GCL used in raw water storage reservoir to restore Walleye habitat - Case Study
- Fremont Raw Water Storage
- Fremont, Ohio
- BENTOMAT DN
- BENTOMAT 200R
Constructed in 1911, the Ballville Dam serves as the source of water for the city of Fremont, Ohio. It alsoblocks fish movement on the Sandusky River, preventing walleye access to an important spawning habitat. As a result, the City of Fremont teamed up with the Ohio Department of Natural Resources to construct a new water supply reservoir, allowing the Ballville Dam to be removed and walleye movement to be unobstructed.
The soil at the site was porous karst soil, which is not conducive to liquid containment.
Also, there was extreme hydraulic head due to the deep depths of the reservoir.
In lieu of trucking in clay for a compacted clay liner, the engineer chose to use a geosynthetic clay liner (GCL). Moreover, a composite liner system was selected due to the depths of the reservoir. This also assured that any leaks in the geomembrane would be backed up by the GCL. A 40 mil linear low-density polyethylene (LLDPE) textured liner over BENTOMAT DN was used on the slopes and a 40 mil LLDPE smooth liner over BENTOMAT 200R was used on the base to reduce cost. In addition to supplying the geosynthetic clay liner, CETCO provided engineering support to ensure that the project stayed on budget, while meeting performance expectations.
The use of a GCL reduced the number of truckloads of material that were required to line the surface area of the reservoir, providing an enormous transportation cost savings over trucking in clay. After the project is complete, the Ballville dam can be removed and is expected to restore the fish spawning habitat in the Sandusky River and bring tourism back to the area. In addition, the reservoir will provide a quality water supply.