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Using Forestry to Secure America’s Water Supply1
Abigail R. Kimbell and Hutch Brown

Abstract. America’s water supplies are under siege due to climate change and population growth. Forests play a critical role in protecting and delivering the Nation’s water supplies. Through sustainable forestry, forest landowners and land managers can help secure America’s water supplies. The Forest Service is doing so in a number of ways, including restoring streams in high mountain meadows, working with the Environmental Protection Agency to better meet requirements under the Clean Water Act, helping to establish ecosystem services markets for water quality, and striking innovative agreements with States to secure instream flows on national forest land.

Archeologists in the Sonoran Desert have made a startling discovery. A thousand years ago, what is now the greater Phoenix area was covered with homes and farms, courtyards and workshops—a civilization far greater than once thought (Childs 2007). The civilization flourished for centuries, and then the climate changed. The Salt River became unreliable, reduced by terrible droughts. The great Sonoran civilization, no longer sustained by dependable waterflows, was decimated by conflict and finally disappeared. All that remains, besides ruins and artifacts, is the name Hohokam, a Pima word meaning “all used up.”


Are we, too, in danger of becoming “all used up”? Climate change … water shortages … battles over water sources … these harbingers of doom for the Hohokam sound eerily familiar today. But there is hope. Americans are finding ways of working together to sustain their water resources. History need not repeat itself if we build on what we know, working together to ensure that future generations of Americans will have sufficient pure, clean water. Foresters can help lead the way.


Water Challenges

Few forces are more important than water in shaping the human condition. Water has been called the central organizer of ecosystems (Sedell and others 2000), sculpting the physical landscape and governing its vegetation, laying the very basis for human life and civilization. Like the Hohokam, most of the world’s great civilizations developed near rivers. When rivers are full and flowing, they bring prosperity; but when they run dry, they bring ruin and despair.


Today, some 1.1 billion people worldwide lack sufficient clean water and some 2.4 billion people lack sufficient sanitation (WWDP 2007). According to the Millennium Ecosystem Assessment (2005), up to 25 percent of global freshwater use exceeds sustainable supplies, and global water quality is deteriorating. By 2025, 40 percent of the world’s population could be living in water-scarce regions, especially as the climate changes (Cassara et al. 2002).

American water supplies are also at risk (CSG 2008; NSTC 2007). Much of the Southwest is in long-term drought; one study found a 50-percent chance that Lake Mead will go dry by 2021 (Barnett and Pierce 2008). “In the American West,” noted another study, “… water of acceptable quality is becoming harder to find because local sources are allocated to prior uses, depleted by overuse, or diminished by drought stress” (Anderson and Woosley 2005). It is tempting to think of drought as temporary, but in an era of climate change, that is wishful thinking. One expert put it this way (Gertner 2007): “You can’t call it a drought anymore, because it’s going over to a drier climate. No one says the Sahara is in drought.”

Water shortages are also reaching into the Eastern States. In 2007, a severe regional drought—reportedly the worst in a hundred years (Goodman 2007)—led Georgia to ration water and declare a state of emergency in its northern counties. At one point, Atlanta’s main source of water, Lake Lanier, had barely four months of water left; Georgia established statewide, year-round restrictions on outdoor watering that remain in place. The governor of North Carolina, warning that his State also faced a state of emergency, asked residents to stop using water for “nonessential” purposes. Such regional water shortages are likely to continue; the U.S. Government Accountability Office (2003) projected that at least 36 States would face water shortages in the 10-year period from 2003 to 2013.

Climate change is part of the problem. The Intergovernmental Panel on Climate Change (2007) predicted that runoff and water availability will decrease by 10 to 30 percent at middle latitudes around the world, including much of the United States. The West will likely see smaller snowpacks and more winter flooding (Fischlin and others 2007; Mote and others 2004; Snyder and Sloan 2005), with earlier snowmelts contributing to lower summer streamflows. As temperatures warm and streamflows decline earlier each year, fire seasons will likely become more severe (Bachelet and others 2003; Brown and others 2004).

At the same time, demand for water will continue to grow, placing new strains on sources that are often already oversubscribed. From 1950 to 2000, water used nationwide for electricity rose by almost 500 percent and for irrigation by about 50 percent (USGS 2005). Water withdrawals have stabilized since 1985, but the U.S. population is projected to rise from about 300 million to about 570 million by 2100 (Cordell and Overdevest 2001), with the fastest growth expected in the drought-prone West. Already, many water tables have fallen due to unsustainable use, particularly on the High Plains. The Ogallala Aquifer underlies parts of nine States, from Wyoming to Texas, providing 30 percent of the Nation’s water for irrigation. In its central and southern reaches, the Aquifer has been reduced to half of its original volume, because withdrawal rates are 14 times greater than recharge rates (CSG 2008).  


Increasingly, water quantity issues are tied to water qualityissues. Ground water withdrawals have led to saltwater intrusions into municipal water supplies in Texas and almost every State along the Atlantic seaboard (USGS 2007). Drawdowns in the urban corridor along Lake Michigan, from Indiana to Wisconsin, have reduced water quality for millions of urban residents. In suburban Milwaukee, for example, radium in the aquifer exceeds safety standards for drinking water (Grundl and Cape 2006). Surface water pollution has also caused illness and even death


From 1990 to 2000, there were at least 10 instances of contaminated drinking water due to cryptosporidium, a waterborne pathogen (Corso and others 2003). The worst case was in 1993 in Milwaukee, where about 403,000 people became seriously ill, resulting in 69 deaths.


The Forestry Connection

Conservationists have long understood the connection between forests and water. “For when the earth was covered with the forest,” wrote George Perkins Marsh (1864), “perennial springs gushed from the foot of every hill, brooks flowed down the bed of every valley.” Spongy forest soils soak up rain, recharging aquifers and releasing high-quality water for downstream use. They also keep sediments and nutrients from impairing water quality in lakes and streams. Fifty-three percent of the water supply in the contiguous United States originates on forestland, even though forests cover just 29 percent of the surface area (Brown and others 2005; U.S. Forest Service 2007). Gifford Pinchot, who helped found American forestry at the turn of the 20th century, put it this way: “The relationship between forests and rivers is like father and son. No father, no son.”


The Forest Service has an obligation to manage the national forests and grasslands for water, among other things. The Organic Administrative Act of 1897 made “securing favorable conditions of water flows” one of the purposes of the forest reserves, forerunners of the national forests. In the contiguous United States, 18 percent of the water supply originates on the National Forest System; in the 11 contiguous States of the West, it is 51 percent (Brown and others. 2005; U.S. Forest Service 2007). The National Forest System provides drinking water to about 3,400 municipalities, slaking the thirst of some 60 million Americans (Sedell and others 2000). Public and private forestlands combined furnish water supplies for more than 138 million Americans. One of the Forest Service’s highest purposes is to help sustain the health of the watersheds that supply so much of the Nation’s drinking water.

Most watersheds on national forest land are healthy, but that has not always been the case. National forests in the East were largely assembled in the 1920s-50s from hard-scrabble farms with few trees, depleted soils, and deep scars from erosion. No longer checked by forests, storms sent water rushing downhill, swelling rivers and causing epic floods, such as the 1936 deluge that covered Pittsburgh in 46 feet of water, the worst flood in the city’s history. Under careful management, Federal lands in the East slowly recovered, and now dense forests regulate downstream flows while supplying eastern cities with water. From Vermont to Florida, from the Great Lakes to the Gulf of Mexico, Federal forestry has played a key role in restoring healthy, functioning watersheds.

In the West, past practices have also degraded some watersheds, and the Forest Service is working to restore them. An example comes from California’s Sierra Nevada, where channelized streams on the Plumas National Forest have worn gullies into floodplains, drying out the surrounding meadows, raising downstream temperatures, and flushing downstream habitats with sediment. Using a “pond-and-plug” technique, national forest managers have elevated streams to their original meandering floodplains and raised water tables. Storms no longer send floods ripping down gullies, but rather spread streams across their entire floodplains, allowing the original meadow vegetation to return. The meadows again act like sponges that soak up snows and rains and gradually release the flows in summer, when the water is needed downstream. Through such techniques, land managers can restore the hydrological functions of forests and meadows—functions that are critical for controlling floods, storing water, and sustaining downstream habitats for fish and wildlife.


Restoring Water Quality

Decades after the Clean Water Act was passed in 1972, water quality remains a concern. In 2000, 39 percent of the rivers and 45 percent of the lakes tested nationwide were found to be impaired (EPA 2006). Although most waters on national forest land are clean and healthy, some are not. The top five reasons for water quality impairment on the national forests are, in descending order of importance, high temperatures, excessive sediment loads, habitat modification, excessive mercury content, and excessive metal loads.

Under the Clean Water Act, a stream or lake listed as impaired requires a costly 2-year study to establish target standards and a restoration plan. The resulting target is known as a TMDL, or “total maximum daily load.” By one estimate, all the TMDL studies needed for impaired waters on the National Forest System would cost more than $400 million—funds that might better be used for actual remediation. Based on decades of research and management experience, the Forest Service has best management practices for restoring watersheds without the need for costly, time-consuming studies. Fortunately, the Clean Water Act has a classification known as “category 4b” for streams where “existing control measures,” such as best management practices, are likely to restore an impaired stream or lake. In these cases, the Clean Water Act does not require a TMDL, creating opportunities for streamlining water quality improvements.

In 2007, the Forest Service signed a memorandum of agreement with the Environmental Protection Agency (EPA) to explore such streamlining opportunities. The agency is now working with various States, using EPA funds, to pilot-test imaginative ways of repairing watersheds based on streamlined TMDL studies or no TMDLs at all. For example, Idaho found that Bear Valley Creek on the Boise National Forest has excessive sediment loads. In response, the Forest Service is restoring streambanks, eliminating nearby grazing, and remediating old mine sites to reduce sediment loads, activities that collectively qualify Bear Valley Creek for a category 4b classification. As such pilot projects proceed, the Forest Service is developing tools for streamlining processes under the Clean Water Act in ways that might ultimately benefit State, private, and other landowners as well.

Water Quality Markets

Too often, the delivery of clean water to downstream users is simply taken for granted, despite the costs of keeping upstream watersheds forested and healthy. Cities such as New York are beginning to recognize that paying upstream landowners to maintain forests can be more cost-effective than constructing costly water treatment facilities (Daily and Ellison 2002). Downstream water quality also depends on keeping nutrients such as nitrogen and phosphorus out of local streams. Forestry can help protect municipal water supplies and restore estuaries degraded by nutrient runoff, such as the Chesapeake Bay.


Private forest landowners own 57 percent of America’s forests. Given the role that forests play in water supply and purification, the importance of maintaining intact private forestlands will only grow. However, private landowners face rising pressures to convert their lands to urban uses; more than 11 percent of the Nation’s private forestland—about 44.2 million acres, an area the size of New England—is likely to see increases in housing density from 1997 to 2030 (Stein and others 2005).

Working with partners, the Forest Service can help keep private forestlands intact, partly by augmenting their income streams. The agency is promoting ways of remunerating private forest landowners for delivering a key ecosystem service—water purification. In the Chesapeake Bay watershed, for example, the Forest Service is working with partners to develop the concept of a Bay Bank. The Bank would be a central clearinghouse for buyers and sellers of water quality credits in the Chesapeake Bay watershed. For example, by planting a riparian forest, a landowner could keep nutrient-laden runoff from reaching a river. A facility that generates phosphorus or nitrogen could install technology to do the same, but it might be cheaper for the landowner to plant a forest. If so, then the forest landowner could sell a water quality credit to the facility through the Bank. The overarching goal would be to meet regional targets for limiting nutrients in the Chesapeake Bay, thereby helping the Bay to recover. In the process, forest landowners would be paid for helping to clean up the Bay.

Finding Common Ground

Mark Twain once quipped that whiskey was for drinking and water for fighting over, based on his experience of a West where water was already in short supply. Twain could have been commenting on California, where 19th-century cattle barons struggled for control over water rights. Since then, Californians have famously fought each other over water in the Klamath, Owens, and Sacramento Rivers, just as Coloradans have fought each other over water in the South Platte River. Water wars have extended across State lines, with States battling each other over water rights to rivers such as the Truckee (California and Nevada) and the Republican (Colorado, Kansas, and Nebraska). The most famous example, the Colorado River, is now oversubscribed; the Colorado River Compact, signed by seven States in the 1920s, was based on a period of above-average rainfall, and withdrawal rates have been “too high for sustainable extraction” (CSG 2008). In the South, Georgia has tried to redraw its border with Tennessee so it could tap the Tennessee River; and Alabama, Florida, and Georgia have seen 18 years of bitter court battles over water sources that cross State lines, with the Federal Government struggling, so far in vain, to broker a water-sharing agreement.

The Forest Service has also seen fights over water, especially in the West. Each State has primary authority for water allocation, but the Federal Government retains regulatory authority over water on Federal lands. In fact, Congress has passed more than 30 laws governing the management of water resources on national forest land. The Federal Land Policy and Management Act of 1976, for example, authorizes the Forest Service to regulate water use to “minimize damage to scenic and aesthetic values and fish and wildlife habitat and otherwise protect the environment.” In effect, Federal and State authorities share jurisdiction over waters on the National Forest System, resulting in confusion and bitter legal fights.

In 2007, after 15 years of often contentious negotiations, the Forest Service signed a compact with the State of Montana to address water rights on national forest land. The compact reserves water rights for Forest Service administrative uses and for instream flows for the wild and scenic South Fork Flathead River as well as 77 other streams. According to a spokesman for the State, the compact balances the interests of the agricultural community against those of Montana’s many recreational users (Backus 2007). However, neither side got everything it wanted; for example, the compact does not protect instream flows for about 750 streams on national forest land, although it does set up a process for negotiating future protections.

Nevertheless, it is a good first step away from years of rancor and litigation, costing each side millions of dollars for no gain. “This is an important model that we hope other States will embrace,” declared Under Secretary of Agriculture for Natural Resources and the Environment Mark Rey (Backus 2007). “People will hold up Montana as a good example of how these disputes should be resolved in the future.”

A Watershed of Opportunities

The lesson of the Hohokam is clear: Rising demographic pressure on a declining water source can doom a civilization—unless it is prepared to adjust. The Hohokam lacked modern technology, yet their plight pales by comparison to the climatic and demographic challenges facing the world today. Their fate remains a warning.

Forests can help secure water supplies, even in an era of climate change—so long as people are ready to work across jurisdictions to protect and restore forested watersheds. No single landowner or land manager can do it alone. Fortunately, people are coming together across the Nation to find better ways of managing their water resources. The Forest Service is helping by facilitating partnerships, conducting research, providing technical assistance, and addressing the challenge of climate change. It is up to all of us in forestry, working together across borders and boundaries, to consolidate and continue the gains made, for the benefit of generations to come.


The authors thank Daniel Morris, a former student intern for Policy Analysis, Forest Service, Washington, DC, for writing the initial draft of the manuscript. For helping us revise the manuscript, we also thank Sherry Hazelhurst, Water Quality Program Leader, Forest Service, Washington, DC; Denise Ingram, Policy Analyst, Forest Service, Washington, DC; and Jean Thomas, Water Rights Program Leader, Forest Service, Washington, DC. We would also like to acknowledge the many suggestions and contributions by reviewers, including Tom Brown, Economist, Rocky Mountain Research Station, Forest Service, Fort Collins, CO; Rick Cables, Regional Forester for the Rocky Mountain Region, Forest Service, Golden, CO; Chris Carlson, National Ground Water Program Leader, Forest Service, Washington, DC; Tom Crow, National Program Leader, Ecological Research, Forest Service, Washington, DC; Harv Foersgren, Regional Forester for the Intermountain Region, Forest Service, Ogden, UT; Polly Hays, Water Program Manager, Rocky Mountain Region, Forest Service, Golden, CO; Frank McCormick, Environmental Scientist, Forest Service, Olympia Forestry Sciences Laboratory, Olympia, WA; Ge Sun, Research Hydrologist, Southern Global Change Program, Forest Service, Raleigh, NC; Rick Swanson, Special Projects Biologist, Forest Service, Washington, DC; and Josh Trapani, Policy Analyst, Forest Service, Washington, DC.

End Notes

1This article appeared in Journal of Forestry 107(3) [April/May 2009]: 146-149. Gail Kimbell is a Chief Emeritus of the U.S. Forest Service living in Missoula, MT; Hutch Brown is a Forest Service policy analyst in Washington, DC.


Anderson, M.T.; Woosley, L.H., Jr. 2005. Water availability for the western United States—Key scientific challenges. Circular 1261. Reston, VA: U.S. Geological Survey.

Bachelet, D.; Neilson, R.P.; Hickler, T.; Drapek, R.J.; Lenihan, J.M.; Sykes, M.T.; Smith, B.; Sitch, S.; Thonicke, K. 2003. Simulating past and future dynamics of natural ecosystems in the United States. Global Biogeochemical Cycles 17(2):1045-1066.

Backus, P. 2007. Forest Service, state agree on water compact. The Missoulian. 18 April.

Barnett, T.P.; Pierce, D.W. 2008. When will Lake Mead go dry? Journal of Water Resources Research. In press. http://meteora.ucsd.edu/~pierce/journal_articles.html.

Brown, T.C.; Hobbins, M.T.; Ramirez, J.A. 2005. The source of water supply in the United States. RMRS-RWU-4851 Disc. Pap. Fort Collins, CO: U.S. Forest Service, Rocky Mountain Research Station.

Brown, T.J.; Hall, B.L.; Westerling, A.L. 2004. The impact of twenty-first century climate change on wildland fire danger in the western United States: An applications perspective. Climatic Change 62: 365-388.

Cassara, A.; Layke, C.; Ranganathan, J.; Tunstall, D.; Doering, D.S.; Vanasselt, W. 2002. Tomorrow’s markets: Global trends and their implications for business. A collaboration of the World Resources Institute, United Nations Environment Programme, and World Business Council for Sustainable Development. Washington, DC: World Resources Institute. http://www.wri.org/publication/tomorrows-markets-global-trends-and-their-implications-business

Childs, C. 2007. Phoenix falling? High Country News. 16 April 2007. http://www.hcn.org/servlets/hcn.Article?article_id=16939

Cordell, H.K.; Overdevest, C. 2001. Footprints on the land: An assessment of demographic trends and the future of natural lands in the United States. Champagne, IL: Sagamore Publishing.

Corso, P.S.; Kramer, M.S.; Blair, K.A.; Addiss, D.G.; Davis, J.P.; Haddix, A.C. 2003. Cost of illness in the 1993 waterborne Cryptosporidium outbreak, Milwaukee, Wisconsin. Emerging Infectious Diseases 9(4). http://www.cdc.gov/ncidod/EID/vol9no4/02-0417.htm

CSC (Council of State Governments). 2008. Water scarcity: Preventing water shortages. Issue brief: Trends in America. http://www.csg.org/pubs/Documents/TIA_WaterScarcity.pdf

Daily, G.C.; Ellison, K. 2002. The new economy of nature: The quest to make conservation profitable. Washington, DC: Island Press.

EPA (Environmental Protection Agency). 2006. 2000 national water quality inventory. http://www.epa.gov/305b/2000report/

Fischlin, A.; Midgley, G.F.; Price, J.T.; Leemans, R.; Gopal, B.; Turley, C.; Rounsevell, A.; Dube, O.P.; Tarazona, J.; Velichko, A.A. 2007. Ecosystems, their properties, goods, and services. In: Parry, M.L.; Canziani, O.F.; Palutikof, J.P.; van der Linden, P.J.; Hanson, C.E., eds. Climate change 2007: Impacts, adaptation and vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press: 211-272.

Gertner, J. 2007. The future is drying up. The New York Times. 21 October.

Goodman, B. 2007. Drought-stricken South facing tough choices. The New York Times. 16 October.

Grundl, T.; Cape, M. 2006. Geochemical factors controlling radium activity in a sandstone aquifer. Ground Water 44(4): 518-527.

Intergovernmental Panel on Climate Change. 2007. Climate change 2007: Impacts, adaptation, and vulnerability—Summary for policymakers. Working Group II. Fourth assessment report. 13 April 2007. http://klima.hr/razno/news/IPCC.pdf

Marsh, G.P. 1864 [2003]. Man and nature. D. Lowenthal, ed. Seattle, WA: University of Washington Press.

Millennium Ecosystem Assessment. 2005. Ecosystems and human well-being: Current state and trends. Washington, DC: Island Press.

Mote, P.W.; Hamlet, A.F.; Lettenmaier, D.P. 2004. Variability and trends in mountain snowpack in western North America, in Proceedings of the 15th Symposium on Global Change and Climate Variations. Seattle, WA: American Meteorological Society.

NSTC (National Science and Technology Council). 2007. A strategy for Federal science and technology to support water availability and quality in the United States. Committee on Environment and Natural Resources, Subcommittee on Water Availability and Quality, Washington, DC.

Sedell, J.; Sharpe, M.; Apple, D.D.; Copenhagen, M.; Furniss, M. 2000. Water and the Forest Service. FS-660. U.S. Forest Service, Washington, DC.

Snyder, M.A.; Sloan, L.C. 2005. Transient future climate over the western United States using a regional climate model. Earth Interactions 9(11): 1–21.

Stein, S.M.; McRoberts, R.E.; Alig, R.J.; Nelson, M.D.; Theobald, D.M.; Eley, M.; Dechter, M.; Carr, M. 2005. Forests on the edge: Housing development on America’s private forests. Gen. Tech. Rep. PNW-GTR-636. Portland, OR: U.S. Forest Service, Pacific Northwest Research Station.

U.S. Forest Service. 2007. Assessment of the status and trends of natural resources from U.S. forest and range lands: 15 key findings. FS-875. U.S. Forest Service, Washington, DC.

U.S. Government Accountability Office. 2003. Freshwater supply: States’ views of how the Federal Government could help them meet the challenges of expected shortages. GAO-03-514. Washington, DC: Government Accountability Office. http://www.gao.gov/new.items/d03514.pdf

USGS (U.S. Geological Survey). 2005. Estimated use of water in the United States: Trends in water use, 1950-2000. Circular 1268. http://pubs.usgs.gov/circ/2004/circ1268/

USGS (U.S. Geological Survey). 2007. Freshwater-saltwater interactions along the Atlantic coast. http://water.usgs.gov/ogw/gwrp/saltwater/

WWDP (World Water Development Programme). 2007. Meeting basic needs. United Nations Educational, Scientific and Cultural Organization. http://www.unesco.org/water/wwap/facts_figures/basic_needs.shtml


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