Funnel and Gate Systems
Muskegon, MI: Funnel/Gate Project
This project demonstrates the adaptation of standard slurry wall technology in an effective, practical, and constructable solution for the treatment of impacted groundwater. Funnel and Gate systems utilize low permeability wall segments (funnel) to channel groundwater flow through treatment zones (gates) where the groundwater is treated in-situ as it migrates off-site. In this case soil-bentonite slurry wall segments were used for the funnel, and a series of wells equipped with Oxygen delivery systems comprised the gate areas.
The site was the location of a former MichCon Foundry Facility. The property is bordered by Lake Muskegon (Lake Michigan) on two sides. A portion of the site was since developed and is now the location of a marina, restaurant, hotel, and conference center. A funnel and gate system was designed to channel groundwater flow through a series of treatment zones intended to reduce or eliminate contaminants as the groundwater migrated towards the lake. The funnel/gate consisted of 5 soil-bentonite slurry wall segments totaling 1,350 LF by up to 55-feet deep. The walls were interrupted in 4 locations by treatment zones or gate areas. Each gate contained 6 wells; these wells were equipped with ISOCR down well Oxygen delivery systems. The slurry wall segments were excavated using Geo-Con's custom made long-reach CAT 375 Boom and Stick. The slurry wall's minimum permeability of 1x10-7 cm/sec virtually eliminated any migration of water through the funnel wall.
This project presented many unique challenges due to its proximity to the before-mentioned businesses and facilities. Geo-Con effectively coordinated its activities with the management of the facilities to minimize the construction's impact on day-to-day operations.