Sediment Dynamics Associated With Managed Realignment; Freiston Shore, the Wash, Uk

Symonds, Andrew M.; Collins, Michael B.

doi:10.1142/9789812701916_0256

Cited by 8 publications

(13 citation statements)

References 17 publications

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“…Other research using kinematic GPS revealed that the realignment area is a net sediment sink, with a 2:1 ratio of sediment entering versus exiting the area (Symonds and Collins, 2004). Initial sediment accretion is most evident in the vicinity of the breaches, which has been qualitatively attributed to the reworking of loose material from creek and breach excavation (Rawson et al, 2004).…”

Section: Sedimentationmentioning

confidence: 98%

“…This delay allows creeks in the outer saltmarsh and mudflat to flow for much longer periods than before the breach, since they are partially fed by run-off from the MR site (Rawson et al, 2004). The duration of tidal ebb now exceeds tidal flood by 5:1 (Symonds and Collins, 2004). As a result, and in response to the additional volumes of water being carried, the intertidal creek system seaward of the MR site is experiencing headward erosion at roughly 28 times the pre-breach rate (450 m/yr post-breach versus 16 m/yr prebreach) (Symonds and Collins, 2004).…”

Section: Geomorphological Changementioning

confidence: 99%

“…The duration of tidal ebb now exceeds tidal flood by 5:1 (Symonds and Collins, 2004). As a result, and in response to the additional volumes of water being carried, the intertidal creek system seaward of the MR site is experiencing headward erosion at roughly 28 times the pre-breach rate (450 m/yr post-breach versus 16 m/yr prebreach) (Symonds and Collins, 2004). Overbank flow occurs along sections of the saltmarsh creeks due to higher water volumes, leading to overland flow in the intertidal zone.…”

Section: Geomorphological Changementioning

confidence: 99%

“…Overbank flow occurs along sections of the saltmarsh creeks due to higher water volumes, leading to overland flow in the intertidal zone. Overland flow has occurred consistently since breaching of the MR site, and is thought to contribute to saltmarsh creek erosion (Symonds and Collins, 2004). Rawson et al (2004) suggest that much of the material eroded from outer creeks is being deposited immediately adjacent to them.…”

Section: Geomorphological Changementioning

confidence: 99%

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Sediment transport on the Freiston Shore managed realignment site: An investigation using environmental magnetism

et al. 2008

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Section: Sedimentationmentioning

confidence: 98%

Section: Geomorphological Changementioning

confidence: 99%

Section: Geomorphological Changementioning

confidence: 99%

Section: Geomorphological Changementioning

confidence: 99%

See 2 more Smart Citations

Sediment transport on the Freiston Shore managed realignment site: An investigation using environmental magnetism

et al. 2008

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“…Rotman et al, 2008;Symonds and Collins, 2005). However, the Medmerry MR scheme is located on an open coast, a considerable distance (approximately 7.5 km eastwards from Chichester Harbour entrance and on the opposite side of the peninsular from Pagham Harbour) from any external preexisting saltmarshes, and is banked by a shingle beach.…”

Section: Fettweis Et Al 1998)mentioning

confidence: 99%

Sedimentation rhythms and hydrodynamics in two engineered environments in an open coast managed realignment site

2017

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Managed Realignment (MR) schemes are considered by many coastal managers and engineers to be a preferable method of coastal flood defence and compensating for habitat loss, by creating new areas of intertidal saltmarsh and mudflat habitat. Monitoring of MR sites has tended to focus on short term ecological factors, resulting in a shortage of high frequency, high resolution long term measurements of the evolution of the sediment erosion, transportation, deposition and consolidation cycle (ETDC) in newly breached sites. This is particularly true of analysis of the formation and preservation of sedimentary rhythmites and evaluations of sedimentation rates (and their variability) in newly inundated intertidal environments. This study provides an evaluation of sedimentation rhythms and hydrodynamics from two contrasting sites within the Medmerry Managed Realignment scheme, the largest open coast realignment in Europe (at the time of site inundation). Bed sediment altimeter data highlighted different sedimentation patterns at the two sites; near constant deposition of sediment occurred near the breach resulting in 15.2 cm of sediment being accreted over the one year monitoring period, whereas periodic accretion and erosion of sediment occurred inland leading to 2.7 cm of net accretion. Differences in the relationship between suspended sediment concentrations and site hydrodynamics were observed on a semi-diurnal to annual scale. This study highlights the need for further consideration of the sedimentation processes in MR schemes in order to enhance the design and construction of these sites. Advancements in the understanding of these processes will increase the success of MR schemes in terms of the evolution of the sediment regime and the ecosystem services provided, particularly as they are more widely accepted as a form of coastal flood defence and intertidal habitat creation method.

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The establishment and degeneration of a temporary creek system in response to managed coastal realignment: The Wash, UK

Symonds

Collins

2007

Earth Surf Processes Landf

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The present investigation examines the growth and decay of an ephemeral creek system produced in response to a managed realignment at Freiston Shore, The Wash. In addition, the natural and anthropogenically enhanced developments of the creek system are compared.The creation of a managed realignment caused sheetflow to occur on the adjacent intertidal zone, approaching and throughout the period of low water, during spring tides. The resultant creek development led to annual headward (landward) extension rates of up to 400 m yr − − − − −1 , over 20 times greater than those taking place during natural conditions. Rapid development of the creek system continued for 2 years, following initiation of the managed realignment. Over the succeeding 12 months, the creek system degenerated; it silted up and reverted to a similar pattern to its original geometry, prior to the managed realignment. Siltation of the creek system coincided with the cessation of sheetflow from the managed realignment. The natural creeks connected to the breaches in the embankment (as part of the scheme) became enlarged sufficiently to accommodate the increased flow produced by the drainage of the managed realignment site, without overbank flow occurring. The natural and anthropogenically enhanced developments of the creek system were similar to those described in the fluvial models described by Schumm et al. (1987): expansion by headward growth, followed by the extension of rapidly growing, long creeks, with tributaries added to fill the drainage network.

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Sediment Dynamics Associated With Managed Realignment; Freiston Shore, the Wash, Uk

Cited by 8 publications

References 17 publications

Sediment transport on the Freiston Shore managed realignment site: An investigation using environmental magnetism

Sediment transport on the Freiston Shore managed realignment site: An investigation using environmental magnetism

Sedimentation rhythms and hydrodynamics in two engineered environments in an open coast managed realignment site

The establishment and degeneration of a temporary creek system in response to managed coastal realignment: The Wash, UK

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