ENVIRONMENTAL DREDGING SERVICES
Environmental dredging projects require complex construction activities performed in a diverse array of environments, climatic conditions and geologic settings to address environmentally impacted water body systems. ENTACT brings more than 30 years of dredging expertise, plus our own specialty equipment, to every project.
Let Us Meet Your Challenge.
ENTACT has performed numerous projects involving excavation of sediment, soils replacement, channel configuration and stabilization, construction of predation barriers, habitat construction and restoration planting for both emergent freshwater wetlands and tidal marsh regimes.
Our crews are proficient in managing stormwater and tidal influences encountered in salt marshes and tidal mud flats where earthworks are exposed to the inundation of natural flows. We also have experience performing complex environmental dredging jobs where the removal and segregation of contaminated media must be restricted from migration outside the work area.
Environmental Dredging Services
- Mechanical Dredging
- Wetlands Remediation
- In-Situ Capping and Covers
- Liquids/Solids Separation, Dewatering & Water Treatment
- Isolation Barriers
- Subaqueous In-Situ Stabilization/Solidification (ISS)
- Habitat Restoration
- Shoreline & Bank Stabilization
ENTACT Teams Solve Problems, Even During Difficult Conditions
Although ENTACT encountered a 500-year storm event during construction activities, our crew was able to complete creek remediation at this RCRA Corrective Action Site on schedule and without an overtop event. ENTACT’s project team redesigned the original bypass pumping system for the final two phases of the project to use an overland diversion system, which included a temporary bridge that increased our truck access to the load-out area and allowed ENTACT to double capacity.
Environmental Dredging Challenges.
Size: Mechanical dredging of ~30,000 cubic yards
Canal Segment Contaminated Sediment Remediation
ENTACT performed remediation of mercury- and lead-contaminated sediments from an approximate 3,600-linear-foot segment of a closed canal. Scope of work included protection of surrounding structures and existing pavement; asbestos abatement and demolition of a building and shed; construction of a temporary remediation support area with two dredge processing cells and a temporary water pretreatment system area, multiple staging areas along the canal, and a temporary water management system; cleanout of an existing culvert; mechanical dredging of ~30,000 cubic yards of sediment from a floating barge assembly; dewatering and conditioning of sediments; characterization, transportation and off-site disposal; placement of a subaqueous cap and cover system consisting of 14,000 cubic yards of granular backfill within the canal; placement of 26,800 cubic yards of granular fill and topsoil for construction of a multiuse path; extension of City storm sewers; and restoration of canal banks with coir fabric and seed.
Size: Excavation of 55,000 cubic yards of contaminated sediment
PCB-Impacted Sediment Removal
ENTACT performed Interim Remedial Measures (IRM) at this site to address polychlorinated biphenyl (PCB)-impacted aluminosilicate material (ASM) present in the uplands area, peninsula, inner wetlands and embayment connected to a tidally influenced creek. Major site activities included clearing; construction of a stone berm to isolate the embayment area and inner wetlands; installation and removal of 2,500 linear feet of steel sheet pile up to 40 feet deep; use of a dewatering system and construction water management system to remove water from within the sheet piled area and enable excavation of sediments in the dry; treatment and discharging impacted water to the embayment; excavation of 55,000 cubic yards of ASM material and PCB-contaminated sediments and 32,000 cubic yards of upland soils; conditioning/solidification, as needed, and off-site disposal of over 120,400 tons; and restoration of the embayment and uplands areas.
Size: Mechanical dredging of 1,300 cubic yards of impacted sediment
River Dredging Project
ENTACT performed dredging of petroleum-impacted sediments from this major river system resultant from a spill event. The scope included construction of temporary facilities, such as a stockpile management area, dewatering pad, laydown area, office facilities, etc.; construction of a temporary access haul road connecting the staging area to the United States Army Corps of Engineers (USACE) causeway and over the flood levee structure; capping an upstream outfall; dredging 1,300 cubic yards of impacted sediment from 0.5-3.8 feet deep from the river; dewatering of sediment, moisture conditioning with Portland cement as necessary, and off-site transportation and disposal of 2,500 tons; management and off-site transportation and disposal of construction water; backfilling the river bottom with 2,450 tons of stone; removal of temporary roads and the causeway; and site restoration, including regrading, revegetation and installation of erosion control blankets.
Size: Treatment of 115,000+ tons of soils and sediments
Southeast Multistate Sediment Removal Program
ENTACT remediated former phosphate fertilizer production and manufacturing sites throughout the Southeast to address lead- and arsenic-impacted soils, sediment and groundwater. Sites were located in commercial, residential and industrial zones; tidally influenced areas located adjacent to navigable waterways; marshes and uplands; and areas adjacent to active rail lines and major highways/rights-of-way. The majority of the projects involved treatment of hazardous materials, in which ENTACT successfully designed numerous bench-scale treatability studies at our in-house laboratory to cost-effectively render those soils nonhazardous.