10.2190/DXPA-T7RD-XNT2-656F DXPAT7RDXNT2656F 5 Planning Aids to Measure the Physical Impact of Urbanization 69 82 20020509 20020509 20020509 20020509 DXPAT7RDXNT2656F.pdf http://baywood.metapress.com/link.asp?target=contribution&id=DXPAT7RDXNT2656F 1 Timothy R. Lazaro Mount Rogers Planning District Commission, Marion, Virginia <p>Urbanization causes rapid land use changes. These modifications alter the surface structure of the landscape and its hydrologic responses. The analysis of data from a natural region (a watershed) in the process of urbanizing can indicate the physical impact of these land use changes. This paper outlines several applied analytical techniques, and suggests that if these methods were employed on a variety of watersheds, the collection of these studies would prove useful as a planning aid for the physical planner.</p><p>The methodology consists of examining growths in population and defining the consequent change in surface structure (using aerial photography). Next, hydrologic techniques along with a distribution-free test are employed to analyze the modified hydrologic response. The ultimate manifestation of the rapid land use changes, the greatly decreased flood return period, is illustrated graphically by the results of the California method.</p> T. R. Lazaro, The Effect of Urbanization on Streamflow of the Northeast Branch of the Anacostia River, Masters Thesis, University of Maryland, Department of Geography, College Park, Maryland, p. 13, August, 1974. A. O. Waananen, Urban Effects on Water Yield, in <i>Effects of Watershed Changes on Streamflow</i>, W. L. Moore and C. W. Morgan, (eds.), University of Texas Press, Austin, p. 169, 1969. W. M. Snyder, Summary and Evaluation of Methods for Detecting Hydrologie Changes, <i>Journal of Hydrology, 12</i>, pp. 311-338, 1971. R. H. McCuen and L. D. James, Nonparametric Statistical Methods in Urban Hydrologie Research, <i>Water Resources Bulletin, 8</i>:5, pp. 965-975, October, 1972. T. R. Lazaro, Nonparametric Statistical Analysis of Annual Peak Flow Data From a Recently Urbanized Watershed, <i>Water Resources Bulletin, 12</i>:1, pp. 101-107, Feb. 1976. S. Siegel, <i>Nonparametric Statistics for the Behavioral Sciences</i>, McGraw Hill, New York, 1956. U. S. Department of Commerce, Bureau of the Census, <i>Census User's Handbook</i>, 1971. T. Dalrymple, Flood-Frequency Analyses, U. S. G. S. Water Supply Paper #1543-A, Washington, D. C., p. 15, 1960.