Computer modeling is commonly employed to help understand erosion and sediment transport

at regional scales (Jetten et al., 1999 and de Vente and Poesen, 2005). Many of these models, such as ANSWERS (Beasley et al., 1980), WEPP (Nearing et al., 1989), KINEROS (Woolhiser et al., 1990), and EUROSEM (Morgan et GSI-IX nmr al., 1998) emulate physical processes that incorporate parameters affiliated with hydrology, meteorology, and soil characteristics. Given numerous complex input parameters, these models may not present a straightforward and/or accessible solution to land managers interested in fast assessments of soil loss. GIS-based soil-erosion models applying the empirically derived Universal Soil Loss Equation (USLE; Wischmeier and Smith, 1965 and Wischmeier and Smith, 1978) are a popular alternative to strictly process-oriented models given their ease of use, input-data availability, GIS-compatibility,

and ability to simulate changes in land use and/or other conditions across a broad spectrum of spatial scales (Blaszczynski, 2001 and Chou, 2010). The USLE has become the most widely used equation for estimating soil loss given its simple structure and low data requirements (Sonneveld and Nearing, 2003). Originally developed for estimating soil loss 3-Methyladenine clinical trial from shallow agricultural plots in the US heartland, the USLE is now applied in regions and for land uses outside the range of conditions used for initial model calibration, ranging from steep mountain terrains (Dabral et al., 2008) to urban construction sites (Renard

et al., 1991). GIS-based erosion models applying the USLE are developed for a variety of geographic settings (i.e. varying climates and topographies), land uses (i.e. forests, farmland, urban Morin Hydrate areas, etc.), and watershed scales, providing an extensive body of literature for model comparison and application assessment (Lufafa et al., 2003, Sivertun and Prange, 2003, Erdogan et al., 2007, Pandey et al., 2007 and Ozcan et al., 2008). Continued research into the effects of different land-cover types is needed to further constrain the application of USLE-derived models to understudied regions and land uses, particularly within rapidly expanding urban environments as areas of population growth are associated with landscape fragmentation and complex landcover distributions (Schneider and Woodcock, 2008). Urban lands in the US are expected to increase from 3.1% in 2000 to 8.1% by 2050 (Nowak and Walton, 2005); however, while many studies specifically address effects of urbanization on surface hydrology and channel processes (Trimble, 1997 and Paul and Meyer, 2001), influences of various urban land-cover types on sediment yields are not well constrained.