News

Ask Matt ... about Publix's plans for drainage

By Matt Matteson, Published: August 16, 2017

Q. Will the runoff from the Publix grocery store parking lot affect the flooding on Greenville Highway such as from the big July 8 storm?

I asked Hendersonville City Engineer Brendan Shanahan about the project. Shanahan rolled out the drawings for the 6.9 acre Publix property and pointed out two locations for detention devices — one along Greenville Highway and another behind the store near Mud Creek. Plans call for a high tech underground system of collection chambers that will occupy an area equivalent to about 25 parking spaces. Yes, right under the parking lot! You can see them on the ground now, looking like rows of bright yellow plastic dog houses.
Here’s how it works. Water runs off the asphalt surface and is collected in long plastic chambers buried 24 inches below the surface. These chambers are made of high strength half-pipe sections interconnected and set on a bed of gravel. The idea is to slow the stormwater entering Mud Creek and of course, Greenville Highway. Shanahan said that the Publix system is designed to detain 10,275 cubic feet of water or — for us non-engineers — the first 1.3 inches of rainfall. Eventually the impounded water seeps into the ground or is slowly discharged into Mud Creek flowing northward under the Steinmart-Fresh Market parking lot towards downtown Hendersonville.
Shanahan added that the system is designed to trap parking lot debris and suspended solids. In other words, to keep the trash and mud out of Mud Creek. Maintenance of the entire system falls on Publix. The city will do annual inspections. If you want to see a neat clip on how the system works, search for “StormTech pipe animation video.”
Whenever you disturb an acre of land, stormwater rules kick in. Above-ground retention ponds can usually be constructed at minimal cost but if the site is low-lying there are fewer options and stormwater detention gets expensive. The former Atha Plaza shops and adjacent buildings held back very little stormwater so what Publix is doing could improve conditions. It won’t take long to see what those little underground dog houses can do.

Q. How do you pronounce the name of the new brewery being built on Seventh Avenue?

Triskelion, according to brewery owner Jonathan Ayers, is pronounced tris-kell-ee-on with the emphasis on “Tris” as in Triscuit crackers. The word is of Greek origin meaning “three legs” but many historians consider it Celtic because the symbol was used in the late 19th century in Britain and Ireland. The triskelion symbol is captured on the current flag of Sicily which, of course, is a region of Italy. Need help saying words? Just go online and YouTube will pronounce it for you.

* * *

Send questions to askmattm@gmail.com.