Depth-limiting resistant layers restrict dimensions and positions of estuarine channels and bars

Depth-limiting resistant layers restrict dimensions and positions of estuarine channels and bars

Pierik, H.J.
Leuven, J.R.F.W.
Busschers, F.S.
Hijma, M.
Kleinhans, M.G.

2022

Estuaries comprise channels vital for economic activity and bars as valuable habi tats. They are increasingly under human-induced pressures (e.g. sea-level rise and dredging), resulting in morphological changes that affect navigability, flood safety and ecology. Antecedent geology may strongly steer how estuary channels will adapt to these pressures, but is surprisingly absent in most models. Here geo logical data and a unique bathymetry dataset covering 200 years from the Ems Dollard estuary (Netherlands/Germany) were used to demonstrate how local resistant layers force the position and dimensions of confluences and bars on the scale of an entire estuary. These layers limit channel depth and consequently cause widening, resulting in mid-channel bar formation and increased channel curvature. This could lead to unexpected estuary widening and may cause land loss in densely populated areas. With increasing channel volume (as may hap pen again under future sea-level rise), resistant layers in the estuary's substrate become more exposed, which enhances their effects. Many systems around the world contain shallow resistant layers that potentially constrain estuary channel dimensions and steer bank erosion. This highlights that resistant layer effects are important to consider as part of mixed depositional processes in coastal environ ments. It is therefore necessary to globally account for the effects of inherited resistant layersin the possible response of estuariesto sea-level rise and increased tidal penetration

Antecedent geology
Channel-bar pattern
Estuary
Holocene
Geological Survey Netherlands
2015 Energy

http://resolver.tudelft.nl/uuid:0ed07d79-bf3e-449d-8c6a-dea5229747ad

https://doi.org/10.1002/dep2.184

967557

John Wiley and Sons Inc

2055-4877

The Depositional Record, 1-20

article