The evolution of embryonic creek systems in a recently inundated large open coast managed realignment site

Abstract

Managed realignment (MR) schemes are being implemented to compensate for the degradation of coastal habitats. However, evidence suggests that MR sites have lower biodiversity than anticipated, which has been linked to poor drainage. Despite creek networks playing an important role in enhancing site drainage in natural intertidal environments, there remains a shortage of data on the formation and evolution of creeks within MR sites. This study evaluates creek development at the Medmerry Managed Realignment Site, UK. Creek development is investigated using differential global positioning system (dGPS) data, supported by sedimentological analyses and a high-resolution digital surface model (DSM) derived from images taken using a small unmanned aerial vehicle. Measurements indicated that creeks will develop relatively quickly, but are influenced by differences in the sub-surface sedimentological conditions. A suitable level of agreement was found between the DSM and dGPS measurements, demonstrating the appropriateness of this method to study creek development within intertidal environments at a higher resolution than traditional surveying techniques. These results are used to propose the collapse of sub-surface piping as the primary creek formation mechanism. Findings are discussed in terms of increasing the success of MR schemes and enhancing site design to maximise the ecosystem services provided.

A Stochastic Approach to Modeling Tidal Creek Evolution: Exploring Environmental Influences on CreekTopologies Through Ensemble Predictions

“…The processes and phenomena the model aims to simulate, that is, the formation and evolution of creek networks, are characterized by high levels of uncertainty (Whitehouse et al, 2000;Dale et al, 2018). The results illustrate the application of the model which emphasizes the use of Monte-Carlo simulation.…”

“…The results illustrate the application of the model which emphasizes the use of Monte-Carlo simulation. The processes and phenomena the model aims to simulate, that is, the formation and evolution of creek networks, are characterized by high levels of uncertainty (Whitehouse et al, 2000;Dale et al, 2018). These uncertainties are accounted for through random headward expansion direction selection in each individual model run and represented as heat maps by way of Monte-Carlo simulation.…”

“…Consequently, these areas are commonly managed and engineered to reduce damage, loss of life, and environmental degradation caused by natural hazards originating from the sea. However, sea-level rise and increased storminess due to global warming (e.g., Sayers et al, 2015) are putting unprecedented pressure on these managed systems, rendering some of them uneconomical and unsustainable to maintain, in which case we adopt either a "no active intervention" or a "managed realignment" strategy (Dale et al, 2018;French, 2006;Turner et al, 2007).…”

Impact of Barrier Breaching on Wetland Ecosystems under the Influence of Storm Surge, Sea-Level Rise and Freshwater Discharge

“…Direct interventions in the back-barrier to steer landscape evolution in the wetland, such as creating creeks and developing the necessary topography, can ultimately compensate for habitat loss induced by seawater intrusion (e.g. Dale et al 2017Dale et al , 2018Lawrence et al 2018). For example, the fast seawater ingress promoted by high connectivity of the drainage network mentioned above could be impeded by construction of embankments that disconnect the network.…”

“…Further, financial resource limitations may require a move from 'hold the line' to 'no active intervention' or 'managed realignment' options (Esteves and Williams 2017) for coastal management which can potentially impact back-barrier wetlands and habitats (Rupp-Armstrong and Nicholls 2007;Friess et al 2014;Brady and Boda 2017). Notable managed realignment examples in the UK include Tollesbury (Garbutt et al 2006), Freiston (Friess et al 2014), Hesketh Marsh (Tovey et al 2009), and Medmerry (Dale et al 2017(Dale et al , 2018.…”