Towards Sustainable Watershed Dvelopment: A Geographic Information Systems based Approach
- ORNL
With an unprecedented projection of population and urban growth in the coming decades, assessment of the long-term hydrologic impacts of land use change is crucial for optimizing management practices to control runoff and non-point source (NPS) pollution associated with sustainable watershed development. Land use change, dominated by an increase in urban/impervious areas, can have a significant impact on water resources. Non-point source (NPS) pollution is the leading cause of degraded water quality in the US and urban areas are an important source of NPS pollution. Most planners, government agencies, and consultants lack access to simple impact-assessment tools despite widespread concern over the environmental impacts of watershed development. Before investing in complex analyses and customized data collection, it is often useful to utilize simple screening analyses using data that are already available. In this paper, we discuss such a technique for long-term hydrologic impact assessment (L-THIA) that makes use of basic land use, soils and long-term rainfall data to compare the hydrologic impacts of past, present and any future land use change. Long-term daily rainfall records are used in combination with soils and land use information to calculate average annual runoff and NPS pollution at a watershed scale. Because of the geospatial nature of land use and soils data, and the increasingly widespread use of GIS by planners, government agencies and consultants, the model is integrated with a Geographic Information System (GIS) that allows convenient generation and management of model input and output data, and provides advanced visualization of the model results. An application of the L-THIA/NPS model on the Little Eagle Creek (LEC) watershed near Indianapolis, Indiana is illustrated in this paper. Three historical land use scenarios for 1973, 1984, and 1991 were analyzed to track land use change in the watershed and to assess the impacts of land use change on annual average runoff and NPS pollution from the watershed and its five sub-basins. Results highlight the effectiveness of the L-THIA approach in assessing the long-term hydrologic impact of urban sprawl. The L-THIA/NPS GIS model is a powerful tool for identifying environmentally sensitive areas in terms of NPS pollution potential and for evaluating alternative land use scenarios to enhance NPS pollution management. Access to the model via the INTERNET enhances the usability and effectiveness of the technique significantly. Recommendations can be made to community decision makers, based on this analysis, concerning how development can be controlled within the watershed to minimize the long-term impacts of increased stormwater runoff and NPS pollution for better management of water resources.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC05-00OR22725
- OSTI ID:
- 931600
- Country of Publication:
- United States
- Language:
- English
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