New Website Lets You Calculate Water Quality Consequences

Constructed by Shane Parson as part of his doctoral dissertation in Agricultural and Biological Engineering, the website is designed to enable beginners to take advantage of the outcomes of sophisticated hydrological computer modeling -- without having to do the math.

The website is "a first attempt at combining mathematical tools and the Internet in a way that's relevant for the average person who wants to know how their actions might affect water resources," he says.

Parson, who worked under the direction of Dr. James M. Hamlett and Dr. Paul D. Robillard, both associate professors of agricultural engineering, successfully defended the thesis recently and will receive his Ph.D. degree at commencement ceremonies in May.

The website, called InterWET, is available through the Penn State Agricultural and Biological Engineering homepage, at http://server.age.psu.edu/, under the research web page in the area of Natural Resource Conservation and Management.

Parson says, while much of the information available on the website is focused on Spring Creek, the point and click calculators are useful to users both inside and outside Pennsylvania. He has received positive responses from users ranging from teachers in Washington State to middle school students in Canada.

The point-and-click calculators can, for example, be used to help middle school students understand the different rain runoff patterns among parking lots, forests and pastures. They can help anglers identify and locate, on a highlighted map, the streams and creeks in the Spring Creek watershed where their catches won't be edible due to pollution. They can also help an interested voter calculate the percentage change in surface runoff with changes in housing development policy or the effect of new sewers on neighboring creeks.

The user navigates InterWET by pointing and clicking on a master menu of topics including surface runoff, groundwater, sediment erosion, in-stream nutrients and fish populations. These topics can be explored from the perspective of a researcher, conservationist or policymaker.

The researcher perspective enables the user to behave like a scientist and use the calculators to experiment "to see what happens" to runoff, for example, when it rains a lot, or a little, or on a parking lot, or a forest, or a wide variety of other environments.

The conservationist perspective offers interactive maps that display the overall connectivity of Spring Creek watershed and give a three-dimensional view of hydrologic monitoring data.

The policy perspective enables the user to select a variety of policies from a menu and observe the percentage change in the watershed.

Parson cautions that InterWET is designed to be an educational tool, not a substitute for scientific inquiry. He writes, "While it is based on established hydrologic modeling and monitoring techniques, many simplifying assumptions were made to emphasize only the most important underlying concepts for each water resource component.

"InterWET was not designed to replace the work of scientists and engineers in watershed planning, but rather to help others understand the underlying concepts and relationships used in their work."

In constructing InterWET, Parson used a variety of techniques. The calculators are modeled using JavaScript. The interactive maps run on a Java-based geographic information system. The calculators that predict future change based on policy use the Generalized Watershed Loading Functions hydrologic model. Artificial neural networks were developed for water resource components affected by many policies. InterWET uses a Forward-Backward Propagation artificial neural network, which Parson says greatly increases the speed of the calculations.

The research was supported, in part, by a grant from the U.S. Department of Education.