Flooding fixes raise spending decision for city
Posted on Friday, May 2, 2008
URL: http://www.nwanews.com/nwat/News/64722/
Estimates to fix stormwater drainage problems in the area hit hardest by 2004 flooding — when water ran bumper-high down some Fayetteville streets — range up to almost $ 1. 5 million.
McClelland Engineering, which was commissioned to study ways to limit flooding in part of the Scull Creek watershed, offered a range of alternative solutions each with a range of costs.
Doing the least of the work identified in the study would cost the city about $ 134, 000, while making all of the suggested changes could cost about $ 1. 5 million.
“ I guess you could say they left it up to us to choose, ” said Sarah Wrede, Fayetteville staff engineer and flood plain administrator.
City Engineer Ron Petrie said the city is waiting for a final report. He said he expects to be prepared to make recommendations and “ restart the discussion on how do we get this work done and paid for” probably in June.
Following heavy rains in 2004, the city’s Street Committee commissioned a study of storm-water drainage in an area roughly east of College Avenue to Mission Boulevard and from Lafayette Street to Cleburn Street.
“ We had damage throughout the city, but in that area we had several basements that got flooded, ” Petrie recalled. “ We had water running down the street at incredible heights. Debris piled up to the height of car bumpers. ”
He said there are two main problems: an area with few or no culverts and water running down the streets with nowhere to go except into yards and basements, and an area with an old, too small culvert with no good maintenance access.
“ The system is extremely old, built probably around the 1920 s, ’ 30 s and ’ 40 s, ” Petrie said. “ There’s very little drainage infrastructure and, of course, high density. It’s been a long-standing problem.
“ Through a great deal of that (drainage area ) there is an old native stone box culvert that’s been filled in over the years. There’s houses built on top of it. There’s no drainage easements at all, so a culvert system. There’s no openings except at the ends. ”
He should know. He spent about an hour crawling through about a quartermile of it.
“ There’s some places where it’s choked down to just a 30-inch pipe, ” he said. “ There’s some places where it’s 10 feet wide and about 2 feet high, and there’s some places where it’s about 4-by-4 native stone box. It really varies. ”
Petrie said the culvert, which seems to follow original streams, has a lot of rubble in it. He said it is definitely undersized and lacks maintenance access except through the large grates at the ends.
“ There were problems many years ago, ” he said. “ It was stopped up midway down, and they just had to dig up half the world to find it and repair it. ”
The upper grate tends to get plugged, too, and that also causes flooding problems.
The study identified four areas for improvements: Rebecca Street and Olive Avenue; Johnson Street and Walnut Avenue; Willow and College avenues; and a southern system around Olive Avenue and Lafayette Street.
McClelland Engineering suggested a variety of solutions to the problems in each of the four areas depending on if the city wants to convey the water from 10-, 25- or 50-year storms.
Solutions range from clearing brush and debris from open channels, to removing 24-inch clay pipes in one area and installing 800 feet of 42- to 54-inch pipes in another.
In some areas, the culvert would be made larger; in others it would be replaced.
Generally, Wrede said, the differences in solutions are the differences in how big the pipes should be.
The idea is to answer the question, “ How do you convey a certain amount of water from Point A to Point B without damaging people’s property ? ” Petrie said.
If nothing is done, nothing changes.
“ It will continue the way it’s been for really the last 80 years, ” Petrie said. “ Once every five to 10 years, these houses will flood, at least in their basements. ”