Adding saltwater to a river is sometimes considered beneficial, sometimes harmful.
If the saltwater is running off roadways, the environmental effects are usually considered harmful. If the saltwater is purposely introduced by tidal elevation as part of an effort to wash contaminants from the waterway, the same results are viewed as beneficial. Experts call the former "salinization" and the latter "restoration."
The Herring River Restoration Project's proponents claim that twice-daily saltwater inundation of the river's freshwater marsh will improve the waterway's ecosystem. Yet those who decry salinization consider the introduction of saltwater to be detrimental.
Consider the effects of salinization reported in a 25,000-word scientific review titled Emerging threats and persistent conservation challenges for freshwater biodiversity published in 2018. The review's 16 authors were faculty members at research universities in five countries, including Canada, the United States, Australia, Wales, and China.
"Effects are evidenced for amphibians, fishes, invertebrates, microbes, plants, turtles and waterbirds, with potential for ecosystem-level changes through bottom-up and top-down processes. … Moving forward, we advocate hybrid approaches that manage fresh waters as crucial ecosystems for human life support as well as essential hotspots of biodiversity and ecological function. Efforts to reverse global trends in freshwater degradation now depend on bridging an immense gap between the aspirations of conservation biologists and the accelerating rate of species endangerment."
No evidence exists that the scientists planning the Herring River salt-marsh restoration tried to find a way to control or remove contaminants degrading the river's water quality without destroying a stable freshwater ecosystem by salinizing it. (See Alternatives for further discussion.)Top of page