ABSTRACT
CONTENTS 18.1 Introduction ............................................................................................. 369 18.2 Estimation of Hortonian Overland Flow ............................................ 371
18.2.1 Characteristics of Impervious Areas ..................................... 371 18.2.2 Simple Method .......................................................................... 372 18.2.3 SCS-CN Method........................................................................ 372 18.2.4 Hydrologic Models................................................................... 374
18.3 Impervious Surface Area Estimation................................................... 375 18.4 Example Studies on Runoff Response to Impervious Surface........ 376
18.4.1 Study Areas................................................................................ 376 18.4.2 Red River of the North Basin ................................................. 378
18.4.2.1 Land-Cover Change Analysis................................ 378 18.4.2.2 Imperviousness Dynamics ..................................... 379 18.4.2.3 Runoff Response Analysis...................................... 380
18.4.3 Simms Creek Watershed ......................................................... 380 18.4.3.1 Imperviousness Dynamics ..................................... 380 18.4.3.2 Hydrograph Comparison ....................................... 381
18.5 Summary .................................................................................................. 382 Acknowledgments ............................................................................................. 384 References ........................................................................................................... 384
Impervious surface areas are characterized as surfaces that impede the natural infiltration of water into the soil and accelerate rainfall runoff processes and transport (USDA-SCS, 1986). Such surfaces are usually a result of urbanization and development, and they include roads, buildings, and parking lots. Urbanization, which converts pervious surfaces to
impervious surfaces, is a global trend because of the population and transportation pressures. The impacts of this conversion on ecohydrological settings have been studied by a number of researchers (e.g., Hirsch et al., 1990; McCuen, 1998; Chin and Gregory, 2001; Rose and Peters, 2001; Booth et al., 2002).
