DATE: March 9, 2015
TO: Board of Mayor and Aldermen
FROM: Eric Stuckey, City Administrator
David Parker, City Engineer/CIP Executive
Paul Holzen, Director of Engineering
William Banks, Staff Engineer
SUBJECT:
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Presentation and Discussion of the Drainage Improvements to the Figuers Drive and 400-Block Battle Avenue Areas
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Purpose
The purpose of this memo is to bring forward to the Board of Mayor and Aldermen (BOMA) the presentation and discussion of the drainage improvements to the Figuers Drive and 400-Block Battle Avenue Areas.
Background
For years, there have been properties in the Figures Drive, Perkins Drive, and 400-Block Battle Avenue areas that have experienced localized flooding. During the May 2010 flood, there were approximately 10 properties that reported damage.
A professional services agreement (PSA) (COF Contract No. 2012-0144) with Neel-Schaffer, Inc. was approved on July 24, 2012, for the Battle Avenue Drainage Study. It included the development of a hydrologic and hydraulic model to determine existing conditions, flows and elevations, the development of alternative options to improve the localized flooding, and a detailed structural inspection/report of the bridge over Sharpe's Branch.
At the May 9, 2013 Capital Investment Committee (CIC) meeting, a draft Battle Avenue Drainage Study was presented. At this meeting, Figuers Drive area residents brought up the past flooding issues affecting them. After further discussions with the Board, City Engineer, and City Administrator, it was determined that staff should include the Figuers Drive, Perkins Drive, and Alicia Drive areas into the overall scope of any upcoming 400-Block Battle Avenue improvements project. Ongoing flooding is an issue for many homes in the expanded Figuers Drive area.
Survey letters were sent to area residents at the end of May 2013, so problem areas in the vicinity of Figuers Drive could be determined. In early July 2013, staff and Neel-Schaffer began monitoring the areas reported in the survey responses. On September 3, 2013, a Figuers Drive neighborhood meeting, to present and confirm our findings with the neighborhood residents, was held at Franklin Elementary School (FES). The majority of the neighborhood attended and provided staff and Neel-Schaffer with excellent information pertinent to the main areas that are prone to flooding. A summary of the collected complaints and concerns are shown in Exhibit A.
On November 26, 2013, BOMA approved a new PSA with Neel-Schaffer, Inc. for the Preliminary Engineering of the Figuers Drive Area Drainage Improvements Project (COF Contract No. 2013-0182). The drainage area (Exhibit B) included Figuers Drive, Perkins Drive, Alicia Drive, and the 400-Block of Battle Avenue. The existing 5-year flows and percentages of overall peak flow within the drainage area are shown on Exhibit C. This PSA allowed Neel-Schaffer to provide the City with a detailed preliminary plan of improvements that can be made to help the Figuers Drive area residents. Neel-Schaffer was instructed to incorporate the previous Battle Avenue Drainage Study findings and to develop a comprehensive drainage basin improvement plan.
Throughout 2014, City staff and Neel-Schaffer developed numerous design alternatives. We looked at any and all options that could make improvements for the residents. Our findings are below
Design Options and Financial Impacts
Generally, the Figuers Drive drainage basin has 3 district problem areas
1. The Figuers Drive East area near Franklin Elementary School.
2. The Figuers Drive West area, which includes the wet-weather conveyance running between 417/419 Figuers Drive and 417/419 Perkins Drive.
3. The 400-Block of Battle Avenue. The Figuers Drive East and West areas converge near Alicia Drive and drain directly to the 400-Block of Battle Avenue. The following options are detailed below:
Figuers Drive East Option 1 - Option 1 consists of improving/regrading the existing Quarry Branch channel and replacing the Figuers Drive and Perkins Drive cross drains. This option and the corresponding results table are shown on Exhibit D.
· You will see in the attached results table that for the most part, Option 1 gives protection for the homes up to a 10-year storm event. Unfortunately, 1414 Figuers would not be helped by this option. The only way to help that home is to divert upstream flows (e.g. Option 2 below).
· However, we only provide a 2-year level-of-service (LOS) at the road crossings (even with the pipe upgrades). This is because the water can still overtop low areas in the roads.
· Figuers Drive East Option 1 Preliminary Engineer's Estimate =
Construction Cost $255,957.50
10% Contingency $26,000.00
Survey, Eng., Permits $40,000.00
CEI $25,000.00
Total $346,957.50
Figuers Drive East Option 2 - Option 2 consists of concrete channel improvements along the existing Quarry Branch channel, replacing the cross drains, installing a diversion structure upstream of Figuers Drive, and building a concrete diversion channel. We attempted to keep the proposed concrete diversion channel along the eastern side of Figuers Drive, near FES. However, we determined it is not feasible to do so, because the east side of the road is in a different watershed. Also, that channel is already undersized for the amount of acreage draining to it. So, we are still showing the diversion crossing under the street to run along the west side of Figuers Drive near Perkins Drive. This option is anticipated to provide 100-year protection for affected properties. This option and the corresponding results table are shown on Exhibit E.
· Figuers Drive East Option 2 Preliminary Engineer's Estimate =
Construction Cost $844,972.50
10% Contingency $85,000.00
Survey, Eng., Permits $60,000.00
CEI $60,000.00
Total $1,049,972.50
Figuers Drive West - These improvements affect the wet weather conveyance that runs between 417/419 Figuers Drive and 417/419 Perkins Drive. This area drains to West Main Branch, which connects to Quarry Branch/Figuers Drive East. We are only presenting one option for the west area of Figuers Drive. Based on the latest analysis, it appears that upstream detention is not necessary. We are able to provide at least a 50-year LOS by upgrading the cross drains only. Local site grading will be necessary in order to prevent/solve the local/nuisance flooding issues. This option and the corresponding results table are shown in Exhibit F.
· Figuers Drive West Preliminary Engineer's Estimate =
Construction Cost $143,728.00
10% Contingency $15,000.00
Survey, Eng., Permits $13,000.00
CEI $15,000.00
Total $186,728.00
400-Block of Battle Avenue -
From the 2013 Battle Avenue Drainage Study, the original findings for the 400-Block of Battle Avenue were as follows: possible removal of a downstream pedestrian bridge, channel maintenance, Battle Avenue bridge replacement, construction of a detention basin and flood proofing. All of the alternatives explored had no impact of removing structures from the 50 and 100 year storm event. For this reason, staff did not recommend proceeding with any type of capital project.
The Figuers Drive area preliminary design supports the original study data. The area draining through the 400-Block of Battle Avenue is approximately 295 acres (Exhibit G). The only way to solve the 400-Block drainage problems is to build a series of detention ponds (Exhibit H), or one mega-detention pond. The detention basin that would provide a 100-year level of protection for the 400-Block of Battle Avenue would have to receive/control runoff from 93% of the Figuers Drive watershed and would be 15-20 acres in size. The City would have to purchase approximately 47 parcels to protect five homes along the 400-Block of Battle Avenue. Also, any improvements performed to the Figuers Drive East or West areas do not reduce the flooding impact to the 400-Block.
See Exhibit I for pictures, provided by area residents, of flooding in the 400-Block of Battle Avenue.
Financial Impact
Total project funding included as a part of FY2015 Stormwater Budget under Capital; 89410 Drainage; Various is $1,500,000.00. Because of the current project workload, approximately $24,000.00 of the current budget has been spent. Staff anticipates spending another $75,000.00 on additional design in the current budget year. The proposed FY2016 Stormwater Budget is proposed to include $800,000.00 for final design and construction, under Capital; 89410 Drainage; Various.
Recommendation
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Staff is seeking Board input on a possible drainage improvements project for the Figuers Drive area. With all of the above options, it should be noted that most of the drainage issues in the Figuers Drive area involve nuisance flooding. However, some improvements can be made to decrease the impact of future flooding.