Lawmakers hear scientific, agency and conservation concerns over wastewater assimilation in coastal wetlands

The House Committee on Natural Resources and Environment on March 18 received technical testimony and stakeholder concerns about the state’s wastewater assimilation program and its effect on coastal wetlands, including cases at Hammond, Thibodaux and Mandeville.

Committee members heard researchers and conservation groups say some receiving wetlands are converting to open water and showing signs of nutrient oversaturation, while state agencies described gaps in monitoring and coordination.

The session focused on House Study Request No. 7 (2024 session), an informational review of wetland assimilation projects. Eugene Turner, identified in the hearing as a retired faculty member and researcher, described aerial and field observations from multiple sites and said the receiving wetlands are showing rapid change. "It has a very high ammonia content, for example, and that's toxic," Turner said, and he described cases where forested wetlands opened to permanent standing water within a few years of discharge. Turner testified that in his measurements of constructed and assimilation wetlands he has repeatedly observed reduced root and rhizome development…