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Combined Sewer System

The City's combined sewer system comprises approximately 540 acres and is located in the Old Town area. During most wet weather events, combined sewage (mixture of wastewater and stormwater runoff) discharges through one of four outfalls into receiving waterways. The City is developing a plan to reduce the impacts of combined sewer discharges on the environment. More information about the City's combined sewer system and current planning efforts is provided below.


WHAT'S NEW

Ad Hoc Combined Sewer System Plan Stakeholder Group - Next Meeting Thursday, February 4, 2016 at 7:00 PM

On June 23, 2015, Alexandria City Council approved a resolution to establish an Ad Hoc Combined Sewer System Plan Stakeholder Group (Stakeholder Group) to assist in monitoring the development of the Long Term Control Plan Update for the City’s combined sewer system. This Long Term Control Plan Update is required by the Virginia Department of Environmental Quality (VDEQ) to meet new permit requirements and is due to VDEQ by August 23, 2016. The Stakeholder Group will provide input to staff on a final recommended plan to VDEQ, including considerations on the City’s budget, meeting environmental goals, and minimizing impacts to the community. The Stakeholder Group will convene its next meeting on Thursday February 4, 2016 at 7:00 PM. The meeting will be held at 301 King Street (City Hall) in the Sister Cities Conference Room 1101 (first floor). The meeting is open to the public.

Information From Previous Meetings

 January 7, 2016 Meeting

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #3 Materials

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #3 Summary

November 2, 2015 Meeting

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #2 Materials

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #2 Summary

October 7, 2015 Meeting

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #1 Materials

Ad Hoc Combined Sewer System Plan Stakeholder Group - Meeting #1 Summary



Background 

There are two types of storm sewer systems in the City of Alexandria, a separate sewer system, and a combined sewer system.  Separate sewer systems consist of two pipes: one pipe conveys stormwater runoff (rain water) from storm drains to local waterways with little or no treatment to remove pollutants.  The other pipe conveys sanitary sewage to a local wastewater treatment plant (operated by Alexandria Renew Enterprises) as shown in the figure below.

CSS Separate Sanitary and Stormwater Systems 
source: www.dcwater.com 

In contrast, Combined Sewer Systems (CSS) have only one pipe which conveys both sanitary sewage and stormwater to a local wastewater treatment plant. About 540 acres in the Old Town is served by a combined sewer system, which was designed to carry sewage from inside homes and businesses and stormwater runoff from streets, rooftops, and parking lots in a single pipe—a “combined sewer.” During dry weather, all raw sewage flows to the treatment plant operated by Alexandria Renew Enterprises. When it rains, the pipes can become overloaded with polluted stormwater. This mixture of stormwater (about 90%) and raw sewage may overflow into local streams through one of the four permitted outfalls.

CSS Combined Sewer System 
source: www.dcwater.com 

Over period of time, much of the combined sewer system has been separated, and only 5% of the City, approximately 540 acres, primarily in Old town is served by Combined Sewer System.  The map below shows where remaining CSS is located and the location of remaining four CSOs in the City of Alexandria.

Overview Map of Combined & Sanitary Sewer System 

The City of Alexandria has received a 5 year renewal of its permit to operate Combined Sewer System. In 2011, the City applied to Virginia Department of Environmental Quality (VDEQ) for its Virginia Pollution Discharge Elimination Permit, which regulates discharges from the City’s Combined Sewer System (CSS). The City’s Combined Sewer System, a legacy infrastructure built in 19th and early 20th century, is a combination of storm and sanitary sewer systems serving approximately 540 acres in Old Town.

As part of the City’s Eco-City Alexandria initiative, and in coordination with VDEQ, this new permit ensures regulatory requirements are met and the environment is protected. Under the permit negotiated by the City with VDEQ, the City will be updating its Long Term Control Plan (LTCP) over the next three years, and implementing several additional projects to improve water quality in Hunting Creek, Potomac River, and Chesapeake Bay. The LTCP to be developed will identify the strategy, projects, schedule, additional infrastructure investments and long-term impacts on the community and will be implemented no later than 2035. In addition to developing the LTCP, the permit also requires the City to implement several important construction projects within the five year permit cycle. These projects are needed to improve the system and to continue to reduce the impacts.

The City plans to start planning and implementation of several new and expanded initiatives required under the new CSS permit , including the following:

  • Update the LTCP within three years from the issuance of the permit.
  • Construction projects to improve sewer system performance, and improve water quality.
  • Develop and implement green infrastructure pilot projects within the CSS.
  • Continue implementing CSS Area Reduction Plan that requires developers to separate sewers in the CSS as redevelopment occurs.

In addition, the City is required to submit a Work Plan to VDEQ which details the process and schedule for how the City will prepare the update to the LTCP, including public participation. The Work Plan was submitted in May 2014 and approved by VDEQ in July 2014. The City has been submitting to VDEQ a series of technical memoranda throughout the Long Term Control Plan Update process in accordance with the approved Work Plan. Technical memoranda submitted to VDEQ to date include the following:

How can residents provide input?

The City of Alexandria encourages residents to participate in public process for the development of Long Term Control Plan Update over next three years that will help bring long-term improvements to Alexandria’s sewer system infrastructure, improve water quality, and meet new regulatory requirements. Comments and input should be provided to Erin Bevis-Carver, P.E., Sanitary Section Lead, Stormwater and Sanitary Infrastructure Division, Transportation and Environmental Services at 703.746.4154 or at erin.beviscarver@alexandriava.gov.

Outreach and Presentations

The City has been holding a number of public information meetings related to the Combined Sewer System Long Term Control Plan Update and the Combined Sewer System Permit issued by the Virginia Department of Environmental Quality in August 2013. The agenda, presentation and video recording of these meetings can be found below.

June 18, 2015 - A public meeting was held that explained the progress to date the City has made in developing an update to its Long Term Control Plan to comply with new regulatory requirements. Information related to this meeting, including the presentation, can be found below.

February 15, 2015 - A public meeting was held o present information related to its ongoing combined sewer system planning efforts that are required to meet new water quality regulations in order to reduce the impacts of combined sewer overflows on receiving waterways. The City is required to update its Long Term Control Plan to meet the new regulations and must submit it to the Virginia Department of Environmental Quality by August 2016. The presentation, video recording, informational handout, and feedback form related to this meeting can be found below.

August 5, 2013 - A public meeting was held to present the draft CSS permit and inform residents how to provide comments on the permit to the Virginia Department of Environmental Quality.

The City is also providing updates to City Council throughout the planning process.   

Combined Sewer System Annual Reports

As part of the City’s VDPES permit for its combined sewer system, the City must submit to VDEQ an annual report on operation and maintenance activities in the combined sewer system by March 31st of each year.  Annual reports for Calendar Year 2013 and subsequent years are provided below.