Journal of Conference Abstracts

Integrating Small Watershed and Regional-Scale Data to Interpret Regional Environmental Trends

Peter S. Murdoch¹ (pmurdoch@usgs.gov), Gary R. Wall¹ (grwall@usgs.gov), Patrick J. Phillips¹ (pjphilli@usgs.gov), Gregory B. Lawrence¹ (glawrenc@usgs.gov), John L. Stoddard² (stoddard@heart.cor.epa.gov), David M. Wolock³ (dwolock@usgs.gov) & James W. Hornbeck⁴

¹ U.S. Geological Survey, 425 Jordan Rd., Troy, New York, 12180, U.S.A.

² Dynamac Inc., 200 SW 35th St., Corvallis, Oregon, 97333, U.S.A.

³ U.S. Geological Survey, 4821 Quail Crest Place, Lawrence, Kansas, 66049, U.S.A.

⁴ U.S. Forest Service, Durham, New Hampshire, 03824, U.S.A.

Integrated monitoring of watersheds combines data from research stations, regional surveys, and remote-sensing programmes to provide comprehensive ecosystem assessments for a region. This method has been proposed to transfer information on watershed processes gained from research stations to the regional scale at which environmental policy is applied. The National Science and Technology Council (NSTC) Committee on Environmental and Natural Resources (CENR) has published a proposed framework for integrating the myriad of environmental research and monitoring programmes in the United States to improve assessments of environmental status and trends. To date, however, few examples of how integrated monitoring could improve environmental assessment capabilities have been offered. This presentation offers three examples in which data collected at one temporal or spatial scale are correlated with data from another through nested-basin or linked intensive-extensive (site-intensive vs survey) monitoring strategies. The presentation also provides an overview of the proposed national framework for environmental monitoring.

(1) Acidic deposition: Regional stream surveys in the Catskill Mountains of New York during the mid-1980's indicated that 7 % of the streams are acidified at base flow, primarily by sulphuric acid. Data from intensively monitored small watersheds have shown that additional streams become acidified from snowmelt and rainstorms, mainly by nitric acid. Applying models of episodic acidification developed from the small-watershed studies to data from the regional survey provides regional estimates of the extent of episodic acidification for the region sampled. These estimates indicate that 15 % of the streams and lakes in the Northeast become acidified episodically.

(2) Depletion of soil Ca: Analysis of soil chemistry data from recent regional soil surveys conducted in the 1930's, 1970's, and 1993 indicate that forest soils of New England have become depleted in Ca over the past 60 years. Detailed Ca budgets at Cone Pond in the White Mountains of New Hampshire indicate that efficient uptake of Ca by plants leads to reduced leaching of Ca from soils to surface waters. A survey of Ca concentrations in lakes and ponds in New England suggests that this depletion can significantly decrease the availability of base cations for leaching to surface waters in the region.

(3) Pesticide-laden runoff: Data from small research watersheds in urban and agricultural settings in the Mohawk River Basin of New York indicate that the concentration of pesticides and nutrients in storm runoff is a function of the timing of storms relative to the time of pesticide or nutrient application. Urban and suburban watersheds are the primary source of carbaryl in the Mohawk River, and agricultural lands are the primary source of atrazine. Data from these single-land-use watersheds, where these watersheds are nested in larger, multi-use landscapes that are also monitored, can be integrated for interpreting the trends in pesticide and nutrient runoff in large areas of changing land use. Regional estimates of atrazine concentrations in runoff in the Midwest have been made from topographically indexed models of overland runoff and rates of atrazine application in 40 small watersheds.

The examples presented above illustrate how integrated watershed monitoring can be an effective means of bringing scientific findings into management and policy decision-making.