passive restoration practices in dryland agricultural ecosystems

M. Florencia Miguel, H. Scott Butterfield, Christopher J. Lortie

This meta-analysis provides a global synthesis of the which restoration practices – active vs. passive – are most successful at restoring plants, animals, and other ecosystem functions to dryland agricultural (grazing and farmlands) ecosystems, including the San Joaquin Valley of California where The Nature Conservancy…


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

The utility of environmental DNA from sediment and water samples for recovery of observed plant and animal species from four Mojave Desert springs

Maura Palacios Mejia, Emily Curd, Kiumars Edalati, Mark A. Renshaw, Roy Dunn, Daniel Potter, Naomi Fraga, Jenna Moore, Justin Saiz, Robert Wayne, Sophie S. Parker

This paper presents results from the Mojave Desert Springs research project. The authors used an environmental DNA (eDNA) technique to assess biodiversity at four naturally occurring springs. They compared the effectiveness of detecting DNA in water and sediment with conventional field survey and…


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

Bridging the knowledge‐implementation gap between agency and academia: A case study of a graduate research experience

Aviv Karasov‐Olson, Alicia K. Bird, Amy C. Collins, Emily E. Graves, Julea A. Shaw, Eric F. Tymstra, T. Rodd Kelsey, Mark W. Schwartz

Conservation biology is particularly susceptible to the knowledge‐implementation gap where academic pursuits do not always meet the needs of practitioners. Providing future practitioners with relevant training and experiences as graduate students can help narrow this gap. An example of one such experience was a partnership…


2020 | Freshwater | Terrestrial | Technology | Science | Maps & Webmaps

Planting Stormwater Solutions

Brian Cohen, Kelsey Jessup, Sophie Parker, John Randall, Jill Sourial

Cities across Southern California are investing in new infrastructure to address the challenges of stormwater management. We promote the use of nature-based solutions to ensure projects both treat stormwater and yield multiple additional benefits. TNC’s spatial analyses, summarized in this poster, help prioritize where to site…


2020 | Freshwater | Science | Publications & Reports

Groundwater Thresholds for Ecosystems: A Guide for Practitioners

Melissa M. Rohde, Laurel Saito, Ryan Smith

In addition to benefiting humans, groundwater is a critical water supply to many ecosystems, providing a buffer during dry periods and critical habitat for rare and endemic species. Increasing groundwater use to meet human water demands can outcompete these ecosystem water needs, causing irreversible damage to…


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

Shaping land use change and ecosystem restoration in a water-stressed agricultural landscape to achieve multiple benefits

Benjamin P. Bryant, T R. Kelsey, Adrian L. Vogl, Stacey A. Wolny, Duncan J. MacEwan, Paul C. Selmants, Tanushree Biswas, H S. Butterfield

Irrigated agriculture has grown rapidly over the last 50 years, helping food production keep pace with population growth, but also leading to significant habitat and biodiversity loss globally. Now, in some regions, land degradation and overtaxed water resources mean historical production levels may need to…


2020 | Freshwater | Science | Publications & Reports

Evaluating and Protecting Environmental Water Assets: A Guide for Land Conservation Practitioners

Author: Chris Alford, Editors and Reviewers: Amy Campbell, Monty Schmitt, Sara Press, Wendy Eliot, Bob Neale

Evaluating and Protecting Environmental Water Assets: A Guide for Land Conservation Practitioners, a publication by TNC and the Sonoma Land Trust (SLT), provides provides easy to understand guidance, resources, and tools that California land trusts, open space districts, resource conservation districts, and others can…


2020 | Freshwater | Science | Publications & Reports

Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

Michael J. Paul, Ben Jessup, Larry R. Brown, James L. Carter, Marco Cantonatie, Donald F. Charles, Jeroen Gerritsena, David B. Herbst, Rosalina Stancheva, Jeanette Howard, Bill Isham, Rex Lowe, Raphael D. Mazor, Patina K. Mendez, Peter R. Ode, Alison O'Dowd, John Olson, Yangdong Pan, Andrew C. Rehn, Sarah Spaulding, Martha Sutula, Susanna Theroux

Water resource agencies assess stream water quality by determining the bugs and algae present to develop biotic indices. Yet translating these technical measures into meaningful language is difficult. This study finds that by placing technical numerical measures/indices into categories of condition allows resource manages to…


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

Mojave Desert Springs: setting an ecological baseline

Sophie S. Parker

This article appears in the Desert Report, a news publication of the Sierra Club California/Nevada Desert Committee. The article introduces the Mojave Springs Research Project, led by The Nature Conservancy, that involves a research collaboration with UCLA, the California Botanic Garden, and Partner Engineering and…


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

Jack and Laura Dangermond Preserve Integrated Resources Management Plan

Butterfield, H.S., M. Reynolds , M.G. Gleason, M. Merrifield, B.S. Cohen, W.N. Heady, D. Cameron, T. Rick, E. Inlander, M. Katkowski, L. Riege, J. Knapp, S. Gennet, G. Gorga, K. Lin, K. Easterday, B. Leahy, M. Bell

This Plan frames the biological and cultural significance and provides the short- and long-term goals, objectives, and priority actions for the Jack and Laura Dangermond Preserve.


2020 | Freshwater | Marine | Science | Microsite

State of Salmon in California

Sally Liu, Megan Webb, Jeanette Howard, Jennifer Carah

Chinook, coho and steelhead were once tremendously abundant in most of California’s major rivers and streams. As recently as the 1960s, salmon and steelhead were so plentiful in streams that horses would get spooked trying to cross. Due to water damming and diversions, habitat degradation and…


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

Technology Catalyst Fund - 2019 Annual Report

Matt Merrifield, Sue Pollock

Conservation needs to harness technology to meet the complex challenges of today’s world. The Technology Catalyst Fund provides early stage resources to investigate and prototype technologies that have high potential for impact and have effectively disrupted the status quo in other sectors. The Fund empowers…


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

Conservation Science Catalyst Fund - 2019 Annual Report

Brynn Pewtherer

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 requires agility. The Conservation Science Catalyst Fund enables our science team to mobilize quickly — and produce the information…


2020 | Freshwater | Science | Publications & Reports

A functional flows approach to selecting ecologically relevant flow metrics for environmental flow applications

Sarah M. Yarnell, Eric D. Stein, J. Angus Webb, Theodore Grantham, Rob A. Lusardi, Julie Zimmerman, Ryan A. Peek, Belize A. Lane, Jeanette Howard, Samuel Sandoval-Solis

The authors of this paper are engaged in developing flow criteria for California Streams through California Environmental Flows Framework (CEFF) collaboration. The effort is funded by the State Water Resources Control Board. This collaboration is a working group within the California Water Quality Monitoring Council. This…


2019 | Freshwater | Planning | Science | Publications & Reports

Dynamic multibenefit solutions for global water challenges

Melissa M. Rohde, Mark Reynolds, Jeanette Howard

In this article, the authors provide an example of how dynamic multi-benefit solutions used to provide “pop-up” wetland habitat for migratory birds also replenishing depleted aquifers to create environmental and water supply benefits and broadens it to the global scale. Additionally, this article outlines six…