Due to their adaptability and ease of design, retention/detention ponds utilizing geosynthetics enjoy widespread acceptance. Examples can be can be found in all types of climates, soil conditions and project settings.
However, retention/detention ponds are not without their problems. Water is a drowning hazard and can be a habitat for mosquitoes to breed. Ponds can also superheat, increasing some nutrients resulting in excessive plant growth and decay. This causes a lack of oxygen and severe reductions in water quality, fish, and other animal populations. However, proper design, including gravel sub-drains, reduces or eliminates most of these issues.
- Widely Accepted
- Adaptable to Climate and Soil Conditions
- GRI Developed Design Charts
The main geosynthetic element in these ponds is a geomembrane. These are impermeable liners made of Polyvinyl Chloride (PVC) or Polyethylene (PE). Properly protecting the geomembrane from tearing or puncturing during construction is paramount. Additionally, the liner must be protected from punctures and tears caused by gravel or other deleterious materials above or below the liner.
Research indicates that a properly selected nonwoven, needle-punched geotextile cushion installed above and/or below the geomembrane can effectively protect it from construction and operational damage. A nonwoven placed under rip-rap can also aid in reducing erosion along the bank and scour in channels.
The use of cellular confinement is an option if space is limited. Including cellular confinement as part of the retention/detention pond system can help to reduce its overall size by accommodating steeper banks while also mitigating erosion.
US Fabrics cannot design or recommend products. However, The Geosynthetic Research Institute (GRI) has developed a method for choosing the correct geotextile and simplified, conservative design charts exist for quickly determining the correct geotextiles. These charts list typical applications and important factors for consideration such as load and subgrade soil conditions. There are also industry standards for geomembranes.
US Fabrics offers a complete line of PVC and PE geomembranes, cellular confinement and nonwoven geotextiles for your retention/detention pond project. Please click on the links below for additional information and data sheets