Journal of Environmental Management 88 (2008) 1119–1130 Assessing hydrological impact of potential land use change through hydrological and land use change modeling for the Kishwaukee River basin (USA) Woonsup Choi a,Ã,1 , Brian M. Deal b,2 a Department of Geography, University of Illinois at Urbana-Champaign, 607 S. Mathews Avenue, Urbana, IL 61801, USA b Department of Urban and Regional Planning, University of Illinois at Urbana-Champaign, 111 Temple Buell Hall, 611 E. Lorado Taft Dr., Champaign, IL 61820, USA Received 23 September 2006; received in revised form 26 May 2007; accepted 2 June 2007 Available online 8 August 2007 Abstract We connected a cellular, dynamic, spatial urban growth model and a semi-distributed continuous hydrology model to quantitatively predict streamflow in response to possible future urban growth at a basin scale. The main goal was to demonstrate the utility of the approach for informing public planning policy and investment choices. The Hydrological Simulation Program—Fortran (HSPF) was set up and calibrated for the Kishwaukee River basin in the Midwestern USA and was repeatedly run with various land use scenarios generated either by the urban growth model (LEAMluc) or hypothetically. The results indicate that (1) the land use scenarios generated by LEAMluc result in little changes in total runoff but some noticeable changes in surface flow; (2) the argument that low flows tend to decrease with more urbanized areas in a basin was confirmed in this study but the selection of indicators for low flows can result in misleading conclusions; (3) dynamic simulation modeling by connecting a distributed land use change model and a semi-distributed hydrological model can be a good decision support tool demanding reasonable amount of efforts and capable of long-term scenario- based assessments. r 2007 Elsevier Ltd. All rights reserved. Keywords: Urban growth modeling; Hydrological modeling; HSPF; Environmental impact assessment 1. Introduction Streamflow plays an important role in establishing some of the critical interactions that occur between physical or ecological processes and social or economic processes. Socio-economic processes including population dynamics, land use transformation, migration, transportation and agricultural practices closely interact with and greatly affect ecological processes, such as vegetative growth, ecological succession, habitat formation and maintenance (Voinov et al., 1999a). In both cases, hydrology and hydrologic dynamics can work as a medium or canvas for understanding both the conditions for interactions to take place and the consequences that such interactions some- times elicit. One of the most important socio-economic processes for establishing far-reaching and long-term ecological effects is land use transformation, especially the human-induced variety termed ‘urbanization.’ The far- reaching effects of urbanization can best be described by its enormous impacts on basin hydrology and water quality (Ferguson, 1996; Bertrand-Krajewski et al., 2000; Valeo and Moin, 2000). Large proportional increases in imper- viousness in the form of roofs, sidewalks, roads, parking lots, and turf grass can dramatically increase the speed and magnitude of runoff (Dunne and Leopold, 1978; Cheng and Wang, 2002). Understanding these complex socio- hydrologic dynamics is imperative for planning a more sustainable future. ARTICLE IN PRESS www.elsevier.com/locate/jenvman 0301-4797/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jenvman.2007.06.001 Ã Corresponding author. Tel.: +1 204 474 6337; fax: +1 204 474 7513. E-mail addresses: choi@cc.umanitoba.ca (W. Choi), deal@uiuc.edu (B.M. Deal). 1 Present address: Department of Civil Engineering, University of Manitoba, Winnipeg, MB, Canada R3T 5V6. 2 Tel.: +1 217 333 5172.