A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Sustainable Hydraulic Assessment to Improve Ecological Values of Urban Streams Without Impacting Flood Risks
The Stream Ecological Valuation (SEV) was developed by interdisciplinary scientists based on a methodology developed by the US EPA and US Army Corps of Engineers for wetlands. SEV comprises 14 functions and 28 variables that evaluate natural streams’ hydraulic, habitat provision, biotic and biogeochemical parameters. The hydraulic valuation examines the natural flow regime, floodplain particle retention and intact, connectivity for species migrations, and connectivity to groundwater. In 2010, an SEV of Saltwater Creek, a 2.8-km urban stream in Napier, New Zealand, identified significant losses of ecological functions. Numerous structures were categorized as barriers to fish passage, preventing or constraining fish migrations. It was recommended that where practical ecological enhancement is incorporated into the improvements of new structures, existing stream, and flooding studies. The proposed SEV improvement plan required increasing the density of vegetation to provide deeper and slower water flows for fish habitats. However, allowing higher water levels can increase flood risks for surrounding areas. The present work aimed to investigate improving the hydraulic SEV parameters for Saltwater Creek and assess the impact of changing the vegetation scheme along its floodplains. Studied options included (1) low roughness: existing conditions, i.e., mown grass, (2) moderate roughness: low-growing native grasses, sedges, and rushes, and (3) high roughness: diverse native and/or exotic trees and shrubs. Different planting schemes were reviewed to estimate Manning’s roughness coefficients of various vegetation options. MIKE URBAN, MIKE HYDRO, and MIKE 21 modeling frameworks were used to model the storm pipe networks, the open drain flow, and 2-D surface runoff, respectively. Simulations included the 1:100 year 4-h design storm, with an additional option for the 2050 horizon considering future developments and climate changes. Flood extents for different vegetation options were estimated, and respective mitigation plans were developed. These plans comprised oversizing culvert crossings by 50%, cross-section widening, and altering channel morphology. Vegetation options and mitigation plans are being finalized with the City of Napier based on infrastructure conflicts and operational considerations.
Sustainable Hydraulic Assessment to Improve Ecological Values of Urban Streams Without Impacting Flood Risks
The Stream Ecological Valuation (SEV) was developed by interdisciplinary scientists based on a methodology developed by the US EPA and US Army Corps of Engineers for wetlands. SEV comprises 14 functions and 28 variables that evaluate natural streams’ hydraulic, habitat provision, biotic and biogeochemical parameters. The hydraulic valuation examines the natural flow regime, floodplain particle retention and intact, connectivity for species migrations, and connectivity to groundwater. In 2010, an SEV of Saltwater Creek, a 2.8-km urban stream in Napier, New Zealand, identified significant losses of ecological functions. Numerous structures were categorized as barriers to fish passage, preventing or constraining fish migrations. It was recommended that where practical ecological enhancement is incorporated into the improvements of new structures, existing stream, and flooding studies. The proposed SEV improvement plan required increasing the density of vegetation to provide deeper and slower water flows for fish habitats. However, allowing higher water levels can increase flood risks for surrounding areas. The present work aimed to investigate improving the hydraulic SEV parameters for Saltwater Creek and assess the impact of changing the vegetation scheme along its floodplains. Studied options included (1) low roughness: existing conditions, i.e., mown grass, (2) moderate roughness: low-growing native grasses, sedges, and rushes, and (3) high roughness: diverse native and/or exotic trees and shrubs. Different planting schemes were reviewed to estimate Manning’s roughness coefficients of various vegetation options. MIKE URBAN, MIKE HYDRO, and MIKE 21 modeling frameworks were used to model the storm pipe networks, the open drain flow, and 2-D surface runoff, respectively. Simulations included the 1:100 year 4-h design storm, with an additional option for the 2050 horizon considering future developments and climate changes. Flood extents for different vegetation options were estimated, and respective mitigation plans were developed. These plans comprised oversizing culvert crossings by 50%, cross-section widening, and altering channel morphology. Vegetation options and mitigation plans are being finalized with the City of Napier based on infrastructure conflicts and operational considerations.
Sustainable Hydraulic Assessment to Improve Ecological Values of Urban Streams Without Impacting Flood Risks
Lecture Notes in Civil Engineering
Desjardins, Serge (editor) / Azimi, Amir Hossein (editor) / Poitras, Gérard J. (editor) / Gaafar, Mohamed (author) / Jones, Chris (author) / Paine, Ali (author) / Cody, Neal (author)
Canadian Society of Civil Engineering Annual Conference ; 2023 ; Moncton, NB, Canada
Proceedings of the Canadian Society for Civil Engineering Annual Conference 2023, Volume 9 ; Chapter: 11 ; 151-164
2024-10-10
14 pages
Article/Chapter (Book)
Electronic Resource
English
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