Helping Rivers by Slowing Urbanization and Maintaining Forests

First posted on 08-19-2010

The Ozarks is home to pristine rivers like the Buffalo, the White, the Little Red and the Spring. As more people discover this land we call home, protecting those rivers and the ecosystems they nourish becomes increasingly important. Bryan Pijanowski, an associate professor of forestry and natural resources at Purdue University, conducted a recent study that demonstrated how reigning in urban sprawl while at least maintaining forest lands were the most effective means of decreasing flooding and controlling future runoff.

Pijanowski constructed a model of a river system in Michigan and was able to accurately simulate watershed runoff rates from 1900 to the present. He then used the model to look at runoff 30 years into the future while adjusting scenarios that included urbanization, forest regrowth, and buffers between streams and expanding cities. Pijanowski analyzed the impact of each scenario on the health of rivers and creeks throughout the watershed.

“Changes in the land’s surface feed back to runoff. Urban sprawl and impervious surfaces are the biggest culprits,” Pijanowski said. “If you’re able to control development, it is the most effective way to save our river ecosystem.”

According to Pijanowski, urban areas in the United States will double 20 years from now if they continue to expand at the current rate. In his model, doubling an urban area predicted a 1 1/2 times increase in runoff.

Flooding is a major result of runoff, but it also means agricultural waste and chemicals plus urban pollutants have a greater chance of entering watersheds, negatively impacting aquatic life. Runoff can also raise water temperatures, a consequence that could also have a negative affect on anglers who ply the trout impoundments of this region.

While decreasing urbanization was the single most effective means of controlling runoff, Pijanowski’s study also pointed to increasing forest land near rivers and requiring buffer zones between cities and rivers as other methods of controlling the problem.

Luckily, none of Pijanowski’s findings showed the escalation of runoff that occurred as logging and farming resulted in a rapid deforestation during the 1890s and 1900s.

“The past is the worst we’ll ever see over a 140-year period. Even the worst-case scenarios show that the landscape won’t be as bad as what we had in the 1890s and early 1900s,” Pijanowski said. “The lesson here is that with time and care, these systems can be restored. Recovery is possible.”

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