Why do we have a CSO problem?
By the close of the 19th century, Lynchburg was prosperous enough to follow the lead of urban centers like Boston and San Francisco in the construction of sanitary sewer systems. When our sewer system was first built more than 100 years ago, it was among the finest in the nation, utilizing state-of-the-art technology. Unfortunately, the “state-of-the-art” at the time was to pipe sewage away from densely populated areas ... and into the nearest creekbed or stream. As a result, most of Lynchburg’s untreated sewage eventually made its way downstream into the James River.
By the mid-nineteen hundreds, cities like Lynchburg had recognized the shortcomings of the old sewer technology. So in 1955 Lynchburg built a wastewater treatment plant to reduce the pollution of area rivers and streams. This wastewater treatment plant was fed by a network of large underground pipes called interceptors, which transported sanitary wastewater to the treatment plant from the city’s 21 neighborhood drainage basins.
This system worked well enough in dry weather, but lacked the capacity to handle the combination of storm water and sanitary wastewater that would result from heavy rainfall. Therefore, the design of this combined sewer system incorporated “overflow outfalls,” which allowed excess stormwater and sanitary wastewater to be quickly diverted through pipes into nearby streams or ditches. These outfalls reduced the chances that untreated sewage would back up and flood into streets and homes when the combined flow of rainwater and wastewater exceeded the sewer system’s capacity.
The antiquated “combined sewer” system we have inherited still serves more than 11 square miles of the City. Although many of the overflow outfalls have been eliminated in the first stages of the CSO construction work, many others remain active in the system. And as a result, during heavy rainfall, Lynchburg’s untreated sewage is still being discharged into the James River—and occasionally into streets and yards.
How did we choose a solution?
For more than a decade, Lynchburg studied ways to upgrade the outdated parts of our wastewater treatment system. An exhaustive study conducted by the City between 1974 and 1979 (the Infiltration/Inflow Evaluation Survey Report) helped to provide strategic direction for the upgrade efforts. This report utilized the U.S. Army Corps of Engineers’ storm computer model to help quantify the extent of the overflow problem. It also identified corrective alternatives and made recommendations, which provided direction for the city’s initial sewer improvement efforts. As a result of the study’s recommendations, Lynchburg began work, investing over $4 million during the 1980s to close several CSO points and to gather the data needed for a long-term control plan to eliminate combined sewer overflow.
In 1989, the 1974-79 study was updated, using more sophisticated computer modeling techniques to make an estimate of the combined sewer system inflow and of the frequency, volume, and pollutant loads of each overflow under various rainfall conditions—all information that was required by the Virginia State Water Control Board. The 1989 studies further prioritized Lynchburg’s combined sewer regions into 59 different project areas. These projects were ranked based on a matrix approved by the Virginia Department of Health and the Department of Environmental Quality, which incorporates criteria such as aesthetics, public health considerations, environmental characteristics, water quality, and impact on the James River.
Over the years, the City evaluated many possible ways to correct our sewer problems, ranging from the construction of huge retention basins to the introduction of elaborate water filtration systems. Lynchburg’s current three-part plan offered the most technically and financially sound options.
The Environmental Protection Agency (EPA), Virginia’s Department of Environmental Quality (DEQ), and the City agreed that local funding for this federally mandated program would come from usage fees and not taxes. Recognizing that sewer customers would bear most of the costs, the City secured a Special Consent Order from the state. This agreement was the first of its kind to be approved by the EPA and allowed the City to keep sewer rates in line with Lynchburg’s median household income. Future increases will also match median household income growth.
In the early 1990s, three representative neighborhoods were the sites of test projects (Franklin Street, Fairway Place, Woodland Avenue), and lessons learned in those pilot-project areas were used to establish policies and procedures for the current City-wide work.
Recent state and federal laws (most notably the Clean Water Act) have further added momentum to Lynchburg’s CSO efforts—and also to the efforts of many other cities nationwide, such as Richmond, Alexandria, and Boston, with similar sewer problems.