Modeling the relationship between land use and surface water quality.

Area of Science:

• Environmental Science
• Hydrology
• Water Quality Management

Background:

• Watershed hydrology is influenced by land use, climate, and soil conditions.
• The specific impacts of diverse land use types on surface water require quantification.
• Understanding these relationships is crucial for effective water resource management.

Purpose of the Study:

• To comprehensively examine the hydrologic effects of land use at regional and local scales.
• To quantify the relationships between land use and water quality parameters.
• To assess the utility of the BASINS model for watershed analysis.

Main Methods:

• Statistical and spatial analyses were used to assess regional land use impacts in Ohio.
• Geographic Information Systems (GIS) identified contaminant hotspots and land use patterns.
• The Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) model was applied to a local watershed.

Main Results:

• Significant correlations were found between land use and in-stream water quality, especially for nitrogen, phosphorus, and fecal coliform.
• GIS analysis pinpointed watersheds with high contaminant levels linked to agricultural and urban land.
• Hydrologic and water quality modeling indicated that agricultural and impervious urban lands are primary sources of nitrogen and phosphorus.

Conclusions:

• The integrated regional and local scale approach effectively characterized land use impacts on water quality.
• The BASINS model proved to be a reliable tool for watershed assessment and can be adapted for future studies.
• Findings provide essential data for resource managers, planners, and policymakers to develop sustainable land management strategies and protect aquatic ecosystems.