Title
A RESOLUTION AUTHORIZING AND DIRECTING THE CITY MANAGER TO ADVERTISE FOR BIDS FOR THE NORFOLK SOUTHERN RAILROAD CULVERT IMPROVEMENT PROJECT; AND DECLARING AN EMERGENCY.
Executive Summary: The Norfolk Southern Railroad Culvert Project will involve the installation a new 36" storm sewer system to provide for improved drainage from the area between SR 303 and Owen Brown Street on the west side of the Norfolk Southern Railroad Tracks.
Body
Legislative History
14-32; authorized a construction agreement and force account with Norfolk Southern.
Purpose & Explanation
In 2004, the City hired ARCADIS to perform a study on the railroad culvert following the 2003 flood. In 2009 a second study, performed by B &N, was requested to review the findings of the ARCADIS study and to determine how several new improvements may affect the proposed design. Both studies were conducted to determine if the existing 18" diameter culvert under the railroad tracks, which is undersized for the drainage area and is prone to blockages and continual maintenance per our Public Works staff, could be upsized. The studies identified what size culvert would effectively improve drainage from the twenty four (24) acre area located on the west side of the railroad embankment between SR 303 and Owen Brown Street. The analysis indicated that while a 24" diameter pipe would meet the criteria for design, the minimum culvert diameter allowed by Norfolk Southern is 36". In addition, the downstream storm sewer system was analyzed due to the increase in pipe size from 18" to 36". The studies show that after the improvement, additional capacity will remain in the existing downstream storm sewer systems. No downstream degradation is anticipated in the Brandywine Creek Tributary due to the overall large drainage area (1,100 acres) contributing to this section of Brandywine Creek Tributary versus the relatively small drainage area (24 acres) associated with this new culvert installation.
The Norfolk Southern Railroad Culvert project will consist of the installation of approximately 150 feet of new 36" epoxy coated, smooth steel culvert under the railroad tracks and 400 feet of 36" concrete storm sewer adjacent to the railroad tracks. The alignment of this section of culvert under the trails was chosen to avoid relocation costs of existing fiber optic communication lines in the area. The new storm sewer system will connect to two outlet pipes: one is an existing 30" storm sewer near Morse Road that discharges to Village Way and eventually to the Brandywine Creek Tributary. The other connection is to an existing 24" storm sewer that discharges directly to the Brandywine Creek Tributary.
The new 36" culvert under the railroad tracks will be approximately 17 feet deep and is required by Norfolk Southern to be jacked and bored under the tracks. The remaining sections of new storm sewer that are not under the tracks can be installed by traditional open-cut methods. The project will also include new a full-height headwall, manholes and a backflow preventer which is designed to minimize the storm water from the Brandywine Creek Tributary from backing up into the new 36" storm sewer system and the west side of the tracks. After installation of the new storm sewers are completed, the existing 18" culvert will need to be grout filled and abandoned in place per Norfolk Southern requirements.
Engineer's Estimate = $486,000
Timing Considerations
Following the approval of this Resolution by City Council, the Engineering Department will advertise in the local newspaper and receive bids for this project. Following the bid opening staff will return to City Council to award the contract to the lowest and best bidder.
Fiscal Impact
X Currently Budgeted ($520,000-431 fund)
Supplemental Appropriation Required
Appropriation Not Required.
Recommendation
Suggested Action
Staff recommends that Council approve this authorization for the City Manager to advertise and receive bids for the Norfolk Southern Railroad Culvert. We are requesting an emergency clause be added to this project in order to protect the public health and welfare with improvements to the undersized infrastructure.
Submitted by,
Scott N. Schroyer, Interim City Manager
Thomas J. Sheridan, PE, PS, City Engineer
Bradley S. Kosco, PE, PS, Civil Engineer