Water quality in hydrologically sensitive areas; predicting runoff and pollution


1995 to 2009


This project is bridging the perpetual gap between scientific advances and environmental protection by finding ways to better predict where runoff and, by association, pollution is generated in the landscape. We refer to these runoff source areas as "hydrologically sensitive areas" or HSAs. Over three decades of research by Cornell's Soil and Water Lab has clearly shown that HSAs often appear in areas of the landscape where the soil is especially prone to saturating. Furthermore, it is clear that traditional water quality models and dogmas are based on assumptions that miss these areas. We are working to develop new tools and revise existing, widely used water quality models to correctly predict where HSAs develop. Part of mission is to make some of these tools readily accessible via the Internet using technologies like Google Earth. At the same time, we continue to improve our basic, scientific understanding of the various roles HSAs play in water quality and recent research suggests these areas may be microbial hotspots that play important roles that impact nitrogen and phosphorus loading to the nation's streams and lakes.


To paraphrase Thales and Aristotle "water is the original essence of all life [things]." And while we probe Mars for water in our search for extra-terrestrial life, plentiful, clean water is rapidly becoming a critically dwindling resource on Earth. Indeed, in the light of the scientific advances that have taken us to Mars, it is shocking that our management practices for controlling contaminant transport from the landscape to rivers and lakes are based on half-century-old science. Of course, the issue is not that our scientific understanding of environmental contaminant transport has remained stagnant, it has grown tremendously. The issue is that the institutional knowledge-base of agencies charged with protecting water quality is badly outdated and not refreshed quickly enough by new university graduates. Thus, another mechanism is needed to bridge the science-application gap to improve water quality protection strategies.


The Cornell Soil and Water Lab has been at the forefront of hydrological science and contaminant transport for over thirty years. Since the early 1990s it has engaged more directly with agencies and professionals working to protect water quality, especially those in the New York City water supply watersheds. We are working closely with end-users and stakeholders to find ways of translating our basic science into accessible risk assessment concepts, tools, and models, as well as directly into pollution control practices. The two focus areas that we have concentrated on to date are "runoff mechanisms" and "subsurface transport." We have developed a website with information describing scientific advances in the processes controlling runoff and subsurface transport and the implications, pollutant transport, and providing illustrative examples, animations, and photographs. We have also developed several water quality simulation models and are working to make them freely available via the Internet. Our Web resources also include various point-and-click, map-based risk assessment tools. Over the next several years we hope to expand our Web resources across the Northeastern US and, perhaps, Ontario Canada. We also intend to develop tools for real-time and forecasted risk assessment.


This program has radically changed the way water quality professionals and agencies think about land management. Most notable may be our concept of "hydrologically sensitive areas," or HSAs, a term that refers to locations in the landscape that are prone to generating runoff. The HSA concept has become part of the national "phosphorus (P) index" effort, appearing in most state's rubrics for quantifying P risks. Locally, we have worked with the Tompkins Co. Environmental Planning Dept. to create GIS maps of HSAs to help identify areas to protect from development. We also have re-conceptualized 2 prominent and widely-used water quality models, SWAT and GWLF, so that their hydrology is consistent with current hydrological science. These are already being used by the New York City (NYC) Dept. of Environmental Protection (DEP). Due in part to our partnership with the NYC-DEP and other agencies in the NYC watersheds, P levels in the reservoirs have dropped dramatically. More than 15 graduate students have participated in this program, i.e., the next generation of professionals working in agencies like the NRCS and providing a direct link between our program and federal water quality activities. We have received enthusiastic international (>10 countries) feedback for our online resources. We are currently using the HSA concept to develop better criteria for delineating riparian buffers.

Submitted by: 

  • Walter, M. Todd T

Researchers involved: 

  • Steenhuis, Tammo
  • Goehring, Larry
  • Walter, Michael F
  • Parlange, J. Y
  • Easton, Zach
  • Lembo, Arthur
  • Czymmek, Carl
  • Shoemaker, Christine
  • Schneiderman, Elliot
  • Gburek, William

International focus: 

  • United States of America
  • Canada

United States focus: 

  • New York
  • Pennsylvania
  • Delaware

New York State focus: 

  • Delaware
  • Tompkins