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03
JAN
0

Fairfax County, Va., is subject to the same stormwater problems encountered by municipalities across the nation: aging infrastructure; increasingly stringent regulations; degraded streams; litter; and limited funding.

Faced with these challenges, the county’s Department of Public Works and Environmental Services is developing a comprehensive, sustainable asset management program to effectively operate, maintain, and reinvest in its stormwater conveyance system. The new asset management program helps identify risks before failure occurs, which enables staff to prioritize maintenance and optimize reinvestment.

Prior to developing the program in the Stormwater Infrastructure Branch, service requests were generated from citizen complaints for problems such as sinkholes, blockages, flooding and erosion. “The complaints we receive give us an opportunity to assess the problems particular to stormwater,” said Branch Chief Val Tucker, P.E.

Technicians perform condition assessments through walking surveys and with pole cameras, recording findings in GIS. They’re also using CCTV cameras to obtain videos of defects within the pipes. “We find off-set joints and holes along with intrusions and unauthorized connections that must be removed,” Val said. “We see utility lines in the pipes. There are downspouts, sump pumps, and other plumbing intrusions, and there are break-ins by fence posts, guardrails, and utility poles.”

The three teams (condition assessment, closed system and open system) work together to keep stormwater flowing and to achieve water quality benefits. In addition to sediment and litter, pipe-cleaning crews find animals and tree roots in the pipes.

The county’s asset management program is achieved through:

  1. An inventory of assets (Fairfax County manages 1,300 miles of pipe, more than 62,000 storm structures, and 100 miles of improved channels and outfalls).
  2. A condition assessment of the inventory.
  3. Considering risk and prioritization: Can the operations and management investment be optimized? Is reinvestment needed, necessary or urgent?
  4. Predicting future needs and creating a funding strategy.  

As of October 2017, approximately 75 percent of the county’s pipes have been inspected and assessed. Some are in good shape, about 3 to 5 percent require attention. The remaining 25 percent are scheduled to be assessed within the next two years.

Where possible, rather than replacing pipes, staff renews them using cured-in-place pipe liner techniques, which saves time, money, and trees and disruption to adjacent properties.

Finally, using natural channel design improves water quality by reducing erosion and excess nutrients, which earns the county Total Maximum Daily Load (TMDL) credit toward compliance with its Municipal Separate Storm Sewer System (MS4) permit. The asset management program allows the stormwater infrastructure team to proactively identify problems before they develop into safety concerns, negatively impact residents or threaten the environment.

Irene Haske
Information Officer
Fairfax County Department of Public Works and Environmental Services