Record Rainfall Challenges Construction Sites

Record Rainfall Challenges Construction Sites

Hotline available to report problems.

Last weekend’s rain pushed the annual rain totals for the Washington metro area to over 62 inches – breaking the record set in 1889. All this rain wreaks havoc on the many constructions sites in the area. As a result, Fairfax County officials said they received more than twice as many complaints about erosion and sediment control problems on construction sites in the first ten months of 2018 than were received in all of 2017.

Currently, more than 1,500 construction sites are active in Fairfax County, each of them monitored by inspectors from the Site Development and Inspections Division (SDID) of Land Development Services (LDS). When construction disturbs the ground, it is much more susceptible to eroding. Rainfall events can loosen soil and carry it with the rainfall runoff to adjacent properties or streams.

The Fairfax County Erosion and Sediment Control Law requires that anyone who disturbs more than 2,500 square feet of land must prepare an erosion and sediment control plan to protect communities and local waterways from the impacts of construction. This is a state-mandated program that is enforced by localities.

IN JULY ALONE, the National Oceanic and Atmospheric Administration recorded over 11 inches of rain at the Washington Dulles International Airport. July’s average during the last ten years has been about four inches. Adding to the challenge: There has rarely been a break in between rain events, which would allow time for contractors to repair the erosion and sedimentation controls.

To respond to this situation, county inspectors are proactively reaching out to site managers to help them maintain compliance with erosion and sediment control regulations. In addition, inspectors rely on residents to report construction sites that may have erosion and sediment issues. Inspectors respond to resident complaints within 24 hours.

Before construction begins, the contractor must install controls around the perimeter of the active construction area. The controls include a series of measures that trap the sediment before it leaves the site. For example, silt fence is a permeable fabric stretched between wooden stakes that allows water to pass through but traps most sediment particles before leaving the site. Even when the controls are operating, brown-colored water may still be seen leaving the construction area. The best system of controls is only about 75 percent effective.

AFTER A RAIN EVENT, the contractor on the site is responsible for repairing and replacing any damaged controls, such as broken silt fencing or clogged sediment traps. The excess rainfall seen this year presents even more challenges to construction managers’ attempts to capture the sediment and clean and maintain the controls. SDID conducts a series of on-site inspections to make sure construction is moving ahead correctly and the erosion and sediment controls are working properly. Inspectors will also visit the site after a significant rainfall event to make sure the contractor is maintaining the controls in compliance with regulations.

LDS is committed to protecting communities and the environment from excessive sediment leaving construction sites. If you observe a construction site that seems to have malfunctioning erosion and sedimentation controls, you can submit your concern online via the Site Construction Hotline Submission Form or call 703-324-7470, TTY 711.

Source: Fairfax County