Project is 15% overall complete. Marine work is underway and scheduled to be complete by February 2022. A project sign with bar code is installed on Stockton Parkway. Another sign will be installed on Woodlawn Park before the end of this month. The bar code can be scanned for access to the website link. Work continues in the creek (in the marine region) with construction entry from Stockton Parkway.
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The Little Hunting Creek sanitary sewer pipe serves approximately 480 homes and one church. This 12-inch diameter, cast-iron pipe, constructed in 1961, conveys wastewater (used water from cooking, laundry, bathing, and flushing toilets) to a pump station and on toward a treatment plant.
The pipe, which runs beneath Little Hunting Creek between Woodland Lane and Thomas J. Stockton Parkway for 789 feet, has developed a sag that is causing blockages and could possibly lead to pipe failure. The most effective solution identified is to excavate and replace the damaged pipe.
The interior of the Little Hunting Creek sanitary sewer pipe was inspected in 2015 using closed-circuit television cameras mounted on remote-controlled robots. Large amounts of debris and three major sags were discovered. The footage also revealed a buildup of fats, oils, and grease (FOG) throughout the pipe, which required the sewer line to be placed on a 90-day pressure cleaning schedule.
A study was conducted to investigate options for rehabilitating or replacing the pipe. The location of the pipe in a tidal creek surrounded by neighborhoods presents challenges to typical construction methods. After considering nine possible alternatives, the study concluded that using the open cut method with a coffer dam would provide the best long-term solution. This method reduces the amount of onshore work in proximity to residents; nonetheless, a significant amount of on-shore work will be necessary, such as material delivery and hauling away excavated material.
Replacing the Little Hunting Creek sanitary sewer pipe will
reduce the maintenance frequency and eliminate the need for the high level of maintenance currently required to keep the pipe operating;
prevent costly emergency repairs;
and reduce risks to public health and the environment.
The new pipe is expected to serve the community for the next 50 years.
The project design phase, which included plan and specification production, wetlands delineation, field and vegetation surveys and a geotechnical investigation was completed in June 2019. Easement acquisition was completed in August 2019. All regulatory permits and approvals were obtained by April 2020. Additional project coordination with the community was conducted through July 2020 when the project was advertised for public bids. The construction contract was awarded in December 2020. Construction is expected to be completed in August 2022.
What to Expect
This project will be awarded to a contractor through a bidding process once design is completed. Construction activities will be mobilized on both sides of Little Hunting Creek. Staging areas and access points off-site are being studied. All work will be supervised by county staff.
Every effort will be made to minimize the impact to the park and boat ramp, and to schedule construction activities to minimize interference with recreational activities. There will be no interruption to sanitary sewer service.
Project Cost and Funding Source
Replacing the Little Hunting Creek sanitary sewer is estimated to cost approximately $1.6 million. Sanitary sewer projects are funded by sewer service fees paid by residents.
Presentations to the Community
The project was presented during a community meeting held on Dec. 11, 2017, at Mount Vernon High School.