Rhode Island, as many other states, faces the problem of suburban sprawl in the past decades. Suburban development consumes green space, increases impervious surface areas (ISA), widens urban fringes, and puts pressure on environmentally sensitive inland and coastal areas. Impervious surface is defined as any impenetrable material that prevents infiltration of water into the soil. Urban pavements, such as rooftops, roads, sidewalks, parking lots, driveways and other manmade concrete surfaces, are among impervious surface types that featured the urban and suburban landscape. Urban runoff, mostly through ISA, is the leading source of pollution in the Nation¡¯s estuaries, lakes, and rivers (Arnold and Gibbons, 1996, Booth and Jackson, 1997). Impervious surface has been identified as a key environmental indicator due to its impacts on water systems and its role in transportation and concentration of pollutants (Arnold and Gibbons, 1996). A large body of research consistently has found that impact begins to occur at very low levels of overall watershed imperviousness. When less than 10% of a watershed is impervious, impervious are measurable but slight, at between 10% and 25% water quality is impacted and at above 25% water quality is degraded ((Schueler, 1994, Arnold and Gibbons, 1996, Prisloe, et al., 2000). Therefore, quantification of the percentage of ISA in landscape has become increasingly important with growing concern over water quality in this country (Civco et al., 2002)..

This project is to integrate space-borne and airborne remote sensing data and subpixel information extraction modeling to accomplish the following objectives:

• To obtain the most current spatial coverage and distribution of ISA information of Rhode Island using 2003-2004 true-color digital orthophotographs of the state.
• To examine the spatial patterns of effective impervious surface areas of the state. and
• To evaluate the impacts of ISA and EIA on watershed hydrology of the inland and coastal waters of the state by improved hydrologic modeling.