Combined Sewer Overflow (CSO) in Richmond

Richmond's sewer system included 29 overflow outfalls along the James River
Richmond's sewer system included 29 overflow outfalls along the James River
Source: Richmond Combined Sewer Overflow (CSO) Project

Richmond was one of the first cities in Virginia to create a system to carry sewage away from the urban center. The city covered Shockoe Creek and converted the natural drainage in Shockoe Bottom into two underground systems, a 17-foot by 12-foot concrete sewer known as the Shockoe Box and a pressure conduit known as the Shockoe Arch. Sewage was dumped, untreated, in the James River.

The state capital ended up with 12,000 acres draining into a combined sanitary/stormwater pipe system, the largest Combined Sewer Overflow (CSO) area in Virginia. There are 29 overflow outfalls along the James River or its tributaries (especially Shockoe Creek and Gillies Creek), and 2/3 of the city's total CSO Area is in the Shockoe Basin drainage.

Richmond built its wastewater treatment plant in 1958 and located it on the southern bank of the river, near the Port of Richmond. The city built a 96-inch Shockoe Creek Interceptor pipe to gather waste/stormwater from the north bank, plus twin 66-inch pipes to carry that polluted water underneath the river from the downstream edge of Chapel Island (near Great Shiplock Park) to the wastewater treatment plant on the opposite side of the river.

One third of Richmond had a consolidated sanitary/stormwater system. Like Lynchburg and Alexandria, Richmond separated some sanitary and stormwater pipes to reduce the amount of untreated waste that was discharged into the James River during rainstorms. The costs and disruptions caused by construction to separate pipes limits the benefits of that solution.

Richmond's primary solution in its Long Term Control Plan was to build a massive storage system to capture the surge of stormwater mixed with raw sewage after a rainstorm, then treat the captured water after the storm subsided and flows dropped to normal dry weather conditions. Two underground tunnels were excavated in the Petersburg granite to store 57 million gallons. The hard granite minimized the amount of groundwater that would infiltrate into the tunnels when they were empty, and blocked the wastewater from leaking out when the tunnels were full.

In 1983, the city built the 50-million gallon Shockoe Retention Basin on Chapel Island just downstream from the former mouth of Shockoe Creek. It was designed to capture the initial surge or "first flush" of stormwater runoff from a rainstorm.

At the beginning of a storm, the initial stormwater runoff contained the greatest amount of contaminants that had accumulated since the last storm. By capturing the dog waste, oil and grease from automobiles, and litter in the first flush, Richmond could reduce the impact of releases when heavy storms exceeded the storage capacity of the Shockoe Retention Basin and forced outfall gates to open.1

Shockoe Retention Basin on Chapel Island (red outline) is on the north bank of the James River, not far from the State Capitol (yellow circle)
Shockoe Retention Basin on Chapel Island (red outline) is on the north bank of the James River, not far from the State Capitol (yellow circle)
Source: ESRI, ArcGIS Online

The underground retention basin included an aeration system intended to keep solids in suspension until the storage was emptied. By 2008, however, a 10-foot thick layer of sewage had settled on the bottom, similar to the solids that accumulate on the bottom of a septic tank.

The city had not designed a clean-out option in 1983. It had to spend over $12 million to build a ramp down to one wall of the Shockoe Retention Basin, cut a hole in the wall, and use backhoes to remove the solidified sewage.2

rainfall required for discharge from 29 different overflow outfalls in Richmond  (before construction of the Hampton McCloy Tunnel)
rainfall required for discharge from 29 different overflow outfalls in Richmond (before construction of the Hampton McCloy Tunnel)
Source: Richmond Combined Sewer Overflow (CSO) Water Conditions

Storing that initial runoff helped the city avoid overwhelming the wastewater treatment plant with too much inflow. Some Richmond CSO outfalls discharge sewage less than once/year on average, but others regularly pour a mixture of water and untreated waste into the James River.

CSO6, one of 29 overflow outfalls in Richmond, has a pattern of discharging polluted water at least four times in every month of the year
CSO6, one of 29 overflow outfalls in Richmond, has a pattern of discharging polluted water at least four times in every month of the year
Source: Richmond Combined Sewer Overflow (CSO) Monthly Reports (June 2016)

To stop discharges from two CSO outlets upstream from the river rapids that attract a great deal of recreational use, the city built a $50 million, 600-foot long, 14-feet wide underground tunnel between Hampton and McCloy streets (the Hampton McCloy Tunnel) in 2003.

The city located the underground storage for 7 million gallons in Petersburg granite, to minimize the amount of infiltration, and designed the tunnel so water from the James River and Kanawha Canal could be used to flush out the solids. The tunnel was carved out of the bedrock 70 feet below the sewer line, so special engineering was required to dissipate the energy of the water as it dropped into the tunnel.3

The underground retention basin and Hampton McCloy Tunnel can trap 60 million gallons of combined sewage and stormwater, but the city still discharges untreated waste each year, but a 10-minute rainstorm can completely fill up the underground storage. Bacteria levels in the James River exceeded state standards for half the weekends in the summer of 2016.

In contrast to its mandates on Alexandria meeting water quality standards, the General Assembly has not imposed a deadline on Richmond for eliminating discharge of untreated waste. As one Richmond official noted:4

It just takes time to rebuild a city from underneath.

Eliminating the discharges from overflow outfalls on the western side of the city resulted in cleaner water for recreational use downstream in James City Park, especially for popular rafting/kayaking activity at the Fall Line. However, cleaning up the pollution in the West End of Richmond exposed city officials to charges of environmental prejudice. The city's population on its western side is wealthier and includes less minorities.

the Hampton McCloy Tunnel stretches from McCloy Street near I-195 to Hampton Street east of Maymont Park, and red dots in the East End indicate where untreated sewage is still released as of 2016
the Hampton McCloy Tunnel stretches from McCloy Street near I-195 to Hampton Street east of Maymont Park, and red dots in the East End indicate where untreated sewage is still released as of 2016
Source: Richmond Combined Sewer Overflow (CSO) Project Overflow Points

EPA conducted a "knee-of-the-curve" economic analysis to define a point where increased clean-up expenses in a Long Term Control Plan would no longer be matched by a reasonable set of increased environmental benefits. For its Combined Sewer Overflow project, Richmond proposed to reach compliance with Clean Water Act standards for 92% of the James River.

Using EPA's willingness to consider costs as well as benefits, Richmond told to the State Water Control Board and EPA that the costs to implement 100% of the possible clean-up actions would fully exceed the benefits.

economic analysis indicates a point (knee of curve) where incremental costs to reduce pollution increase dramatically after 92% of the James River miles comply with water quality standards
economic analysis indicates a point ("knee of curve") where incremental costs to reduce pollution increase dramatically after 92% of the James River miles comply with water quality standards
Source: State Water Control Board, City of Richmond Reasonable Grounds documentation

Richmond's proposed solution for avoiding the costs of the remaining 8% includes reclassifying Gillies Creek through a Use Attainability Analysis. Reclassification would exempt the city from reducing pollution enough to permit recreational use. Reclassifying the creek would eliminate recreational use as an objective would lower the threshold for clean-up.

after Richmond's wastewater treatment plant (WWTP) reaches its maximum inflow, the excess water/waste is discharged directly to the James River and its tributaries through different overflow outfalls
after Richmond's wastewater treatment plant (WWTP) reaches its maximum inflow, the excess water/waste is discharged directly to the James River and its tributaries through different overflow outfalls
Source: Robert Steidel, Accomodating CSO Flows/Loadings in the Chesapeake Bay Nutrient TMDL (Wet Weather Partnership 2010 Workshop Presentation)

From where the creek enters the city to its confluence with the James River near the old Fulton Gas Works, the natural channel of Gillies Creek was replaced with concrete in 1974. Paving the creek reduced flooding and sediment erosion, but did not reduce the excessive levels of bacteria that contaminate the water.

The city claimed it would have to spend $300 million to construct a 30-million gallon storage tunnel to capture stormwater and divert it to the wastewater treatment plant. The city also noted that Gillies Creek:5

...is absolutely unique in the James River watershed. There is no other creek or waterway like it. Not only is the entire length that runs through the City concrete on the bottom and sides (no grass, no rocks), but the function is unlike any other creek in the watershed.

Gillies Creek was designed in 1973 to efficiently convey floodwaters to the James River. The paved channel stopped the pre-existing stream from meandering, and was also designed to prevent stream erosion from carrying sediment downstream to the James River.

Richmond's proposal for a Use Attainability Analysis notes that Gillies Creek has a normal flow of water only 2
Richmond's proposal for a Use Attainability Analysis notes that Gillies Creek has a normal flow of water only 2" deep except in rainstorms, offering little opportunity for swimming or wading, so Primary Contact Recreation is not currently an existing use
Source: State Water Control Board, City of Richmond Reasonable Grounds documentation

In 2011, the State Water Control Board rejected the city's request to conduct a Use Attainability Analysis. The city could conduct its own study, but the state agency did not want to appear to endorse a solution that would not require any reduction in the pollution levels.6

Five years later, the city viewed Gilles Creek more as an asset rather than as an open sewer. The Gillies Creek Greenway was proposed, to create a pedestrian/biking corridor as part of revitalization in the East End. At the James River, the greenway would connect to the Virginia Capital Trail near the new Stone Brewing Company development at the former Intermediate Terminal. The other end would be anchored at the former Armstrong High School, in a low-income area of the city.7

Richmond chose to reduce CSO overflows on the West End first, and delayed cleaning up Gillies Creek on the East End
Richmond chose to reduce CSO overflows on the West End first, and delayed cleaning up Gillies Creek on the East End
Source: ESRI, ArcGIS Online

Combined Sewer Overflow (CSO) Locations in Virginia

Combined Sewer Overflow (CSO) in Alexandria

Combined Sewer Overflow (CSO) in Lynchburg

Links

References

1. Robert C. Steidel, Robert Stone, Lin Liang, Edward J. Cronin, Federico E. Maisch, "Downtown Shall Not Flood Again," Proceedings of the Water Environment Federation, WEFTEC 2006, pp.3770-3772, http://dx.doi.org/10.2175/193864706783751401; "McDonnell proposes $40 million to help clean up RVA’s wastewater system," RVANews, December 26, 2012, http://rvanews.com/news/mcdonnell-proposes-40-million-to-help-clean-up-rvas-wastewater-system/78637 (last checked October 4, 2013)
2. "At First Flush," Richmond Style Weekly, January 13, 2010, http://www.styleweekly.com/richmond/at-first-flush/Content?oid=1369472 (last checked October 4, 2013)
3. Rob Baker, "Management of Combined Sewer Overflows," pp.6-7, 2005, http://home.eng.iastate.edu/~tge/ce421-521/Baker.pdf; "Diverting Stormwater," Stormwater, April 13, 2004, http://www.stormwater.org/SW/Editorial/Diverting_Stormwater_16949.aspx (last checked October 4, 2013)
4. "From sewer to scenic: $120 million in waste treatment plant upgrades have made the James, Chesapeake Bay healthier," Richmond Times-Dispactch, May 5, 2017, http://www.richmond.com/news/from-sewer-to-scenic-million-in-waste-treatment-plant-upgrades/article_0b22319c-ba9c-562c-8bd0-6eeff767f05c.html (last checked May 10, 2017)
5. "Reasonable Grounds Documentation to Conduct a Recreational Use Attainability Analysis for Gillies Creek, City of Richmond, Virginia under VAC 62.1-44.19:7," City of Richmond, August 24, 2010, http://www.deq.virginia.gov/Portals/0/DEQ/Water/WaterQualityStandards/Gillies_Creek_UAA_Reasonable_Grounds_8-26-2010.pdf (last checked October 4, 2013)
6. "Excerpt from Proceedings," State Water Control Board, February 4, 2011, http://www.deq.state.va.us/Portals/0/DEQ/Water/WaterQualityStandards/Board_Minute_Gillie_Creek_UAA_4FEB2011.pdf (last checked October 11, 2016)
7. "Gillies Creek Greenway," City Of Richmond Pedestrian, Bicycles And Trails Commission, 2015, p.4, http://murp.vcu.edu/projects762/S15/Gillies_Creek_Greenway.pdf (last checked October 11, 2016)


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