The potential for natural flood management to maintain free discharge at urban drainage outfalls

Abstract This study examines whether catchment‐scale natural flood management (NFM) interventions could help to manage water levels in downstream urban watercourses and promote free discharge from surface drainage outfalls. A coupled modelling approach consisting of Dynamic TOPMODEL, HEC‐RAS, and In...

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Main Authors: Charlie R. Ferguson, Richard A. Fenner
Format: Article
Language:English
Published: Wiley 2020-09-01
Series:Journal of Flood Risk Management
Subjects:
Online Access:https://doi.org/10.1111/jfr3.12617
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author Charlie R. Ferguson
Richard A. Fenner
author_facet Charlie R. Ferguson
Richard A. Fenner
author_sort Charlie R. Ferguson
collection DOAJ
description Abstract This study examines whether catchment‐scale natural flood management (NFM) interventions could help to manage water levels in downstream urban watercourses and promote free discharge from surface drainage outfalls. A coupled modelling approach consisting of Dynamic TOPMODEL, HEC‐RAS, and Infoworks ICM models is used to characterise the response from a small Cambridgeshire catchment. Four different NFM scenarios (consisting of in‐channel woody debris and wider catchment afforestation) are defined. The attenuation of catchment response created by these measures is evaluated for an historic event and six different design storms. The consequent moderation of water depths at two downstream drainage outfalls is investigated with respect to maintaining free discharge from a surface drainage system. The case study results show that greatest reductions in the time of outfall inundation from NFM occur during frequent storm events (e.g., up to 5.75 hr during a 5‐year event). These reductions diminish with increasing storm severity but, by slightly desynchronising rural and urban responses, upstream interventions continue to have modest benefit for downstream drainage performance (e.g., preventing system capacity being exceeded during a 100‐year event). These results may interest water companies (increasingly involved in catchment‐scale NFM projects) looking to improve performance of surface water drainage.
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spelling doaj.art-0a620f0c991740c69ed5e2ae091ec5df2022-12-21T17:25:04ZengWileyJournal of Flood Risk Management1753-318X2020-09-01133n/an/a10.1111/jfr3.12617The potential for natural flood management to maintain free discharge at urban drainage outfallsCharlie R. Ferguson0Richard A. Fenner1Centre for Sustainable Development, Department of Engineering University of Cambridge Cambridge UKCentre for Sustainable Development, Department of Engineering University of Cambridge Cambridge UKAbstract This study examines whether catchment‐scale natural flood management (NFM) interventions could help to manage water levels in downstream urban watercourses and promote free discharge from surface drainage outfalls. A coupled modelling approach consisting of Dynamic TOPMODEL, HEC‐RAS, and Infoworks ICM models is used to characterise the response from a small Cambridgeshire catchment. Four different NFM scenarios (consisting of in‐channel woody debris and wider catchment afforestation) are defined. The attenuation of catchment response created by these measures is evaluated for an historic event and six different design storms. The consequent moderation of water depths at two downstream drainage outfalls is investigated with respect to maintaining free discharge from a surface drainage system. The case study results show that greatest reductions in the time of outfall inundation from NFM occur during frequent storm events (e.g., up to 5.75 hr during a 5‐year event). These reductions diminish with increasing storm severity but, by slightly desynchronising rural and urban responses, upstream interventions continue to have modest benefit for downstream drainage performance (e.g., preventing system capacity being exceeded during a 100‐year event). These results may interest water companies (increasingly involved in catchment‐scale NFM projects) looking to improve performance of surface water drainage.https://doi.org/10.1111/jfr3.12617flood hazardland managementnatural flood managementsurface drainagewater‐level management
spellingShingle Charlie R. Ferguson
Richard A. Fenner
The potential for natural flood management to maintain free discharge at urban drainage outfalls
Journal of Flood Risk Management
flood hazard
land management
natural flood management
surface drainage
water‐level management
title The potential for natural flood management to maintain free discharge at urban drainage outfalls
title_full The potential for natural flood management to maintain free discharge at urban drainage outfalls
title_fullStr The potential for natural flood management to maintain free discharge at urban drainage outfalls
title_full_unstemmed The potential for natural flood management to maintain free discharge at urban drainage outfalls
title_short The potential for natural flood management to maintain free discharge at urban drainage outfalls
title_sort potential for natural flood management to maintain free discharge at urban drainage outfalls
topic flood hazard
land management
natural flood management
surface drainage
water‐level management
url https://doi.org/10.1111/jfr3.12617
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