United States 

Department Of Agriculture

Forest Service 

Pacific Northwest 

Research Station

General Technical Report

PNW-GTR-812

June 2010
Authors*

Michael J. Furniss, Pacific Northwest Research Station

Brian P. Staab, Pacific Northwest Region

Sherry Hazelhurst, Washington Office National Forest System

Caty F. Clifton, Umatilla National Forest

Ken B. Roby, Lassen National Forest, retired

Bonnie L. Ilhardt, Eastern Regional Office

Elizabeth B. Larry, Washington Office State and Private Forestry

Albert H. Todd, Washington Office State and Private Forestry

Leslie M. Reid, Pacific Southwest Research Station 

Sarah J. Hines, Northeastern State and Private Forestry

Karen A. Bennett, Pacific Northwest Region

Charlie H. Luce, Rocky Mountain Research Station

Pamela J. Edwards, Northern Research Station

*All are USDA Forest Service, with units specified

Major Contributors*

Pete Bisson, Pacific Northwest Research Station

Hilaire Bojonnel, Washington Office National Forest Systems

Thomas C. Brown, Rocky Mountain Research Station 

Christopher P. Carlson, Washington Office National Forest System

Jessica Halofsky, Pacific Northwest Research Station 

William Hansen, Francis Marion-Sumter National Forest

Polly E. Hays, Rocky Mountain Regional Office

Barry Hill, Pacific Southwest Regional Office

Jim Morrison, Northern Regional Office

Trista M. Patterson, Pacific Northwest Research Station

Contributors and Reviewers**

Daina Apple, Washington Office Research and Development

Kelly Burnett, Pacific Northwest Research Station 

Courtney Cloyd, Washington Office National Forest System

Anne Connor, Clearwater National Forest

David Cleaves, Washington Office Research and Development

Robert Cunningham, Washington Office National Forest System

Matt Dare, Rocky Mountain Research Station

Ron Dunlap, Washington Office National Forest System

Rick Edwards, Pacific Northwest Research Station

Kelly Elder, Rocky Mountain Research Station 

Pam Froemke, Rocky Mountain Research Station

Robert Gecy, Blue Mountains Forest Plan Revision Team

Gordon Grant, Pacific Northwest Research Station 

Deborah Hayes, Washington Office Research and Development

Rick Hopson, Intermountain Regional Office 

Dan Isaak, Rocky Mountain Research Station

Randy Kolka, Northern Research Station

Suzanne Krieger, Southern Regional Office 

Russ Lafayette, Eastern Regional Office

Mike Leonard, Prescott National Forest

Tom Lisle, Pacific Southwest Research Station

Bruce McCammon, Pacific Northwest Regional Office, retired 

Kevin McGuire, Plymouth State University

Greg McPherson, Pacific Southwest Research Station

Jim Maxwell, Rocky Mountain Regional Office

David M. Merritt, Washington Office Stream Systems 

 Technology Center

Randy Moore, Pacific Southwest Region

David Mott, Alaska Regional Office

John Potyondy, Stream Systems Technology Center 

Charles C. Rhoades, Rocky Mountain Research Station

Larry Schmidt, Stream Systems Technology Center, retired

Jim Sedell, Pacific Southwest Research Station, retired

Rob Spangler, Chugach National Forest

Rick Swanson, Washington Office National Forest System

Traci Sylte, Lolo National Forest

Rick Swanson, Washington Office National Forest System 

Jean A. Thomas, Washington Office National Forest System

Jim Vose, Southern Research Station

Mark Weinhold, White Mountain National Forest

Debra Whitall, National Partnership Office 

Steve Widowski, Shawnee National Forest

Lois Witte, Rocky Mountain Region Office of General Council

Steve Wondzell, Pacific Northwest Research Station

Anne Zimmermann, Washington Office National Forest System

**All are USDA Forest Service, with units specified, 

 except Kevin McGuire

Editors

Lynn Sullivan, Pacific Northwest Research Station

Kathryn Ronnenberg, Pacific Northwest Research Station

Design and Layout

April Kimmerly, Peters Kimmerly Design Associates

Keith Routman, Pacific Northwest Research Station

Photographs

Cover photo © by Gaëtan Bourque

Pages 1, 13, 41, 49, and 60: Tom Iraci, USDA Forest Service

Page 31: Dean Gesch, U.S. Geological Survey

All uncredited photos by USDA Forest Service

Cover and Divider Field Sketches

Luna B. Leopold, Antonio Llanos, Terry Kaplan-Henry

AUTHORS AND CONTRIBUTORS

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ABSTRACT

WATER, CLIMATE CHANGE, AND FORESTS

Watershed Stewardship for a Changing Climate

Abstract 

Water from forested watersheds provides irreplaceable habitat for 

aquatic and riparian species and supports our homes, farms, industries, 

and energy production. Secure, high-quality water from forests is 

fundamental to our prosperity and our stewardship responsibility.

Yet population pressures, land uses, and rapid climate change combine 

to seriously threaten these waters and the resilience of watersheds in 

most places. Forest land managers are expected to anticipate and 

respond to these threats and steward forested watersheds to ensure 

the sustained protection and provision of water and the services 

it provides. 

Effective, constructive watershed stewardship requires that we think, 

collaborate, and act. We think to understand the values at risk and how 

watersheds can remain resilient, and we support our thinking with 

knowledge sharing and planning. We collaborate to develop common 

understandings and goals for watersheds and a robust, durable capacity 

for response that includes all stakeholders and is guided by science. 

We act to secure and steward resilient watersheds that will continue to 

provide crucial habitats and water supplies in the coming century by 

implementing practices that protect, maintain, and restore watershed 

processes and services.

Recommended Citation

Furniss, Michael J.; Staab, Brian P.; Hazelhurst, Sherry; Clifton, 

Cathrine F.; Roby, Kenneth B.; Ilhadrt, Bonnie L.; Larry, Elizabeth B.; 

Todd, Albert H.; Reid, Leslie M.; Hines, Sarah J.; Bennett, Karen A.; 

Luce, Charles H.; Edwards, Pamela J. 2010. Water, climate change, and 

forests: watershed stewardship for a changing climate. Gen. Tech. Rep. 

PNW-GTR-812. Portland, OR: U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Research Station. 75 p.

Pacific Northwest Research Station

Web site http://www.fs.fed.us./pnw/

Telephone (503) 808-2592

Publication requests (503) 808-2138

FAX (505) 808-2130

E-mail pnw_pnwpubs@fs.fed.us

Mailing address Publications Distribution

Pacific Northwest Research Station

P.O. Box 3890

Portland, OR 97208-3890
CONTENTS

CONTENTS 

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

BACKGROUND

Forests and Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Climate Change: Hydrologic Responses

 and Ecosystem Services .. . . . . . . . . . . . . . . . . . . . . . 13

MOVING FORWARD

Think .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Collaborate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Act . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

CLOSING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

EXAMPLES OF WATERSHED STEWARDSHIP . . . . . 68

WATER, CLIMATE CHANGE, AND FORESTS

Watershed Stewardship for a Changing Climate
INTRODUCTION | Water, Climate Change, and Forests

WATER, CLIMATE CHANGE, AND FORESTS | 1
2 | GENERAL TECHNICAL REPORT PNW-GTR-812

INTRODUCTION

Clean, fresh water is our most important natural 

resource. It is essential to sustaining people, agriculture, 

industry, and ecosystems. It is also a resource in crisis 

worldwide. Existing freshwater supplies are highly stressed 

in many parts of the world, including the United States, 

owing to mismatches between supply and demand (fig. 1).

Water pollution, invasive species, and increased 

urban and rural development further threaten our 

capacity to supply adequate clean water and support the ecosystems upon which society depends. 

In some areas, these conditions are causing significant 

social conflict and competition between water users. 

Climate change will likely intensify these problems by 

altering the quantity, quality, timing, and distribution of 

water. For example, in some areas, less winter snow and earlier spring runoff will reduce water availability during the 

summer and fall. Altered streamflow and erosion regimes 

and higher air temperatures will affect water quality and 

aquatic ecosystems. Fire and flood frequency and severity 

will likely increase, and stream networks may contract. 

Addressing these fundamental hydrologic changes and 

their interactions is a formidable and urgent challenge, but 

there is much we can do to respond. Actions taken now can 

enable society and ecosystems to adapt to the changes that 

have already occurred or been initiated, thereby reducing 

future impacts and conflicts. Forest management provides 

important opportunities for adaptation because forests are 

the most plentiful source of the cleanest water; are the last 

refuges of valued species that have been extirpated from 

other areas; are often located in the mountains and thus 

provide the first opportunity to store, filter, and release 

water for downstream uses; and provide the earliest opportunity to measure precipitation and streamflows, thereby 

allowing water managers to forecast supplies and adjust 

downstream water storage systems. 

Figure 1—Global population with relatively low (blue) and high (red) water stress. Water stress is measured with an index of water use 

and streamflow, DIA/Q, where DIA is the use of water by homes, businesses, industry, and agriculture and Q is streamflow, both on a 

mean annual basis (Vörösmarty et al. 2000).

Forests are key determinants of water supply, quality, and quantity, in both 

developing and developed countries. The importance of forests as watersheds 

may increase substantially in the next few decades, as freshwater resources 

become increasingly scarce... 

— Bates et al. (2008) 
WATER, CLIMATE CHANGE, AND FORESTS | 3

Adaptation is a learning process. Mistakes will be made. 

Some actions will be incorrect; others will occur too late. 

Learning from these mistakes will be essential. Planning, 

collaboration, and integrated research will enhance the 

speed and ease with which we learn. Our hope is that the 

collected observations, summaries, ideas, and examples 

herein contribute to the understanding of many and inspire 

steps forward to secure a future with clean and adequate 

water supplies.

Mitigate we might, adapt we must. 

— William Nordhaus, 1994

Two types of actions can be taken 

in response to climate change: 

Adaptation refers to changes in 

natural or human systems that 

enable society to moderate the 

impacts or exploit benefits of climate 

change. Restoring degraded habitats, 

conserving water, or gathering 

more information on snowpacks 

are examples that help people and 

ecosystems adapt to changing climate. 

Mitigation can reduce future 

warming by decreasing emissions 

and enhancing sinks of greenhouse 

gases (Julius and West 2008, IPCC 

2001). For example, water in forests 

can be used in high-head, low-flow 

hydroelectric facilities to produce power 

with minimal greenhouse gas emissions. 

This document is about adaptation, 

specifically in the context of forests, 

water, and aquatic ecosystems.

INTRODUCTION

This report describes some adaptation opportunities associated with forest management, specifically in the context of 

water and aquatic ecosystems. The first two sections describe 

the importance of forests to the Nation’s water resources and 

summarize observed and projected effects of climate change 

on the hydrologic cycle and forested watersheds. Following 

sections outline a feasible framework for response, focused 

on thinking, collaborating, and acting.

A central theme of this report is that adaptation actions 

should generally focus on maintaining or improving watersheds because healthy, resilient watersheds are more likely 

to supply desired ecological services in the face of climate 

change (US GAO 2007). This will necessitate actions that 

address not only the effects of climate change itself, but all 

of the dominant stressors negatively affecting watersheds. 

Specific actions include advancing and sharing knowledge 

about water and climate change, incorporating climate 

change into planning, implementing practices to protect 

and restore key watershed processes and services, encouraging innovation, connecting water users to their watersheds 

through markets and outreach programs, and leveraging 

efforts to reduce water demand. Some of these are novel 

practices and will thus require more exploration and definition as they are applied. Others are not entirely new, but will 

need to be applied in new ways and at unprecedented scales 

in the future. Extensive collaboration and cooperation will 

be essential.

The actions described in this report represent some initial 

steps that can be taken until more comprehensive adaptation 

strategies are developed and limitations in knowledge 

and capacity are addressed. The Forest Service is uniquely 

positioned to participate in these efforts and to help define 

future ones (see box on next page). The agency manages 

193 million acres of national forests and grasslands, connects with thousands of domestic and international communities through many different programs, conducts basic 

and applied research on water and forests, and has a large 

professional work force. The national forests, for example, 

can be managed to supply clean water for downstream users 

and support species that depend on aquatic and riparian 

habitats. Forest Service research can continue to illuminate 

connections between climate, forests, and water, enabling 

forest management to be tuned to meet tomorrow’s needs. 

Perhaps most importantly, partnerships between federal 

land managers, states, private landowners, researchers, and 

the international community can be strengthened to sustain 

freshwater systems in an era of unprecedented challenges. 
4 | GENERAL TECHNICAL REPORT PNW-GTR-812

In the 1880s and 1890s, the United States experienced widespread flooding and erosion. The resulting damage led to a compelling question: Could floods be controlled by land treatments 

in the headwaters of large rivers? In response, Congress in 1897 

reserved headwater forests for the purpose of “securing favorable conditions of water flows.” In 1905, Congress established a 

new agency, the Forest Service, to manage the forest reserves 

for high-quality water and timber in the public’s interest. Gifford 

Pinchot was asked to lead the organization as the first Chief. 

Those forest reserves and other lands acquired since then now 

make up the National Forest System.

Pinchot and federal policymakers of the time were most concerned about preserving forests to sustain critical watershed 

functions. In his 1905 “Primer on Forestry” Pinchot wrote: 

“A forest, large or small, may render its service in many ways. 

It may reach its highest usefulness by standing as a safeguard 

against floods, winds, snow slides.” Five years later, Henry S. 

Graves, the agency's second Chief, established Wagon Wheel 

Gap Experimental Watershed on the Rio Grande National Forest 

in Colorado to study the effects of forest management on water. 

Today, the agency’s mission is to sustain the health, diversity, 

and productivity of the Nation’s forests and grasslands to meet 

the needs of present and future generations. This mission rests 

on a tradition of managing forests to protect the Nation’s water 

supplies, the importance of which increases dramatically in the 

face of the challenges posed by climate change. The Forest 

Service can help society meet those challenges by maintaining, 

adapting, and expanding its current activities and programs 

associated with water resources. 

Tapping our roots: water and the Forest Service

National Forests and Grasslands

• Manages 193 million acres (78 million hectares) of national 

forests and grasslands that contain 400,000 miles (644,000 

kilometers) of streams, 3 million acres (1.2 million hectares) 

of lakes, and many aquifer systems that serve as the largest 

source of drinking water in the contiguous United States.

• Administers over 90,000 water rights in cooperation 

with states.

• Protects and improves habitat for more than 550 rare, 

threatened, and endangered aquatic species.

• Provides outdoor recreation to more than 130 million visitors 

per year near streams, lakes, and other water resources.

• Supports access and operations for more than 200 

hydroelectric facilities.

• Improves, protects, and enhances watershed health 

during forest management activities on public lands.

• Restores degraded watersheds, streams, and wetlands.

State and Private Forests

• Helps landowners and communities manage forest lands 

that provide drinking water to more than 180 million people.

• Partners with states, local governments, and private 

partners to protect, enhance, and restore forested 

watersheds and to promote the understanding and 

use of agroforestry in agricultural watersheds.

• Assists urban communities to conserve, expand, 

and manage green infrastructure and open space 

to reduce development impacts. 

• Works to permanently conserve open space critical 

to watershed health.

• Detects, suppresses, eradicates, or prevents 

destructive forest pests and invasive species that 

threaten watershed health.

• Works with communities to reduce wildfire risks 

to priority watersheds.

Research and Development

• Measures streamflow, snowpacks, weather, and 

water quality in long-term experimental watersheds 

to understand how forests affect water availability, 

timing, and quality.

• Studies effects of climate change, major disturbances, 

water management, land use, and energy development 

on streams and aquatic resources. 

• Provides information needed by land and water 

managers to determine how their actions affect 

water and aquatic habitat and how to more effectively 

protect and restore watersheds.

• Provides strategies for solving complex environmental 

problems that involve multiple conflicting values and 

cumulative effects.

• Develops strategies, methods, and equipment for 

restoring ecosystems and measuring the improvements.

• Tracks trends in atmospheric, hydrologic, vegetation, 

and socioeconomic conditions.

International Forestry

• Works with U.S. international agencies, other countries, 

and nonprofit partners to assist countries around the 

world in protecting and managing important forests, 

watersheds, and ecosystem services.

• Develops and implements management strategies 

that protect the values of transboundary watersheds 

for all stakeholders.

• Shares information and technology to help address 

public health, emergency response, and other issues 

involving forests. 

Forest Service role in water and watershed stewardship

INTRODUCTION
 BACKGROUND | Forests and Water

WATER, CLIMATE CHANGE, AND FORESTS | 5
6 | GENERAL TECHNICAL REPORT PNW-GTR-812

Alaska Hawaii National Forest System Puerto Rico

Forest cover

Rivers

Forests supply many ecosystem services, which are the benefits people 

derive from nature. This chapter 

describes those services associated 

with the provision of water and other 

critical watershed functions, known 

as watershed services. Many of these 

services are vital for life and human 

well-being and cannot be replaced (see 

box on next page). 

Forested watersheds, for example, are 

essential to sustaining the Nation’s 

freshwater supply. More than 50 percent of this supply originates on forest 

lands. In the Western United States, 

65 percent of the water supply comes 

from forests. National forests alone 

provide 18 percent of the Nation’s 

water, and over half the water in the 

West (Brown et al. 2008) (see fig. 2). 

High-elevation forests are particularly 

important because these headwater 

catchments store vast quantities of 

water as snow during the winter, then 

release it gradually through spring 

and summer, sustaining downstream 

water supplies during dry seasons. 

Forested watersheds reduce storm 

runoff, stabilize streambanks, shade 

surface water, cycle nutrients, and 

filter pollutants. Consequently, the 

quality of this water is typically the 

best in the Nation (Brown and Binkley 

1994). Water from these areas is often 

cooler and generally contains less 

sediment, nutrients, and chemicals 

than water from other lands (Binkley 

et al. 2004, Chang 2003, Dissmeyer 

2000, Wear and Greis 2002). Streams 

in forested watersheds also often 

provide high-quality habitat for 

sensitive aquatic species. 

This large volume of high-quality 

water from forests is immensely 

valuable because it supports many 

uses, ranging from meeting basic 

human needs to providing habitat for 

rare and endangered species. It fills 

our rivers, streams, lakes, and aquifers; 

sustains fish, plants, and wildlife; 

supports food, energy, and industrial 

production; enables navigation; and 

Figure 2—The areas that produce the largest volumes of water in the United States are 

forested. The quality of this water is typically the best in the Nation. (A) Forests in the 

National Forest System. (B) Mean annual water supply per unit area of land (mm/year), 

1953–1994 (from Brown et al. 2008).

Forests and Water | Forests Provide Many Ecosystem Services. 

Watershed Services Are the Most Important. 

BACKGROUND | FORESTS AND WATER

A

B

pours from the faucets of our homes 

and businesses. Some of these uses 

are described in further detail in the 

following sections. 
WATER, CLIMATE CHANGE, AND FORESTS | 7

Ecosystem services are benefits obtained from nature that 

are critical to human health and well-being. These services are 

typically grouped into four categories: regulating, supporting, 

provisioning, and cultural (Millennium Ecosystem Assessment 

• Regulating services are benefits obtained from the 

regulation of ecosystem processes. Examples include flow 

regulation (surface and groundwater flow), erosion control, 

water purification, and water temperature control.

• Provisioning services include products obtained from 

ecosystems. Principal watershed services from forests 

include freshwater supply for domestic, agricultural, 

commercial, industrial, and other uses.

• Supporting services include the basic ecological elements 

and processes necessary to sustain ecosystems. These 

include processes like soil development, and nutrient and 

water cycling. 

• Cultural services are nonmaterial benefits people obtain 

from forests through recreation, spiritual enrichment, 

reflection, and aesthetic experiences. Forests provide 

significant water-based recreational opportunities in 

the form of boating, fishing, skiing, camping, hiking, 

sightseeing, and other activities. They also offer education 

and interpretation opportunities and afford protection for 

culturally and historically important water resources. 

Figure 3—Watershed services.

These services are provided naturally by well-functioning 

ecosystems. They are immensely valuable, because if they are 

compromised, replacing them is often not possible or is very 

costly. Ecological economists have begun efforts to value some 

ecosystem services, with the ultimate goal of enhancing efforts 

to more efficiently use, maintain, and protect them. Provision of 

water is a vital ecosystem service provided by forests, so one 

might ask: What is the value of water?

Water is essential for life——The Nation’s total supply of 

water and ecosystem services provided by healthy watersheds 

are priceless. Because forests provide so much of the country’s 

water, they are of tremendous importance. A lower bound on 

the total value of water from national forests alone is estimated 

to be several billions of dollars per year (Brown 2004). An 

accurate estimate of the total value is impossible to achieve, 

however, because only some products and services are 

assigned an economic market value. Moreover, these values 

apply at the margin, whereas forests tend to provide a large 

(nonmarginal) portion of the total water supply (Brown 2004). 

What are ecosystem services? 

BACKGROUND | FORESTS AND WATER

Regulating 

services

Supporting 

services

Provisioning 

services

Cultural 

services

2005). Watershed services are a subset of ecosystem services 

that are associated with water and watersheds (fig. 3). Definitions 

of these different types of services and examples pertaining to 

watersheds are provided below. 
8 | GENERAL TECHNICAL REPORT PNW-GTR-812

Domestic Use

One of the most important uses of water from forests is 

domestic consumption. As presented in Water and the Forest 

Service (Sedell et al. 2000), at least 3,400 cities and towns in 

43 states, with a total population of more than 60 million 

people, obtain at least a portion of their drinking water from 

watersheds located on National Forest System lands. In the 

Rocky Mountain Region alone, more than 33 million people 

in 13 states are dependent on water from national forests 

(fig. 4). State and private forests are critical as well, particularly in the Eastern United States. For example, New York 

City satisfies the needs of more than 10 million people by 

tapping water from the Catskill and Delaware watersheds, 

which are 90 percent forested. To date, this has enabled the 

city to avoid substantial water treatment costs (Germain et 

al. 2007).

Irrigated Agricultural Use

Irrigation for agriculture is a major use of freshwater, 

accounting for 40 percent of all withdrawals in the United 

States (Hutson et al. 2004). It is even more important in the 

arid West, where these withdrawals compose 81 percent of 

the total extraction in 11 states (Brown et al. 2008). This use 

is highly concentrated, with California (32 percent), Idaho 

(18 percent), and Colorado (12 percent) collectively using 62 

percent of western irrigation water to irrigate 17.25 million 

acres (7 million hectares) (fig. 5). These irrigated lands typically support high-value crops, making irrigated agriculture 

a major economic sector in Western States. Streamflow is an 

important source of this irrigation water, large portions of 

which originate on national forests (Brown et al. 2008)

Figure 4—Counties depending on water from the national forests of the Rocky Mountain Region.

BACKGROUND | FORESTS AND WATER

Texas

Counties using water from

Rocky Mountain national forests

Population of 100,000 or less

100,001—500,000

500,001—1,000,000

1,000,001—1,500,000

1,501,001 or greater

Rocky Mountain national forests

River basin boundaries

Yellowstone

River Basin

Cheyenne

River Basin

Platte

River Basin

Arkansas

River Basin

Rio Grande

River Basin

Colorado

River Basin

LOS ANGELES

SAN DIEGO PHOENIX

LAS VEGAS

SALT LAKE CITY

BILLINGS

SHERIDAN

RAPID CITY

CHEYENNE

DENVER

ALBUQUERQUE

TULSA

WICHITA

OMAHA

BISMARCK

M O N T A N A

U T A H

N E V A D A

C A L I F O R N I A

A R I Z O N A

N E W

M E X I C O

C O L O R A D O

W Y O M I N G

O K L A H O M A

K A N S A S

N E B R A S K A

A R I Z O N A

C O L O R A D O

W Y O M I N G

O K L A H O M A

N E B R A S K A

S O U T H

D A K O T A

N O R T H

D A K O T A
WATER, CLIMATE CHANGE, AND FORESTS | 9

Hydropower Production 

Production of electricity is essential to modern societies. 

About 6 percent of the nation’s electricity is supplied by 

hydroelectric facilities (U.S. Department of Energy 2003). 

This is enough to power 28 million households and is the 

energy equivalent of about 500 million barrels of oil each year. 

In the West, hydropower supplies an even greater percentage 

of energy, amounting to about 15 percent in California, 

Figure 5—Hydroelectric dams in the United States, both on and off national forests. 

for example. Although these facilities can have substantial 

impacts on aquatic ecosystems, they provide a renewable 

source of power with minimal greenhouse gas emissions.

Most of the water that drives these facilities flows from 

forests. With more than 325 hydroelectric dams, representing 

15 percent of all facilities nationwide, national forests play an 

essential role in hydropower generation (fig. 5). 

BACKGROUND | FORESTS AND WATER
10 | GENERAL TECHNICAL REPORT PNW-GTR-812

Aquatic Species and Habitats

Aquatic species are some of the most imperiled in the 

United States and the world (Richter et al. 1997). Many 

of these species inhabit forest lands because the quality 

of water and other habitat features are often much better than in other areas. National forests, in particular, are 

critically important for the conservation of these species, 

as they provide habitat for more than 550 rare, threatened, and endangered aquatic species (fig. 6). More than 

two-thirds of watersheds containing at-risk freshwater 

mussels include lands managed by the Forest Service. In the 

interior Columbia River basin, more than 66 percent of the 

remaining spawning and rearing habitats for species like 

bull trout (Salvelinus confluentus), stream-type Chinook 

salmon (Oncorhynchus tshawytscha), and westslope 

cutthroat trout (Oncorhynchus clarki lewisi) are found on 

federal lands, principally national forests (Lee et al. 1997, 

Rieman et al. 2007). In the Southwest, virtually all known 

remaining populations of Colorado River cutthroat trout 

(Oncorhynchus clarki pleuritieus), gila trout (Oncorhynchus 

gilae gilae), and Apache trout (Oncorhynchus apache) occur 

on federal lands (Rinne 1990, Young et al. 1996).

These lands are equally important in the Southeast, where 

about two-thirds of the crayfish species in North America 

reside, many of them on national forests (Taylor et al. 2007). 

The value of these forest lands for the conservation and 

recovery of aquatic species will increase dramatically in the 

future as private lands are further developed and societal 

demands for water increase.

Figure 6—Number of aquatic species listed as threatened or endangered under the Endangered Species Act in watersheds that contain 

National Forest System lands (Brown and Froemke, in press).

BACKGROUND | FORESTS AND WATER
WATER, CLIMATE CHANGE, AND FORESTS | 11

Critical Watershed Services Are 

Threatened by Existing Impacts 

Although forests naturally supply a steady flow of watershed 

services, long-term provision of these services is not guaranteed. The amount and quality of these services depend 

on the condition of the forest—when watershed conditions 

are stressed or degraded, critical services can be threatened 

or compromised. Today, essential watershed services are 

threatened by a variety of human impacts on watersheds 

and aquatic ecosystems. 

In many areas, these systems have suffered from significant 

alterations of natural flow patterns, water pollution, and 

Figure 7—Level of development pressure on primary drinking water supplies in the Northeast United States. Red areas indicate a 

combination of highly important watersheds with severe pressure, as measured by an index, ability to produce clean water (APCW) 

(Barnes et al. 2009). 

BACKGROUND | FORESTS AND WATER

Concord

Newark New York

Philadelphia

Baltimore

Pittsburgh

Cleveland

Toledo

Cincinnati

Louisville

Chicago

St. Louis

Memphis

Buffalo

Detroit

Milwaukee

Minneapolis

Omaha

Kansas

City

Hartford Providence

Annapolis

Dover

Trenton

Harrisburg

Charleston

Columbus

Indianapolis Springfield

Albany Boston

Montpelier

Augusta

Madison Lansing

St. Paul

Jefferson

City

Des

Moines

Washington

Newark New York

Philadelphia

Baltimore

Pittsburgh

Cleveland

Toledo

Cincinnati

Louisville

Chicago

St. Louis

Memphis

Buffalo

Detroit

Milwaukee

Minneapolis

Omaha

Kansas

City

Hartford Providence

Annapolis

Dover

Trenton

Harrisburg

Charleston

Columbus

Indianapolis Springfield

Concord

Albany Boston

Montpelier

Augusta

Madison Lansing

St. Paul

Jefferson

City

Des

Moines

Washington

Step 4 Composite Score

5 10 15 20 25 30 35 37

(Low APCW; small number 

of water consumers; low 

percentage private forest; 

low development pressure)

(High APCW; large number 

of water consumers; high 

percentage private forest; high 

development pressure)

habitat degradation and fragmentation (Postel and Richter 

2003). Similar impacts exist in many places, but they differ 

dramatically in magnitude and extent. 

In the Eastern United States, for example, some critical 

watershed services are threatened by development of private 

forests (fig. 7). In the arid and semiarid Western United 

States, over-allocation and use of water is a principal threat 

to watershed services and a source of significant social 

conflict (fig. 8). Development threats are not isolated to 

the Eastern United States, however, nor are water supply 

shortages confined to the West. For example, parts of the 

Southeast have large and growing water availability and 

supply problems.
12 | GENERAL TECHNICAL REPORT PNW-GTR-812

Climate Change Further Threatens 

Essential Watershed Services 

Climate change has directly affected and will continue 

to affect the global hydrologic cycle and thus the quality, 

quantity, and timing of streamflows from forests. It has 

also initiated indirect effects on water resources, such as 

increased extent and severity of wildfire and forest mortality. Together, these effects will interact with existing 

threats and impacts (fig. 9). As a result, the consequences 

of this episode of climate change may be larger than those 

that occurred during previous shifts in climate of similar 

magnitude (Reid and Lisle 2008).

The next section summarizes the observed and projected changes in climate for the 20th and 21st centuries, 

describes some of the direct and indirect effects of 

these changes on watershed hydrology, and explains 

how some of these changes will interact with existing impacts. It then describes how those changes will 

affect the flow of watershed services from forests: the 

water we drink, food we grow and eat, the energy we 

generate, the recreation we enjoy, and the quality and 

livability of our communities. 

Figure 9—In some 

areas, climate change 

will interact with 

population growth 

to further increase 

water supply stress. 

This figure displays 

the combined impact 

of future changes in 

climate and population growth on 

a computed water 

supply stress index 

in the Southeast 

for 2020 compared 

to the 1985–1993 

conditions (Sun et al. 

2008).

BACKGROUND | FORESTS AND WATER

Figure 8—Water supply conflicts in the Western United States, 2005. 

Half the water supply in the West comes from National Forest System 

lands, shown in green. Thus, attempts to resolve supply conflicts 

through additional water diversion and storage often have significant 

implications for national forest resources. In particular, water quality 

and aquatic ecosystems can be significantly affected by these activities, 

whether they are located on or downstream of the forests. Adapted from 

USDI Bureau of Reclamation 2005.
CLIMATE CHANGE: Hydrologic Responses 

and Ecosystem Services

BACKGROUND |

WATER, CLIMATE CHANGE, AND FORESTS | 13
14 | GENERAL TECHNICAL REPORT PNW-GTR-812

Knowledge of climate change is based on decades of research 

involving observations of the past and projections of the 

future. This growing body of science has demonstrated that 

the Earth’s climate warmed rapidly during the 20th century, 

leading to significant changes in the hydrologic cycle. These 

changes are expected to intensify in the future and have 

large impacts on forests and the watershed services they provide. This chapter summarizes these changes and expected 

impacts, based on the work of leading authorities such as the 

Intergovernmental Panel on Climate Change (IPCC) and 

the U.S. Climate Change Science Program (CCSP), as well 

as many other individual scientists and institutions around 

the world. 

Observations Show Patterns 

of Global and National Climate 

Change in Recent Decades

Numerous and diverse observations during the last decades 

of the 20th century show that the Earth’s climate is currently 

warming and precipitation is increasing. Mean global annual 

surface air temperature has increased 0.74 ± 0.18 °C (1.33 ± 

0.32 °F) since 1906 (Solomon et al. 2007), a change indicated 

by higher daily minimum temperatures (Easterling et al. 

1997). Temperature increases are widespread over the globe, 

with the greatest increases occurring at the higher northern 

latitudes. Land has warmed faster than the oceans (Solomon 

et al. 2007). Total global precipitation has increased over 

the same period (Nicholls et al. 1996), but not all areas are 

experiencing increases. For example, substantial decreases 

have been observed in many midlatitude areas (Bates et al. 

2008). Lower elevations are receiving more precipitation 

as rain and less as snow, and late spring snow cover has 

decreased (Barnett et al. 2008). Areas affected by drought 

appear to have increased since the 1970s (Solomon et al. 

2007). Observed global warming is linked to these changing 

precipitation patterns as well as to sea level rise, decreases 

in snow and ice extent, and changes in the frequency and 

intensity of extreme events such as heat waves, drought, and 

heavy rainfall. 

Climate Change: Hydrologic Responses and Ecosystem Services 

Comparable levels of warming have been recorded for 

the United States, and both local and regional precipitation patterns are changing. For example, since 1950, the 

frequency of heat waves in the Pacific Northwest 

has increased, as has the frequency of warm nights 

(Alexander et al. 2006). A northward shift of Pacific 

storm tracks has been observed, and storm intensity 

has increased over the North Pacific and North Atlantic 

(McCabe et al. 2001). Interannual variability in precipitation 

has changed in many parts of the West as well, meaning 

wetter wet years and drier dry years (Hamlet and 

Lettenmaier 2007, Luce and Holden 2009, Pagano and Garen 

2005). The frequency and intensity of extreme cyclones 

has increased markedly in the North Pacific, with an 

associated upward trend in extreme surface winds between 

25° and 40° N latitude and major changes in cyclone-related 

circulation patterns in the Gulf of Alaska (Graham and Diaz 

2001). In a broad review of the literature on extreme events, 

Huntington (2006) concluded that observed trends are consistent with an intensification of the hydrologic cycle during 

part or all of the 20th century at regional to continental 

scales (table 1). 

Additional Changes Are Projected 

for the 21st Century 

Complex mathematical models of the climate system, 

known as Global Circulation Models (GCMs), are used to 

project future climates. These models consistently project 

increases in average temperatures across the globe. Increases 

are expected to be strongest inland and at higher latitudes, 

with lesser warming along the coasts (fig. 10). Warming is 

likely to be especially pronounced in high latitudes in winter. Warmer air can hold more water vapor, which is itself 

an important greenhouse gas. This may further accelerate 

warming, with perhaps twice the effects of increased CO2

alone (Dessler et al. 2008). 

BACKGROUND | CLIMATE CHANGE
WATER, CLIMATE CHANGE, AND FORESTS | 15

Shifts are also expected in the spatial distribution, timing, 

interannual variability, and phase (solid vs. liquid) of precipitation. These changes are less consistent geographically 

than those associated with temperature. Some areas will 

likely receive more precipitation and some will receive less, 

with expected high variability in time and space (fig. 10). In 

general, wet areas and higher latitudes are likely to become 

wetter, while dry areas and the middle latitudes are likely to 

become drier (Hamlet and Lettenmaier 2007, Jain et al. 2005, 

Pagano and Garen 2005). Thus the Northern and Eastern 

Figure 10—IPCC Combined Global Climate Model projections of temperature and precipitation over North America at the end of the 

21st Century (2007). DJF refers to winter months; JJA refers to summer months. Projected boundaries should be regarded as highly 

uncertain, and projected changes are large scale. Large divergence from these broad-scale patterns are expected at smaller spatial scales. 

Temperature projections are more reliable than precipitation projections.

BACKGROUND | CLIMATE CHANGE

United States are expected to receive more precipitation, 

while the Southwest will likely become drier. Changes from 

snow to rain are expected primarily at the lowest extent of 

current snow lines (Knowles et al. 2006). These projected 

changes in precipitation are much less certain than those for 

temperature. 

More details regarding observed and projected regional-scale 

climate changes in the United States and its territories are 

provided in table 1. 
16 | GENERAL TECHNICAL REPORT PNW-GTR-812

Northeast

Warmer and wetter.

•

← T: up to 4 °F (2 °C) along coastal margins.

•

← P: 20 percent on average; extremes appear to be 

increasing, while land area experiencing drought 

appears to be decreasing. 

• Period between first and last dates with snow on the 

ground has decreased by 7 days since about 1950.

Significant climate variability. Extreme events such as 

floods, droughts, heat waves, and severe storms are 

characteristic. 

Warmer, but projected temperature increases 

are among the lowest compared to other 

regions. Greatest increases expected for 

winter minimum temperatures.

• ← winter minimum T: 4—5 °F (2—3 °C); 

up to 9 °F (5 °C) by 2100.

Uncertain changes in precipitation.

• P: little change, or up to 25 percent ← P by 

2100. Increased variability in precipitation in 

coastal areas. Uncertain changes in the 

frequency and intensity of winter storms.

Southeast

Temperature trends in the Southeast vary between 

decades.

• 1920s–1940s: warm period.

• 1960s: cooling trend.

• 1970s—present: ← T, 1990s as warm as 1920s—1930s. 

Large increases in precipitation.

• 20—30 percent or more over last 100 years across 

much of the region.

Wide range of plausible scenarios for 

temperature and precipitation over the 

next century.

• ← T: warming expected across Southeast by 

2090s; rates projected by different climate 

models differ significantly.

• ← P: one climate model projects up to 20 

percent increase by 2100.

Midwest

Variable temperature response. Wetter.

• ← T: up to 4 °F (2 °C) in the north, including upper 

Great Lakes.

• ← T: 1 °F (0.5 °C) in the south, along the Ohio 

River valley.

• ← P: 10—20 percent.

Temperatures and precipitation are expected 

to increase at a greater rate than observed 

in the 20th century.

• ←T: 5—10 °F (3—6 °C) across the region.

• ←P: 10—30 percent.

Increases in the proportion of precipitation 

coming from heavy and extreme precipitation are very likely.

Great Plains

Variable temperature and precipitation response.

• ← T: up to 2 °F (1 °C) across Northern and Great Plains.

• ← T: up to 5.5 °F (3 °C) in parts of Montana, North 

Dakota, and South Dakota.

• T: no trend in southern Great Plains.

• ←P: 10 percent in eastern Great Plains.

• ← P: 10 percent in Montana, North Dakota, eastern 

Wyoming, and Colorado.

Texas has experienced significantly more highintensity rainfall. The snow season ends earlier in 

the spring, reflecting the greater seasonal warming 

in winter and spring.

Warmer throughout the region, with the 

largest increases in the western parts of 

the plains. Different climate models project 

different levels of warming. More warming 

is expected in winter and spring than in 

summer and fall. 

Variable precipitation response.

• ← P: across region according to one model; 

another projects increases only across the 

northern portions of region.

• ← P: east side of Rocky Mountains.

BACKGROUND | CLIMATE CHANGE

Table 1—Regional trends and projections of changing climatic conditions

Region | Observed 20th century climate | Projections for 21st century

Source: National Assessment Synthesis Team 2001. 
WATER, CLIMATE CHANGE, AND FORESTS | 17

West

Warmer and generally wetter.

• ← T: up to 2—5 °F (1—3 °C).

•

← P: in much of region, up to 50 percent in some areas.

• ← P: in Arizona.

Highly variable climate with exceptionally wet and dry 

periods. The length of the snow season decreased by 

16 days from 1951 to 1996 in California and Nevada. 

Extreme precipitation events have increased.

Continued warming and increased 

precipitation.

• ← T: 3—4 °F (2 °C) by 2030s and 8—11 °F 

(4.5—6 °C) by 2090s.

• ← P: in winter, especially in California.

More extreme wet and dry years. 

Pacific 

Northwest

Warmer and wetter.

• ← T: 1—3 °F (0.5—1.5 °C)

• ← P: 10 percent on average; 30—40 percent in eastern 

Washington, northern Idaho. 

Significant recurring patterns of year-to-year variability. 

• Warm, dry years with light snowpack, low streamflows.

• Cool, wet years with heavy snowpack, high streamflows.

Much greater average warming over the 

region.

• ← T: 3 °F (1.5 °C) by 2030s.

• ← T: 5 °F (3 °C) by 2050s.

Wetter on average across the region.

• ← P in winter.

• Same or ← P in summer.

Alaska

Warmer and wetter.

• ← T: 4 °F (2 °C) since 1950s.

•

← P: 30 percent from 1968 to 990.

Growing season has lengthened by more than 14 days 

since the 1950s.

Continued warming and generally increased 

precipitation.

• ← T: 1.5—5 °F (1—3 °C) by 2030 and 5—18 °F 

(3—10 °C) by 2100.

• ← P: 20—25 percent in north and northwest.

• P: up to 10 percent along the south coast.

Islands

Warmer.

• ← T: 1 °F (0.5 °C) in Caribbean.

• ← T: 0.5 °F (0.25 °C) in Pacific Islands.

Pacific and Caribbean islands will possibly 

be affected by changes in patterns of 

natural climate variability (such as El 

Niño–Southern Oscillation); changes in the 

frequency, intensity, and tracks of tropical 

cyclones; and changes in ocean currents. 

These islands are very likely to experience 

increasing air and ocean temperatures and 

changes in sea level.

(T = Temperature; P = Precipitation as rain, hail, or snow.) Data regarding projected impacts are being updated at a very rapid rate. Therefore, the most recent 

and local projections should be identified on a regular basis and used accordingly.

Source: National Assessment Synthesis Team 2001. 

BACKGROUND | CLIMATE CHANGE

Region | Observed 20th century climate | Projections for 21st century

Table 1—Regional trends and projections of changing climatic conditions (continued)
18 | GENERAL TECHNICAL REPORT PNW-GTR-812

Changes in Climate Will Differ 

With Spatial Scale 

Climatic changes at global, national, and regional scales 

will greatly influence conditions at smaller scales, down 

to individual watersheds. The changes will differ between 

watersheds and among locations within them. Factors such 

as topography, elevation, aspect, local airflow patterns, vertical mixing and transport, lapse rates, and the tendency for 

inversions to form will govern conditions at individual sites, 

with important implications for land and water management activities (fig. 11). 

Most watershed management actions are planned, designed, 

and conducted at intermediate scales: between 1 and 

Figure 11—Complex topography can result in complex change. Model results for January maximum temperature 

change from current conditions on the H.J. Andrews Experimental Forest in western Oregon, assuming a 2.5 °C 

regional temperature change and accounting for topographic and airflow influences. Climate changes in individual watersheds, the scale at which management activities are generally planned, can differ greatly from average 

changes over larger regions (Daly et al. 2009).

500 square kilometers. This is the scale where watershed 

processes and their relation to services can be readily discerned and analyzed, and the scale at which decisions are 

most commonly made. Global climate models, however, 

provide only very large-scale projections, and regional 

downscaling of models considers only a subset of intermediate-scale influences, unlike the analysis shown in figure 11. 

Thus the reliability of projections is weak for the typical 

scale of watershed planning and decisionmaking, necessitating a scenario-based approach. That is, projections are 

useful for constructing a range of plausible scenarios, but 

not in reliably predicting future climates at managementrelevant scales. 

BACKGROUND | CLIMATE CHANGE
WATER, CLIMATE CHANGE, AND FORESTS | 19

Climate Change Is Hydrologic Change 

The hydrologic cycle—the pathway of water movement on 

Earth and in the atmosphere—is strongly coupled to the 

climate system. The distribution of water on the Earth’s 

surface plays a central role in governing temperature and 

precipitation patterns. It is also controlled by those patterns. 

As a result, hydrologic changes, particularly the changes in 

snowpacks and runoff patterns described below, are among 

the most prominent and important consequences of climate 

change.

Snowpacks

Over many areas of the Western United States, snow water 

equivalent (SWE) on April 1 declined during the second half 

of the 20th century (Lettenmaier et al. 2008, Mote et al. 2005, 

Regonda et. al. 2005). The largest relative declines in April 1 

SWE (many in excess of 50 percent) have occurred in western Washington, western Oregon, and northern California, 

with more moderate declines in the northern Rockies. The 

southern Sierra Nevada and portions of the Southwestern 

United States experienced increases in 

April 1 SWE during this period. In areas 

where decreases were observed, the largest 

changes have been at low and mid elevations, with little to no change observed 

at the highest elevations (often above 

8,000 feet [2440 meters]) or in regions 

that have experienced increases in winter 

precipitation (Moore et al. 2007, Regonda 

et al. 2005, Stewart 2009). Recent trends 

in the amount and timing of snowmelt are 

expected to continue into the future.

Runoff

Spring runoff is occurring earlier in 

snow-dominated watersheds throughout 

much of the West. Changes in the centerof-timing of spring flows (date at which 

half of the year’s runoff has occurred) 

show shifts on the order of 1 to 4 weeks 

earlier between 1948 and 2002 (Stewart et 

al. 2005). The largest changes in snowmelt 

runoff timing are occurring at low and 

mid-elevation sites, whereas high-elevation sites (over 8,000 feet [2440 meters]) 

generally show little change (Regonda et 

al. 2005). Earlier spring flows may yield 

lower late-season flows (Cayan 1996).

Besides changes in streamflow timing, altered total annual 

flows have been observed. For example, a recent analysis 

by Luce and Holden (2009) revealed large regional-scale 

declines in annual streamflows in the Pacific Northwest for 

the driest 25 percent of years (fig. 12). The implications of 

these changes are large, as water supply conflicts are already 

greatest during those years. Changes in average annual 

streamflows are also projected for the future. For example, 

Lettenmaier et al. (2008) made projections for average 

annual runoff for 2041–2060 in each of 18 water resource 

regions in the United States and compared them to observed 

data from the 1901–1970 period. They predicted increased 

annual runoff in the Eastern United States, little change in 

the Missouri and Lower Mississippi basins, and decreased 

runoff in the Pacific Northwest and California. Annual 

runoff in the interior West and Southwest is expected to 

decrease by as much as 20 percent (fig. 13), with serious 

consequences for water supply in the Colorado River system 

(Barnett and Pierce 2008, Rajagopalan et al. 2009).

Figure 12—Percentage change in the annual streamflow of the driest 25 percent of 

years in the Pacific Northwest (Luce and Holden 2009).

BACKGROUND | CLIMATE CHANGE

Streamflow change 

(percent)

-4.3 to 4.3

-12.9 to -4.3

-21.5 to -12.9

-30.1 to -21.5

-38.7 to -30.1

-47.3 to -38.7

Significant at α = 0.1

Not significant at α = 0.1
20 | GENERAL TECHNICAL REPORT PNW-GTR-812

BACKGROUND | CLIMATE CHANGE

Figure 13—The color represents median changes in runoff interpolated to U.S. Geological Survey 

water resource regions from Milly et al. (2008) from 24 pairs of Global Circulation Model simulations for 2041–2060 relative to 1901–1970. Percentages are the fraction of 24 runs for 

which differences had the same sign (positive or negative) as the 24-run median. Results were 

replotted from Milly et al. (2008) by Dr. P.C.D. Milly, USGS. Source: Lettenmaier et al. (2008). 

Groundwater

Timing and rates of groundwater 

recharge will shift to reflect the 

changing patterns of precipitation and runoff. The resulting 

changes in groundwater levels 

will, in turn, influence stream 

baseflows. Groundwater withdrawals may increase in some 

areas in response to losses or 

increased variability in surface 

water supplies. Saltwater intrusion may increase in some 

coastal freshwater aquifers due 

to sea-level rise and, in some 

cases, reduced precipitation. 

Climate Change Will Affect 

Forest Disturbance Regimes 

Besides these direct effects on the hydrologic cycle, 

climate change will directly and indirectly alter ecological 

disturbances that are influenced by hydrologic processes. 

Specifically, alterations in the frequency, extent, and 

magnitude of floods, forest mortality, and fire are expected, 

each with serious implications for people and ecosystems.

Flood Severity

Flood severity is expected to increase in much of the West 

because increased interannual variability in precipitation 

will cause increased runoff in wet years and increased 

rain-on-snow probability in low-elevation snowpacks 

(Hamlet and Lettenmaier 2007). A recent study found a 

relation between sea surface temperatures and global peaks 

in the number and severity of Atlantic hurricanes over the 

past 1,500 years, suggesting that warming will contribute 

to intensification of hurricanes and other cyclonic storms 

(Mann et al. 2009).

Forest Mortality and Fire

Warmer temperatures, less water, or more water can 

cause changes in vegetation and increase forest mortality (Allen et al. 2010, van Mantgem et al. 2009). For 

example, temperature increases have contributed to widespread outbreaks of mountain pine beetles across vast areas 

of the Rocky Mountains (Logan and Powell 2001). Increased 

wildfire spread and severity, also related to changes in 

hydrology, have also been observed (Morgan et al. 2008, 

Westerling et al. 2006). Together, insects and fire have 

already affected large areas of the West (fig. 14). Forests in 

the south and Great Lakes regions are under similar stress 

(Julius and West 2008, Westerling et al. 2006). 

Of these effects, those associated with fires present the most 

alarming risks for forested watersheds. Fires are burning 

hotter and covering larger areas. The resulting changes in 

vegetation cover and soil characteristics can dramatically 

increase flooding and mass wasting, with severe impacts 

to downstream infrastructure and aquatic ecosystems 

(Istanbulluoglu et al. 2004, Miller et al. 2003). Postfire landscapes experience changes in water quality, flow quantity 
WATER, CLIMATE CHANGE, AND FORESTS | 21

BACKGROUND | CLIMATE CHANGE

and timing, nutrient cycles, aquatic food webs, fish population structure and abundance, and stream and riparian 

habitat (Bisson et al. 2003). Fires can also increase stream 

temperatures by killing forests that shade streams (Dunham 

et al. 2007). These increases can further compound stream 

temperature increases caused by higher air temperatures 

(Isaak et al. 2009). 

Increased fire extent may also ameliorate some effects of 

climate change. For example, fires lead to increased water 

yield by killing trees and reducing evapotranspiration 

(Luce 2005). This could mitigate some of the effects of 

reduced streamflows caused by reduced precipitation in 

certain areas. However, the magnitude of these changes is 

unclear and may be limited. First, the increased flows will 

decrease over time if forests regenerate in the burned areas. 

In addition, the “new” water made available from the loss 

of forest cover would come earlier in the year, when it is 

needed least.

Altered Hydrologic and Disturbance 

Regimes Will Affect Forests and the 

Watershed Services They Provide 

Water is a central organizer of ecosystems (Sedell et. 

al 2000). Thus, changes in the hydrologic system and 

associated disturbance regimes will likely have significant impacts on forests and the watershed services 

they provide to people. In addition to changes previously described, water quality, aquatic habitats and 

species, and soil resources will be affected significantly. 

Water Quality

Water temperatures are expected to increase because of 

the combined effects of increased air temperatures and 

wildfire. Erosion is expected to increase as a result of higher 

peak flows and reductions in ground cover from reduced 

snowpacks, as well as increased intensity and frequency of 

wildfire and hurricanes. Sediment loads are thus expected 

to increase, affecting municipal water supplies and aquatic 

habitats.

Figure 14—The area of forested lands in the Western United States affected by wildfire and forest insect infestations has increased markedly in recent decades. This is in part due to climate warming, which increases moisture demand, reduces fuel moisture, and leads to 

favorable conditions for insect infestation and wildfire spread (Westerling et al. 2006). (A) Boundaries of all fire perimeters on Forest 

Service lands in the Western United States, 2001–2007. (B) Extent of areas at high risk of forest mortality from insects and disease.

A B
22 | GENERAL TECHNICAL REPORT PNW-GTR-812

BACKGROUND | CLIMATE CHANGE

Aquatic Habitats and Species

The majority of streams in the Western United States are 

likely to show reduced annual runoff and shifts in runoff 

timing because of changes in precipitation timing and type; 

seasonally flowing streams are expected to show decreases 

in flow duration. Decreased flows will likely shrink habitats 

of all aquatic species at the upstream end. The same influences will result in the contraction and loss of wetlands. 

Altered flows and higher air temperatures will result in 

warmer water temperatures at sites where flow remains 

present, with resulting changes in the composition of 

aquatic communities and increases in primary productivity. 

Temperature changes will likely shrink habitats of cold 

water species near the downstream end, compounding 

losses from the upstream end (Dunham et al. 2007). Thus, 

these species are perhaps at greatest risk. Bull trout, for 

example, are already limited to high elevations and northern 

areas. Projected habitat distributions under climate change 

are greatly reduced by temperature effects alone (Rieman 

et al. 2007). Increased temperatures from wildfire could 

substantially restrict this range even further (Dunham et al. 

2007) (fig. 15).

Figure 15—Effects of recent climate change and recent wildfires on stream temperature and thermal habitat for rainbow trout 

(Oncorhynchus mykiss) and bull trout (Salvelinus confluentus) in a mountain river network (Isaak et al. 2009). The two separate 

but related factors have generally decreased habitat for bull trout. Habitat for rainbow trout has decreased in some areas, but 

increased in others.
WATER, CLIMATE CHANGE, AND FORESTS | 23

BACKGROUND | CLIMATE CHANGE

Soil Resources

Increased flooding and fire are expected to result in substantial increases in erosion and potential losses in soil 

productivity. Changes in temperature, evapotranspiration, 

precipitation, and runoff will affect soil moisture over most 

or all landscapes. The extent of water supply shortages and 

soil moisture decline will likely vary greatly, depending on 

watershed soil properties and the size and behavior of water 

storage in the landscape. In many areas, soils are likely to 

dry earlier in the year, stressing existing vegetation and 

Figure 16—Examples of potential direct and indirect effects of climate change on the hydrologic cycle. Most components are intensified 

by climate warming. Base image from the COMET Program, used by permission.

leading to changes in vegetation communities, forest dieoff, and insect outbreaks. Increased decomposition rates 

will deplete soil organic matter more rapidly. Furthermore, 

decreased carbon fixation because of lower water availability 

and increased moisture stress may reduce loading of organic 

matter from forest litter.

Some of these and other changes in ecosystems and ecosystem services are depicted in figure 16 and summarized 

in table 2.

Less precipitation in some

areas, more in other areas. 

Greater interannual variability.

More evapotranspiration. Drier 

vegetation and 

soils. More frequent 

and severe droughts. 

Increased wildfires 

and area burned.

Water in streams and

lakes becomes warmer.

Earlier spring runoff.

Larger flood peaks.

Lower summer stream

flow. Smaller headwater

stream networks.

Increased reliance 

on groundwater for

basic supply.

Glaciers are reduced or

eliminated. Increased 

high-elevation erosion.

More rain and less snow.

Snow melts sooner in spring.

More intense storms

with more flooding 

and extreme winds.

Sea level rises. More

coastal erosion. Saltwater

intrusion into coastal

freshwater aquifers.
24 | GENERAL TECHNICAL REPORT PNW-GTR-812

BACKGROUND | CLIMATE CHANGE

Warmer air 

temperatures

More pronounced at 

higher latitudes and 

higher elevations, 

and in inland areas. 

Coastal areas are 

likely to warm the 

least.

• Less total streamflow, owing to more 

evapotranspiration.

• Reduced flow duration and discharge 

in seasonally flowing streams.

• More erosion and stream sediment 

pollution from fires, floods, landslides, 

and other large-scale disturbances.

• Warmer water temperatures in streams 

and lakes.

• Increased primary productivity in 

surface waters.

• Increased soil organic matter 

decomposition rates.

• Drier soils earlier in the year.

• Changes in the amounts, quality, 

and distribution of water-dependent 

habitats and associated biota; 

most changes will be adverse for 

coldwater fishes.

• Changes in the availability of water 

supplies.

• Decreased quality of water supplies, 

increased treatment costs.

• Decreased reservoir storage.

• Decrease in coldwater aquatic 

habitats.

• Increase in warmwater aquatic habitats.

• Increased irrigation needs.

More frequent, 

longer, 

and dryer 

droughts

Highly variable, 

mostly Western 

United States

• Larger and more frequent fires, caused 

by lower summer soil moisture, warmer 

temperature, more wind leading to: 

■ More frequent forest mortality.

■ Reduced vegetative cover on 

watersheds. 

■ Short-term increases in water 

yield and flooding.

• Greater near-term inputs of large 

wood to streams, followed by 

decreased inputs in the long term.

• Reduced groundwater recharge.

• Decreased natural flood regulation, 

resulting in damage to infrastructure 

and developed areas.

• Decreased soil productivity.

• Altered recreational and cultural 

experiences.

• Greater frequency of toxic 

blue-green algae in lakes and 

reservoirs.

• Altered nutrient inputs and cycling 

in streams and lakes.

• Increased depletion of groundwater.

Changes in 

precipitation 

amounts 

and timing

Wetter and higher 

latitude areas 

become wetter; drier 

and lower latitude 

areas become drier.

Summer rainfall 

might increase in 

some areas and 

decrease in others.

Dry-season rainfall 

might increase or 

decrease.

• Altered timing and volume of runoff. 

• Altered channel forms reflecting 

changes in runoff, peak flows, and 

sediment loads.

• Changes in drought severity.

• Changes in vegetation.

• Altered erosion rates.

• Changes in groundwater recharge 

and corresponding changes in 

stream baseflow.

• Increases or decreases in availability 

of water supplies.

• Complex changes in water 

quality related to flow and 

sediment changes.

• Increases or decreases in capacity 

for hydropower generation.

• Ecological changes related to 

moisture availability in soils, 

streams, lakes, and wetlands.

Projected

changes

Regional 

variation

Anticipated watershed 

response

Potential consequences

to watershed services

Table 2—Some projected climate changes, hydrologic effects, and potential consequences to ecosystem services
WATER, CLIMATE CHANGE, AND FORESTS | 25

BACKGROUND | CLIMATE CHANGE

Less snowfall, earlier 

snowmelt, 

increased 

snowpack 

density

Most vulnerable are 

“warm snowpacks” 

at lower elevations 

and lower latitudes. 

Western near-coastal 

mountains have the 

greatest areas of 

vulnerable snow.

• Higher winter flows.

• Lower summer flows.

• Earlier and smaller peak flows in spring.

• More frequent rain-on-snow flooding 

in some areas.

• More erosion of areas previously 

protected by snow.

• Changes in stream channels because 

of altered flows and modified sediment 

and wood inputs.

• Altered patterns of groundwater 

recharge.

• Changes in the amounts, quality, 

and distribution of aquatic and 

riparian habitats and biota.

• Decreased capacity for hydropower 

generation in summer when demand 

is greatest.

• Changes in the availability of 

water supplies.

• Decreased quality of water supplies, 

increased treatment costs.

• Decreased reservoir storage.

• Decreased soil productivity.

• Potential for increased frequency 

of toxic blue-green algae in lakes 

and reservoirs.

• Altered recreational and cultural 

experiences.

Intensified 

storms, 

greater 

extremes of 

precipitation 

and wind

Highly variable, 

degree of change 

highly uncertain.

Rainfall variability 

will likely increase.

• Greater likelihood of flooding.

• Increased erosion rates and sediment 

yields.

• Altered channel forms.

• Changes in the delivery of blow-down 

wood to streams.

• Decreased quality of water supplies, 

increased treatment costs.

• Reduced reservoir storage from 

increased sedimentation.

• Changes in aquatic and riparian 

habitats.

• Increased damage to roads, 

campgrounds, and other facilities.

• Reduced availability of water-related 

recreation (e.g., fishing, skiing, and 

so on).

Loss of 

glaciers, 

smaller 

glaciers

Lower elevation 

glaciers affected 

most.

• Short-term increases in summer flow 

in glacier-fed streams, followed by 

long-term reduction of flows.

• Modification of temperature regimes 

in glacier-fed streams.

• More erosion from newly exposed surfaces.

• Modified alpine vegetation near 

glaciers.

• High-elevation erosion hazards.

• Changes in the availability of 

water supplies.

Rising 

sea level

Coastal areas, and 

islands affected.

• Loss of beaches and tidal wetlands; 

changes in area of estuaries.

• Inundation of coastal lowlands.

• Increasing salinity in remaining 

estuaries and tidal wetlands.

• Greater saltwater intrusion into 

freshwater aquifers.

• Increased vulnerability of coastal 

areas to storm damage.

• Habitat changes.

• Loss of water supplies.

• Reduced coastal fishery resources.

• Displacement of human populations, 

increasing pressure at the wildland 

interface.

Table 2—Some projected climate changes, hydrologic effects, and potential consequences to ecosystem services (continued)

Projected

changes

Regional 

variation

Anticipated watershed 

response

Potential consequences

to watershed services
26 | GENERAL TECHNICAL REPORT PNW-GTR-812

BACKGROUND | CLIMATE CHANGE

The Effects of Climate Change 

Are Cumulative 

The effects of climate change will not play out on pristine 

landforms. They will interact with existing conditions 

and generally increase the severity and extent of existing 

problems such as species extirpation, water pollution, 

and water scarcity. As described in the first section, many 

watersheds have already been altered by large-scale water 

diversions, impaired water quality, and degraded habitat 

conditions. On national forests, past grazing, timber harvesting, mining, and road development have left a legacy of 

altered watershed conditions that persist over wide areas. 

For example, uncontrolled grazing on public lands prior to 

the 1930s contributed to soil compaction and gully erosion, 

reduced soil productivity, increased sediment yields, altered 

vegetation, and modified fire regimes. Historical clearing 

of riparian forests for agriculture in the Eastern United 

States is considered one of the most significant impacts on 

coldwater fisheries in that region. Early mining activities 

produced long-lasting impacts from toxic chemical waste, 

altered aquatic and riparian food webs, and physical damage 

to watersheds and streams (Julius and West 2008). Extensive 

road networks were built to support intensive timber management across much of the landscape. These aging road 

systems still exist, but the original management objectives 

no longer do, nor does the funding needed to maintain or 

decommission them. This is a critical issue because poorly 

built and maintained forest roads are major sources of 

landslides, sediment loads, flow alteration, and habitat fragmentation in streams (NRC 2008). 

Thousands of nonnative invasive species have infested 

millions of acres of forests, rangelands, and aquatic 

ecosystems across the Nation. In many areas, aquatic 

invasive plants, mollusks, and fish are replacing native 

species and degrading water quality. Shifting climates 

change the distribution of sites hospitable to the invaders, 

and climatic changes that alter the frequency and intensity of 

environmental disturbances, such as wildfire, can degrade 

soil quality resulting in greater opportunity for invaders to 

spread beyond their present locations. Most changes will 

likely help the invaders; others may assist native species. 

Loss of private forests to homes and other development 

is particularly problematic. As recently reported by the 

National Research Council (2008), “Forests that once provided high quality runoff are becoming developed parcels 

that can adversely affect runoff patterns and water quality." 

Urban land in the contiguous United States is expected 

to nearly triple over the next several decades (Nowak and 

Walton 2005), and loss of private forests to housing growth 

and other development uses is projected in rural and exurban areas (Radeloff et al. 2005, Stein et al. 2005). Much of 

this change is piecemeal, and small fragmented changes 

produce cumulative watershed impacts that are difficult to 

mitigate (NRC 2008). 

Given these impacts, effective climate change adaptation 

strategies will focus not only on the direct impacts of climate 

change. Instead, they will need to focus on maintaining or 

restoring watershed resilience, which will require that all of 

the principal impacts and threats to key watershed processes 

and services be addressed. 

Hydrologic Change Will Complicate 

National Forest Management in 

Many Ways

The direct, indirect, and cumulative effects of climate 

change will greatly complicate management of national 

forests and other forests in multiple ways. Many of the 

greatest challenges are associated with water and aquatic 

resources, as described below. 

Water Use and Diversion

Climate change will strongly affect the amount, timing, and 

variability of water available for both onsite and offsite uses 

in the coming decades, because of changes in precipitation 

and snowmelt. This, combined with a larger population, will 

increase the demand for consumptive uses of water from 

national forests and other public lands. Requests to develop 

or expand facilities to store or divert water for municipal, 

industrial, and agricultural uses will also increase. In many 

cases, these increased demands will conflict with other 

resource objectives, such as protecting and restoring aquatic 

habitats and species. 

Water Quality Management

Although the quality of water from national forests is 

generally high, past management activities have caused 

impairments in some areas. Most of these are associated 

with erosion, sedimentation, and increased temperatures. 

Excessive nutrient loading and metals pollution are also 

common water quality problems. In recent years, substantial 

efforts have been focused on addressing these impairments 

and preventing new ones through protection and restoration efforts. Unfortunately, water quality impacts associated 

with altered hydrologic and disturbance regimes will make 
WATER, CLIMATE CHANGE, AND FORESTS | 27

BACKGROUND | CLIMATE CHANGE

it more difficult to meet water quality standards and support the full range of water uses. In some cases, existing 

standards may not be attainable. These conditions may create substantial legal and social conflicts and reduce the ability of land managers to meet multiple resource objectives.

Aquatic Habitat Management

Climate change, past impacts, and the ongoing development and fragmentation of streams across private 

lands will dramatically increase the role of national forests 

and other conserved wildlands as refugia for aquatic species. This may increase demands for greater habitat protections, which could conflict with meeting other management 

objectives such as increasing energy production, recreation 

access, and water diversions.

Climate change also raises questions regarding priorities for 

habitat protection and restoration. In recent years, scientists 

and managers have placed considerable emphasis on identifying those areas with the greatest conservation and restoration potential, so that limited resources could be focused 

where they will provide the most benefit. Unfortunately, 

the distribution and character of habitats and associated 

biota will change markedly in some areas in response to 

altered streamflows and disturbance regimes. Thus, areas 

that provide high conservation value today may not in the 

future. A critical challenge is to accurately predict how those 

habitats will change and species distribution will shift over 

time. These shifts in habitats and biota will also elevate 

the importance of removing the vast number of barriers 

to migration resulting from dams, water diversions, and 

road crossings. Increasing fire extent further elevates the 

importance of addressing these barriers, as well-connected 

habitats greatly increase the likelihood that populations 

can rebound quickly from disturbance. Increasing wildfire size and severity will make efforts to restore riparian 

shade more challenging. Existing challenges in controlling 

invasive species and their impacts on native species may be 

exacerbated by climate change, as altered hydrologic and 

disturbance regimes are likely to favor invasive species in 

some watersheds. 

Soil Management

Forest management and watershed function depend on 

productive, porous soils. Ongoing and projected climate 

changes compound the effects of other factors on soil 

resources, and increase the need for watershed treatments to 

restore degraded soils and stabilize sites at increased risk of 

erosion, loss of porosity, and loss of soil organic matter. 

Fire and Fuels Management

Increased fire frequency, severity, and extent will accelerate 

demands for aggressive fuels management. Although fuels 

treatments may reduce the watershed effects of fire in some 

circumstances (Ritchie et al. 2007), they can also cause 

adverse effects on aquatic ecosystems, particularly when 

new roads are built or old, unmaintained roads are kept 

open to support these activities. Thus forest managers will 

be increasingly faced with the challenging question of which 

is worse for aquatic habitats, wildfire or the active measures 

intended to suppress it (Bisson et al. 2003).

Forest managers will also be faced with increasingly 

complex challenges associated with managing postfire 

landscapes. Larger burned area, combined with increased 

human populations at risk of postfire flooding and mass 

erosion events, will increase the need to accurately assess 

postfire risks and target mitigation actions accordingly. 

Vegetation Management

Vegetation management. Projected climate changes will 

affect forest vegetation by increasing the elevation of the 

maximum treeline expansion in northern zones, increasing the elevation of the minimum tree line in semiarid 

zones, and increasing drought stress, plant disease, 

and competition from invasive species. Widespread 

temperature-induced drought stress is expected to cause 

increases in the amount of biomass consumed by fire 

throughout much of the West. Current temperature-related 

insect infestations are expected to continue. Increased 

tree mortality from insects has already been observed 

throughout the West (van Mantgem et al. 2009), raising 

concerns about the future distribution of forest vegetation. 

Decreases in growth resulting from changes in water balance have also been observed (Littel et al. 2008).

Forest managers will need to determine the types and densities of vegetation that sites will support in the future. This 

issue will be particularly acute after large-scale disturbances 

such as wildfire and insect and disease outbreaks. In addition, managers may be increasingly pressured to manage 

vegetation for the primary purpose of producing more 

streamflow, despite the proven limitations of such efforts 

(see box on next page).

In rangeland ecosystems, temperature increases and longer 

growing seasons will lead to the expansion of winter range. 

Shifts in forage productivity and the presence of exotic plant 

species in grasslands will likely affect forage quality and 

fire frequency. Higher temperatures will reduce livestock 
28 | GENERAL TECHNICAL REPORT PNW-GTR-812

BACKGROUND | CLIMATE CHANGE

production during the warm and dry season, although 

warmer temperatures may increase production during the 

winter season. The carrying capacity of rangelands is very 

likely to change and become more variable, but the degree 

and rate of change is unknown. 

Infrastructure

Climate change is expected to result in more extreme 

weather events, leading to increased flood severity, more 

frequent landslides, and increased variability of streamflow. Each of these changes increases the probability of 

damage to roads, bridges, trails, and other infrastructure. 

Developments in high-risk settings—such as rain-on-snow 

zones, coastal areas, and landscapes with unstable geology 

are most vulnerable. Such damage can have consequences 

ranging from relatively minor inconvenience (loss of 

recreational access) to major impacts (resource damage, 

destruction of property, and loss of life). The distribution 

and likelihood of infrastructure damage owing to climate 

change is not known and will remain very difficult to 

predict. 

Existing dams, roads, bridges, culverts, campgrounds, and 

other infrastructure were originally designed assuming a 

fixed envelope of climatic variability to determine acceptable risk. Because this assumption is no longer valid (Milly 

et al. 2008), likelihood of failure is no longer known for the 

aging facilities. In addition, uncertainty in designing new 

facilities for acceptable risks is now greater. Determinations 

of acceptable risk will be more difficult, requiring scenariobased approaches to infrastructure planning, design, 

maintenance, and restoration.

The increased variability increases the premium on current, complete, and accurate snowpack and soil moisture 

information to improve streamflow forecasts at daily to 

seasonal time scales. Such data are used for early warning 

of floods and drought and are important for optimizing 

the management of storage and releases from reservoirs 

used for both water supply and flood control. Given that 

the past is increasingly less useful as a guide, it is becoming 

necessary to hedge against potential flooding, reducing the 

amount of water that can be kept in storage for later irrigation. Improved information reduces the amount of hedging 

necessary.

As demand for water increases, especially in the arid West, 

people have asked: Can we remove trees to produce more 

water? Because science shows that water yields can be 

increased by cutting trees, there is a temptation to consider 

removing forest cover to enhance water supply. Increased water 

yield from removing forest cover, however, is not sustainable 

over the long term, nor is the increase significant at scales that 

make a meaningful difference in water supply (Ziemer 1987). 

The issue was recently summarized by the National Research 

Council (2008: 1):

Removing forest cover accelerates the rate that 

precipitation becomes streamflow; therefore, in some 

areas, cutting trees causes a temporary increase in the 

volume of water flowing downstream. This effect has 

spurred political pressure to cut trees to increase water 

supply, especially in Western States where population 

is rising. However, cutting trees for water gains is not 

sustainable: increases in flow rate and volume are 

typically short-lived, and the practice can ultimately 

degrade water quality and increase vulnerability to 

flooding.

So what is the answer? The primary driver of water yield 

in large basins is precipitation, which will likely become 

more variable with a changing climate. Optimizing long-term 

water yield, water quality, and healthy aquatic and terrestrial 

ecosystems will best be accomplished by keeping watersheds 

forested and in good condition and using available supplies as 

efficiently as possible. Efficient use can be facilitated through 

better information about the state of water storage in the 

snowpacks, water bodies,and soil in headwater watersheds.

Do trees take our water? 

The United States should develop 

and expand a variety of forecasting 

and predictive models and systems. 

– National Science and Technology Council, 

 Subcommittee on Water Availability and Quality 2007.
WATER, CLIMATE CHANGE, AND FORESTS | 29

BACKGROUND | CLIMATE CHANGE

Power Production

A growing U.S. population will continue to increase 

demand for electricity. This will add to existing water supply and quality challenges, since virtually every means of 

power production requires substantial volumes of water (fig. 

17). Demand for hydroelectric generation, in particular, is 

expected to increase in the future because of its lower carbon 

emissions (Bates et al. 2008). As a result, additional generating facilities will likely be proposed on national forests, as 

these areas have the substantial volumes of water and vertical relief needed for hydroelectric facilities. This will include 

both large generating facilities on mainstem rivers as well 

as smaller high-head, low-flow facilities on small streams. 

Proposals to change the operation of existing facilities to 

benefit aquatic ecosystems may receive increased resistance 

if they substantially reduce power production. 

Recreation

The majority of recreation activities on public lands, from 

camping and fishing to skiing and kayaking, are water 

related and vulnerable to climate change. Changes in water 

availability will affect recreation opportunities and shift 

patterns of use. Alpine skiing, for example, will decline 

in areas of receding snowpacks, and the demand for snow 

making, which requires local water and power supplies, will 

likely increase (Nolin and Daly 2006). Wildfire activity will 

increasingly constrain summer recreation activities. Fishing 

and hunting opportunities will shift with changes in the 

distribution of fish and game species. Recreation developments, such as campgrounds and ski areas, that are located 

in areas of high risk to flooding or landsliding will be damaged more frequently.

Summary of Hydrologic Effects

The effects of climate change on the Nation’s water and 

aquatic resources will likely be profound and far reaching. 

Many forested headwaters—critical sources of abundant, 

cold, clean water—will be vulnerable to increased temperatures and to changing precipitation and disturbance patterns that will alter runoff timing and volume, sediment and 

nutrient loading, water quality, and aquatic habitats. Such 

effects will differ greatly in different areas and at different 

geographic scales and are challenging to predict with high 

degrees of certainty. 

In some locations, hydrologic changes will lead to less water 

and increased need to protect habitats for imperiled aquatic 

species. Coupled with increased demand for water, these 

changes may result in a “perfect storm” of conflict. Fortunately, 

there is much we can do to respond. Adaptation actions taken 

now can minimize potential negative impacts and unlock 

new opportunities for the future. The primary objective of 

these adaptation efforts 

should be the maintenance and restoration 

of watersheds, w it h 

the goal of improving 

their resilience to climate change. Effective 

responses will require 

actions that address not 

only climate change, 

but all of the dominant 

stressors negatively 

affecting watersheds 

and their ability to provide desired watershed 

services. An outline 

of such an approach is 

provided in the next 

section.

Figure 17—Percentage of U.S. water supply used for various 

purposes. The links between water and energy are fundamental. 

Energy production requires very large amounts of water, and the 

continued delivery of fresh water requires dependable, low-cost 

energy for pumping, distribution, and treatment. Water is used 

to produce all forms of energy, with consumption ranging from 

<0.001 gallons per kilowatt-hour (gal/kWh) (0.004 liters per 

kilowatt-hour [L/kWh]) for solar and wind, to 0.047 gal/kWh 

(0.178 L/kWh) for thermoelectric, to 18 gal/kWh (68 L/kWh) for 

hydroelectric. Conserving water translates to energy savings, but 

the reverse is also true, making water and energy conservation an 

inextricably interlinked challenge (Torcellini et al. 2003).
30 | GENERAL TECHNICAL REPORT PNW-GTR-812
WATER, CLIMATE CHANGE, AND FORESTS | 31

 MOVING FORWARD | THINK | COLLA BORATE | ACT | 

WATER, CLIMATE CHANGE, AND FORESTS | 31
32 | GENERAL TECHNICAL REPORT PNW-GTR-812

Climate change is substantially altering many watershed 

functions and will threaten the stability of both social and 

natural systems. Scientists, land managers, and landowners 

alike must be prepared to understand, respond, and adapt to 

the anticipated effects of climate change. The most effective 

response to a warming world is a renewed commitment to 

the principles and practices of sound watershed management, with the objective of maintaining or improving 

watershed resilience. In the following sections, we lay a 

foundation for what can be done to improve watershed 

resilience in the face of climate change. Reponses have been 

grouped into three distinct categories: think, collaborate, 

and act. Because watersheds are affected by many different 

types of factors, the actions outlined here not only address 

the direct effects of climate change, but other key drivers 

as well. 

Complex environmental and social problems like climate 

change must be adequately understood before they can be 

solved. Thus, thinking is a necessary first step toward effective adaptation. Although some effects of climate change 

are reasonably well characterized, many others are not. 

Consequently, we need to advance and share knowledge 

about water and climate change. Secondly, that knowledge 

will need to be incorporated into landscape and project-level 

planning. Both of these tasks will be extremely challenging 

and will require access to people with substantial expertise 

in Earth and aquatic sciences. 

Advance and Share Knowledge 

About Water and Climate Change

With the substantial uncertainty surrounding the effects 

of climate change on water resources, improving watershed 

resilience will require managers to take action in an environment of great uncertainty. Thus, there is a strong need 

to advance the science and continually share new insights. 

Scientists and land managers will need to continue to 

cooperate so that the most relevant questions and data gaps 

are addressed, and scientific findings and perspectives are 

integrated into management. The following actions would 

help achieve those objectives. 

Acquire Information About Watershed 

Resources at Multiple Scales

Land and water managers will need new information to 

respond effectively to shifting climatic regimes. They will 

need to track and evaluate changing watershed conditions, 

understand the effects of management practices, and forecast the quality, quantity, and timing of water supplies. In 

many areas, basic hydrologic data—precipitation, temperature, and streamflow—are lacking. Management decisions 

are particularly challenging because information on water 

quality, water temperatures, geomorphic processes, aquatic 

habitats, and biota is often not available. This need for reliable and relevant information will be amplified as more 

demands are placed on our water resources. 

National efforts are underway to identify watershed data 

availability, needs, gaps, and protocols at various scales. A 

coordinated effort at multiple levels among federal, state, 

tribal, and local governments and with nongovernmental 

entities will help to achieve cost-effective solutions across 

boundaries. Scientists and managers will need to discuss the 

relative importance of different data, the extent and scale 

of need, options for acquiring the information, available 

resources, and willing partners. Means to store, analyze, 

and make available new information will also be necessary.

THINK | COLLA BORATE | ACT

Adapting to Climate Change by Improving Watershed Resilience 

Quantitative knowledge of U.S. water 

supply is currently inadequate. 

— U.S. General Accounting Office 2003

MOVING FORWARD | THINK

Expand Use and Application of 

New Technologies

Emerging technologies offer unprecedented opportunities 

to advance water resource knowledge and information. 

Some of the most promising ones include thermal infrared 

(TIR) imagery; digital temperature sensing (DTS); advanced 

automated samplers with telemetry; high-resolution digital 

topography; and spatially explicit, process-based hydroecological models. 

The TIR imagery, for example, can generate thermal 

snapshots of entire river systems, allowing scientists and 

managers to understand and respond to the effects of a 

warming world (fig. 18). The DTS technology also monitors 

stream temperatures and can be used to characterize soil 

moisture over large areas (Selker et al. 2006). Such data could 

significantly improve the ability to forecast streamflows, 

predict changes in vegetation, assess threats to forest health, 

quantify wildfire risks, identify vulnerable and resistant 

landscapes, and provide early warning systems for threats 

to people, fish, and wildlife. It could also facilitate the 

implementation of more strategic and effective watershed 

management practices. 
WATER, CLIMATE CHANGE, AND FORESTS | 33

MOVING FORWARD | THINK

Figure 18—A thermal infrared image of Coeur d’Alene River, 

Idaho.

Advances in automated sampling and telemetry technologies 

are also providing important opportunities for wildland 

and urban water resource management. For example, 

stream and well monitoring stations linked via satellite 

telemetry can provide real-time information (Paulson and 

Shope 2007). Use of these systems could be expanded to 

collect and transfer hydrologic data to inform numerous 

activities that will be affected by climate change: water 

quality and supply management, flood warning, reservoir 

management, irrigation management, and hydropower 

generation. 

New technologies are also enabling scientists and managers 

to quickly acquire some of the most important new data sets 

for watershed management, high-resolution digital models 

of topography, vegetation, and water bodies. Light Detection 

and Ranging (LIDAR), for example, can be used to create 

three-dimensional maps of channels and flood plains for 

entire stream networks (fig. 19) (McKean et al. 2008).

Figure 19—High-resolution stream channel and flood plain morphology of Bear Valley Creek, Idaho, obtained with the National Aeronautics and Space Administration’s green LIDAR technology (McKean et al. 2008).
34 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | THINK

Figure 20—Conceptual image of processbased models that use multiple spatial 

data sets (e.g., climate, topography, soils, 

geology, land cover) to estimate the 

hydrologic behavior of landscapes under 

varying land-use scenarios, climatic conditions, and disturbance regimes.

Use the National Forest 

System and Other Public 

Lands as Learning 

Laboratories 

Public forests and experimental 

research sites can make a significant 

contribution to understanding climate 

change and water. National forests 

typically encompass larger, relatively 

undisturbed areas, and often contain 

headwaters where water supplies and 

aquatic ecosystems are not yet influenced by upstream land and water 

uses. As such, they provide a favorable 

environment for assessing the ecological effects of climate change (US GAO 

2007). Study sites and demonstration 

areas maintained on public lands 

allow scientists and managers to 

work together to increase our understanding of climate and ecosystems, 

evaluate management options, test 

solutions, and transfer knowledge to 

key stakeholders. 

Experimental watersheds provide an 

especially important opportunity for 

advancing our understanding of the 

hydrology of forested watersheds, 

the effects of climate and vegetation 

change on water quality and quantity, 

and the impacts of natural and 

human disturbances. Many of these 

watersheds have long records of 

precipitation, streamflow, and other 

data and are thus uniquely positioned 

to address some of the most important 

questions facing us about climate 

change, water, and forests. (See box on 

page 36.)

Technological advances are also 

enabling scientists and managers to 

better and more quickly integrate and 

analyze these immense data sets to 

support land and water management 

decisions. For example, geographic 

information system (GIS)-based mathematical models can be used to predict 

important hydrologic changes under 

existing and potential conditions. 

The systems layer multiple data sets 

to build three-dimensional landscapes 

in which ecological, hydrologic, and 

climatic variables may be altered to test 

management alternatives and model 

outcomes (fig. 20) (Harvey 2007, 

Mitasova et al. 2006). These tools will 

be critical for scenario planning, water 

forecasting, restoration, and land use 

planning. An example is projecting 

changes in streamflow under different 

climate change scenarios, as shown in 

figure 21.

These new technologies could reduce 

present costs for soil and water resource 

inventories and monitoring, and provide broad geographic and temporal 

coverage. Expanded application of 

these technologies and collaboration 

with partners will enable scientists 

and natural resource specialists to 

improve the characterization and 

monitoring of water resources and 

better understand the processes controlling them. 
WATER, CLIMATE CHANGE, AND FORESTS | 35

MOVING FORWARD | THINK

Figure 21—Process-based models can be used to assess streamflows under different scenarios. Here, model-based estimates of streamflow are provided for the current climate (black lines) and a projected future climate (grey lines) in diverse areas of the Pacific Coast USA 

(Tague et al. 2008). Streamflow response to climate change will differ among landscapes depending on dominant runoff mechanisms, 

which are often controlled by the geologic substrate.
36 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | THINK

1. How are precipitation and air temperature changing in 

different locations, and how are these affecting water 

volume, timing, distribution, and quality?

2. How are changes in terrestrial hydrology affecting 

vegetation cover, types, and disturbance regimes, and 

how are these in turn affecting streamflows, surface 

and groundwater levels, and water quality?

3. How will changes in hydrologic regime and vegetation 

disturbance regimes alter sediment and nutrient inputs 

and stream channels?

4. At what rates are snowpacks, snowfields, and glaciers 

declining, and what will be the consequences for local 

flora and fauna and downstream ecology, hydrology, 

and geomorphology?

5. What are the most important gradients (such as 

elevation, distance into rain-shadow, aspect, latitude, 

longitude) driving patterns in climate change effects 

on water resources?

Key questions that experimental watersheds can help answer in light of climate change

6. What are the most important pathways altering water quality, streamflows, soil erosion rates, surface and groundwater 

levels and aquatic habitats (pathways such as reduced precipitation, increased air temperature, increased disturbance 

severity and frequency, changes in infiltration, increased 

atmospheric deposition and evapotranspiration)?

7. How will changes driven by climate interact with the legacy 

of land management activities (such as harvest, road usage, 

fire suppression, grazing) to cause cumulative effects on 

water supply, quality, and timing and on aquatic habitats?

8. To what degree can forest management ameliorate climate 

change effects on streamflow, surface and groundwater 

levels, vegetation, wildlife, and aquatic and water-dependent 

ecosystems?

9. What are the most urgent adaptive changes needed in land, 

fire, and water management to ensure an adequate supply 

and quality of water both for people and for conservation 

of key aquatic species?

10. Where are the highest priorities for applying remediation 

to improve impaired waters and protect endangered 

aquatic species?

Integrate Climate Change in Planning 

Analysis and planning have proven to be integral components of successful watershed management. These 

processes provide watershed and aquatic specialists the 

opportunity to evaluate impacts on water resources and 

to manage for their protection and restoration at project, 

watershed, national forest, and larger scales. Climate 

change greatly increases the importance of these efforts. 

It also adds some new dimensions to an already complex 

world. Existing analysis and planning frameworks now 

need to be expanded to include consideration of changes in 

watersheds and aquatic ecosystems owing to climate change 

and identification of measures to address them to the 

degree possible.

Specifically, effective planning efforts will require some of 

the following steps:

Set Priorities for Management by Watersheds

Watersheds are not equally valuable, nor are they equally 

vulnerable to adverse impacts from climate change. Setting 

management priorities can help to ensure that investments 

provide the greatest possible benefit. Priorities are best set 

at multiple geographic scales with multiple partners, and 

should address projected changes in climate. Otherwise, 

investments may not be effective in retaining or restoring 

critical, high-value watershed services. 

Planning can also identify areas that warrant special protection or changes in management owing to their importance 

in capturing and storing water and supporting particularly 

valuable resources. Protection measures can be developed for 

individual projects, as discussed below, or in forest plans by 

applying protective prescriptions or land use designations. 

Identify Water Uses and Needs

Future needs and demands for water can be identified 

through forest and community planning efforts. Specifically, 

the following questions will need to be addressed: 

• What are the local and regional needs for water?

• How is climate change most likely to increase these needs 

or decrease the available supply or its reliability?

• Can water withdrawals from ground or surface water be 

developed or expanded in a manner protective of aquatic 

and water-dependent ecosystems under changing climatic 

and land use conditions? If so, where and how?
WATER, CLIMATE CHANGE, AND FORESTS | 37

MOVING FORWARD | THINK

Sentinels of change: U.S. Forest Service experimental watersheds

For almost a century, the Forest Service has expanded and 

shared knowledge of wildlands and water. It conducted the first 

paired-watershed experiment on the Nation’s forests beginning 

in 1909. Today, the Forest Service manages 15 experimental 

watersheds distributed across multiple biomes and climatic 

regimes. This network provides an unprecedented glimpse 

of the past——and unparalleled opportunities to grasp the 

consequences of climate change.

Hubbard Brook Experimental Forest

The Hubbard Brook Experimental Forest (fig. 22) in central 

New Hampshire has been a source of pioneering ecological 

research since 1955. It has the longest running precipitation and 

streamwater chemistry record in the United States, which has 

been critical to assessing ecosystem response to air pollution. 

These records are now being used by scientists to understand 

the implications and effects of climate change on Northeastern 

forests. Meteorological records dating back to 1955 show a 

consistent warming trend in mean annual air temperature. 

Winter air temperatures are warming more rapidly than summer 

temperatures and have greater variability (Campbell et al. 2007). 

In addition, snow water and snowpack depth have decreased (64 

mm and 229 mm, respectively) in the last 50 years, and seasonal 

snowmelt appears to be occurring 10 to 17 days earlier. 

Fraser Experimental Forest

In 2007, Fraser, Colorado, lost its recognition as the "Icebox of 

the Nation." Another location in the Midwest has shown colder 

temperatures in the recent record, and Fraser, in fact, shows 

a warming trend over the last few decades. This indicator of a 

changing climate in the Rockies is overshadowed by much more 

dramatic environmental changes. The forests around Fraser and 

across an increasing portion of the West are being affected by an 

unprecedented mountain pine beetle (Dendroctonus ponderosae

Hopkins) infestation (fig. 23). 

Figure 23—Trees killed by mountain pine beetles in Fraser 

Experimental Forest, Colorado.

Figure 22—Hubbard Brook Experimental Forest, New 

Hampshire.

Similar trends can be found in almost all of the biophysical 

records at Hubbard Brook. For example, phenology records 

suggest earlier onset of spring and a longer green-canopy 

period (Richardson et al. 2006), which together with changes 

in snowmelt timing could increase summer drought stress. 

Decreases in snowpack have also spawned interest in 

understanding the implications of increasing soil frost depth 

and duration on ecosystem processes such as nitrogen cycling. 

Scientists at Hubbard Brook are documenting and studying the 

impact of these climate change and variability indicators on 

ecosystem patterns and processes so that we can manage for 

resilient forest ecosystem services for the future.

The warmer winter minimum temperatures recorded during 

the past few decades, coupled with drought and aging forest 

stands have synchronized bark beetle outbreaks that extend 

from Colorado to British Columbia. Current beetle activity is 

predicted to kill nearly all the mature lodgepole pine in Colorado.

Forest Service researchers at the Fraser Experimental Forest 

(FEF) have been monitoring climate, snowpack, streamflow and 

vegetation since the 1940s. Research watersheds at Fraser are 

uniquely positioned to quantify the magnitude of this large-scale 

disturbance on water supplies from the high-elevation forests 

that supply water to much of the interior West. As the climate 

changes, forests altered by disturbances from insects, diseases, 

wind, and fire may dramatically affect the timing, amount, and 

quality of water flowing from forests. Long-term data from sites 

like FEF provide opportunities to detect, predict, and respond to 

these critical changes (fig. 24).
38 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | THINK

Specify Effective Protection Measures

Project-level planning is often the key to developing sitespecific measures for protecting or improving aquatic 

and riparian resources. Measures are based on field 

investigation, modeling, and evaluation by interdisciplinary 

teams. These teams are responsible for planning, design, 

and implementation of land management activities such 

as timber and vegetation management, prescribed fire and 

fuel treatments, mineral and energy development, recreation 

management, range management, watershed restoration, 

and fish habitat improvement. The “Act” section of this 

report includes examples of protection measures for different 

management categories. 

National forest management planning efforts have led to 

the development and application of analytical tools to assist 

watershed and aquatic specialists, such as:

• Watershed analysis (USDA and USDI 1995)

• Hydrologic condition assessment (McCammon et al. 1998)

• Watershed condition assessment (USDA FS 2009) 

• Groundwater handbook (USDA FS 2007b)

• Roads analysis: Informing decisions about managing the 

National Forest transportation system (USDA FS 1999)

Climate change calls for two important additions to the 

planning toolbox: (1) assessment and integration of the 

uncertainty of hydrologic change into analysis and planning, and (2) assessment of watershed vulnerability to 

climate change.

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Figure 24—Average monthly precipitation and runoff are shown for each of the long-term stream gages at U.S. Forest Service 

experimental watersheds. These sites provide unparalleled opportunities for research and monitoring of forest management 

effects and climate change across a broad range of hydrologic regimes (Ziemer and Ryan 2000).
WATER, CLIMATE CHANGE, AND FORESTS | 39

MOVING FORWARD | THINK

Assess and Integrate the Uncertainty of 

Hydrologic Change 

Existing predictions of the effects of climate change differ 

widely, and predictions made at a regional scale do not necessarily apply to all locations in the region. Climate change 

science is advancing rapidly, but uncertainty is expected to 

persist well into the future. To accommodate variation and 

uncertainty, scenario-based planning will be a key tool for 

assessing plausible outcomes and related options.

Scenario-based planning considers a range of potential ecological trajectories, and assesses the benefits and risks associated with an action or set of actions. It can be used in the 

design of contingency plans for unknown events or impacts. 

Such analyses may be used to provide decisionmakers with 

relevant information about specific impacts at a variety of 

spatial scales. 

Conduct Watershed Vulnerability 

Assessments 

Watersheds differ greatly in their vulnerability and resilience to climatic changes. Distinctions between the watersheds can be made by land management specialists based 

on a variety of important factors that differ at managementrelevant scales: values at stake, exposure to climate changes, 

landscape sensitivity to the changes, adaptive capacity, and 

land-use allocations, among others. To design effective 

adaptation measures, important differences and distinctions are ideally best assessed by managers at managementrelevant scales, especially at the subbasin, watershed, and 

subwatershed scales (USGS and NRCS 2009). 

Despite the uncertainty regarding what hydrologic changes 

will occur, managers will be called upon to maintain 

the flow of ecosystem services from forested watersheds. 

Projected hydrologic changes in some watersheds may 

be minimal, but management to improve resilience may 

be high priority because of their increased importance as 

refugia for species or for their ability to sustain flows for 

downstream uses. Change in climate, added to past and 

existing stressors, will result in irrecoverable loss in some 

watersheds. Because time, funding, and personnel are limited, it is critical for managers to direct resources to watersheds where the investment has the greatest likelihood of 

maintaining desired outputs at the least cost. The essential 

question for managers is: In which watersheds will actions 

taken to maintain or improve watershed resilience be most 

useful? Watershed vulnerability assessments are the means 

to address this vital question.

More specifically, watershed vulnerability assessments 

are a tool that will provide managers with answers to the 

following questions:

• What key ecological services are provided by the 

watershed(s) in question and what is their local, 

regional, or national significance?

• What watershed processes, such as snow accumulation and streamflow generation, are most likely to be 

affected by climate change?

• What resources are most vulnerable to these changes 

and the land and water-use changes likely to accompany them? For example:

■ Which important aquatic species may be at risk of 

population decline or habitat loss because of these 

changes?

■ Which areas are most likely to be affected by 

changes in water supply or demand?

■ In which watersheds is the risk to these resources 

greatest?

■ Which watersheds are high priorities for management to sustain desired hydrologic functions under 

changing climate?

■ Which watersheds may serve as climate change 

refugia because they are expected to experience the 

least impact?

• What management actions may reduce the unwanted 

effects of climate change, protect high-value watershed resources, or increase watershed resilience?

• What measures can be used to detect and track evidence of climate-related change as early as possible? 

National-forest-scale assessments could be conducted as 

part of the Land and Resource Management Planning 

process. In almost all cases, these assessments would need 

to be tied to broader bioregional analyses that capture the 

geographic range of the ecosystem services considered. They 

could also be used to update existing watershed analyses 

and develop geographically specific adaptation strategies. 

Existing and readily gathered data and information will 

support preliminary vulnerability assessments in some 

areas, but needed information is not available for many 

locations. This represents an important data gap.
40 | GENERAL TECHNICAL REPORT PNW-GTR-812
 MOVING FORWARD | THINK | COLLA BORATE | ACT | 

WATER, CLIMATE CHANGE, AND FORESTS | 41
42 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | COLLABORATE

After thinking, direct action, of course, will be needed 

to ameliorate the hydrologic effects of climate change. 

Experience over the past few decades has demonstrated, 

however, the importance of another key step before action: 

collaboration. Watersheds often have multiple owners who 

frequently have varied interests and values. Consequently, 

multiparty collaborative efforts are generally necessary to 

effectively manage watersheds. Climate change intensifies 

the importance and complexity of these efforts. The Forest 

Service Strategic Framework for Responding to Climate 

Change recognizes this need, and prioritizes alliances and 

collaborative partnerships as a guiding principle for integrating climate change into the core mission of the agency 

(USDA FS 2008). 

The following section describes a collaborative, participatory approach to adaptation based on connecting people, 

their lifestyles, and land-use decisions to their effects on 

critical watershed services.

Collaborate to Protect 

and Restore Watersheds

Watersheds have multiple owners with multiple interests. 

Only through collaborative efforts can watersheds be 

restored and managed to be resilient in the face of climate 

change. Watershed resiliency is not a goal unto itself. It is 

a means to an end, namely protecting the flow of waterrelated ecological services to and from our watersheds. 

Meeting this goal will require broadening of collaborative 

efforts internally, externally, and globally. Assessing, planning, funding, and implementing efficient and effective 

strategies to maintain and improve watershed resiliency 

will require a renewed commitment to collaboration. The 

Forest Service expects that its work will be conducted using 

an integrated, participatory approach. For example, interdisciplinary teams comprising people with skills in diverse 

disciplines (e.g., geology, soils, hydrology, fisheries, engineering, ecology, forestry) are used to design and implement 

projects. This form of internal collaboration has resulted in 

more integrated watershed projects. Increasingly, however, 

these efforts need to be expanded to engage a broad range 

of stakeholders throughout all phases of resource management. Developing, and more importantly maintaining, 

these types of partnerships requires substantial effort, and 

strong communication and commitment from natural 

resource managers. 

THINK | COLLA BORATE | ACT

Adapting to Climate Change by Improving Watershed Resilience 

Connect Water Users and Watersheds

Global water consumption by agricultural, domestic, and 

industrial sectors has increased dramatically throughout 

the 20th century. Postel et al. (1996), for example, estimated 

that humanity has appropriated over 50 percent of the 

renewable freshwater runoff that is geographically and temporally accessible. Projections indicate that water use will 

grow by 133 percent over the next 20 years (UNEP 2008). 

Personal demand for water is expected to increase with 

elevated global temperatures—a temperature increase of 

1 °C may cause typical urban residents in the United States 

to increase their daily water use by as much as 11 liters 

(Protopapas et al. 2000). At the same time, soil degradation 

across the globe from forest clearing and agricultural pressures has resulted in increased runoff, increased erosion, 

and a reduced capacity to store water. Already nearly every 

region of the United States has experienced water shortages or stress owing to withdrawal rates and demands that 

exceed availability (Alcamo et al. 2003). Water resource 

challenges, exacerbated by a rapidly changing climate, call 

for innovative collaboration in determining where water is 

captured, stored, and released for each watershed and how 

that water is used. 

The Forest Service has an opportunity to collaborate with 

the domestic and irrigation water providers; other federal, 

state, city, and county agencies; and a wide array of nontraditional stakeholders to increase public awareness of the 

ecosystem values of water, its source, and the impact of land 

use decisions on water quality and water supply. Increasing 

public awareness of their community’s connection to water 

and watersheds, and the potential influence of climate 

change on the water-related ecosystem services they enjoy 

is challenging for several reasons. First, the scale of climate 

change disruption has the potential to be large, but the current and localized effects in many areas appear nonexistent 

to many. Watershed ecosystems are poorly understood by 

the public and seem geographically removed. The location of 

water use may also be far from where people live, especially 

for energy and agricultural production. Some geographic 

areas and populations may have experienced water scarcity 

in the past, which will aid in understanding the current 

problem and the link between healthy watersheds and the 

continued provision of this critical resource. 

Identifying the most effective and appropriate behavioral 

changes is critical to public awareness. For suggested 

conservation measures to find traction with the public, 

individuals need to believe their choices are consequential, 
WATER, CLIMATE CHANGE, AND FORESTS | 43

MOVING FORWARD | COLLABORATE

Figure 25—Denver’s Use Only What You Need water conservation campaign. 

positive, and contribute to a larger goal or purpose. By 

tying water-related behavior changes to a specific watershed, and in turn linking that watershed to the theme of 

healthy, resilient forests, conservation programs will have 

a greater chance of success. One successful conservation 

campaign, launched in the summer of 2006, extended into 

people’s lives with eye-catching signs, off-the-wall displays, 

and surprise “guerilla” tactics. The campaign successfully 

engaged the community in a shared awareness of water 

conservation and resulted in significant reductions in 

water use (fig. 25). 

Figure 26—The arid West has some of the Nation’s highest per 

capita residential water use because of landscape irrigation. Xeriscaping and landscaping with native plants can attractively take 

the place of water-intensive lawns. Block pricing of domestic water 

can provide a powerful cost incentive for homeowners to reduce 

their water use and rethink the choices that require large water 

inputs.

Water conservation is one of the most cost effective and 

efficient ways to address water supply limitations. By using 

water more efficiently, supplies can be preserved, money and 

energy can be saved, and fish and aquatic ecosystems can 

be protected. Forest Service managers can lead by example, 

reducing the “water footprint” of Forest Service facilities and 

encouraging others to join them. Opportunities for water 

conservation exist wherever water is used, from domestic 

consumption (fig. 26) to agriculture to energy-related water 

use. The opportunity to improve water efficiencies and 

reduce demand through collaboration with nontraditional 

partners, such as hospitals, utilities, manufacturers, and 

other corporations, is beginning to emerge. Business entities are currently very interested in reducing their often 

significant water footprints, so as to simultaneously reduce 

cost, long-term strategic business risk, and carbon footprint. 

The mutual benefits are considerable and far reaching, 

yet localized and easily quantified, especially when a 

downstream corporation is drawing water from an upland 

watershed. Agriculture and energy interests should be the 

highest priority for partnership development, because their 

use of water is proportionately high (fig. 17), and significant 

opportunities for conservation exist. 

Link to Research and 

Adaptive Management

New technologies provide enhanced access to an everexpanding amount of information, and individuals’ ability 

to synthesize, organize, and think critically about this 

information is more important than ever. Savvy and adroit 

leaders and staff understand the need to constantly gather 

information while maintaining their ability to make critical decisions and, in some cases, take the risks necessary to 

move projects forward in the midst of imperfect information or overwhelming choices.

Managing with uncertainty requires a commitment to adaptive management—a flexible, participatory management 

approach informed by scientific application, monitoring, and 

evaluation, resulting in careful adjustment. Collaboration 

applied to research can foster demonstration projects that 

bring beneficiaries and communities of practice together 

around management issues. Like adaptive management, 

Courtesy of Denver Water

© Andrew Penner/iStockphoto.com
44 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | COLLABORATE

participatory research is a process that involves testing new 

ideas, observing or monitoring results, evaluating success, 

and adjusting for improvement. Rather than involving 

only the land manager or resource professional, it engages 

a broader network in the iterative learning process—those 

who would be affected by advances in the research or management, those who use the watershed outputs being studied, or those who are designing similar methods of inquiry. 

In this way, science and land management are improved 

within a social context, and lessons are more widely shared. 

Demonstration projects that integrate science, management, 

and learning in this way can help create a shared understanding of how land management activities can ameliorate 

the adverse impacts of climate change. Private landowners 

can engage in and learn from participatory research on 

public lands and become better informed about how their 

management actions—or inaction—will affect the delivery 

of ecosystem services as local climates change. 

Improved communication is central to successful participatory research. In addition to publishing research results at 

the end of a demonstration project, scientists and managers 

must engage stakeholder participants in research design and 

decisionmaking and share observations and results through 

workshops, field visits, social networking, and ongoing 

dialogue. 

Engage the Community

Over the past few decades, strong collaborative partnerships have developed around watershed issues in all parts 

of the country. Some of the most important collaboration 

occurs locally, because that is where watershed management 

practices are implemented. Several examples of these efforts 

are referenced in this report (for example, see the spotlights 

on the Verde River and the bottomlands of the Mississippi 

(app.). Partnerships at watershed and river-basin scales will 

assist effective planning and actions to improve watershed 

resilience on the ground. Improvement strategies that are 

cooperatively planned result in opportunities for each of the 

partners to leverage limited funding for improvement and 

assist in allocating those funds to the highest priority areas.

In the formulation of watershed management plans, both 

the attributes of the soil and water resources and the 

socioeconomic factors that affect land use decisions must 

be understood. The effects of various land-use practices 

on maintaining the long-term quality of soil and water 

resources in particular should be taken into account. 

Watersheds are connected from the ridges to the estuary or 

coral reef. Impacts incurred in one area can have cascading 

effects in other portions of the watershed. For example, 

loss of riparian forest in the lowlands can cause water temperature increases above that in which cold-water aquatic 

species will migrate to the uplands, thereby limiting nutrient enrichment in upland forests. Only through integrated, 

participatory approaches to watershed management, in 

which an understanding of the inherent capacity of various 

watersheds to produce resources and the factors limiting 

resource production are understood by all stakeholders, will 

successful and sustainable adaptation and mitigation strategies be developed and implemented. Our ability to understand and implement land-use decisions in line with that 

inherent capacity will determine how resilient a watershed 

will be in response to climate change. 

The connected nature of watersheds necessitates the inclusion of wildland, agricultural, rural residential, commercial, 

and urban populations in watershed management decisions. 

Collaboration in rural and agricultural watersheds may 

involve different partners than wildland areas, but the concepts and utility of the process are the same. State and local 

governments, federal agencies, tribes, corporations, developers, health and environmental organizations, regional 

water managers, city planners, landowners, and others share 

common interests in watershed resources. Establishing 

partnerships with these groups is necessary to expand the 

reach of watershed stewardship to urban areas. Cities, which 

were once overlooked ecosystems within the traditional 

land management framework, are home to half of humanity and represent unique ecosystems critically relevant 

to climate change, watershed resiliency, and biodiversity 

protection. Creating and fostering durable relationships 

among diverse interests and organizations will increase 

the knowledge and capability of local groups to implement 

coordinated actions in response to climate change.1

1 Examples of resources for locating watershed partnership organizations 

include the Environmental Protection Agency’s Adopt Your Watershed 

(http://www.epa.gov/owow/adopt/), the National Watershed Network 

(http://ctic.purdue.edu/kyw/nwn/nwn.html), and the River Network 

(http://www.rivernetwork.org).
WATER, CLIMATE CHANGE, AND FORESTS | 45

MOVING FORWARD | COLLABORATE

A study by the Trust for Public Lands and the American 

Water Works Association revealed that a 10-percent 

decrease in forest cover in a watershed can increase water 

treatment and chemical costs by as much as 20 percent 

(Ernst 2004). Many cities, including New York, Boston, 

Denver, and Portland, Oregon, recognize the value of their 

local forested watersheds and protect large tracts of land 

to sustain clean water supplies. Protecting these lands is a 

more cost-effective way to prevent pollution and maintain 

clean water sources than expanding water treatment plants 

and investing in new infrastructure. Land managers can 

help build a better case for watershed stewardship through 

land conservation and restoration efforts that clearly demonstrate the social link between healthy watersheds and 

human well-being.

Trees in cities are also important. With inner-city temperatures rising—a phenomenon known as the heat island 

effect—adding trees for shade serves the dual purposes of 

cooling ambient air temperatures and reducing the production of harmful ground-level ozone. Cooler temperatures 

reduce peak summer energy demand, thus reducing the 

demand for extraction of water to produce that energy. 

Improving the extent and health of interconnected natural 

ecosystems and waterways through urban, suburban, and 

agricultural areas can serve multiple purposes in our climate change mitigation and adaptation toolbox. Increasing 

tree canopy and adding biofilters helps reduce total annual 

stormwater runoff. For every 10 percent of tree cover added 

to a community, annual stormwater runoff can be reduced 

by as much as 2 percent (Wang et al. 2008). Collaboration 

in rural and agricultural watersheds may involve different 

partners than wildland watersheds, but the concepts and 

utility of the process are the same. Lands converted from 

natural ecosystems to residential, commercial, and agricultural uses often have altered water bodies and aquatic 

habitats, produce greater surface runoff and more nutrient 

enrichment, and have less shade along streams. Urban and 

suburban communities alike are gaining interest in urban 

forestry as they recognize the role of tree canopies in reducing atmospheric carbon dioxide, improving watershed 

health, and enhancing quality of life and neighborhood 

economic value for local people. 

Finally, not all watersheds or portions of watersheds are 

of equal value. As climate change alters temperatures and 

the amount and timing of precipitation and streamflow, 

protecting and restoring key portions of the landscape 

that capture, store, and slowly release water will be critical 

to maintaining species migration and survival. As climate 

change redefines traditional species’ habitat, critical areas 

for conservation of watershed processes and biodiversity 

will be highly valued. Because public lands alone cannot 

be expected to meet all the needs of society, public-private 

partnerships are vitally important to ensure that key portions of watersheds are protected. In these cases, protection 

can be provided through a variety of options including 

deployment of conservation practices, establishing conservation easements, public purchase of the most critical lands, 

and developing ecosystem markets. Identifying and setting 

priorities for protection is best accomplished and supported 

through a collaborative process. 

Link Water From Healthy 

Watersheds to Markets 

As described earlier, ecosystem services are the benefits that 

people obtain from the natural environment. When an economic value is placed on a natural asset, it sets a framework 

for establishing an ecosystem marketplace. Among other 

things, these markets connect natural assets to beneficiaries 

who are willing to help pay for their stewardship (Collins 

and Larry 2007). Perhaps the most advanced market is for 

carbon sequestration. The U.S. voluntary carbon market 

grew by 240 percent from 2006 to 2008 (Hamilton et al. 

2008). The growth of this market reveals that markets are 

influenced by environmental interest and economic goals. 

Experience also shows that investors are most attracted to 

ecosystem markets that have universally accepted standards. 

Attractive markets are also internationally fungible and 

feature tradable units, legal and financial accountability, 

an insurable product, and a scalable solution (http://www.

fs.fed.us/ecosystemservices/).

Collaborative efforts are needed to increase our appreciation 

of the value of water from healthy watersheds. Highlighting 

the value of water will help land managers weigh land-use 

decisions such as the tradeoffs of maintaining intact forests 

to protect watershed values versus the commercial value 

of the timber resources if they were harvested and sold. 

A thorough valuation of the role of healthy watersheds in 

providing water-related ecosystem services may be used to 

make management and policy decisions in the near future. 
46 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | COLLABORATE

Limited markets currently exist for water quality 

and quantity, although these markets and others for 

wetlands and biodiversity are expected to expand. 

By putting nature’s assets on the balance sheet, new market 

opportunities can drive investments in land stewardship 

and restoration. Markets can also provide incentives for 

private landowners to protect or restore their land for the 

ecosystem services it provides. In many cases, investments 

in ecosystem protection and green infrastructure rehabilitation are more cost-effective alternatives to building new or 

improving the efficiency of existing infrastructure designed 

to meet the same goals.

The Forest Service can play a role in advancing ecosystem 

markets by implementing land management projects 

that demonstrate market-based concepts, supporting and 

promoting research that informs market development and 

improves market confidence, and developing partnerships 

and knowledge networks that lead to collaborative innovation and information sharing. It can also lead by making 

use of appropriate opportunities to demonstrate and share 

the values of forest watershed resources in producing clean 

water and in creating healthy aquatic habitats. The spotlight 

on building an ecosystem marketplace for Chesapeake Bay 

(app.) describes a collaborative effort to advance ecosystem 

markets for land stewardship activities that improve the 

health of the bay. 

Employ New Methods that 

Facilitate Collaboration

Technological advances provide opportunities for natural 

resource professionals to improve collaboration and communication within the professional community and with 

the public. The progressive computer age is shaping how 

people share and consume information. Webinars have 

become a preferred education tool, social networking sites 

are a business mainstay, and podcasts are now a customary means of communication. Use of new technologies 

can help individuals and organizations share information 

and expand networks to learn from and reach a broader 

constituency. 

However, new technologies provide enhanced access to an 

ever-expanding amount of information, making individuals’ 

ability to synthesize, organize, and think critically about 

this information more important than ever.

Collaborate Globally to 

Support Sustainable Forests 

Beyond U.S. borders, there is a need to advance and support 

land management planning and actions in developing 

nations that mitigate climate change, foster sustainable 

development, and promote watershed resiliency. In some 

parts of the world, climate-change-induced effects on 

water resources are already affecting lives and livelihoods, 

especially on islands and in coastal environments 

experiencing sea level rise and increasing storm surges (fig. 

27). Worldwide, about half of all jobs are associated with 

water-dependent resources such as fisheries, forests, and 

agriculture (UNFAO 2004). Freshwater aquaculture is the 

fastest growing food production sector.2

Forests represent tremendous opportunities to sequester 

carbon, whereas the loss of forests contributes additional 

CO2 to the atmosphere. Reforestation of degraded areas and 

protection of existing forests worldwide offer the potential 

to reduce climate change effects (fig. 28).

Figure 27—In the winter of 2007 and again in 2008, coastal communities throughout the Federated States of Micronesia (FSM) 

experienced abnormally high tides that flooded homes, washed out 

beaches, and undercut and damaged roads and other infrastructure. 

Such events are expected to become more frequent and destructive, 

as sea level rises and storms intensify.

2 Globally, freshwater aquaculture has increased an average compounded rate of 9.2 percent per year since 1970, compared with 

only 1.4 percent for capture fisheries and 2.8 percent for terrestrial 

farmed meat production systems. Demand for freshwater fish will 

expand because of increasing human population and changing food 

preferences (Millennium Ecosystem Assessment 2005).
WATER, CLIMATE CHANGE, AND FORESTS | 47

MOVING FORWARD | COLLABORATE

With more than 100 years of experience managing national 

forests and grasslands, the U.S. Forest Service has valuable 

expertise to contribute to water and climate change in the global 

context. The Forest Service and developing countries share similar pressures to conserve natural resources without impeding 

economic growth and opportunities. Through its International 

Programs (IP), the agency is well positioned to assist other 

nations as they face forest-related climate change challenges. 

The IP has undertaken climate change initiatives with three 

primary components: reducing deforestation and land 

degradation, policy engagement, and technical cooperation. The 

scope of IP climate change efforts is worldwide, with cooperative 

programs on five continents. Forest Service IP employs a 

variety of tools and approaches to meet the goals of developing 

capacity, strengthening institutions, and developing economic 

alternatives to nonsustainable harvest and management 

practices. The program collaborates with other governments, 

nongovernmental organizations, communities, and private 

stakeholders to contribute technical expertise, develop and 

provide trainings, and participate in forest management and 

policy discussions to promote ecological, social, and economic 

sustainability benefits.

U.S. Forest Service International Programs: climate change efforts

Examples From Eight Countries Where IP Is Engaged in Forest and Climate Change Activities:

• In Mexico, IP supports efforts to stop deforestation in areas 

that are critical to watershed-related ecosystem services.

• Liberia contains over 40 percent of the remaining closedcanopy rain forest in West Africa. IP works with the Government of Liberia to reorganize its forest service and forestry 

sector.

• In the Congo Basin, work is underway to increase local, 

national, and regional natural resource management capacity 

and improve knowledge of a poorly understood region.

• IP has collaborated with Russian partners to promote 

sustainable forestry practices and address forest health 

issues and invasive species. The partnership with the 

Russian Federal Forest Service focuses on combating 

illegal logging and forest fires.

• In Indonesia, IP provides assistance to manage and conserve 

forests at a landscape scale, and to improve fire response 

and control.

• In Jordan, technical assistance is provided to support 

Bedouin communities on community grassland improvement projects.

• IP works with forest technicians, managers, and supervisors in the Brazilian Amazon to apply forest management 

principles and reduced-impact logging methods.

• In the Central Highlands of Vietnam, IP is providing technical assistance to a "payments for ecosystem services" 

program to limit sedimentation to a hydroelectric facility 

by maintaining watershed forest cover and land uses.

The U.S. Forest Service International Programs (IP) illustrate collaboration at the global scale. As illustrated in the 

box below, IP assists international partners in taking both 

adaptive and mitigation approaches that address climate 

change effects. International policy discussions on climate 

change have recently become more focused on the role of 

forests and grasslands in greenhouse gas production. Forest 

managers can support these efforts by collaborating with 

international partners in protecting forests from deforestation and degradation. 

Figure 28—Deforested area on the island of Yap, Federated 

States of Micronesia, where soil productivity is completely 

degraded because of the removal of forests and the loss of critical organic layers. Runoff and soil erosion from these areas is 

greatly accelerated over natural conditions.
48 | GENERAL TECHNICAL REPORT PNW-GTR-812
WATER, CLIMATE CHANGE, AND FORESTS | 49

 MOVING FORWARD | THINK | COLLA BORATE | ACT | 
50 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | ACT

THINK | COLLA BORATE | ACT

Adapting to Climate Change by Improving Watershed Resilience 

Water resources will be affected significantly—and in some 

cases severely—by climate change, but temporal and spatial 

impacts will differ considerably across regions. There is 

substantial uncertainty regarding some of these impacts, 

but there is a very real need and opportunity for us to act. 

Informed and collaborative actions taken now can enable 

people to moderate future impacts or exploit benefits 

caused by climate change. Focusing management actions on 

improving and sustaining watershed resilience is a sound 

response to climatic change (US GAO 2007, Williams et al. 

2007). 

The details of managing for watershed resilience will differ 

depending on the landscape and the needs of surrounding 

communities. Objectives and activities will depend on dominant watershed processes, key ecosystem services, principal 

threats to those services, and social needs and values. 

Watershed stewardship practices—applied more extensively, 

strategically, and in some new ways—will improve watershed resilience and ecosystem services. This section presents 

two broad themes with many associated actions that can 

improve watershed resilience: (1) implement practices that 

protect and maintain watershed processes and services, and 

(2) restore degraded watershed processes.

Implement Practices That Protect and 

Maintain Watershed Processes and Services

More than a hundred years of land management and use has 

resulted in a wide range of watershed conditions on national 

forests and grasslands. Livestock grazing and timber 

management, road construction, mining and energy development, recreation facilities placement and operation, permitted water uses, and fire suppression activities all began 

before their influences and impacts on watersheds and 

aquatic systems were fully recognized. The Forest Service 

adapted by developing procedures, methods, and controls to 

protect water quality and other watershed resources. Water 

resources protection on lands managed by the Forest Service 

now is focused on best management practices (BMPs), 

which are considered the most effective means of preventing 

or reducing the amount of pollution by nonpoint sources to 

a level compatible with water quality goals. 

A healthy, resilient watershed provides a sustained flow 

of desired ecosystem services over the long term. It resists 

and quickly recovers from disturbances such as floods, fire, 

and insect outbreaks.

Key watershed processes and functions, such as the 

following, occur at the desired rates and in the desired 

locations.

• Capture and storage of rainfall

• Recharge of groundwater reservoirs

• Minimization of erosion and protection of soil quality

• Regulation of streamflows

• Storage and recycling of nutrients

• Provision of habitat for native aquatic and riparian 

species 

— Adapted from: Sprague et al. 2006. 

 Vital signs of a healthy, resilient watershed

Protection measures are applied to all Forest Service management activities, and most states have a codified set of 

BMPs that apply to forest management activities. Some of 

the following measures can be implemented at the project 

scale, and some are applicable to watershed, or forest, and 

other broad-scale planning efforts. The nine management 

areas and affiliated activities highlighted here include those 

measures most closely connected to watershed resilience as 

an adaptation to climate change. 
WATER, CLIMATE CHANGE, AND FORESTS | 51

MOVING FORWARD | ACT

Management Domain:

Aquatic Habitat Biodiversity and 

Water-Dependent Ecosystems

Nearly all Forest Service management activities have the 

potential to affect habitats of aquatic and riparian species. 

These habitats range from large river systems and associated tributaries that support anadromous fish, to lakes and 

streams where warm water species flourish, to small or 

isolated springs and wetlands that support rare or endemic 

invertebrate species. Managers can consider how actions 

might impact these habitats, and implement practices to 

protect them.

Aquatic Ecosystems: Practices to maintain 

and improve watershed resilience

√ Minimize temperature increases by maintaining 

well-shaded riparian areas and limiting groundwater 

withdrawals.

√ Protect and restore longitudinal connectivity of 

stream systems to provide species with access to 

habitats that may be disconnected by changes in flow 

regime.

√ Improve lateral channel-flood plain connectivity where 

human disturbance has isolated channels.

√ Ensure that fish have access to seasonal habitats, 

such as off-channel or cool-water areas.

√ Protect and restore riparian near-stream habitats and 

wetlands.

√ Minimize ground disturbance and land-use changes 

that reduce groundwater recharge, and implement 

BMPs that encourage groundwater recharge from 

impervious and disturbed areas.

√ Disconnect road drainage from stream networks to 

restore natural patterns of flow.

√ Reintroduce beaver where appropriate.

√ Strengthen community-based watershed management approaches with partners in multiownership 

watersheds.

Management Domain: 

Energy Development

Energy development on public lands managed by the Forest 

Service is governed by permits, regulations, and executive orders. Demands for energy development are likely to 

increase.

Energy Development: Practices to maintain 

and improve watershed resilience

√ Increase understanding of water-energy interdependencies.

√ Identify where, when, and under what conditions 

new hydroelectric facilities are suitable, at multiple 

scales.

√ Locate new energy development sites and supporting 

road and infrastructure networks outside of wetlands, flood plains, riparian areas, fens, bogs, and 

meadows, and other water-dependent ecosystems.

√ Protect surface and groundwater during energy 

development and production. 

√ Assess the impacts of producing and removing 

bioenergy materials on existing soil organic matter 

pools and carbon sequestration.

√ Analyze the impacts of water consumption and 

return-water quality on ecosystem services. 

√ Wherever possible, include provisions for water 

recycling and reuse in gas, oil, geothermal, and 

other operations.

√ Develop/enhance tools for better environmental 

protection while optimizing hydropower operations.

√ Consider energy requirements for moving and 

treating water when developing measures for 

special-use applications, and when participating in 

water supply negotiations and land management 

planning.
52 | GENERAL TECHNICAL REPORT PNW-GTR-812

MOVING FORWARD | ACT

Management Domain: 

Fire and Fuels

In many regions, assessment, evaluation, and implementation of projects aimed at reducing fire severity and restoring fire-dependent ecosystems are at the top of managers’ 

priorities. Considering watershed processes in these projects 

is necessary to protect soil and water resources. A successful large-scale approach to such planning is described in 

the spotlight on assessing wildfire risks and management 

opportunities for the South Fork Boise River (app.).

Fire and Fuels: Practices to maintain and 

improve watershed resilience

√ Strategically target fuels and vegetation management activities to maintain resilient vegetative 

communities and reduce wildfire severity on a 

priority basis, informed by vulnerability assessments, watershed analyses, and strategies for 

carbon sequestration by forests.

√ Include watershed management objectives 

in wildfire and fuels management plans. 

√ Where appropriate, reintroduce fire to 

approximate more resilient patterns of 

vegetation and disturbance.

√ Develop partnerships with downstream 

water providers to encourage investment 

in the protection and restoration of forested 

watersheds. 

√ Maintain and protect soil and water resources, 

particularly soil infiltration capacity, during 

fire suppression activities, and rehabilitate 

suppression-related damage.

√ Assess the impacts of removing fuels on existing 

soil pools, carbon pools, and nutrient cycling.

Management Domain: 

Infrastructure

Collectively, the American people have invested considerable resources in bridges, recreation areas, roads, and other 

facilities to serve the public. Some of these facilities, especially those near rivers and streams, or located on unstable 

landforms, are vulnerable to damage from higher peak 

flows associated with climate change (fig. 29). Managers 

depend on engineers and earth scientists to conduct risk 

assessments to support infrastructure development and 

maintenance decisions.

High-severity wildfires can result in excessive erosion, 

elevated stream temperatures, and the loss of important 

resources and ecosystem services. Fire is a natural disturbance that maintains vegetation and contributes to watershed resilience, but decades of fire suppression and fuel 

accumulation have changed fire frequency and ecology. In 

addition, climate change has and will continue to exacerbate existing fuel and fire problems by changing precipitation patterns, snowmelt, and vegetation conditions. 

Strategically reintroducing fire as a means to promote 

more resilient patterns of vegetation can help reduce the 

incidence of large-scale, uncharacteristic wildfires. But land 

managers face the challenge of optimizing an entire set of 

restoration activities, not just fuel reduction. Rehabilitating 

roads, enhancing riparian areas, removing fish barriers and 

balancing the needs of local residents with the agency’s 

responsibility to protect water quality, forest health, and 

critical fish and wildlife habitat are also crucial watershed 

health priorities. Integrating biological data (such as critical 

habitat, forest stand condition, and riparian health) and 

physical data (such as postevent debris flow potential, water 

chemistry, and predicted postactivity stream temperature 

changes) into models that predict effects on critical 

watersheds following management activities or disturbance 

can help managers prioritize restoration activities. 

This type of analysis helps managers identify areas where 

watershed conditions are resilient to or could benefit 

from wildland fire (maintenance conditions), areas where 

wildland fire is unacceptable and human intervention 

would be necessary to prevent losses of lives and property 

(engineered habitat), and areas with opportunities for using 

wildland fire to restore terrestrial or aquatic ecosystems 

(restoration areas). Managers in the South Fork Boise River 

(SFBR) basin are applying these models, as shown in the 

spotlight in the appendix. 

Combining technical analyses with priority-setting systems 

based on critical watershed services will help ensure that 

management actions achieve results of value to watershed 

health and public needs. In many areas of the country, 

including the South, East, Rocky Mountains, and Sierras, 

fire and fuel management is complicated by private 

property, investments, and private forest land comingled 

with public ownership. In these situations, partnerships 

and cooperation are the keys to effective planning and 

management response. Among other measures, private 

landowners can address wildfire risks by collaborating 

on community wildfire protection plans and by ensuring 

defensible space around homes. 

A Closer Look: Fire and Fuel Management
WATER, CLIMATE CHANGE, AND FORESTS | 53

MOVING FORWARD | ACT

Figure 29—White River Bridge downstream of Mount Hood, 

Oregon, after the 2006 flood events.

Infrastructure: Practices to maintain and 

improve watershed resilience

√ Identify high-risk watersheds and infrastructure sites 

and develop a range of design and treatment options 

based on climate-aware risk assessment and priority 

setting. 

√ Instead of “design storms” or “design runoff,” use 

“design storm scenarios” with a range of explicit 

assumptions about changes in peak-flow probabilities 

to cope with uncertainties, and display risks 

in a more uncertain future. For example, 

consider infrastructure risks in which the 

100-year storm becomes the 50-year storm, 

or the 10-year storm. 

√ Design culverts, bridges, and dams to limit 

the consequences of exceeding design 

capacity, consistent with the onsite and 

downstream values at risk. Build larger 

factors of safety into structures where 

failure would have substantial or unacceptable 

consequences. Reevaluate flood frequency 

distributions where possible. Where long 

records of streamflow are available, consider 

using only the most recent 30 years.

√ Design in-channel structures to maintain 

hydrologic and biotic connectivity by 

allowing free passage of water, sediment, 

large wood, and aquatic organisms. 

√ Prioritize and treat road networks by stormproofing and decommissioning to restore 

natural flow patterns, reduce erosion, and 

increase system durability.

Figure 30—Probability of postfire debris flows associated with the Old Fire in Southern California. Red areas 

have highest potential, yellow areas the lowest. These 

risk models were developed by the U.S. Geological 

Survey and collaborators such as the U.S. Forest Service, 

Natural Resources Conservation Service, and various 

state agencies. Improved predictions of postfire effects 

are needed. Cooperative, interagency efforts offer the 

greatest potential for meeting critical information needs. 

Modified from Cannon et al. 2004.

Management Domain: 

Natural Disaster Response

Climate change is expected to increase the occurrence of 

weather-related emergencies like floods, landslides, drought, 

wind events, and wildfires. Natural hazards often result 

in loss or damage to capital investments such as roads and 

bridges, severe impacts on critical resources such as water 

supply and fish habitat, and loss of human life (fig. 30).

Natural Disaster Response: Practices to 

maintain and improve watershed resilience

√ Make full use of existing emergency response 

programs and authorities. 

√ Review and update interagency coordination 

systems at national, state, and local levels. 

√ Advance technologies for early detection and 

warning systems.

√ Increase emergency response training at all 

organizational levels.

√ Build flexible, innovative, and responsive 

programs into existing management systems.

√ Ensure that emergency response actions do not do 

more damage to resources than the emergency itself.
54 | GENERAL TECHNICAL REPORT PNW-GTR-812

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Management Domain: 

Soil and Water

Restoring watersheds, riparian areas, and streams is a major 

component of improving watershed resilience. Managers 

use a variety of means to plan and accomplish restoration 

activities including working with partners, and integrating 

soil and water objectives into fuels, vegetation, fisheries, 

recreation, mining, engineering, and wildlife projects. 

Soil and Water: Practices to maintain and 

improve watershed resilience

√ Design and implement measures to keep water on 

and in the land longer, including meadow groundwater 

restoration, road drainage control, and silvicultural 

treatments.

√ Target treatments to restore impaired watershed 

condition and key functions on a priority basis, using 

watershed condition, climate change vulnerability 

assessments, and watershed analysis, as well as 

strategies for carbon sequestration by forests.

√ Implement treatments to maintain and improve soil 

infiltration, nutrient cycling, and ground cover. 

√ Reduce hydrologic impacts of infrastructure, 

particularly road and road-stream crossings, to 

improve overall watershed condition and maintain 

local soil moisture regimes.

√ Restore structure and function of degraded wetlands, 

meadows, riparian areas, and flood plains to enhance 

channel–flood plain connection, promote groundwater 

recharge and keep meadow ecosystems wetter longer.

√ Set and meet soil quality objectives to sustain soil 

productivity and prevent soil erosion and sedimentation 

(Johnson et al. 2007).

√ Reclaim abandoned mines and mine spoils to reduce 

pollution of surface and ground waters by toxic 

acidity and heavy metals, and restore water-based 

habitats.

Management Domain: 

Recreation

Demand for recreation on some Forest Service lands will 

likely increase significantly in the future. Most recreation 

activities on public lands and the facilities that serve them 

are located near water. Climate change brings increased risk 

of damage to these facilities, as well as those related to ski 

areas. Managers can also anticipate changes in the location 

and timing of recreation demand. Planning is needed to 

accommodate changes in uses and protection of water 

resources. 

Recreation: Practices to maintain and 

improve watershed resilience

√ Locate recreational facilities and design and manage 

uses to protect sensitive terrain and minimize risks 

to forest users. 

√ Plan and operate recreation programs to limit effects 

on vulnerable sites and to resources at risk.

√ Build flexibility into permits so that periods of use 

or locations, or both, may be adjusted in response 

to changing climate and hydrologic conditions.

√ Prepare for and adapt to changing recreation uses, 

needs, and opportunities. 

√ Use interpretive programs to inform the public 

about the changing climate and effects on recreation 

and resource values.

√ Manage recreational access to avoid or minimize 

soil and water resource damage.
WATER, CLIMATE CHANGE, AND FORESTS | 55

MOVING FORWARD | ACT

Management Domain: 

Vegetation

Vegetation management is conducted on national forests 

by a variety of means. Merchantable timber is most commonly managed through timber sales, and timber stand 

improvement projects are used to manage submerchantable 

trees. Range and grasslands are typically managed using 

range management allotments. Watershed specialists provide managers with opportunities to protect and improve 

watershed condition during assessment, planning, and 

implementation of these projects.

Vegetation: Practices to maintain and 

improve watershed resilience

√ Integrate watershed management and carbon 

sequestration into vegetation management plans 

and treatments. 

√ Identify, incorporate, and monitor “best management 

practices” as part of rapid response to disturbances 

from insects, drought, and fire.

√ Schedule vegetation management, including 

timber harvest and fuel treatments, to limit 

adverse hydrologic effects, such as reduced 

infiltration and peak flow increases. 

√ Evaluate grazing management plans to address 

range and watershed conditions under changing 

climate scenarios. 

√ Revise grazing intensity where needed to 

improve riparian areas, streambanks, meadows, 

and wetlands.

√ Protect soil quality to sustain soil productivity 

and prevent soil erosion and sedimentation.

Management Domain: 

Water Use and Diversions

Numerous water diversions and storage facilities exist on 

national forest lands (fig. 31). Impacts to groundwater, 

streams, aquifers, aquatic species, or water-dependent 

ecosystems may occur if individual or cumulative effects 

are not adequately addressed. Impacts from new or renewed 

land-use authorizations may be averted through planning, 

evaluation, authorization, and adaptive management. The 

number of requests and claims for water use on and from 

national forests will certainly grow in the future with 

increases in population and demand. At the same time, 

environmental needs to support aquatic species habitat and 

water-dependent systems also will increase.

Water Use and Diversions: Practices to 

maintain and improve watershed resilience

√ Use existing authorities and cooperative 

agreements to set permit conditions for 

developments and diversions.

√ Build flexibility into long-term special use 

authorizations and provide for permit term 

and condition modification as climate and 

hydrologic conditions change. 

√ Develop releases that mimic natural flows 

when possible.

√ Work with permitting agencies to implement 

conservation plans that respond to increased 

demands for hydroelectric power generation.

√ Use the latest scientific information to analyze and 

establish environmental flows (Richter et al. 2006), 

and flows for river restoration (Palmer et al. 2007).

√ Monitor the effects of changes in flow regimes on 

affected systems.

√ Ensure that adequate information about water 

distribution and ecological requirements is available 

to inform decisions intended to balance competing 

interests and demands.

√ Share knowledge and expertise with water managers 

as new water uses, storage facilities, and diversions 

are proposed.

√ Incorporate basinwide evaluations of current and 

future water needs so that access to scarce water on 

national forests and grasslands is provided equitably.

√ Facilitate coordinated, cooperative approaches to 

water withdrawals among users.
56 | GENERAL TECHNICAL REPORT PNW-GTR-812

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Restore Streams and Valley Bottoms

Activities that improve the condition of degraded channels 

and flood plains can extend natural storage, reconnect 

ground and surface waters, mediate local flood flows, and 

support aquatic habitats. Streams and valley bottoms, as 

well as adjacent flood plains, wetlands, meadows, and side 

channels, have attracted multiple users over time, leading 

to various degrees of change. Although some alterations 

are considered minor, others have brought dramatic change 

to the form and function of the aquatic system. Many 

riverine ecosystems no longer support key processes or 

deliver expected services. For example, overgrazing, road 

and railroad construction, channel draining and rerouting, 

and other land-use practices have caused extensive stream 

incision or downcutting (Loheide and Gorelick 2007). 

As a result, water tables are lower and wet meadows have 

been lost, leading to dramatic reductions in key ecosystem 

services such as streamflow regulation, water storage, water 

purification, fish and wildlife habitat, and recreational 

enjoyment. 

Restoration efforts in some areas are promoting the recovery 

of some streams, valleys, and the ecosystem services they 

provide. Benefits are often direct and measurable onsite, 

and significant improvements in overall watershed condition are achieved as the cumulative effects of several projects occur. The spotlight highlighting Resurrection Creek 

restoration in Alaska (app.) illustrates a large stream and 

valley bottom project that had both local and watershedwide improvements. 

Elements of successful watershed

protection and restoration programs 

Watershed protection and restoration programs are 

more likely to succeed if:

• There is substantial federal leadership and funding. 

• All levels of government, nongovernmental organizations, 

and other interested parties are involved.

• Comprehensive prioritization and planning techniques 

are applied. 

• Actions address the most important conditions impairing 

or threatening critical watershed processes, regardless 

of political boundaries.

• Investments are long term. 

—NRC 1992, Roni et al. 2002

Figure 31—Points where water is diverted within and adjacent to 

the boundaries of the Umatilla and Wallowa-Whitman National 

Forests.

“Without an active and ambitious 

restoration program in the United 

States, our swelling population and 

its increasing stresses on aquatic 

ecosystems will certainly reduce 

the quality of human life for 

present and future generations.”

 -National Research Council 1992

Restore Watershed Processes

Implementing restoration actions that maintain or improve 

conditions is key to providing resilient watersheds. Planning 

tools allow managers to determine which watersheds should 

have the highest priority for treatment. Priorities are often 

based on resource values at risk, maintaining or improving 

habitat for sensitive or listed aquatic species, and meeting 

requirments of the Clean Water Act. Treatments differ 

depending on the location and scope of need, but include 

measures to improve or maintain stream channels and 

valley bottoms, riparian areas, and upslope conditions.
WATER, CLIMATE CHANGE, AND FORESTS | 57

MOVING FORWARD | ACT

New methods for restoring degraded stream and valley 

bottom systems are also in development. For example, the 

Feather River Coordinated Resource Management Group 

(FRCRM), a nonprofit partnership of 23 public and private 

stakeholders, is developing and implementing a novel 

technique called “plug and pond” on the Plumas National 

Forest in northern California. The method involves “plugging” incised channels to raise the bed level of the stream, 

and “ponding” water at a higher base level to create a more 

natural channel that reconnects flood plains and shallow 

groundwater, thus restoring hydrologic and ecological form 

and function (fig. 32). These restoration projects restore ecosystem services provided by healthy streams and may help 

to offset some of the local impacts of changing precipitation 

amounts and timing. Working with scientists to quantify 

and monitor the effectiveness of these projects is providing 

new information to expand their application and refine 

project designs.

Restore Riparian Areas and Bottomlands

Prior land uses and past management practices have 

removed forest vegetation from many riparian areas, 

adversely affecting water quality, stream and groundwater 

flows and levels, flooding, and aquatic species. Loss of these 

transition areas between terrestrial and aquatic ecosystems 

causes accelerated bank erosion, channel incision, alterations in stream channel form, loss of habitat, lower water 

tables, and elevated water temperatures, because of lack 

of shade and groundwater exchange. These impacts are 

considered primary factors in the decline of many fisheries, from trout streams in the east to salmon stocks in the 

Pacific Northwest. Restoring natural riparian vegetation is 

a prerequisite to stabilizing stream systems capable of supporting native aquatic life and to responding to extreme 

flow events associated with altered climate regimes. The 

National Research Council (2002) considers riparian restoration one of the most critical environmental challenges of 

our time and a national priority. Several ongoing projects 

in the Mississippi River Basin, as presented in Spotlight on 

Restoring Bottomlands (app.) provide examples of collaborative riparian restoration.

Figure 32—Restoring groundwater levels in eroded meadows and 

valley bottoms can increase watershed resilience in many forested 

watersheds. Warming and late-season drying trends greatly 

increase the ecological importance of wet mountain meadows 

and valley bottoms, which provide myriad ecological services. 

Restoring groundwater levels in these places adds resistance and 

resilience to watersheds, reducing the vulnerability of ecosystem 

services to climate change.

Kathryn Ronnenberg
58 | GENERAL TECHNICAL REPORT PNW-GTR-812

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Restore Upslope Water Conditions

Prescriptions that improve “upslope” watershed processes 

can reduce soil loss and incidence of debris flows, increase 

groundwater recharge, and improve stream habitats. In 

some locations, past land management activities have 

stripped soils of protective cover, causing rill or gully networks to develop and deliver water, soil, and debris directly 

to drainages. Many treatments are used to stabilize or 

restore eroded hillslopes. Reshaping and revegetating them 

are among the most effective practices (fig. 33). Reclaimed 

soils and vegetation absorb and use water that would have 

quickly run off the landscape. In addition, downstream 

ecosystems recover as upstream hydrologic functions are 

restored and sediment inputs are reduced. Water that reenters soil recharges groundwater; reduces overland flow that 

contributes to flooding, channel aggradation, degradation, 

or widening; and reestabilishes seasonal flow timing.

Reconnect Flood Plains and Habitats

Improvements to flood plain structure and habitats maintain channel flow capabilities and help species adapt to 

changing conditions. Climate change will further fragment 

aquatic habitats by increasing temperatures, altering physical habitats, and contracting the perennial stream network. 

A substantial number of salmon and trout populations, 

many of which are already threatened, endangered, or 

considered for listing under the Endangered Species Act, 

Ten years after restoration.

Figure 33—In South Carolina, early settlers cleared native forests and farmed them until erosion and nutrient losses made the land 

unproductive. Deep gullies formed on many eroding hillslopes to become a dominant landscape feature. When the Francis MarionSumter National Forest was created in 1936, it contained an estimated 200 square kilometers of actively eroding gullies and severely 

eroded soils. Some downstream valleys and stream channels were filled with up to 3 meters of soil from the eroding landscape (Trimble 

1974). Decades later, many of the problem lands had still not recovered. Consequently, the forest initiated efforts that have helped to 

stabilize and recover 80 to 90 percent of gullies and eroded areas. Projects such as these are an effective adaptation response to climate 

change because restored hydrologic functions will help prevent flooding and erosion during large storm events and provide greatly 

improved soil moisture for forest growth. The national forest is also working to enhance its capacity to implement these projects 

through the use of advanced technologies such as LIDAR (James et al. 2007).

may be lost owing to the effects of climate change over the 

next century unless fragmented aquatic ecosystems are 

reconnected, invasive species are controlled, and riparian 

vegetation is managed to provide a full range of ecological 

functions needed for healthy streams. One study (O'Neal 

2002) predicted that 18 to 38 percent of suitable salmon and 

trout habitat would be lost by 2090 under current climate 

change scenarios, and these losses will be exacerbated by 

other management actions that impair watershed processes.

National forests alone contain 200,000 miles (322 000 kilometers) of fish-bearing streams—streams that are 

becoming increasingly important to conserving freshwater diversity. Some of these habitats, however, have 

been substantially fragmented by more than 440,000 miles 

(708 000 kilometers) of authorized and unauthorized roads. 

Surveys show that more than 20,000 road-stream crossings 

do not provide full passage for all species and life stages of 

fish (USDA FS 2001). Connecting, restoring and reopening 

existing, high-quality aquatic habitats is the first priority 

for enabling species to adapt to changing conditions (Roni 

et al. 2002) (fig. 34). Other options may include protecting 

and maintaining genetic diversity through conservation 

measures, restoring marginal habitats, identifying aquatic 

populations that are adapted to warmer waters to facilitate 

their transition, and relocating important populations to 

habitats that retain favorable conditions.

Gullied, degraded land. Gully reshaping.
WATER, CLIMATE CHANGE, AND FORESTS | 59

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By 2100, more flood flows in fragmented hydrologic 

networks could double both the costs and the number of 

properties damaged (Kirshen et al. 2005). In watersheds 

dominated by a mosaic of forest, urban, and other land uses, 

flood plains and stream channels have often been altered 

so that floods can no longer follow traditional flow paths, 

be infiltrated and stored adequately in soils or aquifers, or 

be confined within undeveloped lands. Even in watersheds 

without significant infrastructure, past management activities may have affected the water’s ability to flow in its natural 

path. The spotlight on Resurrection Creek (app.) illustrates 

flood plain and channel restoration efforts where past 

mining activities impaired both streamflows and fisheries 

habitat. This successful project and the partners involved 

were recognized for outstanding results in 2008 with a Rise 

to the Future Award from the U.S. Forest Service. These and 

other such flood plain restoration projects are the primary 

means to reconnect natural hydrologic systems to attenuate 

local flooding events. Other adaptation strategies may be 

considered in developed watersheds where restoring flood 

plains is not feasible because of cost or land limitations. 

Such solutions include engineered structural and nonstructural features to retain or divert flows. Engineers, scientists, 

and planners will need to consider the impacts of climate 

change and other influences by modeling hydrographs that 

incorporate potential changes in flow peaks, volume, and 

timing.

Figure 34—Restoring fragmented flow paths and habitats on the Chequamegon-Nicolet National Forest. At Armstrong Creek Crossing, 

five undersized culverts in various stages of disrepair (photo on left) were replaced with a 30-foot (9-meter) clear span wooden bridge 

(photo on right). The culverts, which had a total waterway opening of 24.5 square feet (2.3 square meters), would fill to capacity during 

a 2-year flood; the road would overtop during a 100-year flood. The realigned crossing restores flow to a meander that was abandoned 

when the culverts were installed, restores fish passage for brook trout, and improves habitat connectivity for other aquatic organisms. With a waterway opening of 200 square feet (19 square meters), the new structure can accommodate flood flows in excess of the 

500-year flood and enable the stream to function more naturally during large runoff events. For additional examples, see http://www.

stream.fs.fed.us/fishxing/case.html.

The principles and actions presented in these chapters suggest how land and water managers can incorporate climate 

change considerations into watershed management today 

and into the future. Many actions provide a means for 

managers to respond to the anticipated challenges of climate 

by focusing on maintaining and improving resiliency of 

watersheds managed by the Forest Service. This approach 

is necessitated by high uncertainty in the magnitude and 

extent of the effects on local watersheds, environmental 

services, and people. Because projected changes will occur 

across all watersheds, regardless of ownership, innovation 

and expanded partnerships will be key factors in creating successful ventures across ownerships and ecotypes. 

Ultimately, caring for the Nation’s forests and grasslands 

at the watershed scale, in a way that enables species, ecosystems, or resources to adapt to change, will be the most 

rewarding climate change strategy. Healthy watersheds that 

are less vulnerable to changing conditions are more likely 

to supply a broad array of ecosystem services in the face of 

climate change and other disturbances.
60 | GENERAL TECHNICAL REPORT PNW-GTR-812

“Good management is the art of 

making problems so interesting and 

their solutions so constructive that 

everyone wants to get to work and 

deal with them.”

—Paul Hawken (1987)
WATER, CLIMATE CHANGE, AND FORESTS | 61

CLOSING | Water, Climate Change, and Forests

History provides vivid examples of societies that were either 

destroyed or maintained when climates changed. Noted 

scientist and author Jared Diamond (2005) discussed the 

Greenland Norse (986 to c. 1420 A.D.) who thrived during 

a warm period, but were unable to survive like their native 

Inuit counterparts when the climate cooled. Accounts of the 

Norse settlements’ demise suggest that they did not anticipate that changes would be long term and require adaptation. They were inflexible and did not adopt the approaches 

that allowed the Inuit to persist.

Today, overwhelming scientific evidence synthesized by 

the Intergovernmental Panel on Climate Change, the U.S. 

Climate Change Science Program, and others indicates 

trends of increasing temperatures and variable precipitation 

patterns that have begun to affect people and communities 

around the world. Scientists, governments, and industries 

are anticipating the consequences of warming and investing 

in research to reduce uncertainties and understand options. 

Resource managers, landowners, and citizens are working 

to understand these changes, the range of future conditions, 

and options for maintaining ecosystems, communities, 

and livelihoods.

The stakes for good watershed stewardship are raised dramatically by climate change and population growth. How 

best to respond is no mystery: watersheds must remain 

resilient to adapt to land use and climate change, rebound 

from disturbances, and adjust to new conditions. There is 

much we can do, and we have a long history and abundant 

knowledge and experience in doing this work: the science 

and practice of sound watershed stewardship. 

We have good reason to hope and every reason to act. We 

know how to practice effective stewardship so that the 

watersheds we depend on and value will remain intact and 

continue to provide life-supporting services. Climate change 

offers us the opportunity to advance our skills, rethink our 

stewardship, innovate, and work with our partners for the 

benefit of healthy watersheds and communities. 

America's forests and grasslands are immensely valuable, 

locally and globally. They will certainly remain as national 

jewels in a warming, crowded, and challenging future. 

These lands are and will continue to be crucial refugia 

for plants, animals, and fish displaced from other lands 

and waters. These lands will remain the “water towers” 

of the Nation, providing water security and prosperity 

to a growing population and future generations. As we 

work together, we can ensure that these valuable watersheds 

continue to meet the many needs of people and nature into 

the next millennium.
62 | GENERAL TECHNICAL REPORT PNW-GTR-812

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When you know Multiply by To find

Millimeters (mm) 0.0394 Inches

Centimeters (cm) .394 Inches

Meters (m) 1.094 Yards

Meters 3.28 Feet

Kilometers (km) .621 Miles

Square meters (m 2) 10.76 Square feet

Square kilometers (km 2) .386 Square miles

Hectares 2.47 Acres

Cubic meters (m3 ) 35.3 Cubic feet

Cubic meters 1.307 Cubic yards

Liters (L) .0353 Cubic feet

Liters .265 Gallons

Liters 33.78 Ounces (fluid)

Liters per kilowatt-hour (L/kWh) .264 Gallons per kilowatt-hour

Degrees Celsius/Centigrade (°C) 1.8 °C + 32 Degrees Fahrenheit

English Equivalents
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68 | GENERAL TECHNICAL REPORT PNW-GTR-812

Examples of Watershed Stewardship

Spotlight on aquatic restoration in the Pacific Northwest: reevaluating priorities 

in the context of climate change 

EXAMPLES

Figure 35—USFS priority river basins and watersheds for aquatic restoration in the 

Pacific Northwest. River basins (large polygons) with the highest priority for restoration 

are shown in blue, moderate priority are shown in light green, and lowest priority are 

shown in gray. Priority watersheds (small polygons) within the basins are shown in 

dark green.

The U.S. Forest Service (USFS) recently began implementing an 

Aquatic Restoration Strategy to improve watersheds and aquatic 

habitats on national forests in the Pacific Northwest (PNW) 

Region. A central component of the strategy is the identification 

of priority areas for restoration, at river basin and watershed 

scales, with regional and local partners (fig. 35). Initial priorities 

were based on the existing condition of aquatic resources, the 

nature and scale of threats to those resources, the sensitivity 

of different watersheds to these threats, and opportunities for 

mitigating them. Areas with the healthiest native fish stocks and 

the greatest manageable risks are the initial focus for restoration.

Initial implementation of the strategy has been promising. For 

example, the USFS and numerous partners——federal, state, and 

local governments, nongovernmental organizations, private 

landowners——have developed watershed restoration plans for 

many of the priority watersheds and 

are concentrating their investments in 

these areas. Partners are substantially 

leveraging and amplifying each others’ 

funding, skills, and capacity. 

For many reasons, however, success is 

far from guaranteed. Climate change 

is among the greatest uncertainties, 

as it is likely to magnify existing 

impacts and threats. To improve 

the likelihood of success, managers 

and researchers are collaborating to 

conduct a multiscale climate change 

vulnerability assessment for key 

aquatic species across the PNW Region. 

This assessment will use information 

regarding existing species population 

status, the location and distribution of 

key habitats, and projected changes 

in stream temperatures, low flows, 

peak flows, and disturbance regimes 

to determine species and locations 

that are most susceptible to climate 

change (see, for example, figures 36 

and 37). Subsequent efforts will involve 

local managers and field specialists in 

identifying more localized constraints 

on these species and habitats and 

opportunities to address them through 

management activities.

Results of the vulnerability assessment 

may verify or alter existing restoration 

priorities, depending on how aquatic 

resources are likely to be affected 

and whether or not the effects can be 

mitigated.
WATER, CLIMATE CHANGE, AND FORESTS | 69

EXAMPLES

Figure 36—Areas with thermally suitable habitat for bull trout under current climate conditions and 

a projected 1.6 °C increase in air temperature (Rieman et al. 2007, Isaak et al. 2007). Model estimates 

exclude western Washington and Oregon.

Figure 37—Likelihood 

of winter precipitation 

changing from snow to 

rain, potentially leading to 

increased winter peak flows 

and decreased summer low 

flows (Casola et al. 2005).
70 | GENERAL TECHNICAL REPORT PNW-GTR-812

EXAMPLES

Spotlight on assessing wildfire risks and management opportunities

for the South Fork Boise River

Location: South Fork Boise River (SFBR), Idaho

Figure 38—Subwatersheds identified for restoration work related to various 

conditions.

Background: The 2,500-km2 SFBR watershed, 

which contains lands managed by the Boise and 

Sawtooth National Forests, has not experienced a 

significant fire in at least 100 years. The watershed 

supports people, communities, and infrastructure, 

a mix of low- and high-elevation forest types, and 

thousands of kilometers of streams inhabited by 

numerous species, including bull trout, that are 

protected by the Endangered Species Act.

Actions: Researchers at the U.S. Forest Service 

Rocky Mountain Research Station integrated 

spatial data on forest condition, bull trout 

(Salvelinus confluentus) habitat, wildland-urban 

interface, roads, and fish passage barriers into a 

map of maintenance, engineered, and restoration 

conditions. Researchers built a model to predict 

the persistence of bull trout habitat following 

wildland fire and postfire disturbances, such 

as debris flows. Results were used to prioritize 

subwatersheds for restoration work (fig. 38). 

Based on this analysis, researchers determined 

that the density of restoration needs and presence 

of bull trout in the northwest portion of the SFBR 

made this area a high priority for restoration. The 

eastern portion of the SFBR has a small human 

footprint and large, well-connected patches of bull 

trout habitat. As a result, fire has been suggested 

as the primary tool for habitat maintenance and 

renewal in this portion of the watershed. The 

western portion of the watershed was identified 

as a high priority for fuel treatment because of 

the risk of high-severity wildfire in and around the 

wildland-urban interface.

Outcomes: With priority areas now identified, 

land managers are moving forward with implementing specific, high-priority restoration actions. 
WATER, CLIMATE CHANGE, AND FORESTS | 71

EXAMPLES

Spotlight on restoring the bottomlands of the Mississippi River

Location: Mississippi River basin

Actions: The Forest Service has played a key role in bringing 

together partners in the Upper Mississippi Forest Partnership. 

A recent assessment completed with the U.S. Geological Survey 

showed reforestation priorities along the river and is helping 

guide efforts on the ground. Working with the National Fish and 

Wildlife Foundation, the Mississippi Watershed Fund has been established and has provided over $500,000 in grants to complete 

innovative restoration projects. 

In the Middle Mississippi River Partnership, the Shawnee National Forest with other federal and state agencies and nonprofit 

groups are restoring resilience to 195 free-flowing miles (314 

kilometers) of the Mississippi River in Illinois and Missouri. The 

forest was able to expand its administrative boundary to allow 

purchase and donation of marginal cropland in the flood plain so 

it could be returned to highly productive bottomland hardwood 

forest. Over 3,000 acres (1200 hectares) have been acquired 

and restored to forest land. Partners work together to contribute 

resources or expertise on each property that is added. 

Historically, the bottomland forest 

of the Lower Mississippi Alluvial 

Valley occupied 24 million acres 

(9.8 million hectares) in parts of 

seven states, and served as an immense filter for the river’s floods 

and sediment and a buffer for the 

coastal plain of Louisiana. Now less 

than 5 million acres (2 million hectares) of this forest exists. Since 

the mid-1980s, active restoration 

programs by multiple agencies and 

nonprofit groups have reclaimed 

over 10,000 acres (4050 hectares)——an important step beginning the journey back to a healthy 

bottomland hardwood ecosystem.

Outcomes: Easement acquisitions, native forest reestablishment, wetland re-creation and water management improvements 

are returning natural hydrologic function to the river flood plain 

and improving watershed resilience. Concurrently, reconnection 

of forests is conserving them as rich habitats for wildlife and fish, 

improving water quality, enhancing recreation, and providing a 

scenic landscape even as climate change impacts are beginning 

to become more pronounced. 

Mississippi River Basin.

Background: The Mississippi River drains nearly two-thirds of 

the contiguous 48 states. Key to the resilience of this river and the 

Gulf of Mexico downstream is the 1,500-mile (2400-kilometer)-

long flood plain corridor. Prior to dense human settlement, 

streams and rivers bordered by forest and prairie delivered 

water, nutrients, and sediment to the Gulf. Sediment built and 

replenished soils, and floods were spread across extensive 

forested flood plains. Today, more than half of these bottomland 

hardwood forests have been cleared for farming or the cities 

that depend on the river for their commerce, recreation, and 

livelihood. 

Climate change threatens to increase the loss of these 

bottomlands, as increased precipitation on bare soils will result 

in greater soil erosion and sedimentation. Partnership efforts 

that share common objectives——restoring flood plain forests and 

wetlands that are the heart of the river's ecological function——

are underway along the entire river corridor. 

Remaining forest in 

1992 (shown in green).

U.S. Geological Survey
72 | GENERAL TECHNICAL REPORT PNW-GTR-812

A closer look: improve or decommission roads

EXAMPLES

The national forest road system is vast. This network of about 

380,000 miles (611 000 kilometers) of authorized roads and at 

least 60,000 miles (96 000 kilometers) of unauthorized roads 

is over twice as large as the entire federal highway system. 

These roads provide numerous benefits to society, including 

access for recreation and land management. Expansive road 

networks, however, can impair water quality, aquatic habitats, 

and aquatic species in a number of ways, often to a greater degree than any other activities conducted in forested environments (Gucinski et al. 2000, MacDonald and Stednick 2003, 

USDA FS 2001). Roads intercept surface and subsurface flows, 

adding to the magnitude and flashiness of flood peaks and accelerating recession of flows (Jones and Grant 1996). Road 

networks can also lead to greater channel incision, increased 

sedimentation, reduced water quality, and increased stream 

habitat fragmentation. Modern road location, design, construction, maintenance, and decommissioning practices can substantially mitigate these impacts, but most forest roads were 

built using older methods and are not adequately maintained 

owing to a lack of resources. In addition, many critical drainage 

components like culverts, are nearing or have exceeded their 

life expectancy. 

These deteriorating road conditions threaten our ability to 

manage forests and pose significant risks to watersheds. Climate 

change elevates these risks by increasing the frequency and 

magnitude of large storm events and flooding. 

There is a need to balance the benefits and costs of roads by 

decommissioning those we no longer need and improving those 

that are essential. A balanced portfolio of restoration actions 

will be needed to address this challenge. Intensive treatments, 

such as decommissioning and road realignments are essential, 

but can only be implemented on small portions of the landscape 

because of cost. These will need to be complemented with 

simpler, less expensive treatments, such as stormproofing roads 

by preventing streamflow diversions at road-stream crossings 

and outsloping roads, that can be applied across broad areas. 

Ongoing efforts to assess and reconnect streams that are 

currently fragmented by inadequate stream crossings will be 

equally important (Furniss et al. 2009).

Strategically applied road decommissioning or road improvements can help restore natural flow patterns, increase flood 

plain and habitat connectivity, decrease peak flows, and reduce erosion and temperature impacts. Such changes can help 

ameliorate climate change impacts and contribute to improved 

watershed resilience.

The Lolo National Forest in Montana has been a national leader 

in this type of work (fig. 39). From 1996 to 2007, the forest 

and its partners decommissioned 788 miles (1269 kilometers) 

of unneeded roads. Through stream crossing removals and 

replacements, the forest opened 333 miles (536 kilometers) of 

fish habitat by removing 329 stream crossings and replacing 55 

others.

Figure 39—In this project on the Lolo National Forest in 

Montana, the original road paralleled a stream channel that 

often eroded portions of the road, delivering large volumes of 

sediment to the stream. Through a stewardship timber sale 

contract, a new road was built away from the stream, and the 

old road was decommissioned.
WATER, CLIMATE CHANGE, AND FORESTS | 73

A closer look: sustain water flows and levels that support ecosystem and stream processes 

A river’s flow regime——the pattern of high and low flows between 

different seasons, years, and decades——is an indicator of overall health and resilience. It is generally recognized that some 

amount of water can be diverted from a river for human use 

without substantially compromising the river’s ability to support 

a desired array of ecosystem services. As the amount of diverted water increases, so does the risk and likelihood that some 

desired services will be lost (Postel and Richter 2003). Balancing 

water use with the maintenance of key ecosystem features and 

processes has been a significant challenge for land and water 

managers. These challenges will increase in severity and extent 

as the combined effects of population growth, land use change, 

and climate change intensify water demand and create variability in supply. The spotlight on the Verde River, Arizona, below 

presents an example of threats to environmental flows and considerations for protection and management.

Spotlight on managing for environmental flows in the Verde River, Arizona

“Water made the West, and its historic evaporation will unmake 

it—unless this generation is as creative as its forebears in finding 

sustainable ways to live with the 20 inch [annual precipitation band].” 

— David M. Kennedy, 2008

Background: The Upper Verde River is a remarkable natural 

resource. Thirty-seven miles of this spring-fed, desert stream 

flow freely through the Prescott National Forest (PNF). It 

traverses deep limestone canyons, basalt mesas, and alluvial 

valleys lined with cottonwood (Populus fremontii Wats.), willow 

(Salix sp.), walnut (Juglans major (Torr.) Heller), sycamore 

(Platanus occidentalis L.), and ash (Fraxinus velutina Torr.) trees, 

and meadows of sedges and bulrushes. The riparian community 

and high-quality water provide for a remarkable diversity and 

abundance of fish and wildlife species, including one of the last 

assemblages of native fish species in Arizona. Because of these 

values, the Upper Verde was classified as eligible for designation 

as a Wild and Scenic River in 1993.

The river, however, is central to an increasingly common controversy in the arid West. Human populations in Arizona, especially 

in the Verde River Basin and Yavapai County, have skyrocketed 

in the last decade. This growth is taxing existing water supplies, 

and as a result, these communities are evaluating opportunities 

to import water from other sources. The primary source being 

considered is an aquifer connected to headwater springs that 

supply the river with cool, clean water. 

Actions: If the aquifer’s groundwater were pumped as proposed, 22 miles (35 kilometers) of river on the PNF might be 

dewatered. This would substantially adversely affect national 

forest resources and users and could result in severe reductions 

in water availability to downstream communities and holders 

of water rights. Despite these impacts, 

the Forest Service 

has limited recourse 

because it has no 

authority to manage 

the groundwater on 

adjacent lands. 

Recognizing the importance of this issue, Congress enacted 

Title II of the Northern Arizona Land Exchange Act, which empowers the Forest Service to support communication and planning among stakeholders. Many diverse stakeholders are now 

involved in this effort, and unusual partnerships are converging 

to protect the treasures of the Upper Verde River. The municipalities proposing the project are interested in maintaining the 

river’s integrity. To support these efforts, the PNF and the USFS 

Rocky Mountain Research Station are examining research priorities that would lead to a better understanding of how this unique 

desert stream functions.

Outcomes: The outcome of these efforts remains uncertain. 

Several key unanswered questions include: 

• Will the need to protect environmental flows, surface water 

rights and high-value fish, wildlife, and recreation resources 

on the PNF influence the way people consider and use water 

resources that sustain the river? 

• Will diverse stakeholders come together and develop a 

reasonable solution that meets people’s needs for water, 

as well as the river’s long-term capacity to provide other 

ecological services?

Location: Upper Verde River, Prescott National Forest, Arizona 

EXAMPLES
74 | GENERAL TECHNICAL REPORT PNW-GTR-812

EXAMPLES

Spotlight on resurrecting Resurrection Creek, Alaska

Location: Resurrection Creek is a 161-square-mile (417-squarekilometer) watershed that flows northward into Turnagain Arm 

at Hope, Alaska. 

Background: During the early 1900s, portions of the creek were 

heavily mined for placer gold with hydraulic mining equipment 

that used high-pressure water jets to strip away vegetation and 

soils so they could sort through underlying gravels for gold. 

The coarse tailings were placed into high piles along the valley 

bottom. The creek was diverted into a straight, steep, simplified 

channel along one side of the valley, separating it from the 

functional flood plain. Tailings piles had restricted overbank 

flood flows and left poor growing conditions for vegetation. Side 

channels that provide rearing habitat for salmon and streamside 

forests that provide habitat for eagles, bears, and numerous 

other riparian species were substantially degraded. Although the 

mining activity is over, the creek would have needed centuries to 

reestablish its original character without intervention.

• Shaped 50 acres (20 

hectares) of flood 

plain to accommodate 

overbank flows while 

preventing flood cutoff of newly created 

meanders.

• Constructed more 

than 2 miles (3 

kilometers) of new 

side sloughs and 

ponds adjacent to the 

new stream channel, 

providing flood relief 

for the main channel 

and high-quality 

rearing habitat for 

salmon and trout. 

• Placed more than 1,000 trees into 20 engineered log jams 

along the channel to allow for moderation of side slough 

flows, provide nutrients and cover for spawning and rearing fish, and capture additional natural logs and branches 

during flooding. 

• Hauled and spread 8,000 cubic yards (6100 cubic meters) 

of soil and woody debris onto the new flood plains to enhance natural revegetation and future planting efforts. 

• Moved an existing access road out of Resurrection Creek’s 

flood plain. 

• Removed 4,000 cubic yards (3000 cubic meters) of 

tailings to create additional parking for the Resurrection 

Pass Trailhead.

Outcomes: By 2006, the channel and flood plain were restored 

to conditions much closer to their pre-mining condition. All five 

Pacific salmon species are spawning in the creek once again. 

Fishermen and hikers of the popular Resurrection Trail that 

parallels the creek now see a natural, productive, meandering 

stream instead of an aging gravel quarry. 

In the coming years, the channel is expected to continue changing, naturally shifting within the valley bottom as upstream and 

flood plain surface and groundwater flow pathways are reconnected. Riparian vegetation will recolonize streambanks and 

the flood plain. Large wood and sediment from upstream will 

become lodged into the new bed and banks, diversifying habitat 

features for aquatic species. 

Young workers from the Youth 

Conservation Corps helped with 

vital restoration work at Resurrection Creek in Alaska.

The top photo shows Resurrection Creek in 2002; the bottom 

photo was taken in July 2006 following completion of construction illustrating the restored channel and flood 

plain through the valley. 

Actions: In 2005, the Chugach National Forest and partners 

including the Youth Conservation Corps and local contractors 

began construction of a mile-long restoration project on 

Resurrection Creek. The project accomplished the following:

• Redistributed 140,000 cubic yards (107,000 cubic meters) 

of tailings to develop a new stream channel and flood plain.

• Excavated, shaped, and “stepped” 1.3 miles (2.1 kilometers) 

of new stream channel with natural pool/riffle/glide 

sequences, increasing the channel length by 30 percent.
WATER, CLIMATE CHANGE, AND FORESTS | 75

EXAMPLES

Background: The future health of Chesapeake Bay depends 

greatly on the actions of private landowners. Emerging 

ecosystem markets can provide landowner incentives to 

conserve or improve their land. Currently, access to markets is 

confusing and difficult without a centralized marketplace that 

connects landowners to potential buyers of ecosystem credits. 

The Alliance for the Chesapeake Bay, the Pinchot Institute for 

Conservation, the U.S. Forest Service, and other stakeholders 

are developing an ecosystem services marketplace for the 

Chesapeake Bay called the Bay Bank.TM

The ultimate mission of the Bay Bank is to improve the health 

of Chesapeake Bay by fostering stewardship activities on private forest and farm lands that provide cleaner air, clean water, and quality wildlife habitat. The Bay Bank will also help to 

advance markets that protect valuable forests threatened by 

development. Keys to success include guaranteed high market 

standards, consistent and appropriate protocols for credit establishment and trading, and the ability to direct landowners to 

market opportunities. 

Actions: Bay Bank development includes the following 

components:

1. Baseline: Analysis of current regulatory drivers for 

ecosystem markets in the Chesapeake, as well as state 

and federal regulations and guidelines for generating 

and trading credits.

2. Forestry for the bay: An effort to provide online, coached 

land stewardship; this program will provide the initial link 

between landowners and a spatial land registry. 

3. Spatial land registry: A Web-based mapping tool that 

allows landowners to spatially select and register their 

parcels of land, identify land management practices that 

may generate credits, and determine eligibility for current 

and emerging ecosystem markets. The spatial land 

registry will link to the Bay Bank online marketplace. 

4. Verification and certification: Requirements for onthe-ground verification of practices and third-party 

certification to ensure high-quality credits. 

5. Centralized marketplace: An online portal for ecosystem 

market transactions in existing and emerging exchanges/

registries. 

6. Regional trust mechanism: A means to leverage funding 

streams to purchase credits generated by high-quality, 

third-party certified private stewardship activities and 

target investments for ecologically meaningful watershed 

restoration.

Ecosystem Markets

Carbon sequestration— 

Credits for increasing carbon storage and 

rates of removal from the atmosphere

Forest conservation— 

Credits for maintaining and enhancing 

forest lands

Habitat conservation— 

Credits for maintaining and/or enhancing 

endangered species and high-value habitats

Wetland conservation— 

Credit for maintaining and enhancing 

wetland areas

Spotlight on building an ecosystem marketplace for Chesapeake Bay

Location: Chesapeake Bay, Middle Atlantic Region