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Pinchot focus areas:

Climate & Energy
Healthy Forests & Healthy Waters
Will Price and Stephanie P. Dalke

The influence of forests on water yield and quality is a debate that stretches back centuries. Earliest observations on the possible results of deforestation claimed trees draw water from the skies to deliver more water to streams and the towns along them, starting a controversial debate involving kings, generals, and presidents — and pitting forests against engineers (Andreassian 2004). Some of the earliest scientific attempts to measure this relationship occurred in watersheds near Nancy, France — provoking comment from Gifford Pinchot, who noted that “...questions of this kind cannot be answered without long and careful observation...[and] The friends and enemies of the forest have both said more than they can prove.” (Andreassin 2004)

Allegheny NFAround the time of this testimony, friends and enemies of the forest were embroiled in the same debate, sparked by the floods and fires that appeared directly connected to the widespread deforestation across the North American continent (Hornbeck and Kochenderfer, 2004). President Theodore Roosevelt and allies in Congress framed a conservation agenda around protection from floods, water for cities, and navigable waterways. Meanwhile, floods in the denuded landscapes of New Hampshire, West Virginia, and Pennsylvania caused millions of dollars in damage (Forest History Society, 2013). Testimony to this effect won the support of business and conservation interests alike to eventually bring about the passage of the Weeks Act in 1911, the National Waterways Commission, and support for federal science and agency action (Hornbeck and Kochendorfer, 2004).

Forest conservation for the protection of water resources had begun, but the science of source water was only beginning. Appended to the 1912 Proceedings of the National Waterways Commission was a report by Raphael Zon of the Forest Service, concluding that among their influences forests cannot in themselves protect against major floods, but that forests can reduce their destructiveness. At about the same time scientists with the USGS had established research in New Hampshire, and a circle of colleagues within the Forest Service—including Zon, C. G. Bates, A. J. Henry, Bernard Fernow, and others—started to pair watersheds for treatment studies to settle the “streamflow controversy.” (Dodds 1969; Schmaltz 1980; Hornbeck and Kochendorfer, 2004).

The first truly paired study, the Wagon Wheel Gap Study in Colorado, showed a version of the relationship replicated many times since (with variations and some exceptions)—that deforestation increases yield. Over time, stations and studies have emerged around the country—notably Forest Service Research Stations, Coweeta in North Carolina, Hubbard Brook in New Hampshire, Fernow in West Virginia, and H. J. Andrews in Oregon—but many others, and complemented by scientists in other places. As summarized by Alden Hibbert, who by looking at 39 forest treatment studies concluded that: “Reduction of forest cover increases water yield; establishment of forest cover on sparsely vegetated land decreases water yield; and, response to treatment is highly variable and, for the most part unpredictable.” (Hibbert 1965).

Much still needs to be learned in experimental watersheds, paired or not, to unravel the influence of forests and the possibility of managing forests for “favorable flows.” This information must still support the larger challenge of managing large watersheds and entire river basins, where the response of forested catchments may indeed be the easiest to measure.

Managing Watersheds
Perhaps the greatest value that forests provide is that they are better than whatever replaces them. Much of the forests and open space being lost, at a national rate of 6,000 acres a day, are irrecoverably urbanized or dissected and diminished by roads—and this development is no longer offset through abandonment and reversion of agricultural lands to forest, as occurred in the second half of the 20th century. The forests of the western US are also lost to development, but many forested watersheds in the backcountry are increasingly susceptible to disease and fires so severe they volatize and harden soils, sending torrents of sediment into reservoirs and towns.

So the principal scientific challenge not only requires understanding how removal of forest affects streamflow, but how the impervious surfaces that replace forests, and coinciding point and nonpoint source pollution, will affect streamflow and quality. Flow and water quality management in urbanizing watersheds is now informed by four decades of research focused on impervious cover and its relationship to urbanization (Brabec. et. al., 2002). Themyriad studies have increased with the sophistication of geographic information systems to consider: placement of impervious surface; connectivity to waterways; the limits of riparian forests in denuded watersheds; the role of other types of pervious cover; engineered retention that simulates natural durations of storage and release; etc. They suggest there is no magic threshold for a watershed—of say 10% impervious, or 75% forested (Brabec et. al. 2002; Booth et. al. 2003). Rather, it appears that for each watershed there is a condition somewhere along a continuum of cumulative forest loss, poor stormwater management, and degraded floodplains at which hydrological and ecological changes depart from acceptable limits. These multiple factors of the landscape are in aggregate called “green infrastructure.”

Losing this green infrastructure to other uses makes rivers and streams less drinkable, swimmable, and fishable. Efforts to protect and restore green infrastructure encounter the same institutional and financial challenges faced when water pollution regulations were first enacted. This long and complex history will not be covered here, other than to draw institutional lessons for source water protection. A century of legislation and case law has set and reset policies and measures, beginning with the River and Harbor Acts of 1899, and punctuated by Water Quality Act (1965), Federal Water Pollution Control Act Amendments (1972, “Clean Water Act”), Safe Drinking Water Act (1974), and the Nonpoint Source (NPS) Initiative of 1991. Some of the challenge in meeting water quality targets has been institutional, requiring coordination among state, federal, and local agencies that intersect throughout a watershed. In some cases shared problems have been vested in institutions like water basin commissions and estuary partnerships, but they still rely on the support and endorsement from many parties.

At times these policies demanded science and analysis tools that were yet undeveloped. For example, the wasteload allocation process implicit in the Water Quality Act of 1965 simply could not be implemented in a manner to protect water bodies (Shanahan 1996). The US still works toward goals set in the 1972 Clean Water Act while trying to accommodate a population that has grown 50%. Similarly, it is a scientific challenge to decide among green infrastructure priorities—e.g. in which cases will stormwater management, floodplain restoration, forest protection, etc. have a greater impact?

Protecting Source Water
Trying to win back the green infrastructure that is lost—to recover a now developed floodplain, re-route and retain stormflows, or simply bring forests back to land—can be far more expensive than protecting it in the first place. Similarly, treating the watery aftermath of floods or pollution is expensive. Some studies have documented this difference as the cost-benefit of land protection vs. water treatment, with one report by the Trust for Public Land showing two dollars in treatment costs saved for every dollar spent in forest protection (Freeman 2008). Another recent study predicted the net benefits,mostly through avoided costs of flood damage, if riparian areas were kept as green space and not developed (Kousky 2011). Perhaps the most well known example is theNew York City watershed, which for 16 years has been protecting land to avoid filtration expenses. There are other examples, some of which are described in this issue by James Mulligan and Todd Gartner.

Delaware RiverCommon Waters, a partnership of organizations in the Delaware Basin, has been working to develop a source water protection fund for the Delaware called the Common Waters Fund. The Delaware Basin includes four states, 38 counties, and hundreds of municipalities. The river serves 16.2million people for drinking water alone, 5% of the US population, and contributes an estimated $25 billion each year to the region’s economy (Kauffman 2011). Waters flowing from reservoirs and the remainder of the watershed provide electricity (via cooling water for natural gas, coal, and nuclear facilities) and drinking water (delivered by more than 100 purveyors) for 8 million people living within the basin and 8 million in New York City.

The Common Waters Fund is investigating the ways in which utilities and other major downstream water users can invest in source protection upstream in a large river basin such as the Delaware. Most operational water funds, like in Denver, Raleigh, or New York City, are sustained by rate surcharges that directly pass the cost of headwater investments onto downstream customers; in these cases they all also depend on reservoirs for their water supply. In the Delaware, there are no urgent water quality issues or looming regulations to make the case for proactive source protection clear (or mandatory). In addition, the wide range of water users and other stakeholders—who withdraw at different points along the mainstem—each have a different stake in the quality and flows of the river. Because user fees for source protection are still a very remote possibility in the Delaware Basin, the Fund is working with water users and the scientific community to develop more compelling data to support proactive investments to maintain existing forests. The Fund is also learning more about different sectors’ and stakeholders’ concerns about future operational risks and about their interest in philanthropic engagement beyond their local community to find the best way to engage each water user in a source protection fund.

In a basin of this size and complexity, the same institutional challenges with managing point and nonpoint source pollution under laws like the CleanWater Act are factors affecting protection of green infrastructure. It requires concerted and coordinated actions. The same will be true for many of the highly populated basins throughout country. The Common Waters Fund is one of several initiatives to take on this challenge to help unify land protection priorities and encourage investments from parties who will share the benefits of headwater forest protection.

Will Price is Director, Conservation Programs at the Pinchot Institute in Princeton, NJ. Stephanie P. Dalke is Project Director at the Pinchot Institute in Washington, DC.

Andréassian, Vazken. “Waters and forests: from historical controversy to scientific debate.” Journal of Hydrology 291.1 (2004): 1-27.

Barten, Paul K., et al. “Massachusetts: managing a watershed protection forest.” Journal of Forestry 96.8 (1998): 10-15.

Brabec, Elizabeth. “Impervious surfaces and water quality: a review of current literature and its implications for watershed planning.” Journal of planning literature 16.4 (2002): 499-514.

Dodds, Gordon B. “The stream-flow controversy: A conservation turning point.” The Journal of American History 56.1 (1969): 59-69.

Forest History Society. “The Weeks Act: Passing the Act.” March 1, 2013. Web. May 31, 2013. http://www.foresthistory.org/ASPNET/Policy/WeeksAct/PassingAct.aspx

Freeman, Jade, et. al. “Statistical Analysis of Drinking Water Treatment Plant Costs, Source Water Quality, and Land Cover Characteristics.” Trust for Public Land. http://cloud.tpl.org/pubs/landwater_9_2008_whitepaper.pdf. (2008): 1-30.

Hibbert, Alden R. Forest treatment effects on water yield. Coweeta Hydrologic Laboratory, Southeastern Forest Experiment Station, 1965.

Hornbeck, James W., and James N. Kochenderfer. “A century of lessons about water resources in northeastern forests.” A Century of Forest and Wildland Watershed Lessons, edited by GG Ice, and JD Stednick (2004): 19-31.

Kauffman, Gerald J., and Del Newark. “Socioeconomic Value of the Delaware River Basin in Delaware, New Jersey, New York, and Pennsylvania.” (2011).

Kousky, Carolyn, et al. “The Role of Land Use in Adaptation to Increased Precipitation and Flooding: A Case Study in Wisconsin’s Lower Fox River Basin.” (2011).

Mandarano, Lynn A., Jeffrey P. Featherstone, and Kurt Paulsen. “Institutions for Interstate Water Resources Management.” JAWRA Journal of the American Water Resources Association 44.1 (2008): 136-147.

Schmaltz, Norman J. “Raphael Zon: forest researcher.” Forest & Conservation History 24.1 (1980): 24-39.

Zon, Raphael. Forests and water in the light of scientific investigation. US Government Printing Office, 1927.

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