DATE: December 22, 2014
TO: Board of Mayor and Aldermen
FROM: Eric Stuckey, City Administrator
David Parker, City Engineer/CIP Executive
Paul Holzen, Director of Engineering
Patricia Proctor, Utilities Engineer II
SUBJECT:
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Consideration of Resolution 2014-87 - A Resolution to Adopt the Southwest Basins No. 2 & No. 3 Sanitary Sewer System Study of August 2014 (01/13/15 WS)
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Purpose
The purpose of this memorandum is to provide the Board of Mayor and Aldermen (BOMA) with information to consider Resolution 2014-87 - A Resolution to Adopt the Southwest Basins No. 2 and No. 3 Sanitary Sewer System Study of August 2014.
Background
BOMA approved the design contract (COF 2014-0048) for the Southwest Basins No. 2 & No. 3 Sanitary Sewer Study on March 11, 2014. The final document dated August 2014 was submitted for Staff review in September 2014 (see Exhibit A). Both basins are located in the southwestern section of the City's Urban Growth Boundary. Southwest Basin No. 2 is comprised of approximately 2,045 acres and has an anticipated population at full development of 6,486 residents. It has borders roughly comprised of: Coleman Road to the north, Goose Creek Bypass to the east, Snowbird Hollow and West Harpeth River to the south, and Kelly Branch to the west. Southwest Basin No. 3 is comprised of approximately 2,092 acres and has an anticipated population at full development of 5,316 residents. The borders for this basin are roughly comprised of: Snowbird Hollow to the north, Lewisburg Pike to the east, West Harpeth River to the south, and Hunter Road to the west.
There are three options outlined within the study to serve the Southwest Drainage Basins No. 2 and No. 3. Option 1 is to construct a 16-inch force main to the intersection of Snowbird Hollow Road and Goose Creek Bypass to a proposed 27-inch gravity sewer line to be installed on the south side of the Goose Creek Bypass to the Five Mile Creek Interceptor sewer. These improvements would handle a total projected flow of 8.05 MGD (million gallons per day). Option 2 includes the 16-inch force main to the intersection of Snowbird Hollow Road and Goose Creek Bypass but to a proposed 24-inch gravity sewer line from this intersection to the existing 18-inch gravity sewer line along Goose Creek in the Berry Farms Development. The 18-inch gravity sewer line would also have to be upgraded to a 24-inch line. These improvements would handle a total project flow of 5.56 MGD. Option 3 is to construct the 16-inch force main the entire length to the existing 18-inch gravity sewer line in Berry Farms. The estimated total peak flow for this scenario is 5.77 MGD.
Financial Impact
The engineer's estimated costs for each option are:
Option 1 $22,489,000.00
Option 2 $21,733,000.00
Option 3 $20,142,000.00
These costs would be incurred over time as the system is built out as driven by development and funded through impact/system development fees.
Recommendation
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Staff recommends approval Option 3 for the Resolution 2014-87 - A Resolution to Adopt the Southwest Basins No. 2 & No. 3 Sanitary Sewer System Study of August 2014.