DATE: August 11, 2016
TO: Board of Mayor and Aldermen
FROM: Eric Stuckey, City Administrator
Paul Holzen, Director of Engineering
SUBJECT: Consideration of an Agreement, COF 2016-0246, between the Department of the Army and The City of Franklin for the Harpeth River, Franklin, TN Section 205
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Purpose
The purpose of this memorandum is to provide the Board of Mayor and Aldermen (BOMA) with information to consider an agreement between the Department of the Army and the City of Franklin, TN for the Harpeth River, Tennessee Feasibility Study
Background
The Harpeth River and its tributaries drain the 870 square mile Harpeth River Watershed with over 1,000 miles of streams. The watershed contains large portions of Williamson, Davidson, Cheatham, and Dickson Counties, and small portions of Rutherford and Hickman Counties, Tennessee. The Harpeth River and its tributaries are subject to frequent flooding and major flooding every few decades, with the most recent major flood occurring in May 2010. The May 2010 flood event saw devastation throughout the watershed, causing 4 fatalities and over $480 million in direct economic impacts in the Harpeth River Watershed alone. The Watershed also provides habitat to 6 federally listed endangered species in addition to one endemic snail species.
Preliminary reconnaissance, documented in the Harpeth River, Tennessee Section 905(b) reconnaissance report, dated May 2012, finds over 850 structures in the regulated floodplain within the basin, including several structures recognized by FEMA to be repetitive loss structures. These structures are primarily located in the City of Brentwood, the City of Franklin, Williamson County, and Davidson County. There are additional aquatic ecosystem issues found throughout the basin, primarily involving stream bank erosion and a loss of riparian buffer and/or wetlands. An Investigations Feasibility study was initiated in 2013 with four Non-Federal sponsors, and preliminary analysis of flood risk measures found one viable alternative located within only the City of Franklin’s jurisdiction. Additionally, the cost of the alternative is relatively low and falls well within the Continuing Authorities Project (CAP) Section 205 dollar limit. For these reasons, the Investigations study is being terminated, and the feasibility study is being resumed under CAP Section 205 with only the City of Franklin as a Non-Federal sponsor.
The identified alternative includes one structural measure and twenty-four nonstructural house elevations. The structural portion includes the addition of two 10’x18’ culverts adjacent to the Main Street Bridge near downtown Franklin, TN. The culverts will greatly increase the high flow capacity of the river. The nonstructural portion of the project includes raising 24 residential structures at an average of 4.62 feet (two of which are floodway structures). The structures would be raised to one foot above the 100-year floodplain elevation. All 24 structures are within the City of Franklin’s boundaries. The estimated total project cost of the recommended plan is $3.3M.
As part of this feasibility study, the National Economic Development (NED) plan will be confirmed. Prior to progressing into a detailed analysis and detailed cost of the recommended plan, the team will get sponsor buy in, possibly resulting in moving forward with the Locally Preferred Plan (LPP) instead of the NED plan.
Financial Impact
The shared study costs are projected to be $575,000, with the USACE cost projected to be $287,500 (50%) and the Non-Federal Sponsor’s share of such cost projected to be $287,500 (50%). Following the study there will be an additional funding opportunity for the Army Corp to participate in funding (with a City match) in the construction of the physical improvements.
Recommendation
Staff recommends approval of the Agreement between the Department of the Army and the City of Franklin.