Tributary 7 of Potash Brook flows through the Butler Farms and Oak Creek Village (OCV) neighborhoods. The brook passes beneath City streets via culverts in four locations before flowing into the Wheeler Nature Park located to the north of the neighborhood. The OCV Culvert Replacement project involves replacing the two existing culverts on Moss Glen Lane in the OCV neighborhood.
When the culverts under Moss Glen Lane were originally designed, permitted and constructed they met the current requirements for culvert sizing. However, over time these standards have evolved and these culverts are now considered undersized relative to the standards in use today. Under current standards, new culverts must have sufficient capacity to pass stream flow during a 25-year storm event (4.0 inches of rain in a 24 hour period). In order to meet this standard, these culverts would need to be able to accommodate flows up to 204 cubic feet per second (cfs). Through hydrologic modeling, it was determined that the current culverts in OCV only have sufficient capacity to pass 138 cfs of water.
This project proposes to replace the existing corrugated metal pipe culverts in both locations under Moss Glenn Lane with precast concrete box culverts that is 3.5 feet tall by 16 feet wide. The new culverts will provide sufficient capacity (~224 cfs) to allow the stream to pass under the road without overtopping during the 25-year storm event. This project will result in improvements to stream health and reduce flooding in the neighborhood during large storm events. It will also improve the ability of aquatic organisms to move in the stream.
Best Management Practices
Replacement of undersized and aging drainage infrastructure with new appropriately sized drainage infrastructure.
The City is now accepting bids from pre-qualified contractors until 2:00 pm, on Thursday, May 4, 2017 at the South Burlington Public Works Office located at 104 Landfill Road. We anticipate construction will begin in the spring/summer of 2017. Culverts located in the Butler Farms neighborhood that allow the brook to flow under Butler Drive are also being designed. However, a replacement schedule for these culverts has yet to be determined.
This project has received $300,000 in funding support from the Transportation Alternatives Grant Program administered by VTrans. The remaining project costs will be paid using stormwater utility capital project funding.
Page last updated: 4/17/2017