Network Characteristics in Suburbanizing Streams

William L. Graf, University of South Carolina - Columbia


Analysis of hydrologic, geomorphic, and suburbanization data from a small instrumented drainage basin near Iowa City, Iowa, indicates that channel networks are radically altered when suburban development overtakes a drainage basin. Changes in channel networks are such that the network becomes much more efficient in collecting water quickly, so that lag time and kurtosis of storm hydrographs are altered to produce the familiar flash floods of urban areas. The data show that network changes are closely associated with lag lime and kurtosis of storm hydrographs and suggest that corrective measures should be concentrated on the internal links of the network. Changes in characteristics of channel networks should be considered in addition to changes in areas of impervious surfaces when the hydrologic impact of suburbanization is assessed.