GLSR Approaching End of Grand Calumet River Remediation Project
The eight-inch dredge Grand Calumet works in a phragmites-infested wetland.
Great Lakes Sediment Remediation, LLC (GLSR) has nearly completed a contract to restore the East Branch of the Grand Calumet River in Northwest Indiana under a Great Lakes Legacy Reauthorization Act contract, awarded by the U.S. Environmental Protection Agency Great Lakes National Program Office (GLNPO).
GLSR is a small business joint venture between J.F. Brennan Company Inc., Natural Resource Technology Inc. (NRT), and Environmental Restoration, LLC (ER). It was formed to provide GLNPO with a team that demonstrates the full range of understanding, expertise, experience and capabilities to construct the sediment remediation projects of the Great Lakes Legacy Act (2002) and Great Lakes Legacy Reauthorization Act (Legacy Act).
This aerial view of the 21-acre east half of Seidner Marsh shows the progress in May of this year.
The East Branch of the Grand Calumet River is a Great Lakes Area of Concern (AOC), a designation created by the U.S. Environmental Protection Agency to describe a location that has experienced environmental degradation. The 1.7-mile-long river channel is 100 feet wide and was contaminated with pesticides, PAHs, VOCs, SVOCs and PCBs (polycyclic aromatic hydrocarbons, volatile organic compounds, semivolatile organic compounds, polychlorinated bi-phenyls) and heavy metals, including mercury, cadmium, chromium and lead. These pollutants originated from both point and non-point sources. Legacy pollutants in the sediments at the bottom of the river created the largest problem. Non-point sources include industrial waste site runoff, CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act of 1980) sites (five of which are on Superfund’s National Priority List), RCRA (Resource Conservation and Recovery Act) hazardous waste sites, underground storage tanks, atmospheric deposition, urban runoff and contaminated groundwater. Point sources are industrial and municipal wastewater discharges and combined sewer overflows.
Workers place sand in East Seidner Marsh using Brennan’s amphibious earth-moving equipment.
J.F. Brennan dredged and capped 1.7 miles of river channel and six adjacent wetlands, including creating a sediment basin at the east end of the project. The company is also excavating and remediating the 18.8-acre West Seidner Marsh and 20.6-acre East Seidner Marsh from September 2014 to July 2015. Brennan removed an abandoned railroad bridge and gas pipeline along with other large debris in the river.
NRT performs turbidity monitoring, effluent water testing, and quality control and material testing to ensure that the capping materials conform to specifications. Prior to the project, NRT prepared quality control documents and project plans.
Brennan began dredging on August 2, 2013, finishing the channel and five of the six wetland areas on October 28, and completed the sixth wetland from October 29 to December 19.
All contaminated material was pumped into geotextile tubes during dredging in 2013, and allowed to dewater over the winter. Beginning in May of this year, partner company Environmental Restoration began hauling the dry material to a landfill.
The company’s two eight-inch swinging ladder dredges operated 24 hours a day, five days a week, pumping into geotextile tubes on a seven-acre dewatering pad on the north side of the river. The greatest pumping distance was about 1.4 miles, and a booster was used for much of the project. The dredges are designed with articulated ladders that accommodate the undulating design surface and shallow draft requirements common to environmental projects. Each dredge is outfitted with RTK GPS, customized dredging software and HYPACK to minimize overdredging. The dredges were designed by Brennan engineers in cooperation with DSC Dredges, and built by DSC.
Brennan began placing sand in the wetlands this summer on June 11, and expects to finish by September 10.
The dewatering pad was built on top of an abandoned brownfield site adjacent to the river and operated by partner Infrastructure Alternatives. The temporary water treatment facility treated and discharged decant water collected from the geotextile tubes, providing 4,000 gallons per minute of treatment capacity. The effluent was used for polymer makedown water and GAC (granular activated carbon) backwash. The material was allowed to dewater in the tubes over the winter, and beginning in May of this year, teammate Environmental Restoration began hauling it to a landfill.
Infrastructure Alternatives designed and managed the dewatering facility. Polymers were added to the dredged slurry in the geotextile tubes, seen in the top of the photo, to enhance dewatering, and the effluent was treated and returned to the river.
Beginning January 20 of this year, Brennan excavated 102,000 cubic yards of material from the east half of Seidner Marsh, using special amphibious equipment, and saving more than a million dollars by eliminating the need to build temporary roads needed for traditional equipment. Excavation was complete on April 23, and Brennan placed sand in the marsh from April 17 to June 20.
The amphibious equipment provides a much safer work environment compared to traditional equipment, because it can float, which prevents it from being “swallowed up” in the extremely soft portions of the marsh.
The Capping Operation
Beginning in September 2014, Brennan crews will begin placing the cap in the river channel, one of the most highly technical processes in the project.
It includes the installation of both an inert and a reactive sediment cap. These multilayer caps are being installed with Brennan’s patented Broadcast Spreader (BCS).
Overview of the project shows the elements of the project, a full-fledged environmental remediation of a historically contaminated area in the northwest corner of Indiana.
AquaBlok Ltd. was the chosen adsorptive material supplier. Along with GLSR, AquaBlok performed extensive pre-project planning with respect to properly mixing and spreading the adsorption medium AquaGate, which creates a water-permeable layer that can capture oils and non-aqueous phase liquid (NAPL) organic contaminations.
AquaGate is created by adhering CETCO’s Organoclay® to an aggregate particle. It has settling properties much like fine gravel, settling to the bottom without remaining in suspension, and so will not be transported out of the intended placement area.
Mixing and subsequent placement of the reactive cap layer requires the use of the BCS system to place the reactive cap as accurately as possible. This is important to the project, because the amendments in the multilayer cap are extremely expensive and any over-placement of material creates a significant cost impact.
Brennan used tracked, amphibious equipment to excavate East Seidner Marsh. Because the equipment could operate in the soft material, no access roads were built, which saved about a million dollars.
The BCS overcomes these challenges by quality control checks performed throughout the system. These controls include positioning of the placement barges and the metering of the material. The BCS distribution barge is outfitted with real-time kinematic (RTK) GPS for precise control and cap placement. The onboard computer uses DREDGEPACK® and customized GLSR software as the operator interface. DredgePack displays and tracks the barge’s position, while the customized software tracks and records the amount of material spread.
Monitoring and quality control of the material delivery process begins at the land-based BCS capping material plant. The tons of material delivered each week by the aggregate suppliers are monitored, and in combination with RTK, stockpile surveys, completed at the end of each week’s operations, are used to estimate the amount of material placed. The capping material volume is metered at the land-based plant by a variable-speed belt with an adjustable opening that transfers the sand into the slurry hopper. The land-based conveyor is also equipped with a belt scale that records the total tons delivered to the slurry hopper each day. These values are compared to the daily results from the belt scale on the BCS barge.
The restored contractor Area 1 and Wetland A. This work was completed in May 2014. All wetland and marshland areas will be seeded, matted and re-planted using native plugs.
The marine-based BCS placement of capping material also measures and controls the material delivery to ensure accurate cap construction. The primary volume measurement is calculated with the belt scale, which is an integral part of the BCS equipment. The belt scale tells the exact amount of capping material delivered to the broadcast spinners, and the information is tracked and recorded for each movement of the barge. The software calculates the material being placed versus the required amount so that before each movement of the BCS, the precise amount of material has been placed. All of these volumes are tabulated and monitored against the placement area and summarized in the daily and weekly reports.
Capping is scheduled to be complete by the end of December.
Partner company Cardno JFNew has been performing habitat restoration since May 2014, and is expected to complete the project in early July 2015. West Seidner Marsh will be excavated from January 12 to March 19, 2015, and sand will be placed from March 20 to May 7. Demobilization is scheduled for May 8 to July 16, 2015, ending the process and leaving a clean river and restored wetlands.Edit Module