Surface Elevation and Accretion Monitoring for the Maurepas Swamp Alternative-2 Mitigation Project
USGS will install and maintain up to six rod surface-elevation table (RSET) rods and paired accretion monitoring stations at the location of the Maurepas Swamp Alternative-2 Mitigation Project.
The Science Issue and Relevance: The Maurepas Swamp, one of the largest freshwater forested wetlands in Louisiana, has declined in health since its supply of freshwater, sediments, and nutrients from the Mississippi River was almost entirely cut off after construction of flood control levees. To reestablish the connection between the Mississippi River and the Maurepas Swamp, the Louisiana Coastal Protection and Restoration Authority (CPRA) has approved the Maurepas Swamp River Reintroduction Project. This diversion will reconnect river and swamp, providing the fresh nutrients, water, and sediment vital to the restoration of this degraded swamp ecosystem.
The Maurepas Swamp River Reintroduction Project has been approved as wetland mitigation for the nearby West Shore Lake Pontchartrain Hurricane Protection Project, which is being implemented by U.S. Corps of Engineers (USACE). The monitoring portion of this project is known as the Maurepas Swamp Alternative-2 Mitigation Project, the scope of which includes monitoring a variety of parameters prior to, and during, the diversion operation. To that end, CPRA has contracted with USGS to conduct surface elevation change and accretion monitoring in the diversion outfall area from 2023 - 2027.
Methodology for Addressing the Issue: USGS will install and maintain up to six rod surface-elevation table (RSET) rods and paired accretion monitoring stations. USGS will collect RSET and accretion monitoring data twice per year until the Maurepas Diversion begins operation, and thereafter annually when the diversion is not operating or in low water. USGS will use real-time kinematic (RTK) elevation measurements to establish long-term horizontal and vertical control marks at each RSET rod. The long-term monitoring conducted by USGS will allow project managers to assess surface elevation change and accretion in the primary and secondary impact areas of the project.
Site installation and data collection will be done in accordance with established Coastwide Reference Monitoring System (CRMS) methodology outlined in A Standard Operating Procedures Manual for the Coastwide Reference Monitoring System-Wetlands and the System-Wide Assessment and Monitoring Program: Methods for Site Establishment, Data Collection, and Quality Assurance/Quality Control (Folse et al. 2020). All approved data will be publicly available on the Coastal Information Management System (CIMS) database.
Future Steps: Surface elevation changes and accretion rates observed by USGS in association with the Maurepas Swamp River Reintroduction Project may enhance current understanding of how wetland mitigation efforts impact degraded freshwater systems, enabling advances in future mitigation design and implementation.
USGS will install and maintain up to six rod surface-elevation table (RSET) rods and paired accretion monitoring stations at the location of the Maurepas Swamp Alternative-2 Mitigation Project.
The Science Issue and Relevance: The Maurepas Swamp, one of the largest freshwater forested wetlands in Louisiana, has declined in health since its supply of freshwater, sediments, and nutrients from the Mississippi River was almost entirely cut off after construction of flood control levees. To reestablish the connection between the Mississippi River and the Maurepas Swamp, the Louisiana Coastal Protection and Restoration Authority (CPRA) has approved the Maurepas Swamp River Reintroduction Project. This diversion will reconnect river and swamp, providing the fresh nutrients, water, and sediment vital to the restoration of this degraded swamp ecosystem.
The Maurepas Swamp River Reintroduction Project has been approved as wetland mitigation for the nearby West Shore Lake Pontchartrain Hurricane Protection Project, which is being implemented by U.S. Corps of Engineers (USACE). The monitoring portion of this project is known as the Maurepas Swamp Alternative-2 Mitigation Project, the scope of which includes monitoring a variety of parameters prior to, and during, the diversion operation. To that end, CPRA has contracted with USGS to conduct surface elevation change and accretion monitoring in the diversion outfall area from 2023 - 2027.
Methodology for Addressing the Issue: USGS will install and maintain up to six rod surface-elevation table (RSET) rods and paired accretion monitoring stations. USGS will collect RSET and accretion monitoring data twice per year until the Maurepas Diversion begins operation, and thereafter annually when the diversion is not operating or in low water. USGS will use real-time kinematic (RTK) elevation measurements to establish long-term horizontal and vertical control marks at each RSET rod. The long-term monitoring conducted by USGS will allow project managers to assess surface elevation change and accretion in the primary and secondary impact areas of the project.
Site installation and data collection will be done in accordance with established Coastwide Reference Monitoring System (CRMS) methodology outlined in A Standard Operating Procedures Manual for the Coastwide Reference Monitoring System-Wetlands and the System-Wide Assessment and Monitoring Program: Methods for Site Establishment, Data Collection, and Quality Assurance/Quality Control (Folse et al. 2020). All approved data will be publicly available on the Coastal Information Management System (CIMS) database.
Future Steps: Surface elevation changes and accretion rates observed by USGS in association with the Maurepas Swamp River Reintroduction Project may enhance current understanding of how wetland mitigation efforts impact degraded freshwater systems, enabling advances in future mitigation design and implementation.