SNAPP TEAM:Water Flow Impact
How can nature-based solutions alleviate the risks posed by both water shortages and excess water?

Floods and droughts are expected to increase with continued shifts in climate. Maintaining reliable freshwater flows is essential for human health and well-being, sustainable economic development, and ecological integrity. This entails a minimum amount of water in rivers and streams during dry seasons, and high flows that are within natural ranges of variation during wet seasons. To effectively implement the right actions in the right places, managers and planners need to understand how and where different nature-based solutions can contribute to reliable freshwater flows.


OUR APPROACH: To address this issue, hydrology and adaptation experts are examining the science, then working with stakeholder group representatives to interpret its meaning through the lens of those groups (downstream utilities and municipal managers, humanitarian groups working with upstream communities, and aquatic ecologists).

This project is funded in part by the Gordon and Betty Moore Foundation through Grant GBMF7100 to The Nature Conservancy to support the work of the Science for Nature and People Partnership (SNAPP).

Team Status: COMPLETED
Team Critical Challenges: Food and Freshwater, Climate Resilience

A review of the empirical evidence
Our research confirmed that context matters. Surface and groundwater resources (in locations & quantities where people can take advantage of them) are generated by a complex interaction of weather, vegetation, soils, geology, and terrain, and nature-based solutions can only influence some of these factors. Restoring forests and wetlands can often help to reduce peak flows, and implementing best practices in production lands can improve water retention in soils, making them more drought-resistant.
Information gaps
We found that most field studies are not measuring and tracking the right metrics at a scale to match the ambition of proponents of nature-based solutions. Existing evidence helps with predictions of how small-scale projects can affect local water cycling in some geographies, but we still have a lot to learn about how a growing number of small-scale tree-planting efforts or other commonly promoted nature-based solutions in agriculture or rangelands will scale up to influence regional downstream water flows.
Some basic guidance
The science is clear that protection of intact natural ecosystems is much more effective at delivering water security benefits than restoring an ecosystem once it’s been lost. We also know that the scale of implementation needs to match the scale of ambition — we cannot expect to improve water security for downstream populations or industries through small investments in nature upstream. If we invest as much in the science-based design of specific nature-based projects as we would in conventional engineered water infrastructure, we can make informed decisions with the best combination of approaches.


“To scale up smart and effective investment in nature-based solutions for water security, decision makers need a more clear understanding of expected impacts, based on real-world evidence. This SNAPP group provides a view into that evidence and packages it for people who don’t have a degree in hydrology.”

– Adrian Vogl, Project co-Leader

Key Products
Assessing the water quantity benefits that flow from nature-based solutions

This slide deck provides a high-level summary of this SNAPP project’s findings.

Navigating the Transition to a Climate-Resilient Future

Watch a recording of an online session with contributions from team members.

Nature-Based Solutions and Water Security

Edited volume from 2021 with a chapter informed by this project’s findings.

Literature Review Datasets

Evidence of impacts on water flows for both forest and wetland protection & restoration, and agriculture & rangeland management practices.

OpEd: Building Back Better and Greener: Embracing Nature-Based Solutions for Water

A hard look at the published evidence on what happens to water flows when common nature-based solutions are implemented is relevant for public policy

Click here to see more products from this SNAPP Team
Robin Abell
Conservation International
Kari Vigerstol
The Nature Conservancy
Adrian Vogl
Natural Capital Project and The World Bank Group
Carlos Aguilar
Catholic Relief Services
Newsha Ajami
Stanford University
Craig Beatty
World Wildlife Fund
Vivien Bonnesoeur
Kate Brauman
University of Minnesota
Gregg Brill
Pacific Institute
Wouter Buytaert
Imperial College
Jan Cassin
James Dennedy-Frank
Lawrence Berkeley National Laboratory
Daniela Giardina
Lissa Glasgo
Global Impact Investing Network
Tom Gleeson
University of Victoria
Ted Grantham
University of California, Berkeley
Paul Hicks
Catholic Relief Services
Astrid Hillers
Global Environment Facility
Stan Kang
The Nature Conservancy
Wendy Larson
John Matthews
Alliance for Global Water Adaptation
Neil McIntyre
University of Queensland
Robin Miller
Kate Moran
WaterNow Alliance
Sydney Moss
Natural Capital Project and Stanford University
Raul Muñoz
Inter-American Development Bank
Virginia Newton-Lewis
Suzanne Ozment
World Resources Institute
Robert Stallard
U.S. Geological Survey
Rebecca Tharme
River Futures
Nick Wobbrock
Blue Forest Conservation
Winston Yu
The World Bank
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