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Northern Research Station
One Gifford Pinchot Drive
Madison, WI 53726
(608) 231-9200
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You are here: NRS Home / Research Programs /Urban Natural Resources Stewardship / Air and Water Quality / Role of Thermal Fluxes and Patterns in the Ecology of Urban Streams
Urban Natural Resources Stewardship

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Role of Thermal Fluxes and Patterns in the Ecology of Urban Streams

Research Issue

Urban streams are intimately connected to their landscapes through highly engineered drainage networks. Stormwater runoff from impervious surfaces (e.g., roofs, streets, parking lots) causes greater runoff and an increased frequency of runoff events.  These flows also carry greater thermal loads, both because of the direct transfer of heat from surfaces from air and solar insolation, etc.  These thermal impacts are part of the “urban stream syndrome” and present important stresses on aquatic communities and microbial processes.  Minimizing these thermal transfers presents a challenge for managers seeking to minimize degradation of streams so that these are available to people in both a recreational and ecosystem services context.

Our Research

These investigations of the thermal stream ecology focus on the role of impervious surfaces and tree cover with respect to a) the landscape, b) within urban riparian zones, and c) within drainage networks and groundwater. Continuous water temperatures were recorded for over thirty stream and storm drain sites in the Baltimore metropolitan area, including the streams of the BES LTER network, with most sites co-located at or near USGS streamflow gauges.  Most sites are on small urban headwater catchments, where little thermal work has been done.

Expected Outcomes

Data from these sites will be used to examine dynamics (e.g., thermal spikes from summer runoff events) and seasonal patterns as they relate to land cover and impacts on aquatic ecosystems.  Collaborative efforts are also being planned with the CUERE urban water budget work is also being planned to further use this temperature data to study and model stream temperatures as they relate to influences of groundwater and nearby terrestrial built environments.  By combining this data with continuous flow data and remotely sensed land cover and topography, models will be built to link terrestrial and riparian tree cover to the thermal stream environment and to enable the application of hydrologic models to evaluate these effects entire stream networks and to enable the projection of long-term impacts on ecosystem health and processes.

Research Results

These results suggest that urban catchments, with their mosaic of vegetated and impervious areas, can present a large range of thermal impacts on urban streams.  These are expressed as both ambient (e.g., higher summer air temperatures) and transient phenomenon, such as runoff spikes having potentially different modes of impact.  The data also suggest that thermal stresses present large challenges to aquatic communities in small urban streams. For example, the data has shown warm buried stream flows (groundwater) in ultra urban areas, summer storm runoff spike effects in small headwater catchments, and cooling effects on suburban streams from buried stream tributaries.

A number of publications are in progress.

Kim, Hyun Jin.  2007. Temperatures of urban streams: impervious surface cover, runoff, and the importance of spatial and temporal variations. MS thesis, UMBC Civil and Environmental Engineering

Pouyat, R.V., D.E. Pataki, K.T. Belt, P.M. Groffman, J. Hom, and L.E. Band.  2007. Effects of urban land-use change on biogeochemical cycles. In pages 45-58, Canadell, J.G., D.E. Pataki, and L.F. Pitelka (eds.) Terrestrial Ecosystems in a Changing World.  The IGBP Series, Springer-Verlag, Berlin-Heidelberg-New York.

Welty, C., A. J. Miller, K. T. Belt, J. A. Smith, L. E. Band, P. M. Groffman, T. M. Scanlon, J. Warner, R. J. Ryan, R. J. Shedlock, and M. P. McGuire.  2007.  Design of an Environmental Field Observatory for Quantifying the Urban Water Budget, in Cities of the Future: Toward Integrated Sustainable Water and Landscape Management, Vladimir Novotny and Paul Brown, Editors. IWA Publishing.– International Water Association.

Research Participants

Principal Investigators

  • Kenneth Belt, US Forest Service, Northern Research Station Hydrologist
  • Dr. G. Heisler, US Forest Service, Northern Research Station Meteorologist
  • Dr. C. Welty, UMBC Professor & CUERE Director,
  • Dr. S. Kaushal, UMCES CBL Assistant Professor
  • Dr. R. Pouyat, US Forest Service, Washington Office Bioclimatologist

Research Partners

  • E. Doheney, USGS MD-DE-DC Water Science Center Network Chief & Surface-Water Specialist,
  • G. Fisher USGS MD-DE-DC Water Science Center Hydrologist, Surface-Water Specialist,
  • Dr. P. Groffman CIES,W. Stack, Baltimore City DPW, 
  • Dr. C. Swan, UMBC GES Assistant Professor

Partner Links

Last Modified: 10/03/2019