MANASOTA & PEACE RIVER BBDs Meeting Notebook 10-21-09.docx

L902
Lake Wales - Imp. BMPs Twin Lakes
Project Type Cooperative Funding
AOR(s)
Flood Protection
Basin(s) Peace River
Cooperator(s)
Lake Wales
Project Manager FRIES, GEORGE
Task Manager(s)
Status Ongoing
Description
This is a multi-year funded project to perform the Implementation of Best Management Practices (BMPs) element of
the District's Watershed Management Program (WMP) for the Twin Lakes Watershed. Implementation of BMPs
includes the following tasks: design, development of construction documents, construction permitting, land acquisition,
bidding and contractor selection, construction of the BMPs and construction engineering and inspection. The
watershed covers an area of 0.6 square miles and is located in the City of Lake Wales. The goal of this improvement
is to minimize flooding in the residential areas surrounding Twin Lakes. A Watershed Management Plan for the City of
Lake Wales was completed through a cooperative funding agreement with the District (K734). The WMP study area
included the City of Lake Wales as well as areas outside the City limits that are served by the City's drainage system.
One of the projects identified in the WMP for providing adequate flood protection is the Twin Lakes Flood Protection
project. In FY2008 the City requested $300,000 in cooperative funding to design and construct a 23-cfs pumping
station and force main from Twin Lakes to Lake Altamaha for subsequent discharge to Peace Creek through the
existing 48-inch diameter outfall. A channel/pipe connection will be constructed between the east and west lakes so
they can be controlled and pumped from a single location on the westerly edge of the two lakes. The Basin Board
provided $150,000 in cooperative funding. For FY2009 the City is requested and received the remaining $150,000 in
cooperative funding for the project.
Benefits
The project will provide the City with the ability to manage water elevations in Twin Lakes and prevent extensive
structural flooding, as well as road flooding for adjacent roads, including potentially S.R. 60. Water quality benefits
may be provided if pump discharges are run through a pre-fabricated treatment system such as a CDS or Vortex unit.
Costs
The total budgeted amount for this project is $600,000 of which the District's share is $300,000 and the City's share is
$300,000. Since this is a multi-year funded project, for FY2008 $150,000 was included in the Basin Board's
budget. For FY2009 the remaining $150,000 of cooperative funding was budgeted. The probable construction costs
are based on a BMP alternative analysis developed by the cooperator. The District's funding amounts shown in the
table include staff salaries.
Additional Information
Water levels in Twin Lakes rose significantly during 2004 and 2005. The water elevation reached 124.5 NAVD, that is
5.4 feet above the low lake guidance level of 119.10 NAVD. Seven apartments in an apartment complex located east
of the lakes flooded once and two apartments flooded on a second occasion during this time frame. Computer
modeling results indicate that flooding elevations during the 100 year/5-day storm event would exceed those in
2004-2005 by over 14 inches. Under those conditions, numerous other apartment units would also experience
flooding and water elevations would be within two feet of the S.R. 60 road grade. S.R. 60 is an evacuation route. In
addition, it is anticipated that a 100-foot portion of Grove Avenue would experience flooding depths up to 18 inches.
Currently the City does not have a readily available way to reduce lake levels. The pumping facility will utilize a
portable pumping unit to allow use of the pump at other locations and to reduce maintenance costs. The facility will
include pump connections for rapid installation of the portable pump. Funding is included to begin the implementation
of the BMP. A cooperative funding expenditure agreement with the City will be developed contingent on the approval
of future funding to complete the Implementation of BMPs. This is a multi-year funded project that will require a
cooperative funding request each fiscal year until completed. The project will be ranked and compete for funding in
future fiscal years.The City will manage the project, where the District project manager must approve any agreements
to accomplish project tasks.
020 - Peace River Basin 304