Sediment Management and Remediation

Sediment management and remediation projects require complex construction activities and a thorough understanding of regulatory requirements. ENTACT brings more than 30 years of sediment management expertise, plus our own specialty equipment, to every project.

Let Us Meet Your Challenge.

ENTACT has performed numerous projects involving excavation of sediments, 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 sediment remediation jobs where the removal and segregation of contaminated media must be restricted from migration outside the work area. 

Our projects have included construction of waterway bypass systems, coffer dam structures, and waterway re-construction in varying degrees of complexity to enable sediment removal activities to occur. These projects have been performed in a diverse array of environments, climatic conditions and geologic settings. Most of these projects have required either substantial wetlands protection measures, or mitigation for impacted wetland systems. 

ENTACT owns and operates specialty equipment in support of this type of work in saturated soils and flooded conditions. Long reach excavators working on crane mats, marsh buggies, drag lines, mud cat dredges and excavators operating on floating barges are all techniques that we have deployed. In addition to skilled operators and specialized equipment, ENTACT also has technical professional staff knowledgeable in the permitting, design and implementation of wetlands features compliant with state and federal water resources regulations.

Sediment Management
and Remediation Benefits:

Put Us to Work

Our sediment management and remediation services include:

Mechanical dredging

We have the specialized equipment and experienced employees to complete your mechanical dredging needs with precision and limited downtime. Our team of expert operators will use our owned equipment to remove and dispose of sediment from even the most complex water environments.

Sediment dewatering, solidification and stabilization

ENTACT removes groundwater or surface water from a site prior to excavation work to help lower water tables and limit on-site water collection. Dewatering helps to create safer worksites and reduce potential construction challenges.

Water treatment

Our experience includes water treatment, dewatering and water management. We design, install and operate both temporary and long-term water treatment systems as well as fixed well point extraction systems. We also offer portable point source dewatering systems.  

Bypass pumping and diversion systems

Our projects have included construction of waterway bypass systems, coffer dam structures and waterway reconstruction in varying degrees of complexity to allow for sediment removal. 

Stream bank and shoreline stabilization

ENTACT’s team is proficient in managing stormwater and tidal influences and realigning streams to return them to natural flows. Our work also includes reconfiguring channels of water and restoring stream banks and shorelines to increase their strength and stability.

Natural contour installation

TBD

Fine grading

TBD

Uplands and wetlands planting, seeding and sodding

Conserving uplands and wetlands includes planting, seeding and sodding remediated areas. Increasing vegetation in these environments provides food and habitat for local organisms, helps improve water quality and helps to control erosion. 

Channel configuration and stabilization

TBD

Construction of predation barriers

TBD

Habitat construction

Most of our sediment-related projects have required either substantial wetlands protection measures or mitigation for impacted wetland environments. Your project will include at least one ENTACT associate with expertise in the permitting, design and implementation of wetlands features in compliance with regulations. 

Subaqueous capping

Capping is a nonremoval remediation method that isolates waste or contamination in its original location by topping it with a layer of soil or other materials. This layer prevents spread of the impacted materials and is often more cost efficient. 

Sediment Management
and Remediation Challenges.
ENTACT Solutions.

PCB-Impacted Sediment Removal

Location

Northeast

Method

Interim Remedial Measures

Size

55,000 cubic yards of aluminosilicate material (ASM) and polychlorinated biphenyl (PCB)-contaminated sediments; 32,000 cubic yards of upland soils

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.

Active Steel Mill Creek and Ditch PCB Sediment Removal and Restoration

Location

Midwest

Method

Phased removal of polychlorinated biphenyl (PCB)-impacted sediments

Size

3,000 linear feet of ditch line; 5,600 linear feet of creek channel

ENTACT completed multiyear, phased removal of polychlorinated biphenyl (PCB)-impacted sediments located within a flash flood tributary basin of a river. General site activities included site preparation; installation of 50,000 gallons per minute (GPM) and 9,000 GPM bypass pumping systems to reroute water flow around the work areas; directional boring of a new sewer discharge line under the ditch and existing rail line to the existing publicly owned treatment works (POTW) sewer system; treatment and discharging of water to Dick’s Creek or the Mill’s Water Treatment Plant; segregation, stockpiling and management of PCB-impacted flood plain soils and sediment, including those containing free product, prior to load-out and off-site disposal; removal and segregation of PCB-impacted sediment, clay and other native material from an outfall channel; installation of a 550 linear feet cutoff wall using fiber reinforced plastic sheet (FRP) with cement bentonite grout injection; vacuum excavation of multiple fiber optic utilities along an active rail line; and site restoration activities. 

 

A total of 3,000 linear feet (LF) of ditch line and 5,600 LF of creek channel were remediated,178,500 tons were transported off-site for disposal, and 4 billion gallons of water were treated. Management and protection of work spaces in anticipation of flash flood events were critical to the success of the project.

Portage Canal Segment 2 Contaminated Sediment Remediation

Location

Midwest

Method

Remediation of mercury- and lead-contaminated sediments

Size

3,600 linear feet of a closed canal

ENTACT has been engaged to perform remediation of mercury- and lead-contaminated sediments from an approximate 3,600 linear foot segment of a closed canal that flows northeast from the Wisconsin River to the Upper Fox River. The site is situated between a mixture of residential houses and property parcels, two commercial businesses, a county parking lot and a Wisconsin Department of Natural Resources (WDNR) land parcel. 

 

The scope of work includes 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 29,400 cubic yards of sediment from a floating barge assembly; dewatering and conditioning of sediments (as necessary); characterization, transportation and off-site disposal of 44,100 tons; 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; restoration of canal banks with coir fabric and seed; and general site restoration.