For PotomacLocal.com
Stafford County, Va. –– Work on the foundation phase of the Rocky Pen Run Reservoir is behind schedule. But a visit to the project site on Monday showed progress on the earthen dam and reservoir originally slated for completion in May 2013.
Stafford Utilities Department Project Manager Bryon Counsell said construction delays have been encountered on the project.
The original contract called for completion of the current phase of the project on Mar. 5, 2011 with the reservoir becoming operational in May 2013.
The reservoir sits in the southern portion of the county, near Stafford Lakes Parkway. It is the largest public works project in the county since construction on Virginia’s portion of Interstate 95 began in 1957.
General Excavation, Inc.’s project delays have extended the completion date of the current phase. That has also extended the need for engineering management services of Schnabel Engineering.
The Stafford Board of Supervisors is expected to approve an additional $355,000 from the 2011 budget to cover the anticipated additional expenses for this phase of the project at the June 7 regular meeting.
However, county documents indicate that some of the delay cost has been covered by the current contractual agreement with Schnabel.
Additionally, the General Excavation, Inc. contract allows the county to assess liquidated damages for contractor-caused delays that may potentially offset a portion of the additional approved funding.
Counsell explained that although the science of geology has advanced, one never knows exactly what will be encountered under the surface.
This current phase of the project includes work to stabilize the bedrock base of the earthen dam.
The process requires holes to be bored on angles at 20-foot intervals in alternate directions. The holes are then filed with a mixture of concrete grout.
The pressurized application of this fill forces the material into any crevices within the bedrock.
A team stationed in an office along the ridgeline above the excavation monitors data fed back to computers from the work site.
Actual pressure readings during the fill process are compared to their established baselines.
The goal is to ensure that the grout movement is not displacing the rock beneath the surface.
Borings are also taken on a regular basis to ensure the grouting process is meeting the goal.
Additional smaller grids for grouted holes can be incorporated into the process as necessary, based on results during the process.
Since the County Supervisors visit to the site last fall many features of the project have progressed.
The Rocky Pen Run diversion pipe is in place and functioning. When the dam is completed the diversion will be plugged and the creek will be re-routed to a flow-by.
Woods have been cleared for electric poles and lines that will be installed to bring power to the completed project.
The final project includes a pump station to pull water from the reservoir and send it to a water treatment facility on the property at the rate of 15 million gallons per day.
The water will be piped to a new 160-foot tall, 1 million gallon storage tower that will be located near the area of the Hartwood Animal Hospital on Greenbank Road. It is expected to be completed in mid 2012.
“Construction on the new storage facility will begin this summer,” said Counsell. “It will replace the existing tower and will go onto service as soon as it is completed.”
Once the reservoir is completed it will pull 98 percent of the water from the Rappahannock River with a storage capacity of 5.5 billion gallons.
The reservoir will include a labyrinth spillway that is basically just an overflow with no controllable gates. The normal pool level will be at the height of the spillway at 226 feet.
When completed, the project will also serve as a 570-acre recreational lake.
The maximum depth of the reservoir will be 232 feet and according to Counsell would not pose a hazard during any normal flood event.
He also indicated that any catastrophic flood should not impact surrounding property but rather flow downstream into the Rappahannock.
“Very little property would be impacted as most of the land that borders the river is on higher ground,” said Counsell.
The county has applied for a Conditional Letter of Map Revision (CLOMAR) with FEMA to determine any necessary adjustments to the current flood plain.
Despite the recent delays, the reservoir is still expected to become operational in 2013.
Marty van Duyne is an award winning photographer and journalist.
