Colonial Avenue Sewer Separation Project
Project Summary
Current Phase: Planning
Sponsor Project Manager: Mahjan Saleh, Transportation & Environmental Services
Managing Project Manager: Anup Gautam, Project Implementation
Project Description
Several residences in the vicinity of Colonial Avenue and 2nd Street in the northeast area (The Westover neighborhood) of Old Town have reported sewer backups in the basement, flooding in the backyards and flooding of the back alley between Colonial Avenue and Powhatan Street. In order to prevent the sewer backups, City of Alexandria (CITY) the City tasked an engineering consultant to conduct drainage surveys, model storm and sanitary flows, identify capacity deficiencies, and propose solutions. One of the proposed solutions involves separating the sanitary sewer from the combined sewer system and connecting it to a separate sanitary trunk sewer. This project is being undertaken to mitigate the potential for sewer basement backups from the combined sewer being over capacity during periods of significant wet weather.
Stormwater improvements have also been identified to address local flooding concerns. However, these improvements are outside the scope of this project and will be considered following implementation of the sewer separation project and subsequent monitoring.
Project Funding
Total budget: $1,328,104
Planning: $232,104
Design: $256,000
Construction: $844,000
Funding Breakdown
This project is funded using Sanitary Sewer enterprise Fund Revenues and is programmed in the City’s Capital Improvement Program.
Schedule
Planning: Fall 2023- Spring 2024
Design: Spring 2024-Spring 2025
Construction: Summer 2025
Planning Phase
Planning Overview
- Field Investigation – includes resident interview results and dye test procedures, results, and analysis.
- Detailed Survey – all storm, sanitary and combined sewers in the area have been surveyed in order to determine sewer capacity and confirm feasibility of solutions
- Conceptual Design – includes a list of design requirements, existing condition descriptions, proposed alignment alternatives, model assumptions and development, recommendations, and coordination.
- Opinion of Probable Construction Cost – includes an estimated cost of the conceptual design.
Planning Public Outreach
Residents were actively involved through interviews, providing valuable information on sewage backup and flooding events. Their input influenced the study's recommendations and conceptual design.
Contact
Mahjan Saleh
Civil Engineer III
City of Alexandria, Virginia
T&ES/Sanitary Infrastructure Division
(703) 746-4069