National Network of Regional Coastal Monitoring Programmes

iCOASST demonstrated the capability of the methods being developed in two contrasting pilot sites. The results of the modelling the Deben estuary and open coast are given here

Suffolk Coast

The Suffolk coast, eastern England, is north-south orientated and borders the southern North Sea. It is characterised by fairly small tides (spring tide range varies from 1.9 m in north Suffolk to 3.6 m in the south), a bimodal wave climate with waves predominately from the north-east and south, and sand-gravel beaches. In places, large accumulations of gravel form distinct beach-ridge forelands, such as the Orfordness shingle complex. There are a number of small estuaries and barrier-fronted lagoons (Figure 1).

The suite of work conducted on the Suffolk coast as part of the iCOASST Project, included the development of a Coastal and Estuarine System Map of the entire Suffolk coast (available at: http://www.channelcoast.org/data_management/online_data_catalogue/), a model composition in southern Suffolk (outlined below) and a series of participatory workshops with stakeholders (e.g., French et al., 2016; Van Maanen et al., 2016). There are also analyses of coastal change (Burningham, 2015; Burningham and French; 2014; 2015; 2017; French and Burningham, 2015; Horrillo-Caraballo et al., 2015), and model development and application (Karunarathna et al., 2017; Thornhill et al., 2015; van Maanen et al., 2015; Walkden et al., 2015).

Analyses of change in the relative position of shorelines, over decadal to centennial timescales (Burningham and French, 2017), supported much of the development of coastal landform behaviour models. The application of SCAPE+ to the north Suffolk cliffs (Walkden et al., 2015) and coupling of SCAPE+ with MESO_i to the Bawdsey-Felixstowe coastline required information regarding shoreline trends sourced through the digitisation of mean high water (MHW) shorelines from OS maps and EA aerial photography and Lidar. These data have been analysed further, and a new hierarchical cluster analysis method developed (Burningham and French, 2017), to find common behaviours in coastal dynamics at different temporal scales. Unlike EOF and CCA analyses, cluster analysis captures the different modes of coastal behaviour that occur regionally, thereby providing a more objective basis on which to classify dynamics and then investigate the drivers of change.

The Suffolk model composition focuses on the Deben estuary and inlet-adjacent shorelines (Figures 2 and 3). As found elsewhere in Suffolk, the estuary is characterised by a single low tide channel flanked by mud flats and saltmarsh, and the inlet is narrow, bound by small sand-gravel barriers and comprising ebb-delta deposits. The mean tidal prism of the estuary is approximately 17 x 106 m3 (Burningham and French, 2006). The neighbouring open coast shorelines comprise mixed sand-gravel beaches partially backed by soft cliffs in places. Both the estuary and the open coast in this part of Suffolk have been impacted by human interventions, including significant land reclamation and the construction of numerous sea defences, especially in the 19th and 20th century. The ebb-delta shoals at the mouth of the Deben show a broadly cyclic behaviour whereby the updrift shoal progressively extends until it breaches, after which the sediment is released to the downdrift coast. Further details on the composition are found on the model compositions pages.

iCOASST held a series of stakeholder workshops in Suffolk during the course of the project, to understand the area and stakeholder perspectives, as well as present and discuss the results as they emerged. These workshops took place as follows: 22 March 2013 stakeholder workshop (Lowestoft); 26 June 2013 workshop with Suffolk Coastal Forum / EA Coastal Group (Woodbridge) (Figure 4); 29 June 2015 CESM/CSI workshop (Woodbridge); 13 July 2015 Modelling workshop (Lowestoft); and 19 May 2016 (Ipswich). We also engaged with the Suffolk Coastal Forum.

References

Burningham, H. (2015) Gravel spit-inlet dynamics: Orford Spit, UK. In: Randazzo, G., Cooper, J.A.G., Jackson D., Sand and Gravel Spits, Coastal Research Library. ISBN: 978-3-319-13715-5, pp. 51-65.

Burningham, H., French, J.R. (2006). Morphodynamic behaviour of a mixed sand-gravel ebb-tidal delta: Deben estuary, Suffolk, UK. Marine Geology 225, 23-44.

Burningham, H., French, J.R (2014) Travelling forelands: complexities in drift and migration patterns. Journal of Coastal Research. DOI: 10.2112/SI70-018.1

Burningham H., French J.R. (2015) Large-scale spatial variability in the contemporary coastal sand and gravel resource, Suffolk, Eastern UK. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981-4689-96-0

Burningham, H., French, J.R. (2017) Understanding coastal change using shoreline trend analysis supported by cluster-based segmentation. Geomorphology, 282, 131-149. http://dx.doi.org/10.1016/j.geomorph.2016.12.029

French, J., Burningham H. (2015) Wave-driven sediment pathways on the gravel-dominated Suffolk Coast, Eastern UK. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981-4689-96-0

French J.R., Burningham H., Thornhill G., Nicholls R.J. (2016) Integrating estuarine, coastal and inner shelf sediment systems in a common conceptual framework as a basis for participatory shoreline management. Geomorphology and Society, Springer, pp. 245-277.

Horrillo-Caraballo, J.M., Reeve, D.E., Karunarathna, H., Pan, S., Burningham, H. (2015) Multi-scale statistical analysis of beach profiles on the Suffolk coast, UK. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981-4689-96-0

Karunarathna, H., Horrillo-Caraballo, J., Burningham, H., Pan,S. Reeve, D.E. (2016) Two-dimensional reduced-physics model to describe historic morphodynamic behaviour of an estuary inlet. Marine Geology, 382, 200-209.

Van Maanen, B., Walkden, M.J.A., Nicholls, R. J. (2015) Modelling inlet dynamics to explore coupled system behaviour over decadal scales. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981-4689-96-0

van Maanen, B., Nicholls, R.J., French, J.R., Barkwith, A., Bonaldo, D., Burningham, H., Murray, A.B., Payo, A., Sutherland, J., Thornhill, G., Townend, I., van der Wegen, M., Walkden, M.J.A (2016) Simulating mesoscale coastal evolution for decadal coastal management: A new framework integrating multiple, complementary modelling approaches. Geomorphology, 256, 68-80. DOI: 10.1016/j.geomorph.2015.10.026

Thornhill, G, French, J.R., Burningham, H. (2015) ESTEEM - A new hybrid complexity model for simulating estuary morphological evolution at decadal to centennial scales. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981- 4689-96- 0

Walkden, M., Payo, A., Barnes, J., Burningham, H. (2015) Modelling the response of coupled barrier and cliff systems to sea level rise. Coastal Sediments 2015 (Proceedings of). San Diego, ISBN: 978-981-4689-96-0