X-band radar applications for coastal monitoring to support improved management of coastal erosion

The design, construction and management of coastal defences around the UK require information of how the coast changes through time in response to weather conditions, waves and tides. Major storms have an impact in the way sediment moves at the sea bed to and from the shoreline to offshore areas, affecting where and when the coast will erode. However, such information is difficult to obtain and measurements exist for only a limited number of locations and at infrequent intervals. Such lack of knowledge may lead to poor decisions concerning flood and erosion defences, which can result in serious impacts on local communities, businesses and livelihoods.
One way of resolving this lack of information is the use of remote sensing technologies, which are able to measure waves, currents and changes in bathymetry without the need to deploy instruments at sea. Research funded by the Natural Environment Research Council in the past 15 years has developed technology that enables extracting information about waves and currents from data collected by a standard marine X-Band radar (the type of radar often used in ships). The radar records wave conditions over a 3km radius around the radar and uses a software to transform wave data into local water depth and currents using formulations derived from scientific knowledge. Data collected by the radar can then be used to measure changes in water depth in areas where other types of survey are difficult to undertake. The radar can also detect the position of the waterline on the beach and use this information to map the beach topography. A great advantage of the radar is the ability to undertake measurements day and night independently of weather conditions.
This project will test the use of X-Band technology to improve decisions concerning coastal flood and erosion management. Specifically, our objective is to assess whether this technology is cost-effective for a number of practical applications required in the public and private sectors. Potential applications include coastal monitoring of storm impacts; effects of coastal engineering projects; and development of early warning systems for coastal change leading to risk of flooding or cliff retreat.
Researchers from the National Oceanographic Centre and Bournemouth University will work in collaboration with the Suffolk Coastal District Council, Mott MacDonald, the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and residents of Thorpeness (Suffolk) to test whether the X-Band radar can bring a solution to coastal erosion problems threatening the village. The objective here is to obtain information that will improve the understanding of coastal processes to support the development of a sustainable, resilient and cost-effective management solution to the critical erosion affecting the local community.
The main outcome of this project is to demonstrate whether the X-band radar is a cost-effective way to provide coastal monitoring data in support of practical coastal management applications when compared with commonly used methods. This being the case, there is a great potential for research and commercial applications in the UK and internationally concerning coastal monitoring for advancing the understanding of coastal processes and management solutions.

Keywords: X-Band radar; coastal monitoring; coastal management; decision-making; erosion; flood; coastal defences; sustainability; knowledge exchange

Suffolk Coastal District Council
In broad terms the KT activities proposed here will provide to SCDC a cost-effective and practical tool that facilitates coastal monitoring for the purpose of coastal erosion and flood risk management. This will in turn provide the information required to reduce risks and uncertainties associated with future coastal management decisions. It will also enable coastal monitoring and the gathering of intelligence on future costal behaviour that may be affected by changes in the offshore morphology currently unaccounted for. Importantly, the KT process facilitated by the project is expected to find other coastal management applications within the SCDC Coastal Team remit with potential dissemination of good practices to other coastal authorities in the UK.

Cefas and EDF Energy
The knowledge exchange between NOC scientists and Cefas is likely to advance our understanding of how the erosion-resistant Coralline Crag influences shoreline position around the ness. Observations from the NERC-funded radar and Cefas/EDF's radar (the latter being used for measuring waves, shoreline positions and the sand bank near Sizewell) overlap in front of Thorpeness, potentially revealing more detailed information than would be achieved with a single radar. NOC scientists are at the forefront of radar oceanography and this knowledge transfer has the potential to deliver new and improved methods for estimation of wave heights and water depths. This is especially relevant to provide information required for coastal management decisions.

Mott MacDonald (MMD)
KT actions proposed here will provide the information to fill previously identified knowledge gaps concerned with the behaviour of bed features offshore which are thought to focus wave energy at the erosion 'hot-spot'. In addition, results from this project may lead to uptake of the X-Band radar technology to advance numerical modelling studies in a range of projects undertaken by MMD in the UK and worldwide. The spatial and temporal resolution of data provided by the X-band radar system will improve the current ability to calibrate and validate morphological model applications at a greatly reduced cost compared to traditional survey methods. In turn this will greatly assist the process required to reach evidence-based coastal management decisions.

Thorpeness Coastal Futures Group (TCFG)
The most tangible benefit for the TCFG concerns accelerated development of a coastal management strategy that meets community aspirations. The recent severe erosion and exposure of coastal defence installed in 2011is presently managed by local beach recharge. However, the area remains vulnerable and further storm sequences similar to those experienced in 2013/14 are likely to increasingly threaten the village. Progressing quickly to define the best strategy to protect the coast from erosion at this location is therefore urgently required and the KT activities proposed here are seen the residents as the best way of achieving this objective.