AGENDA DATE: 7/1/2015
TITLE:
Title
Carrsbrook Drive Pipe Repair
BODY
SUBJECT/PROPOSAL/REQUEST: Resolution approving a cost-sharing agreement with VDOT to replace an underground pipe and supporting the temporary closure of Carrsbrook Drive (Route 854) during construction
ITEM TYPE: Consent Action Item
STAFF CONTACT(S): Foley, Letteri, Davis, Henry, and Harper
PRESENTER (S): N/A
LEGAL REVIEW: Yes
REVIEWED BY: Thomas C. Foley
BACKGROUND: The upper and lower lakes along Carrsbrook Drive are separated by a dam over which Carrsbrook Drive (State Route 854) runs. Drainage from the upper lake flows through two 42-inch pipes, which serve as the principal and emergency spillways for an approximate 206 acre drainage area. As staff informed the Board last July, these corrugated metal pipes have deteriorated and repairs are needed to restore the integrity of the dam.
At the Board’s direction last summer, staff scheduled and oversaw an emergency project to fill and stabilize a sinkhole on the Eastlack property at 210 Carrsbrook Drive. The Board further directed staff to explore longer-term solutions with the Virginia Department of Transportation (VDOT) and neighboring property owners, including the Eastlacks. It should be noted that the area of the project is outside of normal County responsibility.
After discussions with County staff, VDOT has agreed to procure replacement of the failing underground pipe, provided that the County shares equally in the cost of the initial replacement and assumes all future maintenance responsibility for the replacement pipe.
Replacement of the existing pipes would be accomplished by excavating and removing the two (2) existing 42-inch deteriorated pipes and installing a new 60-inch pipe, manhole and riprap outlet channel in its place.
Travel on Carrsbrook drive would be affected during replacement of the underground pipe. VDOT proposes temporarily closing Carrsbrook Drive for 3 to 4 weeks to allow open-cutting of the road and replacing the deteriorating pipes with a single pipe and new outfall structure.
VDOT would manage this cost-sharing project, with construction scheduled to begin as soon as possible upon the Board’s adoption of the attached Resolution (Attachment B). Construction is anticipated to take 3 to 4 weeks and is scheduled for completion before County schools reopen in the fall.
STRATEGIC PLAN: Prioritize, plan and invest in critical infrastructure that responds to past and future changes and improves the capacity to serve community needs.
DISCUSSION: The estimated construction cost for this project is approximately $250,000. Under a proposed 50/50 cost-sharing agreement, VDOT would contract for the construction of the new underground pipe and associated improvements. The County would pay VDOT one-half of the final estimated cost before construction would begin. Once construction was completed, one-half of any remaining balance would be returned to the County, or if actual construction expenses exceeded the original estimate, the County would reimburse VDOT for one-half of such expenses.
VDOT proposes to completely close the road during construction, and staff supports VDOT’s recommendation.
VDOT’s recommendation includes open-cutting the road, which would:
1) Shorten the duration of the construction when compared to other possible repair options (such as jack-and-bore);
2) Enhance worker safety because traffic would be prohibited from passing over the dam and through the construction zone;
3) Enhance trench safety because the excavation could be sloped instead of needing to use piling to retain slopes;
4) Allow the removal rather than the abandonment of existing pipes . Abandoning the pipes could cause potential seeping/piping issues in the future that could again compromise the dam;
5) Lessen the cost of construction when compared to jack-and-boring a new pipe under the road; and
6) Require the removal of trees on the downstream slope of the dam within 15 to 20-ft of the new pipe.
In addition to the road closure, a waterline would need to be taken out of service for approximately 8 hours before construction could begin since the waterline crosses the dam and is routed over the pipes.
The construction and closure is scheduled for completion while schools are on summer break to mitigate impacts to buses/school traffic. The closure has been coordinated with police, fire departments and school summer programs. VDOT has determined that the detour route(s) to be used will be Old Brook Road, Northfield Road, or Huntington Road, all of which connect to Rio Road (see Attachment A).
BUDGET IMPACT: The appropriated budget for this project is $167,236.00. The estimated construction cost is $250,000, of which $125,000 would be the County’s 50 percent share. In addition, the County would also pay for associated surveying, platting, and tree removal costs, all of which should fall within the project budget.
RECOMMENDATION:
Recommendation
Staff recommends that the Board adopt the attached Resolution (Attachment B) to:
1) approve a cost-sharing agreement with VDOT and authorize the County Executive to sign the agreement once it is approved as to form by the County Attorney; and
2) support the closure of Carrsbrook Drive (Route 854) for up to four weeks during the period of July 2015 through early August 2015
ATTACHMENTS:
A) Detour Exhibit
B) Resolution