Solving Shoreline Storm Water Storage

Feb. 26, 2013
Modular system reduces labor, weight and stone

Renovating a residential property may be commonplace; however, when the upgrades are to a property adjacent to an estuary, things get bit trickier.

The Bayou Texar estuary in Pensacola, Fla., is an ecologically sensitive area regulated by the Florida Department of Environmental Protection. The consulting engineer and contractor had a problem; with limited space, how would they keep storm water on site with the addition of a new pool and covered garage? Traditional stone retention systems, pipe and arched chambers could not be used. The solution turned out to be a lightweight, modular and stackable storm water detention system.

The pool and covered garage were considered impermeable surfaces, requiring the consulting engineer, James Baynes, Jr. of Land Consulting & Improvements, to come up with an innovative solution. The contractor had no way to haul large amounts of stone to the back of the house, where the storm water retention needed to take place. The house backs the Bayou Texar and the upgrades to the home made it impossible to get machinery around the back. Hauling stone by hand would have been too expensive and time consuming, and hauling stone by boat also would have been cost prohibitive. Corrugated plastic pipe and arched chamber systems likewise would  require a percentage of stone to help with storage capacity and structural support, so after this was determined, they were eliminated as solutions.

That is when contractor Brian Batte of Gulf Breeze Plumbing started shopping around.  Batte wanted a lightweight system that could be manually carried to the back of the house. Batte also needed a highly efficient system because the excavation for the system had to be done by hand. Batte, with the help of Baynes, located Rainstore3 storm water detention system, manufactured by Invisible Structures Inc. Rainstore3 weighs only 15 lb per unit, and each unit can store nearly 25 gal of water. Each unit can be stacked like Legos, and each stack can be set adjacent to one another for a modular system. Baynes and Batte had found one solution that met both Baynes’s need for efficiency and function, and Batte’s need for a low weight and convenient installation. 

Land Consulting & Improvements and Baynes went above the local regulations for storm water containment by designing drainage plans to account for the total storm water runoff, not just the new additions or upgrades. To protect the estuary from runoff, Baynes sized his foundation drains, strip drains and Rainstore3 detention chambers for all of the impermeable surface on site: the house, the new pool, the new garage and the paved areas. The sizing led to 495 units of Rainstore3. At 94% efficiency, 495 units will hold 1,643 cu ft of storm water. Baynes ended up with eight individual Rainstore3 chambers, varying from two stacks to 18 stacks, connected by drains and pipe, at different points on site. Each stack was 9 units high, 2.95 ft at 40 in. by 40 in. The individual chambers are configured adjacent to the house, spa, pool, terrace, fireplace, fountain, shoreline retaining wall and garage at different angles and sizes. 

“Easy and user-friendly,” is how Baynes describes his experience with Rainstore3.  “Overall, a positive [experience].”

As of the publication of this article, Rainstore3 has been shipped, is on site and is waiting for installation when the weather permits.