A 1.2-hec man-made lake was initially constructed for an overall retirement community complex in northeast Naples, Florida, USA. Due to the presence of shallow weathered limerock overlain by sandy soils at the site, continual water loss occurred, thus jeopardizing lake use as an area for conservation. The lake geometry together with an island lined with rip-rap presented constraints during the selection process for an engineered liner.
Following an evaluation of yarious liner options, including compacted clays, GCLs, and geomembrane liners, a 40-mil thick geomembrane was selected to minimize water loss and to help contain water in the lake. Field monitoring during liner installation was provided by the geotechnical consultant. After an early delay in late-1991 due to an unusually severe rainy season, liner installation was completed in early 1992.
Construction considerations included proper diking, dewatering, excavation into shallow limerock, and anchoring of the geomembrane in a perimeter upslope trench. Localized unstable lake-bottom areas were stabilized by placement of gravel and a geotextile. Additionally, the geomembrane liner was overlain by a geotextile in the sideslope areas to provide stability during soil cover placement. Close coordination between the installer and the geotechnical consultant assured the quality of construction.
This engineered solution provided an effective method for the development of this water conservation facility. Additionally, the solution resulted in a substantial cost savings for the developer versus other evaluated solutions.
Menu