September 6, 2002
Mr. James Hunt, P.E.
City of Orlando Engineering Department
400 South Orange Avenue, 8th Floor
Orlando, Florida 32801
Re:
Continuing Stormwater / Environmental Contract
Flood Insurance Study – John Young Parkway Corridor North of Colonial Drive
Phase I Hydrologic and Hydraulic Analysis
Dear Mr. Hunt,
WBQ Design & Engineering, Inc. is pleased to present this proposal for professional services in
connection with our continuing contract with the City of Orlando. The purpose of the project is to
establish the 100-year flood elevation for John Young Parkway corridor area between Silver Star
Road and Colonial Drive with a total area of approximate 1,200 acres. There are three separate flood
areas identified on the current FEMA map within the project boundary, which appears to have
discrepancies with the field observations. The following scope of services is based on our field
observations and communications with your office during recent scope review meetings. The first
phase of this project shall include data research, hydrologic and hydraulic analyses to establish a
floodplain elevation within project area. We understand that there are concerns regarding the
accuracy of the recently updated FEMA Flood Insurance Rate Map (FIRM) for the City of Orlando
as it relates to known topographic conditions. WBQ will review the current FIRM and identify the
problem areas, specifically within the depressional areas along John Young Parkway, the area
between Industrial Boulevard and Dineen Avenue lying south of Silver Star Road, the area between
Texas Avenue and Technology Drive, and other stormwater ponds or borrow pits in the project
boundary which are not identified on the FEMA map. As part of the Phase I services, we will
complete a basin analysis to establish a floodplain elevation and boundary for these target areas.
Please see the attached map for the study limits. A letter report summarizing the analysis will be
generated for review by the City. The scope of services is summarized below:
I.
DATA COLLECTION
WBQ will obtain existing site data within the study area, including historical hydrologic data,
records of highwater marks and flooding problems, flood control measures and hydraulic
structures that affect flooding from the City of Orlando, Orange County and the SJRWMD.
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Mr. James Hunt, P.E.
August 30, 2002
Page 2
We will also evaluate other available data specific to the study area, such as community
maps, topographic maps, surveys and elevation control data. In addition, geotechnical and
land use information will be collected for analysis. Much of the required information on the
existing stormwater collection and conveyance systems, stormwater ponds and drainwells
will be obtained from the City of Orlando, Orange County, USGS, the Florida Department of
Transportation and the appropriate water management districts. Field reconnaissance will be
performed to verify the extent and condition of the flood areas and the flood control
structures within the study area. The data collected will be utilized as the basis for the
hydrologic and hydraulic analysis to establish floodplain elevations and boundaries.
WBQ will contact the FEMA regional representatives to obtain the effective FIS study, if
available, including basic data used for hydrologic and hydraulic models.
II.
HYDROLOGIC AND HYDRAULIC ANALYSIS
WBQ will identify the flow pattern and develop a drainage basin map in the study area based
on a comprehensive review of the existing development plans, study reports and field
reconnaissance. A rainfall-runoff model using the unit hydrograph method will be developed
for each basin. Other hydrologic parameters to be used in the model, including curve
numbers (CN) and times of concentration (Tc), will be estimated in accordance with land
use, soils and topographic information. The Orange County rainfall distribution will be used
in the model.
Hydraulic routing analyses will be conducted to determine flood elevations. Since the area
discharges to Lake Lawne through a drainage canal in the middle of the depressional area, the
routing analysis will consider these factors in determining the site storage and tailwater
condition evaluation. The FEMA-approved adICPR Version 2.02 computer software will be
utilized to simulate storm events due to its features of hydrodynamic modeling, continuous
event simulation and utilization of a single unified model. The flows and stages generated by
the computer models will be used to establish the floodplain in the study area.
III.
FLOODPLAIN DELINEATION
The established floodplain boundaries will be delineated on map exhibits to be included in
the project summary report. Available topographic maps, including 1-foot contour maps
provided by the City and USGS 5-foot contour maps, will be used for the exhibit.
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Mr. James Hunt, P.E.
August 30, 2002
Page 3
IV.
SUMMARY REPORT
WBQ will summarize the Phase I analysis and findings in letter report to be submitted to the
City for review. Included in the report will be the calculations and computer models utilized
to establish the flood plain elevations within the project limits, together with the map
exhibits described in Task III, above.
We anticipate a 150-day period from the issuance of the Letter of Authorization (LOA) to complete
Tasks I through IV as detailed above. Should you have any questions or comments regarding this
proposal, please contact our office at your convenience.
Sincerely,
WBQ Design & Engineering, Inc.
Frank Fu, P.E.
Project Engineer
Enclosures
cc:
Derek C. Burke, P.E.
Jennifer Quigley
Dan L. Angel, CCS
Project File: 02-orl.joh
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