Morphological changes due to marine aggregate extraction for beach nourishment in the German Bight (SE North Sea)


Contact
Finn.Mielck [ at ] awi.de

Abstract

Facing the predicted rise in global sea level, sandy shorelines are under increasing pressure. In order to counteract the loss of material at eroding coastlines, beach nourishment is considered to be an environmentally friendly approach worldwide. This has resulted in a rising demand for aggregates, which are frequently extracted from the seafloor near the coast. In order to explore the long- and short-term morphological changes of such mining on the seabed, the largest extraction area in the German Bight (Westerland Dredging Area, established in 1984) was investigated in this study. Several measurement campaigns were conducted between the years 1994 and 2017 using a set of hydroacoustic techniques. The measurements revealed that up to 20-m-deep pits with diameters of more than 1 km were dredged into the seafloor. The depressions caused by this sand mining are still detectable more than 30 years later. Because of slope failures that mainly consist of fine sand, the formerly steep rims at fresh dredging pits smoothed within a few months. However, after approximately 1 year, muddy sediments dominated the deposition. Since the sedimentation rates are slow, a complete backfill of the post-dredging pits is likely to take many decades. A natural regeneration towards the former seafloor conditions is only visible at the shallow rims of the oldest dredging pits.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Publication Status
Published
Eprint ID
48632
Cite as
Mielck, F. , Hass, C. , Michaelis, R. , Sander, L. , Papenmeier, S. and Wiltshire, K. H. (2018): Morphological changes due to marine aggregate extraction for beach nourishment in the German Bight (SE North Sea) , Geo-Marine Letters .


Download
[thumbnail of Mielck_et_al_2018.pdf]
Preview
PDF
Mielck_et_al_2018.pdf

Download (7MB) | Preview

Share
Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email

Geographical region

Research Platforms

Campaigns
HE > 280 - 299 > 294
HE > 300 - 319 > 310
HE > 400 - 419 > 411

Funded by
03F0761


Actions
Edit Item Edit Item