|
Week of Jun. 4, 2007
Winter lessons are basis for summer construction
A culvert being replaced. | The recent spell of blue skies has erased most of the bad-weather memories from last winter, but not in the minds of staff from the King County Road Services Division’s maintenance staff. These engineers and crews don’t want to forget what they saw during the intense storms of November, December and January, because it’s going to help them make things better for the winters ahead.Starting this week, the division is gearing up to tackle more than 30 drainage and culvert-replacement projects before next winter. Many of the projects are designed to fix problems observed during the height of the last storm season. “We learn more about our infrastructure during the winter than we do the rest of the year,” said Maintenance Superintendent Tony Ledbetter. “That’s when we get to observe how our drainage system operates when it’s maxed out by floodwaters and the highest flows of storm runoff.” Under-the-road culverts are a key component of the drainage system in unincorporated King County. Without a way to carry small streams and runoff under the roadway, the roads would act as dams and cause much worse localized flooding. There are more than 17,000 culverts that cross underneath the county’s roads. The Road Services Division’s inventory of culverts ranges in age from 100-years-plus to barely one-month-old. The oldest still-existing culverts are made of wood and clay, while the newest are constructed of reinforced concrete. If the culvert isn’t in good shape, then the stability of the road above can be compromised. Roads can be undermined or even collapse if the culverts beneath them fail to do their job.
A modern culvert made of reinforced concrete. | Many of the county’s culverts are deteriorating or are undersized and will need attention in future years. When a culvert is too small, it forces water through the pipe at a higher velocity, which can cause washouts on the outflow end of the culvert. Similar problems can happen on the intake side of the culvert when it becomes clogged with debris. In steep areas and along slopes, the whole road can slide away if the situation is not fixed.“We have several goals on these drainage projects,” said Ledbetter. “Number one is to protect the road and provide a safe travel surface. But, we also want to protect the shoulders, hillsides and rockeries that support that road. We also want to reduce local flooding. The health of one relatively short pipe can have multiple impacts on the surrounding area.” Replacing the old narrow culverts with larger ones also creates better passage for fish and wildlife. Installing new culverts can be a big job. The largest are 16x10 feet and require a significant excavation at the installation site. They arrive in sections, which can weigh more than 20,000 pounds each. And, it requires a good-size crane and deep excavation to position them below the natural depth of the stream that will flow through them. That is why some county roads are closed for weeks at a time during a culvert replacement. Ledbetter says during storm season not only does his staff get to observe the problems, but they also monitor newer projects to see which are working best and how to improve future projects. That way, lessons learned from last winter – the good and the bad – can be put to use during this summer’s construction season.
South Park Bridge closed Saturday 
The South Park Bridge over the Duwamish River will be closed Saturday, June 9 from 7 a.m. to 7 p.m. During the closure, crews will be repairing the electrical cables that supply power to the draw span motors. While the bridge is closed, there will be no vehicle or pedestrian access on14th/16th Avenue South, but boat traffic on the river will be able to get through because one span will be raised. Motorists can detour via the First Avenue South Bridge.
There will be an afternoon Mariners baseball game on Wednesday, June 6 starting at 1:35 p.m. Fans leaving the game at Safeco Field could affect the late-afternoon commute and early evening traffic in downtown Seattle. Regular commuters may want to adjust their work schedules to leave town earlier that day, or avoid the area around the stadium. For those going to the game, Metro Transit offers lots of regular service that travels near Safeco Field in the mid-afternoon. After the game is over, avoid the congestion, by taking regular bus service home. There is no special shuttle service either before or after the day games. Detailed information for all Mariners service is available on the Metro Online website. Or, call (206) 553-3000 (voice) or (206) 684-1739 (TTY) |
|
Enjoy an unhurried four-hour tour of Seattle's unique trolley system sponsored by the Metro Employees Historic Vehicle Association (MEHVA) on Sunday, June 10. MEHVA members will be driving restored trackless trolley buses from Seattle's busy downtown to several fine old neighborhoods throughout the city. There will be stops for photos and lunch. The tour will depart at 11 a.m. from Second Avenue South and South Main Street, across from the Seattle Fire Department Headquarters. Fares are $5 for adults, $4 for seniors (65 and over), and $4 for children (2-11). Metro transfers, tickets, or passes are not accepted. Please, no food or beverages onboard the historic buses.
Those aren’t four-legged commuters at the Metro’s Tukwila Park-and-Ride today. It’s a herd of 250 goats hired to help the transit agency tackle some thorny weed-control issues. Metro contracted with a goat herder from Eastern Washington to assist with vegetation management at the Tukwila Park-and-Ride on Interurban Avenue and at Metro’s East Base in Bellevue. The goats should finish up mowing down the tall weeds on the hillsides in Tukwila today. Then, they will move to East Base, where they will spend three to four days chomping on blackberries and other weeds. At each location, a shepherd, dog, and a portable fence will control the herd. | Subscribe to DOT DashSign-up to receive an e-mail text version of "Transportation Today," along with other significant DOT news by sending an e-mail to us with subscribe King County DOT Dash in the subject line.
|
