Commonwealth, Ashby, Glebe Flood Mitigation Project

The Commonwealth Avenue, Ashby Street, Glebe Road Project will mitigate flooding by installing new, larger pipes.
Page updated on March 4, 2025 at 2:06 PM
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City Hosts Virtual Community Meeting Wednesday, February 19

The City of Alexandria hosted a community meeting on February 19 to provide an update on the Commonwealth, Ashby, Glebe Flood Mitigation Project. The meeting presentation and recording can be found at the bottom of this page. 

Flood Action

Virtual Open House is Now Open

Click on the link to enter the virtual open house and learn more about the Commonwealth, Ashby, Glebe Flood Mitigation Project. Move around the room and click on each board to read additional details. 

City staff have compiled a list of frequently asked questions (FAQ) asked during the May 2024 open house and virtual public comment period. These responses can be found on the Project FAQ page. 

Overview

CAG Location map

The Commonwealth, Ashby, Glebe Flood Mitigation Project combined the top two large capacity projects will provide flood relief for the neighborhood near the intersections of Commonwealth Avenue and East Glebe Road, and Ashby Street and East Glebe Road. The proposed design includes new parallel relief sewers along Commonwealth Avenue and East Glebe Road, which will increase the capacity of the storm sewer system. Additionally, a new outfall will be installed to discharge flows to Four Mile Run. Finally, green infrastructure practices will be implemented to provide a water quality benefit to the watershed. 

• Status: In design
• Total Estimated Cost: $50,000,000
• Funding Source: Stormwater Utility, Community Flood Preparedness Fund (CFPF) grant 

Project Dashboard map

Capital Projects

Check the status of the City's flood mitigation projects using this interactive map tool.

Background

The City of Alexandria has experienced repeated and increasingly frequent flooding caused by climate change-induced storms near the intersections of Commonwealth Avenue near East Glebe Road, and East Glebe Road near Ashby Street. These increased flooding occurrences corroborate findings from the City of Alexandria’s Storm Sewer Capacity Analysis (CASSCA, 2016), which shows storm sewer networks along Commonwealth Avenue and East Glebe Road within the project area do not have adequate capacity to convey runoff from the intense storm events experienced in recent years. This increased flooding is attributed to old infrastructure, design criteria at the time of construction and climate change. 

Project stages

Planning

A project planning task was developed and awarded to the consulting firm Jacobs in early 2022. Planning tasks are the basis for the design stage of work and is conducted concurrently with the procurement of the design phase contractor. 

Planning tasks: 
• Data collection
• Modeling of existing conditions in the sewershed
• Development of high-performing alternatives to alleviate flooding

The City and the consultant identified a preferred alternative, which acts as the basis for the design stage of work. This work was performed concurrently with the procurement of the design phase contractor. 

Design

The design phase contract was advertised in early 2022 and awarded to Jacobs as the prime contractor in late 2022. Jacobs will lead a multi-discipline team for the duration of the design phase. The project will be developed in close collaboration with City staff and the community. After completion of the design, the project will be advertised for construction.

Design tasks: 
• Detailed site survey 
• Storm sewer modeling
• Development of construction drawings 
 

Construction

Construction is expected to start in Summer 2026 and be completed by Summer 2029.

On-Site: Photos from the project site

A visual look at progress on the Commonwealth, Ashby, Glebe Flood Mitigation Project. 

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A land surveyor contracted by the City uses a theodolite to measure angles on Montrose Avenue. The data collected will be incorporated into the design of the Commonwealth, Ashby, Glebe Flood Mitigation project. (City of Alexandria)
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A land surveyor contracted by the City uses a theodolite to measure angles on Montrose Avenue. The data collected will be incorporated into the design of the Commonwealth, Ashby, Glebe Flood Mitigation project. (City of Alexandria)
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A land surveyor contracted by the City plots points of infrastructure on Montrose Avenue. The data collected will be incorporated into the design of the Commonwealth, Ashby, Glebe Flood Mitigation project. (City of Alexandria)
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Staff from the City and Jacobs conducted a site walk on Nov. 15 in the neighborhoods of Commonwealth Avenue, Ashby Street and Glebe Road to understand how construction equipment will move in the area as they plan a large capacity flood mitigation project. (City of Alexandria)
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Staff from the City and Jacobs conducted a site walk on Nov. 15 in the neighborhoods of Commonwealth Avenue, Ashby Street and Glebe Road to understand how construction equipment will move in the area as they plan a large capacity flood mitigation project. (City of Alexandria)
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Jonathan Whiteleather, technical project manager, reviews a sewer map during a site visit to the neighborhood of Commonwealth Avenue, Ashby Street and Glebe Road on Nov. 15. (City of Alexandria)

News and Public Announcements

Project notices

  • March 10, 2025 – Early April: Field crews from Accumark will be conducting air vacuum test pitting, which is a safe and minimally invasive method of locating and verifying underground utilities. This information will be used for the design of storm sewers associated with the Commonwealth, Ashby, Glebe Flood Mitigation project. There are approximately 30 test hole locations throughout the project area. Residents are encouraged to be mindful of contractor crews working in roadways, traffic controls and any no parking signs.

  • August 2 – September 15, 2023: Crews will be performing geotechnical boring work starting on August 2, 2023. Work is expected to last until September 15, 2023, weather permitting. Work at each boring site will involve a day of preparation and a day of drilling, which will take place approximately one week after the prep work. There are approximately 50 boring sites along the project corridor. This work is done to test soils within the project area. Results will be used to inform the project design and construction methodology. Residents are encouraged to be mindful of contractor crews working in roadways, traffic controls and any no parking signs.

    Please see formal boring notice here.

  • November 15, 2022: Staff from the City and Jacobs conduct a site walk along Commonwealth Avenue, Ashby Street and Glebe Road.
  • Surveyors from RDA will be implementing traffic control, including mobile lane closures, along Glebe Road from Commonwealth Avenue to past Montrose Avenue on Feb. 1. Drivers should heed flaggers and stop as directed. The process is expected to take eight hours.

Past Meetings

Public Hearing on Commonwealth, Ashby, Glebe project
Public hearing help on Commonwealth, Ashby, Glebe project
Public Open House on Commonwealth, Ashby, Glebe project

City staff hosted an open house at the Leonard “Chick” Armstrong Center on September 28th, 2023 to discuss the project and answer public questions.

Public Meeting #1 - Kickoff Meeting, Feb. 21, 2023

 

Public Meeting #2 - Open House, Sept. 28, 2023

City staff shared information about the project and answered questions from the public on Thursday, September 28th at the Leonard “Chick” Armstrong Center. Display boards shared at the meeting are provided below:

 

Public Meeting #3 - Open House May 22nd, 2024

City staff shared updates and insights on key project developments. Project leaders addressed questions and concerns from the public. The meeting focused on the construction impacts of the proposed project improvements.

 

Public Meeting #4 - Virtual Meeting February 19, 2025

The City of Alexandria is hosted a community meeting on Wednesday, February 19 at 7:00 p.m. to provide an update on the Commonwealth, Ashby, Glebe Flood Mitigation Project. The meeting focused on project goals, project status, and impacts during construction. 

Contact

For the community:
Jonathan Whiteleather, P.E. 
Technical Project Manager
703.399.9392
jonathan.whiteleather@alexandriava.gov