Skip to Main Content
A model to integrate urban river thermal cooling in river restorationAuthor(s): Reza Abdi; Theodore Endreny; David Nowak
Source: Journal of Environmental Management
Publication Series: Scientific Journal (JRNL)
Station: Northern Research Station
View PDF (1.0 MB)
DescriptionRiver water quality and habitats are degraded by thermal pollution from urban areas caused by warm surface runoff, lack of riparian forests, and impervious channels that transfer heat and block cool subsurface flows. This study updates the i-Tree Cool River model to simulate restoration of these processes to reverse the urban river syndrome, while using the HEC-RAS model water surface profiles needed for flood hazard analysis in restoration planning. The new model was tested in a mountain river within the New York City drinking water supply area (Sawmill, SM, Creek), and then used for base case and restoration scenarios on the 17.5 km reach of the Los Angeles (LA) River where a multi-million dollar riverine restoration project is planned. The model simulated the LA River average temperature in the base case decreased from 29.5 °C by 0.3 °C when warm surface inflows were converted to cooler groundwater inflows by terrestrial green infrastructure; by 0.7 °C when subsurface hyporheic exchange was increased by removal of armoring and installation of riffle-pool bedforms; by 3.6 °C when riparian forests shaded the river; and by 6.4 °C when floodplain forests were added to riparian forests to cool surface reservoirs and local air temperatures. Applying all four restoration treatments lowered river temperature by 7.2 °C. The simulated decreases in river temperature lead to increased saturated dissolved oxygen levels, reaching 8.7 mg/L, up from the 7.6 mg/L in the base case scenario, providing improved fish habitat and reducing eutrophication and hypoxic zones. This study evaluating the performance of environmental management scenarios could help managers control the thermal pollution in rivers.
- Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat.
- During the capture process some typographical errors may occur.
- Please contact Sharon Hobrla, firstname.lastname@example.org if you notice any errors which make this publication unusable.
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationAbdi, Reza; Endreny, Theodore; Nowak, David. 2020. A model to integrate urban river thermal cooling in river restoration. Journal of Environmental Management. 258: 110023. 9 p. https://doi.org/10.1016/j.jenvman.2019.110023.
KeywordsLos angeles river (LA river), Sawmill creek (SM creek), Urban river, Thermal pollution, Riparian shading, Green infrastructure
- Influence of hyporheic flow and geomorphology on temperature of a large, gravel-bed river, Clackamas River, Oregon, USA
- Global warming of salmon and trout rivers in the northwestern U.S.: Road to ruin or path through purgatory?
- Thermally stratified pools and their use by steelhead in northern California streams
XML: View XML