Case Study on Technologies for Urban Stream Restoration

Patrick McMahon, PhD, PE, CFM & Ken Barry, P.E., CPESC, D. WRE

Urban stream restoration is challenging since project sites are situated in highly modified watersheds that deliver elevated peak flows, diminished base flows, and pollutant laden waters; are hydro-modified and/or lined with hard armor; and are constrained by utility, transportation, and building infrastructure resulting in diminished or non-existent aquatic and riparian habitat and impaired water quality. This case study describes the key technologies utilized for the recently constructed (2019) enhancements to the Second Unnamed Tributary to 4th Creek in Knoxville, Tennessee at the Summit Medical-Deane Hill facility including design considerations, construction challenges, and early monitoring results. The project site receives run-off from the 1970s vintage West Town Mall. Constraints included highly modified flows; infrastructure interference; primary site access through an active medical complex; and limited room for construction equipment operation and staging of equipment, supplies, or excavated soil. This project mixed “traditional” materials (large rock riprap, cross-vanes, constructed riffles, and riparian plantings) with newer technologies (two-dimensional hydraulic analysis, tied concrete block mat, bionic soil media/high-performance flexible growth media, and stormwater bio-retention) to meet the challenges at the site in a cost-effective manner.

Patrick McMahon, PhD, PE, CFM

Ken Barry, P.E., CPESC, D. WRE

Presented by Patrick McMahon, PhD, PE, CFM Senior Engineer & Ken Barry, P.E., CPESC, D. WRE Vice President / Technical Principal

S&ME Inc.

Patrick McMahon is a Senior Engineer and Project Manager at S&ME Inc. and a licensed engineer in Alaska, North Carolina, South Carolina, and Tennessee. He is a graduate of the University of Tennessee earning a Bachelor of Science Degree in Civil Engineering and a Master of Science Degree in Environmental Engineering in 2003 and 2005 respectively. He has over 15 years of experience in water resources-related engineering projects. His expertise and experience include single event and continuous simulation hydrologic modeling; 1, 2, and 3-dimensional hydraulic modeling; sediment transport analyses; stream restoration design; National Flood Insurance Program compliance; MS4 compliance; erosion control; storm drainage design and retrofit; fish passage analyses; dam removal; and bedload transport modeling. In 2013, he earned a Doctor of Philosophy Degree in Civil Engineering from the University of Tennessee for his research in the field bedload transport modeling. Patrick is an Association of Floodplain Managers, Certified Floodplain Manager and plays an active role in the local and regional engineering communities presenting at numerous conferences annually and contributing to various technical Committees.

Ken Barry is a Technical Principal and Vice President for S&ME, Inc. in Knoxville, Tennessee. During his 18 years with S&ME, he worked extensively on stream restoration, wetland mitigation, flood modeling, water quality modeling, and erosion and sediment control projects. Prior to S&ME, Mr. Barry had 19 years of broad experience in civil engineering, environmental engineering, construction, and regulatory issues (including a stint at EPA-Region 4). He is a graduate of Tennessee Technological University (BS Civil Engineering), where he currently serves on the Board of Advisors to the Department, and Clemson University (MS Environmental Systems Engineering). Ken has long been an active member of the American Society of Civil Engineers (Past-President of the Tennessee Section, current Chair of the Section History and Heritage Committee), ASCE’s Environmental and Water Resources Institute (Past-Chair of the EWRI TN Chapter), as well as the Tennessee Section of the American Water Resources Association.