ABOUT
Stormwater temperature is an essential but overlooked aspect of the urban stormwater condition. As urbanization increases, the thermal regime (surface, air, and water) of the surrounding environment is altered. Heated stormwater runoff flows into receiving waters where it mixes and potentially increases the base temperature of surface water in lakes, streams, bays and estuaries. Fish and other aquatic life in particular, are sensitive to thermal pollution. Mobile Bay is home to Alabama's seafood industry and provides estuary service (a place to grow) for many fish, crustaceans and wildlife. The main stormwater outfall for downtown Mobile, AL flows directly into Mobile Bay. The temperature of stormwater runoff (first inch of flow) flowing over impervious surfaces in downtown Mobile has been recorded as high as 50oC (122oF) during the month of July. Low impact development (LID) are stormwater control measures (SCMs) that utilize strategies to reduce the negative impact of stormwater runoff on receiving waters and watersheds. These strategies include pervious pavement and rain gardens. Pervious pavement materials have been used in place of an impervious paved surface to both reduce and potentially treat stormwater runoff. This construction technology is well known as an urban stormwater mitigation practice, but has not been adequately evaluated for thermal heat removal effectiveness. Rain gardens manage stormwater through bioretention. Sediment, nutrient, and pollutant removal occurs as runoff comes in contact with the soil, bacteria, and roots of shrubs or other vegetation within the rain garden. The ability of rain gardens to mitigate thermal pollution in runoff has not been quantified. The objective of this research is to evaluate the ability of multiple pavement types (impervious concrete, pervious concrete, pervious brick pavers), and rain gardens in mitigating thermal pollution in stormwater runoff. Results from this project will be used to establish a baseline measurement of heat removal effectiveness of pervious paving and rain gardens when used alone or in combination (SCM Trains). Microcosms have been designed and constructed to test the hypothesis that pervious pavement and rain gardens can mitigate thermal pollution in stormwater runoff individually or in combination. This research is conducted in the Green Infrastructure Laboratory at the Mike Hubbard Center for Advanced Science, Innovation and Commerce (CASIC) Building in the Auburn University Research Park, Auburn, AL. Here pavement cells receive simulated sun (infrared lamps), and rain (water sprinkler) events. Impervious pavement cells and turfgrass cells are used as controls. Data collected includes microcosm cell surface, internal cell temperature, and water temperature exiting cells. Multiple scenarios of these SMCs are tested. The importance of this research is that it has the potential to impact estuary conditions and receiving waters in Mobile Bay and beyond. Thermal pollution to receiving waters is an urban stormwater problem throughout the world that negatively impacts fish and wildlife habitat.
PROJECT INVESTIGATORS
Charlene M. LeBleu, FCELA, FASLA, AICP
Mark Dougherty
Amy Wright
Keith Rahn
GALLERY
Mitigating Heat Transfer From Impervious Surfaces to Stormwater Design Using Alternative Methods & Pavement Types Stormwater temperature is an essential but overlooked aspect of the urban stormwater condition. As urbanization and build-out occurs, the thermal regime (surface, air, and water) of the surrounding environment is altered. Heated stormwater runoff flows into receiving waters where it mixes and potentially increases the base temperature of surface water in lakes, streams, bays and estuaries. The amount of heat transferred, and the degree of thermal pollution is of great importance for fisheries management and the ecological integrity of receiving waters. Fish and other aquatic life in particular are most sensitive to thermal pollution. (Galli, 1990) This video demonstrates controlled laboratory test to assess low impact development (LID) stormwater control measures as a way to reduce the negative impact of the thermal characteristics of stormwater runoff.  This project hypothesizes that pervious surfaces and rain gardens/bioretention can be used to mitigate ground level thermal loads in stormwater runoff. This research is important because very little has been published on the mitigation of thermal pollution using LID strategies. Data collected will help establish the role of pervious pavement and rain gardens/bioretention to mitigate thermal pollution in stormwater runoff to our nation’s receiving waters.
RESOURCES
 Check out recent content: 2020 2019 2018 2017 Roberts, Trip. Effects of Pervious Concrete Thickness on Leachate Water Temperature during Simulated Rain Events. Capstone Project; Keith Rahn, Committee Head. Master of Building Science. Graduated Aug. 2020. LeBleu, C., M. Dougherty, K. Rahn, A. Wright, R. Bowen, R. Wang, J. Orjuela and K. Britton. Quantifying Thermal Characteristics of Stormwater through Low Impact Development Systems Hydrology 2019, 6(1), 16; doi:10.3390/hydrology6010016 Wang, R. and C. LeBleu. 2018. Experience with Collaborative Research on Thermal Characteristics of Low Impact Development Strategies. Landscape Research Record VII, Council of Educators in Landscape Architecture Conference, March 21-24, 2018 Blacksburg, Virginia, 11pp. Mitigating the Thermal Characteristics of Stormwater Presentation Stormwater Forum Poster
 Graduate Students
Craig Barker (2020-2022)
Awards Alabama ASLA Merit Award, Research Category. Quantifying Thermal Characteristics of Stormwater through Low Impact Development Systems. Green Infrastructure Lab: LeBleu, C., M. Dougherty, K. Rahn, A. Wright, R. Bowen, R. Wang, J. Orjuela and K. Britton. Alabama Chapter of the American Society of Landscape Architecture (2019). Peer Reviewed Publications C. LeBleu, M. Dougherty, K. Rahn, A. Wright, R. B. 2020. “Mitigating Stormwater Thermal Loads Using Low Impact Development SCMs.” Presented at 2020 Bays & Bayous Conference, Virtual; Dec. 01-03, 2020. Proceedings. Peer reviewed. Morash, J., A. Wright, C. LeBleu, A. Meder, R. Kessler, E. Brantley & J. Howe. (2019) Increasing Sustainability of Residential Areas Using Rain Gardens to Improve Pollutant Capture, Biodiversity and Ecosystem Resilience. In Smith, Carl (Ed.), Sustainable Residential Landscapes: An International Perspective (Chapter 1; pp.1-18). 264 pp. MDPI Publications, Basel: Switzerland. Morash, J., A. Wright, C. LeBleu, A. Meder, R. Kessler, E. Brantley & J. Howe. (2019) Increasing Sustainability of Residential Areas Using Rain Gardens to Improve Pollutant Capture, Biodiversity and Ecosystem Resilience. Sustainability 11(12):3269. https://doi.org/10.3390/su11123269 LeBleu, C., M. Dougherty, K. Rahn, A. Wright, R. Bowen, R. Wang, J. Orjuela and K. Britton (2019). Quantifying Thermal Characteristics of Stormwater through Low Impact Development Systems. Hydrology 2019, 6(1), 16. https://doi.org/10.3390/hydrology6010016 Fang, C., C. LeBleu, H-Y. Zhao, H.-Y., S-D. Lui, and B. Yang. 2017. Vision, Pattern, Focus: Research Frontiers of Stormwater Management in 2017 CELA Conference. Modern Urban Research, 2, 2-8. Rahn, K, Davis, P, and M. Dougherty. 2017. Laboratory methods examining the effects of pavement runoff. Proceedings of the Creative Construction Conference 2017, CCC 2017, 19-22 June 2017, Primosten, Croatia. Procedia Engineering 196 (2017) 527-534. http://toc.proceedings.com/36236webtoc.pdf Rahn, K., Dougherty, M., and P. Davis. 2017. Laboratory methods to test thermal and environmental effects of pervious paving runoff. ASC Proceedings, ASC 53rd Annual International Conference, Seattle, WA, Feb. 2017. LeCompte, J.S., A.N. Wright, C.M. LeBleu, J.R. Kessler. 2016. Saline Irrigation Affects Growth and Leaf Tissue Nutrient Concentration of Three Native Landscape Plant Species. HortTechnology 26:309-313. https://journal.ashs.org/horttech/view/journals/horttech/28/6/article-p799.xml Research Presentations LeBleu, C. (presenting), M. Dougherty, A. Wright & K. Rahn. 2019. “Using Low Impact Development to Mitigate Thermal Load.” International Erosion Control Association (IECA) Municipal Wet Weather Stormwater (MS4) Conference, Greenville, SC. May 20-22, 2019. Proceedings. Peer Reviewed. C. LeBleu, M. Dougherty, K. Rahn, A. Wright, R. Bowen and R. Wang. 2018. “Using LID to mitigate thermal pollution in urban streams and coastal receiving waters.” Presented at 2018 Bays & Bayous Conference, Mobile, AL; Nov. 28-30, 2018. Peer reviewed. Rahn, K., (presenting) C. LeBleu, A. Wright, M. Dougherty and R. Wang. 2018. “Low Impact Development (LID) Practices to Mitigate Thermal Pollution in Stormwater Runoff Entering Urban Streams and Sensitive Costal Receiving Waters.” 2018 AL Water Resources Conference, Orange Beach, AL. Sept. 5-7, 2018. Proceedings. Peer Reviewed. Wang, Rui (presenting), C. LeBleu, K. Rahn, A. Wright, and M. Dougherty. 2018. “Collaborative Design Strategies for Stormwater Runoff Heat Removal Using Low Impact Development.” 2018 Annual Conference of the Council of Educators in Landscape Architecture (CELA), Virginia Tech University, Blacksburg, VA, March 21-24, 2018. Proceedings. Peer Reviewed. Rahn, K., C. LeBleu, A. Wright, M. Dougherty, R. Wang and B. Garrett. 2017. “Mitigating the Thermal Characteristics of Stormwater Runoff through Low Impact Development.” AU This is Research Conference, Auburn University, AL; Sept 22, 2017. LeBleu, C. (presenting), A. Wright, K. Rahn and M. Dougherty. 2017. “Qualifying the Thermal Characteristics of Stormwater Runoff through Low Impact Development.” Council of Educators in Landscape Architecture (CELA) Annual Conference, Beijing, China; May 27-29, 2017. Proceedings. Peer Reviewed. Rahn, K., C. LeBleu, A. Wright, M. Dougherty, R. Wang (presenting) and B. Garrett. 2017. “Exploring the Thermal Characteristics of Stormwater Runoff through Low Impact Development.” Presented at the AU Stormwater Forum, Auburn University, AL; May 11-12, 2017. Proceedings. Peer Reviewed. Lamb, A. (presenting), A. Wright, R. Kessler, E. Brantley, and J. Howe. 2017. Growth and Physiology of Three Native Landscape Plant Species in Two Southeastern U.S. Soil Types. HortScience 52:S16 (abstr.) LeBleu, C, K. Rahn (presenting). 2016. “Mitigating Heat Transfer from Impervious Surfaces to Stormwater Discharge.” Associated Schools of Construction conference, Provo, Utah. April 2016. Proceedings. Peer Reviewed. Wright, A.N. 2016. Identification of landscape plant species for use in rain gardens. Alabama Stormwater Symposium, Auburn University, Auburn, AL. Morash, J. (presenting), A. Wright, and R. Kessler. 2016. Tolerance of Three Native Herbaceous Perennials to Repeated Short-Interval Flooding. HortScience 51:S46 (abstr.) Webinars LeBleu, C. (presenting), Mark Dougherty, Keith Rahn and Amy Wright. “The Use of Pervious Concrete to Mitigate the Heat Island Effect in Constructed Landscapes.” Landscape Expo Media Group. Nov. 12, 2020. 86 attendees.
CONTACT INFORMATION
Email: Greeninfralab.au@gmail.com Phone Number: 334-844-0192 Address: 559 DeVall Dr, Lab RM 132, Auburn University, AL 36849