Researchers says large-scale dredging of marine aggregates will have a significant impact on near-field and far-field flow and wave patterns, and flow velocities inside the pits will be reduced and the wave heights may also be reduced, depending on the depth of the pit. As a consequence, the sand transport capacity inside the pit will decrease and sediments will settle in the pit area, resulting in deposition.

Thus, the pit will act as a sink for sediments originating from the surrounding areas and depending on the local flow and wave patterns. This means that erosion of the sea floor will take place in the immediate area around the pit.

Dredging and dumping sand excavated from the seabed could also have a number of direct and indirect, short and long term effects on marine and coastal benthic communities of plants and animals (ecology).

With this in mind, the SandPit project is being used to help assess recovery timescales for ecosystems around dredging activities, and will help gauge the critical depth at which sand mining has no measurable effect on the shoreline.

To do this, the participants in the Sandpit project will dredge a full-size pit in the North Sea, closely monitor it to determine events in the immediate vicinity once the sand is extracted, see how the ecosystem recovers, and measure any changes to the adjacent coastline. These measurements will be compared to the predictions currently available, and existing computer models will be improved as necessary.

Current government guidelines regarding the volume and siting of dredging activities varies from country to country and are often based on information extrapolated from small-scale models, and one of the main aims of SandPit is to help put together guidelines which have a stronger scientific base.