An inexpensive and lightweight dynamic cone penetrometer for the characterization of shallow submerged sediments

Sediment compaction is an indicator of the health of benthic communities. At the same time, many of the extractive or cultivation activities on the coast take place in areas of special environmental interest and remove or compact the sediment by their own activity or simply by access on foot. Measurements of compaction or penetration resistance of marine or river sediments are not common, especially in submerged environments. Although there are devices, such as vane testers, that can be used in non-submerged sediments, lightweight and inexpensive devices for measuring compaction in submerged sediments are rare. An apparatus for measuring sediment penetration resistance based on the dynamic cone penetrometers used in terrestrial environments is described and tested. The device is lightweight and inexpensive, and although it is intended for use in submerged sediments, it can also be used manually in sediments accessible by foot. In the process of testing the apparatus, the penetration resistance values of surfaced sediments have been compared with those obtained with a vane tester to estimate compaction. This new lightweight penetrometer provides inexpensive penetration resistance values as a measure of compaction in the sediment layer of greatest interest for the management of habitats and communities and makes it possible to establish criteria for action and to measure its effectiveness.