Direct Contact and Surface Water Protection – Former Industrial Site
PROJECT SUMMARY
Hamp, Mathews & Associates, Inc. (HMA) was engaged in an environmental assessment of a former industrial site. HMA assessed the distribution of lead (Pb) via XRF analyses and asbestos containing material (ACM) over a seven-acre unregistered landfill (dump) area. The site is directly adjacent to a major river with landfill debris and ACM visible in the riverbank, and with lead impacts broadly dispersed over the landfill surficial materials from the subsequent industrial activity at the site. HMA designed a long-term landfill cover and riverbank protection solution that eliminated multiple Part 201 exposure scenarios
HMA delineated via XRF (X-Ray Fluorescence) the landfill area within the floodplain of a major river in Michigan that contained surficial lead concentrations above the Michigan Part 201 Nonresidential Direct Contact Criteria (DCC) of 900 parts per million (ppm). A major constituent of the landfill material was ACM in the form of clutch plates that were disposed of in the landfill prior to industrial use of the site. The landfill had essentially filled in a 4.5-acre area of the 100-year floodplain with both municipal and industrial debris. This material extended from the surface to seven feet below ground in some places and was visible in erosional areas of the riverbank.
Located within the landfill area was a 0.61-acre wetland containing soils impacted with non-aqueous phase liquid and petroleum impacted soils. A Joint Permit was obtained to perform the remediation work within the 100-year flood plain at both this wetland and along the riverbank.
This wetland area was excavated as a petroleum source area that could possibly impact shallow groundwater and the nearby groundwater/surface water interface (GSI) zone. Standing surface water in the wetland area was removed via pumping and treated using a mobile granular activated carbon unit. An off-set wetland was designed and constructed within the same river watershed to satisfy regulatory replacement requirements. Monitoring of the replacement wetland for growth per the Joint Permit requirements was conducted.
Steel sheeting and a turbidity curtain was installed in the river along the toe of the riverbank. The riverbank was re-shaped to engineered design slopes and 500 feet of ArmorFlex® Articulated Concrete Block was installed atop geotextile to protect the riverbank from erosion, thus eliminating the exposure of impacted materials. The depositional shoreline (600 feet) of the river bend was protected with the ArmorMax® Reinforced Vegetation System. Over 18,000 yd3 of topsoil was placed over the landfill area to create a one-foot protective cover over and eliminate the exposure to the surficial lead impacts. Milkweed has established itself over much of the cover, which is now being protected as a monarch butterfly habitat.
PROJECT HIGHLIGHTS
- Remediation and Replacement of Impacted Wetland
- Direct Contact Protection from Lead and Asbestos
- Surface Water Protection from Impacted Soil
- Creation of 5+ Acres of Monarch Butterfly Habitat.
