Dredging is the operation that consists of cleaning and deepening a body of water, by removing rocks and sediments. It is carried out to increase the depth of a navigable channel "Canal (artificial waterway)") or a river, in order to increase the water transport capacity, thereby avoiding flooding downstream. Likewise, the aim is to increase the draft "Draft (nautical)") of these areas, to facilitate maritime traffic through them without harm to ships, thus avoiding the risk of grounding.

Depending on the bottom material that requires dredging, different types of dredges are used. There are several types of dredges commonly used in this type of operation: mechanical, hydraulic and mixed (mechanical/hydraulic), and each of them has different types of mechanism and operation.

Dredging operations potentially have a significant environmental impact, which must be timely and appropriately evaluated in order to take into consideration possible mitigation measures.

Dredging can disturb and destroy marine and aquatic habitats, affecting the biodiversity of ecosystems. As the sediments of the seabed are resuspended, the turbidity of the water changes, reducing the access of sunlight, harming organisms that carry out photosynthesis, such as reef-forming corals that establish a symbiotic relationship with species of algae. Many species of filter-feeding animals are also affected when their filtration mechanisms become clogged by excess particulate matter.[1]​.

1. Erftemeijer, P. L., Riegl, B., Hoeksema, B. W., & Todd, P. A. (2012). Environmental impacts of dredging and other sediment disturbances on corals: a review. Marine pollution bulletin, 64(9), 1737-1765. https://doi.org/10.1016/j.marpolbul.2012.05.008.