QUANTIFYING URBAN INTENSITY IN DRAINAGE BASINS FOR ASSESSING STREAM ECOLOGICAL CONDITIONS¹

Abstract

Three investigations are underway, as part of the U.S. Geological Survey's National Water‐Quality Assessment (NAWQA) Program, to study the relation between varying levels of urban intensity in drainage basins and in‐stream water quality, measured by physical, chemical, and biological factors. These studies are being conducted in the vicinities of Boston (Massachusetts), Salt Lake City (Utah), and Birmingham (Alabama), areas where rapid urbanization is occurring. For each study, water quality will be sampled in approximately 30 drainage basins that represent a gradient of urban intensity. This paper focuses on the methods used to characterize and select the basins used in the studies. It presents a methodology for limiting the variability of natural landscape characteristics in the potential study drainage basins and for ranking the magnitude of human influence, or urbanization, based on land cover, infrastructure, and socioeconomic data in potential study basins. Basin characterization efforts associated with the Boston study are described for illustrative purposes.

New York Forests, 2012

“…An intact functioning forest also is critical in protecting both surface and groundwater resources (McMahon andCuffney 2000, Riva-Murray et al 2010). …”

Ohio's Forests 2011

“…For example, smaller patches of forest or those in more populated areas are less likely to be managed for forest products (e.g., Kline et al 2004, Wear et al 1999 and are more likely to be "posted" (i.e., not open for public use) (Butler et al 2004), potentially affecting local forest industry, outdoor recreation opportunities, and local culture. Forest land is also a significant factor in the protection of surface waters and groundwater supplies, while fragmentation and urbanization of that forest land has been observed to affect both water quality and quantity (e.g., Hunsaker et al 1992, McMahon and Cuffney 2000, Riva-Murray et al 2010). …”

Climate Change and River Ecosystems: Protection and Adaptation Options

“…Farming has introduced major pollutants in freshwater ecosystems including excessive sediment, fertilizers, pesticides (Silk and Ciruna 2005) and urbanization has further degraded rivers and streams (Walsh and others 2005). As the amount of cleared land and impervious surface area in a watershed increase, there is an increase in runoff, higher peak discharges, higher sediment loads, and reduced invertebrate and fish biodiversity (Dunne and Leopold 1978;Arnold and Gibbons 1986;McMahon and Cuffney 2000).…”