CASE STUDY: STORMWATER COLLECTION POND
PROBLEM: A developer desired to construct a series of single family housing lots in an environmentally sensitive forested area; the developer would be constructing a series of streets and cul de sacs, but did not want the rain water run off to exceed the normal for that area and create flooding for the local streams. In addition, the developer wanted to protect the environment from contaminants that might be caused by the use of asphalt paved surfaces.
SOLUTION: Construct a storm water pond to collect the surge of excess rainwater off the road surfaces and install a plastic liner in the pond which will eliminate percolation in the area which will contain the liquid as well as control the flow to surrounding streams.
CONSTRUCTION DETAILS: A local general contractor put in the utilities, and storm water piping prior to constructing the finish road subgrade. Drain collection points were created and piping diverted this collected rain water to the storm water pond. The size of the pond was designed for a 50 year rain that could collect on the asphalt surface. The pond was next built and select soils were placed as the subgrade. Two 20,000 Square foot 30 Mil PVC panels were placed into the pond and a butt seam across the pond was hot air welded. PVC pipe boots were field fabricated and sealed the geomembrane to the pipes. A 12 inch soil cover was placed over the geomembrane and the surface was seeded with local grass to complete the project and create a natural looking decorative pond.
PROJECT: Stormwater Pond
LOCATION: Duvall, WA
LINER INSTALLER: Northwest Linings & Geotextile Products, Inc.
MATERIAL: 30 Mil PVC
AREA: 40,000 SF