Rehman_et_al.mp4

Recording of presentations at the Suricates project closing conference

Title : Assessing Beneficial Use of Dredged Sediments at the La Rance Estuary Using an Ecosystem Services Model

Authors : Iqra REHMAN*1 , Brano BATEL1 , Joe HARRINGTON1

1 School of Building & Civil Engineering and the Sustainable Infrastructure Research & Innovation Group, Munster Technological University, Bishopstown, Cork, Ireland T12 P928. * Corresponding author e-mail: iqra.rehman@mycit.ie

Summary :

Sustainable sediment management provides a beneficial resource for coastal restoration and ecosystem enhancement and promotes environmental sustainability and the circular economy. The Interreg funded SURICATES project focuses on sustainable sediment management with application at sites including the La Rance estuary in France, where maintenance dredging is required due to ongoing estuary sedimentation. In the context of beneficial use of sediment, the SURICATES project is studying a range of site applications including agricultural spreading, dyke, and dry-stone wall construction.

This paper presents an assessment of ecosystem services (through Provisioning, Regulatory, and Cultural aspects that underpins in supporting services) using a model developed by Munster Technological University. The model allows ecosystem services assessment and valuing under different categories; the model assesses the economic value that humans derive from ecosystems primarily through quantifying unit costs and changes in land use related to sediment management. For this paper the model is applied to assess sediment management approaches proposed and developed for the La Rance estuary site.

The ecosystem services model is applied to the agricultural application which involves spreading approximately 54,000 tonnes of sediment over 64 hectares. This sediment has been stored at the La Hisse storage site for purposes of dewatering and desalination. The food provisioning element is an important ecosystem service for this application that considers the total yield expected after spreading of sediment. Additional materials were added for soil formation that provide essential nutrients and organic matter and are considered in provisioning the overall yield. The quantitative ecosystem service value indicated by the model is €399,400/yr. The dyke application aims to use 34 tonnes of sediment in reality but this paper assumes use of 73,000 tonnes for a large-scale project and the model indicates an ecosystem service value of approximately €1,869,300/yr. In conclusion, incorporating the values and benefits derived from ecosystems contributes to the decision-making process for the management of dredged sediment.

Acknowledgements: The SURICATES project is funded by the European Regional Development Fund (ERDF) as part of the Interreg NWE programme 2014-2020