Deforestation, sprawl increase runoff

Houston faces huge forest loss

Jon Boyd, Aug 29, 10.

Deforestation and sprawl play key roles to increase runoff in our watersheds and make them more prone to flooding, reports UPI. Forecasts in the Houston region predict huge losses of forest land, and this study suggests the region will have increased flooding as a result.

From the UPI story:

WEST LAFAYETTE, Ind., Aug. 19 (UPI) - Less urban sprawl and more forests are keys to decreasing water runoff and disastrous flooding, U.S. scientists said.

Researchers at Purdue University used computer modeling to study the runoff rates of Michigan’s Muskegon River watershed from 1900 to the present and predict them 30 years into the future, a university release said Thursday.

Several variables - including forest re-growth, urbanization, and buffers between development and streams - were analyzed to estimate their impact on rivers and streams.

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

The maps above represent the Houston-Galveston Area Council’s (H-GAC) modeling of four ecological zones, as indicated on the map legend. The “before” map represents 2008 data. The “after” map represents modeling of development patterns consistent with regional population growth forecasts and the transportation network implied by the 2035 Regional Transportation Plan (RTP). H-GAC estimates a loss of 46% of bottomland forest area and a 55% loss of upland forest area. Furthermore, the 2035 map indicates a loss of virtually all significant forest in Montgomery County - upstream from Galveston Bay. Applying the results of the Purdue study, the consequences of rapid deforestation and increased impermeable cover in Montgomery County should increase flooding within the watershed in those areas and others downstream.