Case Study: Prevention of Geomembrane Whaling
Problem: Preventing Geomembrane whaling due to ground water issues. These “whales” generally occur due to the production of methane thru decaying organics or other means and
the inability to vent the methane adequately. Round rock subgrade with a complete geocomposite layer can help mitigate these bubbles as well and provide proper drainage from seasonal ground water.
Solutions: Systems to mitigate these issues include and not limited to: An underdrain system beneath the liner, French type drains to divert groundwater around ponds, geocomposite venting system or full geocomposite layer under liner, a liner ballasting system above liner such as cover soils and rock with adequate cushion or ballast tubes built into floor and air vents. Please consult engineer for design that is project appropriate.
Construction Details: Utility Pond 10 embankments are constructed at a 3:1 slope. Full rolls of Geocomposite were selected due to seasonal ground water flow. For this size and irregular
shaped pond, full geocomposite layer was used over drain rock. A geomembrane liner was placed over the geocomposite. and a layer 16 oz non-woven geotextile was used over the geomembrane as a cushion for cover soil. Air vents were installed to improve movement of gas bubbles up slope.
Location: Driggs, Idaho
Engineer: Rendevous Engineering
Contractor: Tributary
Liner Installer: Northwest Linings & Geotextile Products Inc.
Materials: Materials utilized for this project includes: Megaplast 60 MILM GM13 2 Sided Textured, SKAPS Geocomposite TN 220 2-6 and Tencate 16 oz Geotextile.
Area: 132,628 SqFt