Hitch in the Giddy Up
What do you mean there are no catch basins in the entire parking lot?!
This predicament at the Ford Louisville Assembly Plant (LAP) was more than troubling to a Luckett & Farley engineer. It was puzzling.
So then how does ---? You mean all the rain just ---? And so that’s why the pavement is so ---? Eeeek.
It was the reaction I always imagine the Spartans had upon seeing Xerxes’ vast army: “What have we got ourselves into?”
Since moving to its current location off Fern Valley Rd. in 1955, the Ford Motor Company has expanded to nearly 3.2 million square feet on 400 acres. It is now the home to the next generation of Ford Escapes, and has undergone a $600 million renovation to transform it into the “most flexible automotive assembly operation in the world. “Not only is it now one of the most high-tech facilities in all the land, but it may also have the largest installation of over-sized trench drains ever seen. (Note: not yet confirmed, but the jury is still out if you ask us!)
That is because aside from the facelift and complete retooling, there was the matter of rehabilitating, restriping, and reorganizing their parking lots – all 2,000,000 SF of them. Though a daunting task on its own, the mission elevated even further when it was evident that fixing the drainage (and therefore failing pavement) would be out of the budget’s reach. All of the lots needed resurfacing and they needed to last. A Civil Engineer’s dream (er, nightmare?) Conditions: A flat site, limited funding, a challenging solution, and a brand spanking new toy.
Enter PaveDrain pervious articulated mat paving, and the Louisville Metropolitan Sewer District’s (MSD) Green Infrastructure Incentives Program. Hmm – that didn’t quite roll off the tongue like I had hoped for, but alas, I’m an engineer.
The Spark Plug
Beginning in the summer of 2011, MSD began a pilot program to incentivize Louisville property owners to install Green Infrastructure applications that could handle the stormwater that falls on their site. (See: Rain Gardens, Pervious Pavement, Rainwater Harvesting, et al). Finding themselves in a no-fault Consent Decree settlement with the U.S. EPA, MSD saw an opportunity to fix the community’s Combined Sewer problem while also jump-starting economic development. The basis of the Program comes down to this: Businesses can either fix their flooding problems for little-to-no additional cost, or choose not to. The Ford Louisville Assembly Plant decided to do the former. Working with MSD staff, Luckett & Farley help Ford secure a nearly $1.3 million incentive stipend if the pavement restoration project included sufficient Green Infrastructure. That task wasn’t exactly simple though. The other side of the deal required Ford to store 533,000 gallons of rain in the parking lot on any given day – in a floodplain. Though the numbers and technical data all said it could be done, the school of construction thought still gave us all pause.
We are going to need an Olympic-size swimming pool out there!
Yep, that’s about right.
The Keys to Success
In the long history of Luckett & Farley’s existence (happily Over-the-Hill at 160years!), there have been countless designs for sustainable drainage improvements at an existing site. Pervious concrete/pavers, underground storage, and detention/retention systems have all been done before, but this was different. We needed something HUGE, shallow, and cost-effective. It needed to serve as a drainage feature, a pavement solution, is quick to install, and not require any special training or equipment. Those conditions were all met with a new-to-market product called PaveDrain, the permeable articulated block mat paving system. Think of a bunch of concrete Legos that are strung together in a rectangular fashion. There’s no grout/mortar/gravel chips, no curing time, no rolling, or extensive cutting. Along with a low-profile (2” Tall) drain tile, Luckett & Farley engineers designed 25 installations of shallow pits (think swimming pools!) filled with gravel as PaveDrain let stormwater flow through on top. The result is an underground storage system that allows the 1” Rainfall Event to never leave the Ford property. More than 855,000 SF of pavement is being collected by the PaveDrain installations. The water will eventually infiltrate into the soil, providing for additional capacity in the MSD sewer system and therefore reduce the possibility of a flooding event in the downstream communities. In addition, the employee parking area now drains effectively and will last far longer than standard asphalt pavement.
In a sense, the parking lot went from no catch basins to having more than 86,000 SF of them. Talk about a real “EcoBoost!”
Above: The finished product.