Patrick Womble
Urbanization induced changes to a ravine system and evaluation of land use and infrastructure sustainability at Grand Valley State University, Allendale, Michigan.
Land use practices at Grand Valley State University have dramatically altered runoff, erosion, and slope stability in the ravine system adjacent to campus. Urbanization from campus facilities has resulted in more than 68 hectares of impermeable concrete, asphalt, and buildings. Impermeable acreage, primarily in the form of new parking lots and buildings, increased more than 141% between 1973 and 1998 and 20% between 1998 and 2004. The increase of impermeable surface area has resulted in decreased lag time, concentrated runoff, incision, and accelerated erosion.
Comparison of 2005 LIDAR topographic data with topographic mapping created in 1963, prior to the construction of the university, reveal consistent degradation in the heads and upper portions of some ravines of as much 4 meters; and aggradation in the lower parts of the ravines of as much as 2 meters. Degradation has created undercut slopes and slope instability, while aggradation has reduced channel slopes and buried riparian vegetation.
Four continuous-recording stream gages, installed in the ravines, provide hydrograph data for the summer of 2006. Runoff data, combined with continuous precipitation data, provide lag time estimates for storm runoff. Recent erosion and overbank flooding was observed and documented after a storm event July 11th.
Early attempts to control erosion, through the installation of engineered erosion control structures, have been largely unsuccessful and in some cases have contributed to more lateral erosion and slope instability. Check dams intended to reduce erosion have transferred the erosion to the valley walls resulting in increased slope instability in some areas. Dispersal, rather than concentration, of runoff is likely to provide the best long term solution.
Faculty Mentor: Peter Wampler
UPDATE:
Patrick presented at the Michigan Academy of Sciences, Arts, & Letters Annual Meeting March 9-10, 2007 in Big Rapids, MI.
Patrick presented at the Geological Society of America Annual Meeting October 22-25, 2006 in Philadelphia, PA.
Page last modified July 14, 2009
