City Manager Montre’ Freeman provided updates on Friday about three stormwater and drainage projects in Elizabeth City.
Flora Street and Riverside Avenue Stormwater Drainage Improvements Study
The goal of this project is to identify and design appropriate solutions to resolve nuisance flooding occurring around the intersection of Flora Street and Riverside Avenue.
Water level data for the Pasquotank River indicates that this intersection has flooded due to water levels in the river approximately 40 percent of the time over the last two years.
The potential solutions should consider both flooding due to river levels (during “sunny day” conditions) and flooding during storm events, with flooding due to river levels being the primary consideration.
Alternatives being considered to address these flooding issues include raising the road surface along Flora Street and at the intersection of Flora Street and Riverside Avenue, increasing the pipe capacity conveying flows from the intersection to the river, and constructing a pond or wetland in the vacant lot adjacent to the intersection (owned by the city) to provide storage for stormwater runoff.
Construction documents, permitting applications, and cost estimates will be developed for the alternative preferred by the city. The project will also involve a presentation to the City Council and a public meeting, tentatively scheduled for the end of April.
Dawson–Hunter Streets Stormwater Improvement Study
The purpose of this project is to evaluate stormwater infrastructure in residential areas in the vicinity of Dawson, Hunter, and adjacent streets, in order to identify and prioritize new drainage/flood control projects to mitigate flooding.
These low–lying communities are directly adjacent to Charles Creek and have a history of repetitive flooding, including from tidal flows and routine storm events.
The project has involved a watershed assessment, including a desktop investigation as well as a field inventory of pipes, structures, and
ditches. The work also includes developing a hydrologic and hydraulic model to analyze the areas of interest and to assess the causes of flooding.
Flood control alternatives will be developed using the model and prioritized using criteria established as part of the project.
The city will also gather input on flood prone areas from the public via a direct mail questionnaire to property owners as well as through a public meeting, tentatively scheduled for the end of April.
Findings of the study and recommendations for flood control alternatives will be summarized in a final report to the city.
Rivershore Culvert Replacement
The purpose of this project is to replace a failing culvert structure located near the intersection of Rivershore Rd and Fairfax Ave. During inspection, the culvert was found to be in unacceptably poor condition, requiring that section of road to be closed.
Freeman said in February that a geotechnical team determined that a culvert with shallow foundations would not be feasible at this site. This was a suspected concern after the geotechnical visit last November and was confirmed later.
In summary, the soils at the site are unsuitable for too great a depth that can be conditioned to accept the culvert’s structural loads within an allowable amount of settlement. Therefore, a bridge with deep foundations is required.
The project includes a design and construction of a new bridge structure to replace the existing culvert. The new design may result in a wider
and raised roadway to meet state design requirements.
The design will also include relocation of an 8–inch water main and a 2–inch force main to allow for construction of the proposed bridge. The 2–inch force main will be removed from the existing culvert and relocated to an existing sewer manhole located on Preyer Avenue.
The existing 8–inch water main will be temporarily removed from the existing culvert and reinstalled on top of the new bridge deck.