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Design and Construction of an Urban Runoff Research Facility
Published on: August 8, 2014
Interaction between urbanization and climate variability amplifies watershed nitrate export in Maryland
Sujay S Kaushal1, Peter M Groffman, Lawrence E Band
1University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 1 Williams Street, P.O. Box 38, Solomons, Maryland 20688, USA. kaushal@cbl.umces.edu
Environmental Science & Technology
|September 5, 2008
Summary
Urbanization impacts nitrogen levels in streams, with agricultural and urban areas showing the highest nitrate concentrations. Land use changes can make ecosystems more vulnerable to climate variations in nitrogen retention.
Area of Science:
- Environmental Science
- Ecology
- Hydrology
Background:
- Urbanization and land use change significantly alter watershed hydrology and water quality.
- Nitrate (NO3-) is a key nutrient pollutant affecting aquatic ecosystems.
- Understanding nitrogen dynamics under varying climatic conditions is crucial for watershed management.
Purpose of the Study:
- To investigate the regional effects of urbanization and land use on nitrate concentrations in Maryland streams.
- To assess changes in nitrate-nitrogen (NO3-N) export and retention across an urbanization gradient in Baltimore during drought and wet years.
- To evaluate the influence of climatic variability on nitrogen retention functions in urbanizing watersheds.
Main Methods:
- Analyzed nitrate concentrations in ~1,000 small streams across Maryland.
- Monitored nitrate-N export in 8 small watersheds along an urbanization gradient in Baltimore (2001-2003).
- Calculated nitrogen retention percentages for different land use types under drought and wet conditions.
Main Results:
- Nitrate-N concentrations were highest in agricultural, urban, and then forest streams.
- Nitrate-N exports varied significantly across suburban/urban, agricultural, and forest streams during drought and wet years.
- Nitrogen retention decreased substantially in suburban and agricultural watersheds during the wet year compared to the drought year.
Conclusions:
- Urban land use change can increase the vulnerability of ecosystem nitrogen retention to climatic variability.
- Interannual variability in nitrogen export coincided with record hypoxia in Chesapeake Bay.
- Further research is needed to improve forecasting and restoration efforts for nitrate-N retention in urbanizing watersheds.
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