The University of Southampton
University of Southampton Institutional Repository

The effects of river restoration on catchment scale flood risk and flood hydrology

The effects of river restoration on catchment scale flood risk and flood hydrology
The effects of river restoration on catchment scale flood risk and flood hydrology
A rising exposure to flood risk is a predicted consequence of increased development in vulnerable areas and an increase in the frequency of extreme weather events due to climate change. In the face of this challenge, a continued reliance on engineered at-a-point flood defences is seen as both unrealistic and undesirable. The contribution of ‘soft engineering’ solutions (e.g. riparian forests, wood in rivers) to integrated, catchment scale flood risk management has been demonstrated at small scales but not larger ones. In this study we use reduced complexity hydrological modelling to analyse the effects of land use and channel changes resulting from river restoration upon flood flows at the catchment scale. Results show short sections of river-floodplain restoration using engineered logjams, typical of many current restoration schemes, have highly variable impacts on catchment-scale flood peak magnitude and so need to be used with caution as a flood management solution. Forested floodplains have a more general impact upon flood hydrology, with areas in the middle and upper catchment tending to show reductions in peak magnitude at the catchment outflow. The most promising restoration scenarios for flood risk management are for riparian forest restoration at the sub-catchment scale, representing 20–40% of the total catchment area, where reductions in peak magnitude of up to 19% are observed through de-synchronization of the timings of sub-catchment flood waves. Sub-catchment floodplain forest restoration over 10–15% of total catchment area can lead to reductions in peak magnitude of 6% at 25 years post-restoration.
0197-9337
997-1008
Dixon, Simon J.
abb0d02d-6663-40ea-b3ee-07bc962cd693
Sear, David A.
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Odoni, Nicholas A.
f5193a57-3d7e-47c6-9f96-c0c3a0a35dd1
Sykes, Tim
e622a522-7490-4fc8-9869-0f376f73561c
Lane, Stuart
67d4c48e-0073-4370-a680-b3b7586ea293
Dixon, Simon J.
abb0d02d-6663-40ea-b3ee-07bc962cd693
Sear, David A.
ccd892ab-a93d-4073-a11c-b8bca42ecfd3
Odoni, Nicholas A.
f5193a57-3d7e-47c6-9f96-c0c3a0a35dd1
Sykes, Tim
e622a522-7490-4fc8-9869-0f376f73561c
Lane, Stuart
67d4c48e-0073-4370-a680-b3b7586ea293

Dixon, Simon J., Sear, David A., Odoni, Nicholas A., Sykes, Tim and Lane, Stuart (2016) The effects of river restoration on catchment scale flood risk and flood hydrology. Earth Surface Processes and Landforms, 41 (7), 997-1008. (doi:10.1002/esp.3919).

Record type: Article

Abstract

A rising exposure to flood risk is a predicted consequence of increased development in vulnerable areas and an increase in the frequency of extreme weather events due to climate change. In the face of this challenge, a continued reliance on engineered at-a-point flood defences is seen as both unrealistic and undesirable. The contribution of ‘soft engineering’ solutions (e.g. riparian forests, wood in rivers) to integrated, catchment scale flood risk management has been demonstrated at small scales but not larger ones. In this study we use reduced complexity hydrological modelling to analyse the effects of land use and channel changes resulting from river restoration upon flood flows at the catchment scale. Results show short sections of river-floodplain restoration using engineered logjams, typical of many current restoration schemes, have highly variable impacts on catchment-scale flood peak magnitude and so need to be used with caution as a flood management solution. Forested floodplains have a more general impact upon flood hydrology, with areas in the middle and upper catchment tending to show reductions in peak magnitude at the catchment outflow. The most promising restoration scenarios for flood risk management are for riparian forest restoration at the sub-catchment scale, representing 20–40% of the total catchment area, where reductions in peak magnitude of up to 19% are observed through de-synchronization of the timings of sub-catchment flood waves. Sub-catchment floodplain forest restoration over 10–15% of total catchment area can lead to reductions in peak magnitude of 6% at 25 years post-restoration.

Text
Dixon et al 2016.pdf - Version of Record
Restricted to Repository staff only
Request a copy

More information

Accepted/In Press date: 2 February 2016
e-pub ahead of print date: 17 March 2016
Published date: 15 June 2016
Additional Information: This article also appears in: Stormy Geomorphology: geomorphic contributions in an age of climate extremes
Organisations: Earth Surface Dynamics

Identifiers

Local EPrints ID: 396861
URI: http://eprints.soton.ac.uk/id/eprint/396861
ISSN: 0197-9337
PURE UUID: 715df3df-c537-4b5a-886c-d593c51d44a1
ORCID for David A. Sear: ORCID iD orcid.org/0000-0003-0191-6179
ORCID for Tim Sykes: ORCID iD orcid.org/0000-0002-0665-0368

Catalogue record

Date deposited: 15 Jun 2016 08:27
Last modified: 17 Dec 2019 02:00

Export record

Altmetrics

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×