Residuals Management Project FAQs

Below you will find answers to some of our frequently asked questions regarding the construction phase of the Residual Management Project. If you don't see your question here please check 
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Construction FAQs

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1. What is the proposed project? What is its purpose?

The Washington Aqueduct draws raw water from the Potomac River to make safe drinking water for over one million residents in the greater Washington, D.C. metropolitan area. Like all or nearly all drinking water processes involving river water, the sediments in the raw water must be extracted from the water to make it drinkable. This sediment byproduct must then go somewhere. The proposed project is to alter the disposal process for the sediments from the current one of disposal back to the Potomac River to a process of collection and land disposal or reuse. The purpose for doing this is to comply with the terms of a recently issued National Pollutant Discharge Elimination System (NPDES) permit under the Clean Water Act that effectively prevents discharge of the sediments to the Potomac River. For more information on the project, please visit our website at

For more information about our NPDES permit, DC0000019, please visit the Region 3, Environmental Protection Agency (EPA) website at

2. What is an EIS? What is NEPA?
NEPA is the National Environmental Policy Act, passed by Congress in 1970. The Act mandates that any Federal Agency fully and objectively evaluate and understand the potential implications to the environment before they take a major action (such as creating new sediment collection and disposal facilities.) The Act also requires the agency to involve the public in their evaluation process by allowing them to question and comment upon it. The Environmental Impact Statement (EIS) is the document issued by the agency, after a detailed public involvement process, to the public that describes the environmental evaluation process and results. It is not a decision document, however. The environmental decision document that accompanies an EIS is a Record of Decision (ROD). The ROD documents the selection of one (or more) alternative(s) for how to implement the proposed project.
3. Who will make the final decision on the selection of an alternative for this proposed project?
The U.S. Army Corps of Engineers, in accordance with the Memorandum of Understanding with the Washington Aqueduct Wholesale Customers, will make the final decision on the selection of an alternative to manage the water treatment residuals. Washington Aqueduct is a subordinate organization of the Baltimore District, North Atlantic Division, U.S. Army Corps of Engineers.
4. Why did you select the screening criteria that you did?
At the beginning of any problem solving process (in this case the problem is a new approach to Washington Aqueduct residuals management) the first step is to collect all of the ideas for potential solutions. Some of these ideas might work. Some might not. This leads to the second step. The second step is to determine which ideas, from the full list of all concepts, makes sense for the Aqueduct's real-world legal, time and cost constraints. This second step, called screening, is intended to determine which of the ideas can be developed into a viable or feasible alternative for solving the problem. Feasible alternatives may have a range of different impacts associated with them. The third step is to develop an Environmental Impact Statement to identify, evaluate and disclose these impacts to the public and the federal decision makers.

The screening criteria were selected to determine which initial ideas had the potential to work, that is, which ones had the potential to meet the purpose and need for the project. If an idea will not work it is not an alternative for solving the problem. The screening criteria were intended to be very objective and were purposefully limited to only the legal, time and cost constraints for the Aqueduct. Other concerns, such as community or environmental impacts, may not prevent an idea from being considered as an alternative. However, these types of concerns are very important in the decision making process and are included in the EIS. Many of them are discussed in the public dialog, which is also part of the EIS.
5. When you complete the analysis how will the preferred alternative be selected?
Once the analysis is complete the preferred alternative will be chosen by the Agency  (Washington Aqueduct)  after considering  the full range of potential impacts, including how well an alternative meets the objectives for the project.   The Aqueduct will follow a rational process for determining the preferred alternative and this process will be documented in the Draft and Final versions of the EIS.
6. What did you do to notify the public about the project and offer them a chance to provide input?

Washington Aqueduct sought to inform the public from the start of the EIS process. The process was initiated by the publication of a Notice of Intent to Prepare a Draft Environmental Impact Statement in the Federal Register on January 12, 2004. A public scoping meeting was held on January 28, 2004. A notice for this meeting was included in the Federal Register, and was published in both the Washington Post and Northwest Current on January 22, 2004. In addition, 63 invitation letters were sent to political and governmental officials, neighbors, and environmental organizations that had been involved with Washington Aqueduct environmental issues previously. The public scoping meeting was required under the regulations for NEPA. An article was also published in the Northwest Current about the scoping meeting.

In addition, Washington Aqueduct held a public meeting on May 26, 2004. This meeting was not required by the NEPA regulations, but was held to communicate the results of an initial project alternatives screening process with the public to disclose the four alternatives that would be analyzed in detail in the Draft Environmental Impact Statement. Notices for this meeting were published in the Washington Post on Monday May 24, 2004 and in the Northwest Current on Thursday May 20, 2004 . In addition, 144 letters were sent to neighbors living in the vicinity of the Dalecarlia Reservoir Grounds in Maryland and another 88 letters were sent to neighbors in the District of Columbia.

A third meeting, also not required by NEPA regulations, was held on September 7, 2004. The goal of this meeting was to allow neighbors who may not have been aware of project details to learn about project progress so far, and personally interact with Washington Aqueduct staff and consultants. An open-house format was planned to maximize the interaction and potential for answering questions one-on-one. In addition, an area was set up for questions to be directed to the general manager of Washington Aqueduct. The public participation at the meeting overwhelmed the realistic capacity for this format, which made it largely ineffective as a means of communication between Washington Aqueduct and public stakeholders. Over 1000 invitation letters were sent to neighbors and other stakeholders for this meeting. Notice for this meeting was published in the Northwest Current and Bethesda Gazette on August 25 and September 1 editions. Notice for this meeting was published in the Washington Post on August 31.

A fourth meeting, also not required by NEPA regulations, was held on September 28, 2004. This was a follow-up to the September 7 meeting. The goal of this meeting was to allow the public time to state their comments and concerns and to ask questions. The meeting was held in the Sibley Hospital auditorium. The Washington Aqueduct team made short opening presentations before the meeting was turned over to the public. A moderator maintained a formal question and answer format. The meeting lasted 3 ¾ hours and provided the Washington Aqueduct a significant amount of public input. Over 1000 invitation letters were sent to neighbors and other stakeholders for this meeting. Notice for this meeting was published in the Northwest Current and Bethesda Gazette on September 22 editions. Notice for this meeting was published in the Washington Post on September 21.

A fifth meeting was held on November 16, 2004. This was another follow-up meeting planned to accomplish three things - first, to update the public on the progress made since the previous meeting; second, to provide as much information as possible regarding the input received from the public as of the November 15 deadline for additional options and alternatives; and third, to continue to allow the public to state comments and concerns and to ask questions. Again, over 1000 invitation letters were sent to neighbors and other stakeholders for this meeting. Notice for this meeting was published in the Northwest Current and Bethesda Gazette in the November 10 editions. Notice for this meeting was published in the Washington Post on November 9.

Washington Aqueduct has had a project website with frequent updates of documentation and other information since January 28, 2004. Notices and information about all of the meetings that have been held have been, and are, available on the website.

7. You seem to be going through the NEPA process with a very definite, and very fast, schedule in mind. What is that schedule, and why does it seem to be so fast?
The schedule for performing the NEPA process, and for completing the entire process of getting a new sediment collection and disposal process in place, was established in a Federal Facility Compliance Agreement (FFCA) with EPA. The FFCA was necessary because it would have been impossible for Washington Aqueduct to comply with the terms of its new NPDES permit, first issued in March 2003. EPA was legitimately concerned about how long it should take for the Washington Aqueduct, as the permittee, to fully comply with the NPDES permit by creating a new sediment residuals collection and disposal process. The schedule, therefore, reflects the need to make effective use of all the Washington Aqueduct’s decision-making time, for NEPA decisions about what alternative(s) to use, for project design, and project construction. The compliance schedule is based on the five-year term of the NPDES permit. Washington Aqueduct was able to have EPA agree to a 22 month extension beyond that to allow for all the necessary construction to accommodate all sedimentation basins, but the schedule for the fundamental decisions to include the public involvement in the process must be made in time to bring at least one sedimentation basin into compliance by March 2008.
8. Does the public have any say in the timing of this compliance schedule?
Technically, no. Because the compliance schedule was part of an enforcement and compliance action taken by EPA, no public involvement is normally required or necessary. However, in the case of this FFCA, the EPA, out of concerns expressed by the parties, made the draft FFCA, including the compliance schedule, available for public comment in April 2003. Comments received included requests both for expansion and contraction of the compliance schedule. This, along with the justifications provided for the schedule deadlines, suggested to EPA that there was no need to adjust the schedule. For more information, please visit the EPA website listed above in the answer to FAQ # 1.
9. Are the water treatment residuals toxic?
No. Water treatment residuals are generally considered non-toxic by the regulatory agencies that permit their disposal. State regulators responsible for approving residuals disposal practices throughout the United States typically permit water treatment residuals to be applied on various types of lands, including agricultural sites, forestland, and in lagoons. Prior to permitting the land disposal of water treatment residuals, state regulators typically require a sample of the residuals to be tested for toxicity to define the potential for the residuals to leach hazardous constituents into the groundwater. A standardized toxicity test, known as the Toxicity Characteristics Leaching Procedure (TCLP), is commonly required to be completed on the proposed residuals to confirm they are not toxic. Similar tests have been performed on Washington Aqueduct water treatment residuals in the past and will be performed again as part of this project. Past TCLP tests on Washington Aqueduct water treatment residuals have not found toxic levels of contaminants.

In addition to the previous testing on Washington Aqueduct residuals, the water treatment industry has also conducted toxicity testing on a variety of water treatment samples obtained from water treatment facilities throughout the country. One study of water treatment residuals toxicity data is discussed in a report, “Criteria Development for Water Treatment Plant Residuals Monofills,” published by the American Water Works Association Research Foundation (AWWARF) in 1997. This report examined the toxicity (and other traits) for water treatment residuals produced at 10 water treatment plants. In all cases, the water treatment residuals were found to be non-toxic and suitable for land disposal.

Also, during the process leading to the issuance of the new NPDES, two different studies were completed that analyzed the nature of Washington Aqueduct’s water treatment residuals discharged to the Potomac River. One component of these studies was bioassay toxicity tests. Bioassay toxicity tests are a standard tool used under regulatory guidelines to determine if a particular material causes acute or chronic toxic effects to sensitive species. The bioassay toxicity tests performed on the water treatment residuals indicated neither acute nor chronic toxicity.
10. If the water treatment residuals are not toxic, then why would EPA Region 3 issue a permit prohibiting the discharge of water treatment residuals?

EPA Region 3 did this because it was mandated to do so by the Clean Water Act. Congress established the NPDES permitting process as part of the Clean Water Act. As suggested by the word “elimination” in this acronym’s name, it was Congress’ intent to slowly reduce, then stop, the discharge of any materials to the waters of the United States. In the Clean Water Act, Congress presumed that any discharge is bad, if somehow reasonably preventable. As a result, Congress established two sets of criteria for EPA to consider when issuing permits. The first, for water quality, were meant to reduce or stop discharges to streams and water bodies if water quality was being measurably harmed. The second criteria were technology-based, and focused primarily on the known technological ability to reduce or eliminate a discharge to a water body. Even if water quality is not being affected, if it is technologically possible to reduce or eliminate the discharge, EPA is directed by the Clean Water Act to cause such actions be taken through its permitting process. Also, even if water quality is affected, if the technology criteria place stricter limits on a discharge, they are followed instead of the water quality ones. EPA applied this second set of technology-based criteria when it issued the Washington Aqueduct’s NPDES permit last year. None of this has anything to do with the actual toxicity or contents of the sediments being discharged.

EPA’s decision-making process for the issuance of Permit DC0000019 is described in the Permit Fact Sheet, available at

11. What is a monofill?
A monofill is a landfill that contains only one type of material.
12. If you were to build the monofill alternative, don’t you risk runoff of sediments back to the Potomac River? What about the safety of the drinking water supply itself?
There will be norunoff from any of the proposed residuals management and disposal facilities, including a monofill, directly to the tributaries of the Potomac River. Water runoff is considered unlikely, because the remaining water with the sediments is chemically bound to the sediments in a very strong way. However, runoff from any of the facilities would likely be processed through a permitted stormwater management facility capable of removing any excess sediment contained in the site runoff flow before it is discharged offsite. If there are any waste flows associated with the residuals treatment and disposal facilities, such as thickener overflow, monofill leachate, etc., these will likely be recycled to the Dalecarlia Forebay and treated at the Dalecarlia WTP. The water supply will be protected at all times.
13. What would the monofill look like from my property as well as public areas?
For the EIS, we are preparing computer simulations of the proposed monofill. Some of these simulations were included on the boards presented at the September 7, 2004 public meeting. In general, the height of the monofill should be low enough, when compared to the existing trees planned to remain along the Dalecarlia Boulevard side of the monofill, to minimize any visual impact from public view along Dalecarlia Parkway or from residential areas immediately north of the proposed monofill. The minimum width of the proposed tree buffer area along Dalecarlia Parkway will be 100 feet, screening the monofill from view during months when the trees are not dormant. The inside face of the tree buffer surrounding the entire monofill would also be lined with evergreen trees to maintain a visual screen during the winter months.

We expect that the homes located on the hill overlooking the proposed monofill from the northwest (i.e., such as homes located on Chalfont Place) will have a direct view of the monofill from their backyards, especially during the months when the trees around the monofill have no foliage. This view is partially obscured by an existing stand of trees located on the north edge of the Dalecarlia Reservoir. However, the existing tree screen is not as continuous as the screen along Dalecarlia Parkway. A limited view of the monofill will also be possible from MacArthur Boulevard, although the existing tree buffer between the west edge of the proposed monofill and the reservoir will be maintained.

We will investigate for the EIS screening options to minimize the visual impact of the proposed monofill on the surrounding residents. We will explore an option to construct the monofill in phases, minimizing the number of existing trees to be disturbed at any one time. This may allow the alternating use of the existing trees, and then each reseeded monofill section, to serve as a visual screen.

14. If it is built, the monofill will only last 20 years; won't you have to do something else after it is completely filled?
The limited useful lifetime and any permanent impacts from the monofill are very important considerations in the decision-making process. It is true that, if built, the monofill would never be a fully permanent solution. Another disposal alternative will be required, either instead of, or in combination with, a monofill, if it were to be built. If it were built, however, the monofill would be a permanent landscape feature.
15. Isn’t the proposed monofill located in a place where the Spring Valley project is expanding its investigations? Is there a conflict between the plans for a monofill and the Baltimore District Spring Valley investigation and clean-up plans?
Once the idea of a monofill was proposed, we began coordination with the Baltimore District's Spring Valley Project team to determine how this potential alternative would be affected by the scope and the timing of any investigation and remediation of any ordnance associated with the Formerly Used Defense Site (FUDS) at the American University Experiment Station (AUES). As of now, based on the AUES remediation schedule, we would not be able to build the monofill to meet our FFCA schedule. However, by retaining the monofill as an alternative to trucking and studying its effects in the EIS, we will have a complete understanding of whether it could ever be considered a viable alternative once the FUDS work is complete and the area is clear. Those investigations are currently scheduled to begin in 2008.