Feeding Starved Coasts By Natural Morphological Diffusivity

Summary

Coastal protection is of prime importance for the upcoming century as the majority of the world population and economic value depends on beach and dune strength. Nourishments, where sand from offshore is dumped near the beach, are the principal mitigation measure in adaptive coastal maintenance during times of climate change for many locations. Recently concentrated nourishments have been proposed, where natural forces are needed to spread the sand and feeding the surrounding sand starving coasts. To apply this promising maintenance strategy it’s paramount to have knowledge and a good prediction skill of morphological diffusivity (i.e. the spreading characteristics) and its driving processes. This is currently impeded by a lack of data and understanding on the smaller scales that govern long-term coastal behavior.
Using my unique expertise in coastal measurements and modeling I propose to investigate the spreading of sand by: 1) performing extensive measurements of a man-made shallow mound near the beach that diffuses on the timescale of weeks. The driving processes and sand-water feedbacks will be examined in detail using several recently developed techniques. These measurements are complemented by 2) implementing and assessing morphological diffusivity on multiple timescales in an open source numerical model for coastal flow and transport.
The resulting in–depth knowledge and validated tool enable a prediction of concentrated nourishments in the near future and coastal response to human interventions in general. To reach this objective Rijkswaterstaat, which is responsible for coastal maintenance, and Deltares, the global leader in coastal modeling software, are connected throughout the research.
Currently nourishment volumes are increasing and the Dutch annual expenses are forecasted to reach up to €0.2 billion. The proposed generic tool supports the decision making by evaluating newly proposed designs of coastal protection. Ultimately this contributes to the global need for climate adaptability and cost effective solutions.

Details

Project number

15058

Main applicant

Dr. ir. M.A. de Schipper

Affiliated with

Technische Universiteit Delft, Faculteit Civiele Techniek en Geowetenschappen, Afdeling Hydraulic Engineering

Team members

P. van der Gaag

Duration

01/01/2017 to 31/12/2019

Budget

EUR245,686