Examination of Thermal Impacts from Stormwater BMPs

Results from examination of 4 years of monitoring of runoff temperature for a range of stormwater management best management practices (BMPs) and the affects on stormwater runoff temperatures in relation to established environmental indicators are presented for a study in Durham, NH. Research indicates that thermal impacts are not limited to summer months but include other times important for life-cycle considerations. The statistical distributions of event mean temperatures (EMTs) were examined to assess thermal influences. Results indicate there is an increase in the thermal mass of runoff from a storm sewer system draining an area of asphalt pavement with a 97% impervious cover. For the storm sewer system, the mean EMT value of 53.1°F (± 12.1°F), which is greater than the mean groundwater temperature, which resembles the mean daily average annual air temperature, of 47°F that feed coldwater streams. The examination of stormwater BMPs indicates that the larger surface systems will see greater thermal variations and the larger subsurface systems will see greater thermal buffering. The large surface system, the Pond, with a mean value of 51.5°F (± 13.4°F), was susceptible to greater thermal variations than the large subsurface system, the Gravel Wetland, whose mean value of 48.0°F (± 9.5°F), would indicate a greater thermal buffering. The optimum zone for aquatic species is between 45°F and 65°F, above 65°F the aquatic species become stressed and will die when the temperature reaches 80°F. The mean July temperatures calculated from the preliminary data set of the Runoff, Pond, and Gravel Wetland are 66.7°F, 73.1°F, and 60.2°F respectively.


  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 16p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01152464
  • Record Type: Publication
  • Report/Paper Numbers: 10-1210
  • Files: TRIS, TRB
  • Created Date: Jan 25 2010 10:32AM