By Wayne Savage
Utilities that draw drinking water from the Potomac River for Washington, D.C., and much of Northern Virginia received no official warning in mid-December as 3.5 million gallons of raw sewage spilled into the Monocacy River, a major Potomac tributary.
As public-works employees in Frederick, Md., scrambled to repair an electrical malfunction that crippled the city’s sewage-treatment plant on the evening of December 11, officials of the Maryland Department of the Environment placed urgent calls to the Rockville water-treatment plant and the Washington Suburban Sanitary Commission, the primary water utility for Montgomery and Prince George’s counties.
MDE’s calls warned Rockville and WSSC of the spill, which started at 7 p.m. and continued until 3 a.m. the following day. Frederick’s sewage-treatment plant discharges wastewater into Carroll Creek, some 500 feet above its confluence with the Monocacy River.
But official notification of the December 11 spill never crossed state lines to reach water utilities downstream in Virginia and the District of Columbia, as called for by a longstanding early-warning plan devised by jurisdictions in the Potomac River basin.
Under the early-warning plan ─ which is voluntary and not mandated by federal law ─ MDE should have notified the Interstate Commission on the Potomac River Basin. The ICPRB, in turn, is tasked with spreading the alarm to downstream water utilities so they can take mitigating action, if necessary, in response to contamination events. ICPRB’s role includes running a computer model to determine the times that contamination is likely to reach downstream water-intake pipes.
The Potomac River watershed covers four states and the District of Columbia.
Among the communities left in the dark on December 11 was Leesburg, Va., some 30 miles downstream from Frederick and the closest to the spill.
“I don’t have any documentation in my file that we got notified,” said Larry Taylor, manager of Leesburg’s water-treatment plant. He said, however, his file contains a printout of a story from the Frederick News-Post website.
Tom Jacobus, general manager of the Washington Aqueduct, said he and his staff were unaware of the Frederick sewage spill until contacted for this report. The Washington Aqueduct, a division of the U.S. Army Corps of Engineers, supplies water for Washington, D.C., and Arlington County, Va.
Fairfax Water, which supplies water to a large swath of Northern Virginia, including Fairfax and Loudoun counties, also missed the warning.
“We do not have a record of being notified of that spill,” said Fairfax Water spokeswoman Jeanne Bailey. “I don’t believe we were aware of it.”
Multiple sewage pathogens
Raw sewage can contaminate water with bacteria, viruses, protozoa and parasitic worms that cause human disease, including “serious illnesses such as cholera, dysentery, infectious hepatitis, and gastroenteritis,” according to the U.S. Environmental Protection Agency. “Sensitive populations ─ children, the elderly, and those with weakened immune systems ─ are at a higher risk of illness.”
“In a serious spill, sometimes the [water] utility will need to take measures to avoid contaminating their intakes or change their treatment process,” said Cherie Schultz, director for CO-OP operations at the Interstate Commission on the Potomac River Basin.
The ICPRB has developed models that estimate the time of travel and concentration of contaminants that enter the Potomac River, Jacobus said by email.
“This provides utilities with needed information about a wastewater treatment plant overflow and gives warning so that water treatment plant managers can assess the potential effect of that overflow on the treatment system,” Jacobus said. “These managers may decide that it is prudent to add more chlorine to neutralize the bacteria that are over and above the normal river conditions.”
Jacobus and officials of other downstream water utilities, including Leesburg and Fairfax, said the December spill posed no danger to public health. According to these officials, the sewage was so diluted by the time it reached their intake pipes that it required no change in the routine treatment of raw water taken from the Potomac.
State agency alerted
Frederick officials alerted the Maryland Department of the Environment within an hour after the spill started. But according to multiple sources, the state agency did not pass the word to the ICPRB, as called for by the region’s early-warning plan.
A statement released by MDE confirmed the agency notified WSSC and Rockville ─ the two nearest downstream water utilities in Maryland ─ but not the ICPRB. The MDE said it is “taking steps to address the communications issue” and has strengthened its emergency response procedures by improving its internal communications and by “reminding our staff that under our response plan they should directly contact ICPRB as soon as possible after any spill in the Potomac area.”
Carlton Haywood, director for program operations at the ICPRB, said employees of his agency didn’t learn of the spill until they read a newspaper report on the morning of December 13. That was some 36 hours after the spill started ─ too late for the downstream water utilities serving Virginia and the District of Columbia to take remedial action, had it been necessary.
ICPRB’s computer model showed that the leading edge of the sewage spill would have taken 17 hours to reach Leesburg, about 10 miles downstream from the Monocacy’s confluence with the Potomac, arriving at noon on December 12, with the peak concentration coming at 4 p.m..
After passing water intakes that supply Fairfax Water, the WSSC, and Rockville, the leading edge of the spill would have reached the Washington Aqueduct’s intake at Great Falls at 7 p.m., with the peak coming at midnight, according to the computer model.
Dilution of the sewage spill was aided by a relatively high level of water in the Potomac. At noon on December 12, the river was flowing at 31,300 cubic feet per second, or about 234,000 gallons per second, as measured by the U.S. Geological Survey at Little Falls, 10 miles below Great Falls. That flow rate was more than twice the historic average recorded for December 12 by the USGS.
Noting the Potomac’s high flow, Haywood said that by the time bacteria from the Frederick spill “got down to the Washington-area utilities, the concentrations were likely down to roughly the same as background levels, more or less.”
Similar assurances came from the downstream water utilities.
“In the Potomac River with a dilution factor there shouldn’t have been any problem,” said Taylor, manager of the Leesburg water-treatment plant.
Bailey, the Fairfax Water spokeswoman, said that given the distance the sewage spill traveled, it would not have impacted her utility. Fairfax Water’s two intakes are near the border of Loudoun and Fairfax counties, some 40 miles downstream from Frederick.
“We don’t feel that spill would have had any impact on our water supply or any treatment changes would be necessary,” Bailey said.
Maryland utilities notified
Officials at both Rockville and WSSC said the Maryland Department of the Environment notified those two water utilities of the sewage spill at 9 p.m. on December 11. MDE’s warning calls, however, did not include the Interstate Commission on the Potomac River Basin.
The WSSC found no need to raise chlorine levels in response to the spill, according to spokeswoman Lyn Riggins, who said the raw sewage “was diluted by billions of gallons of river water by the time it got to us.”
“We kept an extra eye out,” Riggins said, “but there was nothing out of the ordinary.”
Marylou Berg, communications manager for the Rockville city manager’s office, said that routine, around-the-clock testing showed no difference after the spill.
“We continually monitor the chlorine level leaving the plant … to get the water quality to the appropriate level,” Berg said. “The amount we needed to maintain the water quality didn’t have to go up.”
Berg described the sewage spill as “really not much of an event for us.”
“Certainly the river was contaminated by this extra sewage,” Jacobus said in an interview, “but the river is always contaminated.” He said raw river water is assumed to be non-potable, and water-treatment plants are designed to make it potable according to EPA standards.
Based on the ICPRB’s computer model of the Frederick spill, Jacobus said there was no need to change the Washington Aqueduct’s treatment process because “the effect of the bacteria would have been incrementally negligible at the intake.” (The aqueduct’s Great Falls intake is some 50 miles south of Frederick.)
“We have a very sound bacterial-disinfection process that can handle what comes to us from the river,” Jacobus said.
Jacobus suggested that a chemical spill, especially petroleum, would be more problematic because water-treatment plants “were not fundamentally designed to handle” such contamination. In 1993, a ruptured pipeline sent 407,000 gallons of diesel fuel into Sugarland Run, a Potomac River tributary near Reston, Va., forcing Fairfax County to shut down its Potomac water-treatment plant for more than a week.
Federal law silent
on interstate warning
Frederick officials were required, as a condition of their sewage-treatment plant operating permit, to notify the Maryland Department of the Environment of the sewage spill. But federal law does not mandate that notification include the ICPRB, which would have warned downstream water utilities of the incident.
“What [utilities] are not obligated to do is report to other agencies in other states, so that is the gap that ICPRB is trying to fill,” said Haywood, echoing a slogan that appears prominently on the ICPRB website: “Watersheds Cross Political Boundaries. That’s Why We’re Here.”
The ICPRB, however, is a non-regulatory body, and participation in its early-warning system by the Maryland Department of the Environment is voluntary.
Jacobus said the breakdown in the chain of notification was the first he knew of in his 16 years with the Washington Aqueduct. He called it “a uniquely rare event in my experience.”
Wayne Savage is the owner of Mid-Atlantic Litter Cleanup Service. He drinks water every day that’s drawn from the Potomac River.
For further reading:
City of Frederick timeline of sewage spill
Statement released by Maryland Department of the Environment
Statement released by Tom Jacobus, general manager of Washington Aqueduct