Calhoun Port Authority Wetland Mitigation Project
The Calhoun Port Authority was required to self-perform USACE required mitigation to offset impacts resulting from dredging related to construction of a new marine terminal. Based on the results of a site selection process, a 14-acre area along the shore of Lavaca Bay (the Bean Tract) was selected as the mitigation site. The designs include a 3-acre levee, 1 acre of channels to provide tidal inundation and circulation, 8.7 acres of low marsh and 1.7 acres of high marsh. The site was constructed by beneficially reusing recently placed dredge material from an upland disposal site. Material was hauled by trucks to the mitigation site and used to construct a protective levee around the exterior and as fill to increase elevations within the levee. Construction of the site was completed in January 2024 with the removal of the access roads and breaching of the dikes to allow tides to enter the site. The site will be allowed to settle/consolidate for a minimum of 60 days, as required by the permit conditions, and then be planted with locally field harvested plants. The initial planting will occur in late spring / early summer. After 60 days, an inspection will be completed to determine if plant survival meets the permit requirements. Any replanting required will occur in the fall and be coordinated with a community education event led by the Port. The event will showcase the Port’s operations in the Bay, discuss the job opportunities related to Port operations, and provide a hands-on opportunity to assist in helping with the wetland plantings. After the replanting, a long-term monitoring program will be initiated to document the establishment of the vegetation.
PHASES OF THE PROJECT
Phase
Title
Summary
Status
1
Design and permitting
Engineering and ecological designs based on biological benchmarks from nearby wetlands
Complete
2
Construction
Movement of previously placed dredged material from the disposal site to the mitigation site in Lavaca Bay. Work included building temporary access roads, a protective berm, and the high and low marshes
Complete
3
Soil Subsidence
A 60-day timeframe to allow the placed material to consolidate and reach final elevations
Complete
4
Initial planting
Planting of high marsh and low marsh species on 3 ft centers to establish initial vegetation cover
October 2024
5
Initial monitoring
Monitoring to determine initial plant survival and if additional planting is needed to meet permit requirement
December 2024
6
Additional planting (as needed)
Additional planting in the fall if needed to replace plants that did not survive
March/April 2025
7
Long term monitoring
Annual monitoring for 5 years to determine if there is sufficient vegetative cover in the high and low marsh areas to meet permit conditions
2025 – 2029