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Intent To Prepare a Draft Environmental Impact Statement for a Proposed Water Treatment Residuals Management Process for the Washington Aqueduct, Washington, DC

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Department of the Army, U.S. Army Corps of Engineers, DOD.


Notice of intent.


The Washington Aqueduct seeks to plan and create a water treatment residuals management process that will comply with the standards established in National Pollutant Discharge Elimination System (NPDES) Permit DC0000019 and will allow for continued safe, reliable, and cost effective production of drinking water. Washington Aqueduct generates residual solids, a byproduct of producing drinking water, and currently periodically discharges this material to the Potomac River. The residuals consist of river sediment and solid materials generated by adding coagulant as part of the drinking water treatment process. NPDES Permit DC0000019 includes effluent standards for the discharge of the water treatment residuals that cannot be achieved by the current Washington Aqueduct residual management process.

This notice advises the public that pursuant to Section 102(2)(c) of the National Environmental Policy Act (NEPA) of 1969, as amended, Washington Aqueduct, which operates the Dalecarlia and McMillan Water Treatment Plants, will prepare a combined Feasibility Study/Draft Environmental Impact Statement. The combined studies will identify, analyze, and evaluate alternatives for reducing or eliminating the discharge of water treatment residuals from the Dalecarlia Water Treatment Plant and Georgetown Reservoir to the Potomac River in order to comply with NPDES Permit DC0000019, effective April 15, 2003, and a Federal Facility Compliance Agreement, signed June 12, 2003. In addition, Washington Aqueduct will consider alternate methods of managing the Potomac River sediment that accumulates in the Dalecarlia Reservoir.


A public scoping meeting will be held on Wednesday, January 28, 2004 between 7 and 9 p.m. at St. Patrick's Episcopal Church and Day School, 4700 Whitehaven Parkway, NW., Washington, DC 20007-1586. Directions are available at

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Questions about the proposed action and the Draft Environmental Impact Statement (DEIS) can be addressed to: Michael C. Peterson, (202) 764-0025,, Environmental Engineer, Washington Aqueduct Division, Baltimore District, U.S. Army Corps of Engineers, 5900 MacArthur Boulevard, Washington, DC 20016.

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1. Background

Washington Aqueduct operates the Dalecarlia and McMillan Water Treatment Plants in Washington, DC, which provide potable water to over one million persons in the District of Columbia and Northern Virginia. Raw water diverted from the Potomac River is collected in the Dalecarlia Reservoir, where river sediment settles naturally. The sediment periodically dredged from the Dalecarlia Reservoir is not returned to the Potomac River.

Raw water flows from the Dalecarlia Reservoir to the Dalecarlia Water Treatment Plant and also via the Georgetown Reservoir to the McMillan Water Treatment Plant. Aluminum sulfate, the chemical used for coagulation, is added from the Dalecarlia Plant to the raw water for both the Dalecarlia and McMillan Water Treatment Plants. Chemically included sedimentation takes place in four basins at the Dalecarlia Water Treatment Plant and two basins at the Georgetown Reservoir. The Dalecarlia facility employs 36 rapid dual media filters and the McMillan facility is equipped with 12 rapid dual media filters. Except for the filter backwash water at the McMillan Water Treatment Plant, which is recycled to the McMillan Reservoir, and the filter backwash water at the Dalecarlia Water Treatment Plant, which is recycled to the Dalecarlia Reservoir, all sedimentation residuals are currently returned to the Potomac River.

2. Regulatory Mandate

In the recently issued NPDES permit, the Environmental Protection Agency has significantly reduced the allowable concentration of residuals that Washington Aqueduct can discharge to the Potomac. This change in the permit requires Washington Aqueduct to evaluate alternate methods of residuals collection, processing, conveyance, and disposal. Washington Aqueduct and Environmental Protection Agency Region III entered into a Federal Facility Start Printed Page 1699Compliance Agreement to allow Washington Aqueduct to continue to produce drinking water while developing and implementing a new residuals management process. The Federal Facilities Compliance Agreement contains deadlines for various compliance milestones including the following NEPA documents (deadline in parentheses):

  • Description of Proposed Actions and Alternatives submitted to Environmental Protection Agency Region III (May 28, 2004)
  • Draft Environmental Impact Statement submitted to Environmental Protection Agency Region III (December 20, 2004)
  • Final Record of Decision submitted to Environmental Protection Agency Region III (June 3, 2005)

3. Objectives of Proposed Action

The objectives of the proposed residuals management process are as follows, not necessarily in order of precedence (measurement indicators in parentheses):

  • To allow Washington Aqueduct to achieve complete compliance with NPDES Permit DC00000019 and all other federal and local regulations.
  • To design a process that will not impact current or future production of safe drinking water reliably for the Washington Aqueduct customers. (Peak design flow of drinking water)
  • To reduce, if possible, the quantity of solids generated by the water treatment process through optimized coagulation or other means. (Mass or volume of solids generated)
  • To minimize, if possible, impacts on various local or regional stakeholders and minimize impacts on the environment. (Traffic, noise, pollutants, etc.)
  • To design a process that is cost-effective in design, implementation, and operation. (Capital, operations, and maintenance expenses)

4. Alternatives

Various alternatives will be considered that include, but are not limited to, different methods of collection, processing, conveyance, and disposal of the residuals as well as the no action alternative. Processing will be evaluated at both onsite and offsite facilities. Conveyance and disposal options are anticipated to include discharging to the sewer, barging to a remote processing or disposal site, trucking to a remote disposal site, pumping to a remote processing facility, and dewatering onsite and disposing in a dedicated monofill.

The alternatives evaluated in the DEIS will be analyzed in depth in areas to include, but not limited to, predicted changes to air quality, aquatic resources, terrestrial and wetland resources, cultural resources, traffic, solid and toxic waste, and infrastructure as well as any environmental justice concerns. Cumulative, secondary, indirect and other associated impacts will be evaluated.

5. Scoping Process

The participation of all affected and interested federal, state, and local agencies, environmental and neighborhood groups, Indian tribes, and individuals is welcome and encouraged. Anyone wishing to contribute ideas or information may submit a comment to the contact above during the 30 day scoping period that immediately follows the publication of this notice. Alternatively, comments will be collected online at Comments and other information can also be presented at the public scoping meeting (see DATES).

6. Availability of the DEIS

The Washington Aqueduct anticipates the DEIS will be made available to the public in October 2004.

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Dated: January 5, 2004.

Thomas P. Jacobus,

Chief, Washington Aqueduct.

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[FR Doc. 04-441 Filed 1-9-04; 8:45 am]