Water Releases From Dams Improve Ecological Health and Societal Benefits in Downstream Estuaries

Abstract

This review study investigated the response of low-inflow estuaries (LIEs) to dam releases as this type of estuary is particularly sensitive to freshwater inflow modification. LIEs occur in arid and semi-arid regions and are subject to periods of little to no freshwater inflow. Case studies were used to identify ecological health and societal benefits associated with flow releases. Successful releases have been made to keep the estuary mouth open, ensure mixing, facilitate a salinity gradient and provide recruitment pulses to the marine environment for fish and invertebrates. Baseflow inputs ensured ecosystem connectivity and maintained estuary water quality gradients. Flow pulse releases in certain seasons stimulated spawning migrations of fish between freshwater and estuarine habitats. Holistic and adaptive restoration approaches were successful in terms of providing ecosystem services and societal benefits such as improved fisheries and livelihoods. Ongoing engagement, inclusion of communities, support from river users, and cooperation between multiple agencies were also important. However, this management solution for LIEs is threatened by increasing abstraction of water, competing water uses, over allocation, and frequent droughts. Moving forward, freshwater releases from dams should be considered an important restoration action that can improve ecological health, estuary function, ecosystem services, and societal benefits. This should take place within a socio-ecological system framework using an adaptive management and monitoring approach. Other key considerations for planning and implementation of future dam releases to LIEs were recommended.

Dam removal blind spots: debating the importance of community engagement in dam decommissioning projects

“…However, the social effects of the removal of dams can also be positive (Adams et al, 2023). For instance, in a study by Leisher et al (2022), it was reported that the removal of two dams in the state of Maine, USA, resulted in changes in the recreational activities and opinions of the local population regarding the river.…”

“…A few important studies on dam decommissioning mention the importance of community engagement (see for example, Born et al, 1998;Tonitto and Riha, 2016;Arthington et al, 2023;Jumani et al, 2023) and its potential contribution to successful dam removals (Jadallah et al, 2019;Adams et al, 2023). However, in some studies, there is no full problematization of "community"; in terms of what it entails, its main tenets and limits, within the dam removal contexts.…”