Effects of Urbanization on Stream Ecosystems (EUSE) Study Basin Ecology Completed

SPECIFIC OBJECTIVES:

1. Determine the hydrological, geomorphic, chemical, habitat, and biological characteristics that respond to land-use changes associated with urbanization in specific environmental settings.

2. Determine the most important landscape features influencing hydrological, chemical, geomorphic, habitat, and ecological responses to urbanization.

3. Compare the hydrological, geomorphic, chemical, habitat, and biological responses to urbanization among a range of environmental settings.

4. Determine the physical and chemical factors associated with biological responses and compare these physical and chemical factors across environmental settings.

5. Develop empirical models to relate physical, chemical, and biological responses to landscape features associated with urbanization.

An investigation of the urban crescent from Raleigh to Winston-Salem N.C. is underway 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. Water quality has been sampled in 30 drainage basins that have similar natural (e.g., climate, elevation, soils) characteristics and represent a gradient of urban intensity.

The urban intensity of each basin is measured using an index that integrates information about the multiple dimensions of human influence on the urban landscape at the drainage basin scale. The index includes information about land cover, infrastructure, population, and socioeconomic characteristics. Some of the variables used in the index may also be important factors for explaining variations in water quality.

The gradient design used in the NAWQA Program to investigate the effects of urbanization is premised on two perspectives about water-quality.

First, instream water-quality is a composite of physical, chemical, and biological characteristics that are influenced by natural factors and by the human activities. Biological communities reflect the integration of these influences.

Second, landscape and stream characteristics reflect both the physical context of a basin and human influences. The character of the urban residential landscape, for example, can vary dramatically as socioeconomic factors - income, age of housing stock, levels of education - change among neighborhoods.

Investigation of the effects of urbanization on water quality must control for the effects of natural factors, while allowing the degree of urbanization to vary between study basins. By narrowing the focus the study to a single ecoregion, the North Carolina Piedmont, the investigation used a regional framework that enforces a measure of control over variability in natural factors that influence water-quality.

The data collected at streams in the study included nutrients, pesticides, and ions in stream water, geomorphic and habitat characteristics, hydrologic stage, water temperature, pH, dissolved oxygen, specific conductance, benthic algae and invertebrate communities, and fish communities.

Sources/Usage: Public Domain.

Watershed Site Information

Biological Richness Information

Sources/Usage: Public Domain.

Sources/Usage: Public Domain.

Sources/Usage: Public Domain.

Sources/Usage: Public Domain.

Sources/Usage: Public Domain.