The urban redevelopment project was completed with Lexington- Fayette Urban County Government’s Water Quality Management Fee and the Stormwater Quality Projects Incentive Grant Program, which uses funds collected through the Water Quality Management Fee to help fund projects in the city. The system Lee designed separates floatable pollutants such as oils/ grease and trash with baffle treatment units, while removing dissolved constituents filtered in a bioretention basin that has a mulch/sand layer and vegetative uptake. To detain stormwater runoff and remove sus- pended pollutants (TSS) in the underground detention unit, Lee used a total of 240 linear feet of thermoplastic pipe from Advanced Drainage Systems, Inc. (ADS) (NYSE: WMS). The watertight 48-inch diameter ADS HP Storm pipe was installed in two parallel runs and can hold 22,500 gallons of runoff. To make connections and to convey water from the roof, 12- and 15-inch ADS N-12® high-density polyethylene (HDPE) pipe was used along with six- and four-inch ADS N-12 dual wall perforated pipe as an underdrain for the bioretention basin and other areas. Two ADS Nyloplast® EnviroHoodsTM were attached to the inside of two of the Nyloplast structures to prevent the outflow of floating debris and oil. Three other InsertaTees were installed as underground inspection ports. The crew also used 1,000 yards of geotextile fabric along the side walls of the excavation to keep fines from migrating into the #57 stone backfill. The HP Storm high-performance polypropylene (PP) pipe for gravity- flow storm drainage applications provides stiffness and premium joint performance. The ADS design couples advanced polypropylene resin technology with a proven, dual-wall profile design for superior perfor- mance and durability. The pipe is corrosion resistant and is unaffected by salts, chemicals and hot soils. Burial cover can range from one foot to 39 feet. The pipe meets or exceeds ASTM F2881 and AASHTO M330. “ADS has a good name in underground detention in our area,” Lee stated. The Columbus-based firm has a manufacturing plant in Livermore, Kentucky and a distribution center in Lexington, plus other plants and yards in the region. In total, ADS has 63 plants and 32 distribution centers worldwide. Working alongside of Lee was Eric Dawalt, P.E., president of Ridgewa- ter, LLC, a Winchester, Kentucky-based design/build firm. “We were involved in the design and managed the construction of the project for Stantec, the engineer of record,” he explained. “ADS and EcoGro (Lexington, KY) were also part of the team. Together, we worked to find a solution to the site constraints. It was the depth. We had a really shallow depth that we had to put the system in and it had to be able to drain back into the existing storm sewer. That’s why we went with the 48-inch pipe rather than a bigger diameter pipe or tanks. We had only about six feet to work with and included the two feet of cover. The ADS pipe had to connect back into an existing storm sewer with posi- tive drainage. That’s why we made the pipes long and skinny rather than big and fat. We looked at fiberglass tanks and also field-welded corrugated metal pipe, which would be quite expensive because of the field installation cost, mainly because doing a weld inside a four-foot diameter pipe is quite laborious.
“The welded fittings were a critical component. ADS did these at its nearby Winchester, Kentucky plant. This is a big plus for the ADS system over others that bid on the project because we didn’t have to do any field welds inside,” Dawalt continued. “We just had to fit it together. If there was one reason other than the price and materials, it was the installation of putting the pipes together that was a whole lot easier than getting a field crew out and welding the pipes together in the field. That was a big solution that ADS was able to provide. Can’t say enough about how easy the HP storm was to install. “Everything below water level was a welded fitting. That was one of the things we went through with the design. There had to be only welded fittings below water level because of the tendency of the area to flood. “The system was not designed for a specific storm event. What we were trying to do was provide the required detention volume that had been proposed in the grant,” Dawalt explained. “One of the other things we were able to do, was, which wasn’t necessarily part of the grant and Chad paid for it, to put in the EnviroHood water quality units that have a baffle system to get out any trash, and it works great.,” Dawalt said. “In doing this old building,” Needham stated, “we wanted to make it a little more ecologically friendly and do a stormwater project here, and that was kind of cool. I think that also makes us unique as we're a developer, and definitely an urban developer. The stormwater system also makes financial sense especially since we got a really nice grant from the city when we presented the plan. I was not familiar with the pipe and so I was really excited when all that pipe got delivered on the truck. But that was a cool way to use that pipe, and I really hadn't known that before. We were excited that Sam and Eric brought that to the table. It was a cool idea and a cool plan. We're pleased with it. “It's always fun to talk about on a tour. People seem very interested in taking an old building and bringing in some new conservation tech - niques. This method is a good example of how it can done for an old building of this size and at what scale you have to do that. It can be done. Plus, it's a great tool for me to talk about to prospective tenants and a great neighborhood discussion. Also, it just brings a new layer of appreciation on top of an old building being redone. That I think speaks to definitely the general public and to new tenants.” The Greyline project will also serve as a stormwater educational center for local universities, engineers, contractors, surrounding municipali- ties and other local organizations including the Kentucky Stormwater Association, which will give tours of Greyline during its conferences and meetings. There is a permanent educational display to explain the stormwater system and its resulting benefits to visitors. Additional information can be found at the ADS website: www.adspipe.com .
September 2022 csengineermag.com
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