This chapter reviews the impacts of mobile and sessile invertebrate macrozoobenthos on hydraulic and sedimentary processes in aquatic environments, emphasising the factors that should be considered when carrying out hydraulic experiments. Here, macrozoobenthos includes animals that greater than 1 mm in length and, therefore, does not include micro-or meio-fauna and the important stabilising effects of their secretions (Wotton, 2011). It also does not include large communities of micro-and meio-fauna, such as corals and bryozoans. In addition, vertebrates including fish, are deliberately excluded from this review; relevant reviews of the interactions between fish, hydraulics and sediment dynamics can be found in Atkinson and Taylor (1991), Butler (1995), Hassan et al. (2008) and Rice et al. (2012), among others. Sessile animals are those that live attached to the solid-water interface whereas mobile animals move freely within or on sediments.