During Remediation Activities - Northwestern Louisiana
Paper Presented at Haz-Mat Conference, Washington, D. C., January, 1995
Dennis Olheiser, Reef Industries, Inc., Houston, Texas
A municipal water supply reservoir had contained a localized area of impacted sediments along its shoreline. Remedial activity was scheduled for the site with a primary objective being the containment of the impacted sediments during the removal phase of the project. The remedial activities that were originally proposed consisted of mechanical excavation of the impacted sediments. Before remediation could commence, isolation and dewatering of the work area was required. Draining of the lake was not considered a viable option due to the potential effect on the surrounding municipality's water supply.
The isolation options available were construction of an earthen containment dike or use of water containment structures. Minimal disruption to the ecosystem was considered the priority to aid the work area in returning to a natural environment as quickly as possible. After a review of the remediation requirements and the comparison between the earth berms and AquaDams®, AquaDams® were selected as the preferred containment method.
AquaDams® consist of two water-filled membrane bags with a woven geotextile outer bag that, when filled, acted as a dam or dike. Four hundred and eleven meters (1,350 feet) of .91 meter (3 foot) high and 200 linear feet of 1.8 meter (6 foot) high AquaDams® were used to enclose the remediation area. Once the structures were installed, work was initiated to remove impacted material from the enclosed work cell.
The sediments were removed from the enclosed area, dewatered and prepared for disposal. During the remediation activity, heavy rains in the area affected the level of the lake. The AquaDams® prevented the lake water from reaching the excavation area and prevented the release of the impacted sediment into the water supply.
AquaDams® provided a cost-effective method for the isolation of the remediation area, eliminating the requirement for the construction and subsequent removal of earth dikes or dams. Since no backfill or earth was used to create dikes, no silt or additional sediment was introduced into the lake. The material was contained in the work area throughout heavy rains, and additional areas of the lake were not affected. AquaDams® were a viable option for the isolation of a contaminated zone during remediation activity.