Central Wetland Unit Wetland Assimilation Project
Previously (2004-2008), while employed by the Sewerage & Water Board of New Orleans (S&WB) Dr. Mack initiated and served as Project Manager for the regional initiative between S&WB and St. Bernard Parish Government to implement the Central Wetland Unit Wetland Assimilation System. Once fully implemented, it will be the largest wetland assimilation system in the world. Dr. John Day conceptualized the Central Wetland Unit Wetland Assimilation Project as well as led the ecological design and baseline ecological study of the project. Dr. Gary Shaffer has also assisted with these efforts.
This project not only enabled Dr. Mack to become an expert in wetland ecology and restoration, it also allowed her to begin to investigate carbon finance as a mechanism to fund wetland restoration. Dr. Mack now serves as the St. Bernard Parish Coastal Advisor and acts as the liaison between the parish government and regional, state and federal agencies on matters related to wetland restoration, levee construction, environmental hazard mitigation and other matters related to flood control.
The East Bank Sewage Treatment Plant (EBSTP) is located in the lower 9th Ward of New Orleans near Bayou Bienvenue. The EBSTP provides wastewater treatment for the entire east bank of Orleans Parish and treats biosolids for both the east and west banks of Orleans Parish. The treatment facility incurred approximately $70 million of damage as a result of the 17-foot storm surge created by Hurricane Katrina, while neighboring St. Bernard Parish suffered catastrophic damage to all seven wastewater treatment plants. In addition to restoring critical infrastructure, both agencies faced upcoming regulatory nutrient limits which would require new energy intensive tertiary treatment systems. The municipalities sought a solution that would integrate human society with the natural environment and provide a less expensive option to restore infrastructure while enhancing deteriorating coastal marshes as a self-sustaining complement to the structural protection of levees.
Hurricane Katrina presented the opportunity for the two parishes to partner to pursue wetland assimilation of secondarily treated wastewater effluent as an alternative to conventional tertiary treatment and hurricane protection. Currently, nutrient rich effluent from both parishes is discharged to the Mississippi River. Rerouting the effluent will significantly reduce energy requirements for pumping and conveyance as well as allow the nutrients to be used to replenish the wetlands, rather than increasing damage to the coastal environment. The resulting Central Wetland Unit Wetland Assimilation System will utilize natural wetlands to assimilate over 100 million gallons a day (MGD) of secondarily treated municipal effluent to restore approximately 30,000 acres of critical cypress wetlands located primarily in St. Bernard Parish that were destroyed by the Mississippi River Gulf Outlet (MRGO).
This type of wetland restoration promotes additional carbon sequestration by reversing wetland loss, enhancing burial, and by reestablishing cypress forests. The wetland assimilation project will integrate sustainability with mitigation measures by enhancing storm surge protection, utilizing natural energies, and sequestering large amounts of carbon. The enhanced wetlands will help protect Orleans and St. Bernard Parishes from future storm vulnerability, while the environmental improvement will enhance the local economy and culture that is dependent on productive wetlands. Importantly, the project establishes a multi-disciplinary, multi-stakeholder paradigm for infrastructure and wetland restoration, as an international model of recovery, sustainability, climate mitigation and adaptation.
S.K. Mack, J.W. Day, R.Lane, T.M. Potter. “Quantification of Potential Carbon Sequestration Rates in Louisiana Wetlands.” State of the Coast – Implementing a Sustainable Coast for Louisiana, Baton Rouge, Louisiana, June 2010. (link)
S.K. Mack, P.J. Fos, J.W. Day, A.J. Englande, R.S. Reimers, M. Lichtvelde. “Wetland Assimilation for Climate Change Adaptation: A Decision Analytic Approach.” WEFTEC 2010 Annual Technical Exhibition and Conference. New Orleans, LA. October, 2010. (link)
S.K. Mack, J.W. Day, A.J. Englande, and R.S. Reimers. “Wastewater Infrastructure, Wetlands, and the Recovery of Hurricane Katrina.” EWA, WEF, & JWA 3rd Joint Specialty Conference “Sustainable Water Management in Response to 21st Century Pressures, Munich, Germany. May 2008. (link)