HomeMy WebLinkAbout2018 07 09 Consent 303 Gee Creek Flood StudyCOMMISSION AGENDA
ITEM 303
Informational
Consent
X
Public Hearings
Regular
July 09, 2018 SB BF
Regular Meeting City Manager Department
REQUEST:
The Community Development Department requests the City Commission's adoption of the
Gee Creek Flood Study.
SYNOPSIS:
The Gee Creek Flood Study is an engineering evaluation of the flooding that occurred along
Gee Creek and its tributaries during Hurricane Irma. The study identifies short and long
term conceptual solutions to mitigate future flooding potential where possible.
CONSIDERATIONS:
Hurricane Irma dropped approximately 14 -inches of rain in the City of Winter
Springs over a 12 -hour period on September 10 and 11, 2017. This volume of
rainfall, which exceeds the 100 -year storm event, caused significant flooding impacts
at various locations throughout the City.
Gee Creek is a major waterway that flows through the southwestern quadrant of the
city, entering the City north of Panama Circle near Murphy Road, and eventually
discharging to Soldier's Creek and Lake Jesup. Gee Creek has road crossings in the
City at Murphy Road, Edgemon Avenue, Moss Road, Hayes Road, Shore Road,
Alton Road, and SR 434.
During Hurricane Irma, significant flooding occurred along Gee Creek at many
locations, including Hacienda Village, Moss Road Bridge, Lido Road, Holiday Lane,
Mockingbird Lane, and the Edgemon Avenue Bridge. In addition, several tributaries
connecting to Gee Creek, including Little Lake Howell Creek and No Name Creek,
Consent 303 PAGE 1 OF 3 - July 09, 2018
also backed up and caused flooding in areas such as Winding Hollow, Sailfish Road,
and Alton Road.
. At the November 13, 2017 City Commission meeting, the Commission authorized
preparation of the Gee Creek Flood Study by CDM Smith. The primary purpose of
the Gee Creek Flood Study is to evaluate and determine what feasible stormwater
management improvements can be made to minimize future flooding potential at the
flood -prone locations.
. The complete Gee Creek Flood Study is attached as Exhibit A. CDM Smith
developed a series of recommendations to address flooding concerns and potentially
mitigate the effects of future significant rainfall events. These improvements, which
are described in detail in the report, are both structural and non-structural in nature
and have been organized and prioritized into the following five classes:
o Priority 1 — Maintenance: this includes activities such as culvert desilting and
removal of obstructions to restore conveyance capacity within Gee Creek.
These are relatively low-cost measures with minimal permitting burden that are
likely to improve flood control level -of -service within the City's portion of the
Gee Creek Basin and are recommended to be among the first improvements
implemented.
o Priority 2 — Local conveyance improvements: these include small drainage
improvements targeting specific residential complaints and can be expected to
provide relief of nuisance flooding for small storms and can be implemented
for relatively low cost and low permitting burden.
o Priority 3 - Bank stabilization: Findings during the field reconnaissance
indicate that bank erosion may be contributing significant volumes of sediment
to Gee Creek and impacting conveyance capacity through accumulation at
Creek ox -bows and at cross -drains. Stabilizing banks through the
implementation of sand -cement rip -rap, gabions, or other appropriate
technologies may have direct flood control benefits by reducing maintenance
burden associated with sedimentation that is occurring downstream of these
areas. These projects have ancillary benefits including improving receiving
water quality.
o Priority 4 - Major conveyance improvements: These include upgrades to
existing cross -drains, specifically those at Alton Road and Shore Road, to
remove potential hydraulic bottlenecks resulting from a decreased conveyance
capacity through the existing culverts as compared to that provided in cross -
drains upstream of these crossings. These are major improvements
representing more significant capital outlays and potential permitting
complications.
o Priority 5 - Storage improvements: These include the construction of
stormwater management facilities on vacant, undeveloped City -owned parcels
located in the upstream portion of the basin. Providing additional storage and
attenuation may mitigate local and downstream flooding issues and provide
ancillary benefits for water quality.
Consent 303 PAGE 2 OF 3 - July 09, 2018
Staff is already implementing a number of the improvements recommended in the
Gee Creek Flood Study, including:
o Federally -funded NRCS project to clear debris from the creek and to remove
sediment at major road crossings
o Federally -funded NRCS project to install sheet pile retaining walls in Hacienda
Village to minimize creek bank erosion
o Site specific grading and drainage improvement projects at 109 Lido Road and
at Brookshire Court in Winding Hollow
o Removal of major creek obstructions (fallen trees, debris, etc.) using local tree
contractors and the City's Public Works Staff
Additional flood mitigation projects and improvements in the Gee Creek Basin, as
recommended in the Gee Creek Flood Study, will be further evaluated, prioritized,
budgeted, and implemented over the next several years using current funding sources.
FISCAL IMPACT:
The City Commission's adoption of the Gee Creek Flood Study has no direct fiscal impact.
The various projects and stormwater management activities to be implemented, based on
the Study's recommendations, will go through the City's normal budgeting and approval
process.
COMMUNICATION EFFORTS:
This Agenda Item has been electronically forwarded to the Mayor and City Commission,
City Manager, City Attorney/Staff, and is available on the City's Website, LaserFiche, and
the City's Server. Additionally, portions of this Agenda Item are typed verbatim on the
respective Meeting Agenda which has also been electronically forwarded to the individuals
noted above, and which is also available on the City's Website, LaserFiche, and the City's
Server; has been sent to applicable City Staff, Media/Press Representatives who have
requested Agendas/Agenda Item information, Homeowner's Associations/Representatives
on file with the City, and all individuals who have requested such information. This
information has also been posted outside City Hall, posted inside City Hall with additional
copies available for the General Public, and posted at six (6) different locations around the
City. Furthermore, this information is also available to any individual requestors. City Staff
is always willing to discuss this Agenda Item or any Agenda Item with any interested
individuals.
RECOMMENDATION:
Staff recommends the City Commission adopt the Gee Creek Flood Study.
ATTACHMENTS:
1. Exhibit A: Gee Creek Flood Study
Consent 303 PAGE 3 OF 3 - July 09, 2018
EXHIBIT A
Report
FINAL
June 2018
Smith
Table of Contents
Section 1 Introduction and Background............................................................................ 1-1
1.1 Introduction and Purpose.....................................................................................................................................1-1
1.2 Background and Location.....................................................................................................................................1-2
Section 2 Data Collection and Review..............................................................................
2-1
2.1 General Data Inventory..........................................................................................................................................
2-1
2.1.1 Stormwater Infrastructure Database.................................................................................................
2-1
2.1.2 Aerial Imagery..............................................................................................................................................
2-2
2.1.3 Topographic Dataset..................................................................................................................................
2-2
2.1.4 Record Drawings Review........................................................................................................................
2-2
2.2 Previous Studies........................................................................................................................................................
2-5
2.2.1 Gee Creek Basin - Engineering Study and Drainage Inventory (SAI, 1996) ......................
2-5
2.2.2 FEMA Flood Insurance Study (FIS).....................................................................................................
2-8
2.2.3 City of Winter Springs TMDL Master Plan (CDM Smith, 2009) ...............................................
2-9
2.3 Hydrologic Data.......................................................................................................................................................2-11
2.3.1 Land Use Data.............................................................................................................................................2-11
2.3.2 Soils Data......................................................................................................................................................2-13
2.3.3 Hydrologic Gage Data (Precipitation, Flow, Stage).....................................................................2-13
2.4 Field Reconnaissance............................................................................................................................................2-18
Section 3 Conceptual Alternatives Identification..............................................................
3-1
3.1 Maintenance................................................................................................................................................................
3-2
3.1.1 Cross Drain Maintenance.........................................................................................................................
3-2
3.1.2 Channel Maintenance................................................................................................................................
3-2
3.2 Local Conveyance Improvements......................................................................................................................
3-4
3.3 Bank Stabilization.....................................................................................................................................................
3-7
3.4 Major Conveyance Upgrades...............................................................................................................................
3-7
3.5 Storage Improvements.........................................................................................................................................3-11
3.6 Opinion of Conceptual Capital Costs...............................................................................................................3-16
Section 4 Summary and Conclusions................................................................................ 4-1
Smith
Table of Contents • Hunters Trace Subdivision Infrastructure Assessment Report
List of Figures
Figure1 Project Location....................................................................................................................................................1-3
Figure 2 Areas of Development - 1995 Aerials.........................................................................................................2-3
Figure3 Contour Map...........................................................................................................................................................2-4
Figure 4 Locations with Reviewed Record Drawings.............................................................................................2-6
Figure5 FEMA Flood Zone Map....................................................................................................................................
2-10
Figure6 Land Use Map.....................................................................................................................................................
2-12
Figure7 Soils Map...............................................................................................................................................................
2-14
Figure 8 Hurricane Irma Cumulative Rainfall Data..............................................................................................
2-15
Figure 9 Gee Creek at SR 434 Stage Data for Hurricane Irma..........................................................................
2-16
Figure 10 Gee Creek at SR 434 Discharge Data for Hurricane Irma..............................................................
2-17
Figure 11 Lake Jesup and Gee Creek Stage Data for Hurricane Irma............................................................
2-18
Figure 12 Creek blockage in Hacienda Village........................................................................................................
2-19
Figure 13 Creek blockage downstream of Shore Road.......................................................................................
2-19
Figure 14 Creek blockage on Church on 434 Property.......................................................................................
2-19
Figure 15 Bank erosion downstream of Murphy Road.......................................................................................
2-19
Figure 16 Bank erosion within Hacienda Village..................................................................................................
2-20
Figure 17 Edgemon Ave cross -drain blockage.......................................................................................................
2-20
Figure 18 Moss Road cross -drain blockage.............................................................................................................
2-20
Figure 19 Hayes Road cross -drain blockage...........................................................................................................
2-20
Figure 20 Alton Road cross -drain blockage.............................................................................................................
2-20
Figure 21 Recommended Maintenance Locations...................................................................................................3-3
Figure 22 Improve Local Conveyance - Lido Rd (C-1) & Holiday Ln(C-2)...................................................3-5
Figure 23 Improve Local Conveyance - Sailfish Rd(C-3).....................................................................................3-6
Figure 24 Bank Stabilization - Murphy Rd to Moss Rd (B-1).............................................................................3-8
Figure 25 Bank Stabilization - Hacienda Village (B-2)..........................................................................................3-9
Figure 26 Bank Stabilization - Shore Rd to Alton Rd (B-3) & Upsize Shore and Alton Cross
Drains(U-1)...........................................................................................................................................................................
3-10
Figure27 Parcel Map.........................................................................................................................................................
3-12
Figure 28 Stormwater Management Facility at Buttonwood Ave (S-1) ......................................................
3-14
Figure 29 Stormwater Management Facilities near Moss Park (S-2 and S-3) ..........................................
3-15
Figure 30 Online Stormwater Management Facility near Murphy Road(S-4).........................................
3-17
Smith
Table of Contents • Hunters Trace Subdivision Infrastructure Assessment Report
List of Tables
Table 1 Study Area City Stormwater Inventory........................................................................................................ 2-1
Table 2 1996 Study - Summary of Gee Creek Deficiencies.................................................................................. 2-7
Table 3 FEMA FIS Peak Discharges................................................................................................................................ 2-8
Table 4 FEMA Flood Zones within the Study Area.................................................................................................. 2-9
Table 5 Land Use within the Study Area....................................................................................................................2-11
Table 6 Soil Hydrologic Groups within the Study Area.......................................................................................2-13
Table 7 Sediment Buildup in Major Cross-Drains..................................................................................................2-21
Table 8 Flow Capacities of Major Crossings of Gee Creek within City of Winter Springs
(Upstream to Downstream)............................................................................................................................................3-11
Table 9 Opinion of Conceptual Capital Costs...........................................................................................................3-16
Appendices
Appendix A Field Reconnaissance Photolog
Appendix B Conceptual Alternative Factsheets
Appendix C Opinions of Conceptual Capital Costs
Smith
Table of Contents • Hunters Trace Subdivision Infrastructure Assessment Report
This page intentionally left blank.
Smith
Section 1
Introduction and Background
1.1 Introduction and Purpose
In December 2017, the City of Winter Springs (City) retained CDM Smith Inc. (CDM Smith) to
conduct an evaluation of the portion of the Gee Creek Basin within the City limits. As a result of
heavy rains associated with Hurricane Irma that occurred on September 10 and 11, 2017,
significant flooding was observed along Gee Creek, resulting in structural damage, impassible
roads, and other adverse conditions. The areas of flooding concern noted by the City include, but
are not limited to, the following locations:
■ Gee Creek crossing under Moss Road, in the vicinity of Moss Park
■ Gee Creek crossing under Alton Road near Lido Road
■ Northern ends of Lido Road, Holiday Lane, and Mockingbird Lane
■ Structural flooding at 109 Lido Road
■ Gee Creek crossing under Costa Rica Drive near Casa Grande Drive, and intersection of Costa
Rica Drive and La Vista Drive in the Hacienda Village mobile home development, with
multiple reports of structural flooding
■ Little Lake Howell Creek crossing under Winding Hollow Boulevard
The City tasked CDM Smith with assessing the potential causes of the observed flooding and
developing preliminary concepts for structural and non-structural improvements that could
potentially mitigate future flooding in the Gee Creek Basin. This effort was divided into three
major tasks.
Task 1 included the compilation and review of available and relevant hydrologic and
hydraulic data in the Gee Creek Basin, including topography, geographic information
systems (GIS) databases, aerial photography, Environmental Resource Permit (ERP)
documentation, design plans, rainfall, flow and water level data, and previous studies. Also
included in Task 1 was field reconnaissance to investigate the existing conditions of the
identified flood -prone areas and identify any potential conveyance deficiencies along Gee
Creek. The results of these analyses and investigations are summarized in Section 2 of this
report.
■ Task 2 included the identification of conceptual improvements that can be implemented
throughout the Basin to potentially mitigate flooding. Proposed improvements include
maintenance activities on existing conveyances, local and regional conveyance
improvements, storage options, and channel stabilization. Conceptual cost estimates were
developed for the recommended improvements. The findings of the conceptual alternatives
identification task are summarized in Section 3 of this report.
Smith 1-1
Section 1 • Introduction and Background
■ Task 3 included the preparation of this report.
1.2 Background and Location
Gee Creek is located in Seminole County, Florida and flows northeast out of Lake Kathryn in the
adjacent City of Casselberry, and meanders through several residential communities before
discharging to Lake Jesup. The City of Casselberry controls flow out of Lake Kathryn by means of a
manually -operated gated spillway at Laura Street, approximately 0.7 miles upstream of the
Winter Springs city limit, which can be opened to control high water levels in Lake Kathryn or to
draw down stages in advance of an anticipated major rainfall event The majority of the creek
length lies within City jurisdiction. A second creek, No Name Creek, follows a similar flow pattern
and merges with Gee Creek approximately 1,000 feet upstream of SR 434.
The entire Gee Creek drainage basin is approximately 11.5 square miles in area. For purposes of
this evaluation, the study area refers to the Gee Creek drainage basin within the City limits (2.8
square miles). The study area includes parts of Sections 34 and 35 of Township 20 South, Range
30 East and Sections 2, 3, 10, and 11 of Township 21 South, Range 30 East. The project location is
provided on Figure 1.
1-2 Smith
..PIRP
o w
OiPj
1 ?
ALTON
_434
m
9'Pi
c9
City of Casselberry
�
3
O
gated spillway at
0
)
N
y
Laura Street
m m
n
tee
No Name Creek
Smith
Figure 1
Project Location
Gee Creek Flood Study
City of Winter Springs
Section 1 • Introduction and Background
This page intentionally left blank.
1-4 Smith
Section 2
Data Collection and Review
CDM Smith compiled a comprehensive inventory and of available and relevant hydraulic and
hydrologic (H/H) data within the study area. Besides the City, data were compiled from other
agencies and jurisdictions including Seminole County, the St. Johns River Water Management
District (SJRWMD), Florida Department of Transportation (FDOT), Federal Emergency
Management Agency (FEMA), and others. Complementing this desktop review was: a field
reconnaissance effort to verify existing H/H conditions throughout the Basin, with emphasis on
the areas reporting flooding during Hurricane Irma and the major conveyances along Gee Creek;
and, identification of potential deficiencies to be addressed in the subsequent conceptual
alternative identification task. This section summarizes the data review efforts in the Gee Creek
Basin.
2.1 General Data Inventory
2.1.1 Stormwater Infrastructure Database
The City provided a geographic information systems (GIS) inventory geodatabase, compiled by
Southeastern Surveying and Mapping Corp (SSMC), of stormwater infrastructure within City
limits. The stormwater infrastructure coverages were clipped to the study area and included
within the Gee Creek project database. The quantities for these features within the study area are
summarized below in Table 1.
Table 1 Study Area City Stormwater Inventory
Componentormwater Inventory Quantity
Cleanout 71
Culverts 17.1 miles
Headwalls 40 feet
Open Channels (manmade, not including Gee Creek or No Name Creek) 482 feet
Structures 991
Control Structure 31
Curb Inlet 160
Ditch Bottom Inlet 314
Flared End 3
Grate Top Inlet 57
Headwall 92
Manhole 150
Mitered End Treatment 104
Other Device 16
Pipe End 63
Tee 1
Ponds 51 acres
Smith 2-1
Section 2 • Data Collection and Review
2.1.2 Aerial Imagery
Recent aerial Imagery was obtained from the online FDOT A -PLUS library. The most recent
imagery is from 2015. 1995 aerial imagery from Seminole County was also obtained to identify
where development within the Gee Creek basin has occurred and may affect the replicability of
the model results from the Gee Creek Basin - Engineering Study and Drainage Inventory (SAI,
1996) under present conditions. The model was finalized in 1996 but most data collection
occurred in 1995 and prior. Both sets of imagery have been assembled to encompass the entire
Gee Creek basin to evaluate the impacts that may be outside of the study area but impact flows
entering the creek.
Areas of development were delineated based on review of the two aerials at a 1:10,000 scale and
are illustrated (against the 1995 aerials) on Figure 2. This effort did not include delineating areas
of redevelopment. Development since 1995 mainly consists of expansion of existing residential
areas and small commercial sites within the study area and more significant commercial
development on the west side of the Gee Creek basin, near Longwood. Approximately 6.2 percent
of the Gee Creek basin is new development presumably not reflected in the 1996 SAI model.
Outside of the new development, there does not appear to be any areas of major topographic
change.
2.1.3 Topographic Dataset
The study area falls within an area where there is a lack of recent topographic data. The study
area is just east of the 2005 SJRWMD LiDAR extent and just west of the 2009 SJRWMD LiDAR
extent. Therefore, the best available topographic data for the study area are 5 -foot contours,
obtained through the Florida Geographic Data Library, digitized based on latest available USGS
quadrangle maps. The USGS contours are shown on Figure 3.
2.1.4 Record Drawings Review
The following record drawings were provided to CDM Smith by the City:
■ Gee Creek Bank Stabilization -Hacienda Village (April 2008)
■ Hacienda Village Bridge Design Drawing (September 1980)
■ Hacienda Village Mobile Home Park (February 1972)
■ Hayes Road and Alton Road - Roadway and Bridge Improvements (July 1997)
■ Moss Road - Roadway and Bridge Improvements (May 1998)
■ North Orlando Ranches (April 1973, June 1979, April 1980)
■ North Orlando Terrace Box Culverts (August 1973)
■ SR 434 from SR 419 to Tuskawilla Road (February 1995)
■ Winding Hollow (December 1998)
■ Winter Springs Erosion Control Projects (March 2009)
2-2 Smith
11
Figure 3
Smith Contour Map
Gee Creek Flood Study
City of Winter Springs
Section 2 • Data Collection and Review
CDM Smith's review of the record drawings yielded several observations relevant to this study:
The Hacienda Village paving and grading plans show that many low lying areas along Gee
Creek were filled in substantially for development with no apparent volume compensation.
While not explicitly delineated within the plans, this fill likely occurred within the 100 -year
floodplain and reduced available storage within Gee Creek. In 2008, four locations along the
south bank of Gee Creek through Hacienda Village were stabilized with a combined total of
318 LF of vertical retaining wall. Per discussions with City staff, the retaining wall was
implemented at critical locations where the bank erosion was threatening to encroach
under existing structures.
■ The 2009 Erosion Control projects designed by CDM Smith included improvements within
the study area, most notably at the Gee Creek crossings under Edgemon Road and Moss
Road. The improvements for the Moss Road crossing included the removal of around 500
cubic yards of sediment obstructing the southern barrels of the bridge culvert. Field
reconnaissance for this effort revealed that in the intervening period since the construction
of the improvements, a large volume of sediment has reaccumulated at this crossing in a
manner very similar to that which existed when survey was performed in January 2009.
The North Orlando Ranches subdivision currently discharges directly to both Gee Creek
and No Name Creek. A 1979 Drainage Improvements Plan shows the plugging of a pipe
along Mockingbird Lane that provided an outfall to No Name Creek. The system was
reconfigured to outfall to Gee Creek instead.
General locations of the record drawing areas are shown on Figure 4.
2.2 Previous Studies
2.2.1 Gee Creek Basin — Engineering Study and Drainage Inventory (SAI, 1996)
Singhofen and Associates, Inc (SAI) conducted the Gee Creek Basin - Engineering Study and
Drainage Inventory for Seminole County in 1996. An H/H model of the Gee Creek basin was
developed using the Interconnected Channel and Pond Routing (ICPR) Model Version 2 and used
the MRCS curve number method for determining basin runoff volumes. Rainfall depths of 8.4 and
11.4 inches were used for the 25 -year /24-hour and 100-year/24-hour storm events,
respectively. A static tailwater elevation at Lake Jesup corresponding to the 100 -year FEMA Flood
Insurance Study (1995) stage, 9.8 ft NGVD for the 100 -year event was used. The 1996 study used
model results to analyze problem flooding areas that did not meet the level of service (LOS) goals
based on Seminole County requirements. Eight deficiencies within City of Winter Springs
jurisdiction were identified. A summary of the deficient areas within City limits is provided in
Table 2.
Smith 2-5
Figure 4
Smith Locations with Reviewed Record Drawings
Gee Creek Flood Study
City of Winter Springs
Table 2 1996 Study — Summary of Gee Creek Deficiencies
Deficiency..
16 Area
Alton Road
One of three culverts blocked by debris, E
over Gee
sediment, and vegetation resulting in 60 percent a
Creek
reduction of flow capacity. Roadway inundation f
of 10 inches in 25 -year event.
Hayes Road
Roadway inundation of 8 inches in 25 -year E
over Gee
event. No blockages or sedimentation reported.
Creek*
c
Hacienda
Roadway inundation of up to 44 inches in 25- E
Village
year event. 15 to 20 homes estimated to be t
impacted by the flood conditions. No blockages E
or sedimentation reported at bridge. r
E
r
x
f
L
Moss Road
All three culverts blocked by sediment resulting f
over Gee
in a 55 to 82 percent reduction of flow capacity. E
Creek*
Roadway inundation over 24 inches in 25 -year r
event. E
Edgemon
Culvert is blocked by sediment resulting in a 29 f
Avenue
percent reduction of flow capacity. Roadway E
over Gee
inundation of nearly 10 inches in 25 -year event. r
Creek
E
Shore Road
Culvert blocked by debris, sediment, and E
over No
vegetation resulting in 60 percent reduction of E
Name Creek
flow capacity. Roadway inundation less than 6 c
inches in 25 -year event. c
E
Moss Road
Structures under both roads are of inadequate I
and
capacity to convey 25 -year event. Roadway c
Flamingo
inundation of nearly 11 inches and 4 inches for i
Street over
Moss Road and Flamingo Street, respectively, in <-
Mosswood
25 -year event. f
Creek
E
Murphy
Drop structure just south of Edgemon Avenue
Road at
has inadequate capacity to convey the 25 -year x
Edgemon
event. Additionally, there are no swales to E
Avenue
convey roadside runoff.
Many of the deficiency areas identified in the 1996 study
problems. The issues of sediment blockage of culverts un
Edgemon Road noted in the 1996 study are comparable t
observed today. Though, one discrepancy is that Hayes R
sediment issues in the 1996 Study but was estimated at 2
CDM Smith's field review in January 2018.
Smith 2-7
Section 2 • Data Collection and Review
In general, the 1996 study model may be limited in its ability to assess flood behavior under
current conditions. As previously mentioned, 6.2 percent of the basin has experienced new
development since 1995 which could affect basin hydrologic parameters. In addition, the Hayes
Road and Moss Road bridges have been replaced since the 1996 Study. CDM Smith recommends a
more robust and current watershed model of the Gee Creek basin be developed with
accompanying survey and LiDAR to better assess the current flooding problems.
2.2.2 FEMA Flood Insurance Study (FIS)
The Seminole County FEMA FIS was last updated in 2007 for several watersheds including the
Gee Creek Watershed. The FIS notes blockage of Gee Creek and Lake Kathryn and several
downstream crossings as areas experiencing troublesome flooding over the years. According to
the report, the creek had come out of its banks, but high-water marks were not available.
According to the FIS, the flood hydrograph for Gee Creek within City limits was developed by
applying the 24-hour rainfall excess to unit hydrographs using the NRCS Type III storm
distribution. The flood hydrographs were then routed and combined using HEC -1 Flood
Hydrograph Package. A constant flow was applied to the Gee Creek system. Peak discharges
within the FEMA FIS for Gee Creek are provided in Table 3. The rainfall utilized for the 1 -percent
(100 -year) chance event is 11.3 inches. According to the FIS, the 1 -percent (100 -year) stillwater
elevation at Lake Jesup is 8.7 feet NAVD.
Table 3 FEMA FIS Peak Discharges
Within the study area, the FEMA FIS flood profile demonstrates overtopping of Alton Road and
Edgemon Avenue in the 2 -percent (50 -year) chance flood and Hayes Road and Moss Road in the
10 -percent (10 -year) chance flood. The reported floodway section areas vary greatly for Gee
Creek within the study area and demonstrate some potential constrictions along the channel. For
example, the cross-section just downstream of Moss Road has a channel opening of 640 square
feet which drops to only 260 square feet at Hayes Road.
The FEMA Flood zone coverage was obtained in GIS format and overlain onto the study area. Both
Gee Creek and No Name Creek are designated as Zone AE floodplains and regulated floodways. The
established base flood elevation (BFE) of Gee Creek ranges from 43 feet NAVD, just downstream of
Lake Kathryn, to 9 feet NAVD at its confluence with Soldier Creek just southwest of Lake Jesup. No
Name Creek has a BFE of 33 feet NAVD at Hayes Road and 16 feet NAVD upstream of its confluence
with Gee Creek. The established BFE of Lake Jesup is 8.7 feet NAVD.
2-8 Smith
5 W Peak Discharge (cfs)
P,10 -Year 50 -Year 100 -Year 500 -Year
(10% Annual (2% Annual (1% Annual(0.2% Annual
Chance).., Chance) Char te) Chance)
AtLakeJesup
At North Winter Park Drive
At State Route 419
Within the study area, the FEMA FIS flood profile demonstrates overtopping of Alton Road and
Edgemon Avenue in the 2 -percent (50 -year) chance flood and Hayes Road and Moss Road in the
10 -percent (10 -year) chance flood. The reported floodway section areas vary greatly for Gee
Creek within the study area and demonstrate some potential constrictions along the channel. For
example, the cross-section just downstream of Moss Road has a channel opening of 640 square
feet which drops to only 260 square feet at Hayes Road.
The FEMA Flood zone coverage was obtained in GIS format and overlain onto the study area. Both
Gee Creek and No Name Creek are designated as Zone AE floodplains and regulated floodways. The
established base flood elevation (BFE) of Gee Creek ranges from 43 feet NAVD, just downstream of
Lake Kathryn, to 9 feet NAVD at its confluence with Soldier Creek just southwest of Lake Jesup. No
Name Creek has a BFE of 33 feet NAVD at Hayes Road and 16 feet NAVD upstream of its confluence
with Gee Creek. The established BFE of Lake Jesup is 8.7 feet NAVD.
2-8 Smith
Section 2 • Data Collection and Review
Table 4 FEMA Flood Zones within the Study Area
FloodFEMA
Zone
Area Area
(Acres)
A
96
5.3% Areas within 100 -year (1 -percent annual chance) with
BFEs not defined
AE
152
8.4% Areas within 100 -year (1 -percent annual chance) with
BFEs defined
AH
0.5
0.0% Areas with 1 -percent annual chance of shallow (1-3 ft
depth) flooding with BFEs defined
X
1,565
86.3% Areas outside 100 -year floodplain
There are many residences within both the Gee Creek and No Name Creek floodplains. There are
52 residences within Hacienda Village that lie in the Gee Creek floodplain. Many of these homes
were constructed in the 1970s at ground level, prior to floodplain ordinances, and were not
elevated to protect the home against flood damage. During a field visit, a newly constructed
manufactured home at the end of Casa Grande Court appeared to be elevated approximately 2
feet from ground level; per Section 8-52 of the City's Code of Ordinances, finished floor elevations
of new construction must be elevated at least 18 inches above an established base flood elevation.
Additional residences within the floodplain include 11 buildings at Mosswood Apartments, 4
homes on Sailfish Road, and 1 house along the Sweetgum Court cul-de-sac. Flood zones are
illustrated on Figure 5.
Through discussions with the City, it does not appear that there are any repetitive loss properties
within the study area. For a property to be considered repetitive loss, it must have 2 or more
claims of more than $1,000 paid by the National Flood Insurance Program (NFIP) within any 10 -
year period. Mitigation of these properties is typically done through buyouts, relocation, or
floodproofing.
2.2.3 City of Winter Springs TMDL Master Plan (CDM Smith, 2009)
In 2009, CDM Smith developed a Total Maximum Daily Load (TMDL) Master Plan for the City of
Winter Springs to evaluate available pollutant loading reduction strategies to improve water
quality in downstream Lake Jesup. The master plan included a review of water quality data for
major waterbodies within the City limits, including Soldiers Creek, Gee Creek, Howell Creek, and
Bear Creek. Gee Creek was found to have an average total phosphorus (TP) concentration of
0.114 milligrams per liter (mg/L) and an average total nitrogen (TN) concentration of 1.14 mg/L
at SR 419. Further downstream at the confluence of Soldiers Creek and Gee Creek, the average TP
and TN concentrations are 0.128 mg/L and 1.74 mg/L, respectively. According to the TMDL
Master Plan, the water quality targets for Lake Jesup are 0.096 mg/L for TP and 1.27 mg/L for TN.
Smith 2-9
Section 2 • Data Collection and Review
Based on the TMDL Master Plan, the Gee Creek subbasin contributes 8 percent of the TN loading
and 9 percent of the annual TP loading for the entire Lake Jesup basin. Four structural pollutant
load reduction options were proposed in the Gee Creek subbasin. The preferred option consisted
of construction of a wet detention pond on City -owned property on the west side of the North
Orlando Terrace subdivision near Buttonwood avenue. An area of 77 acres of residential
development that currently discharges directly to Gee Creek would be re-routed to flow into the
pond for pollutant removal. The outfall of the pond would flow into a tributary of Gee Creek,
located north of Alderwood Street. This BMP option was anticipated to reduce the TP loading to
Lake Jesup by 6.8 pounds per year. This particular recommendation could also provide flood
control benefits relevant to the goals of this study; further detail regarding adapting this
alternative as a flood control BMP is provided in Section 3.5.
2.3 Hydrologic Data
2.3.1 Land Use Data
CDM Smith compiled soils and land use data in support of the Gee Creek flood evaluation. Land
use data were available from SJRWMD (2014) and are shown on Figure 6. The total acreage of
the Gee Creek basin within the study area is approximately 1,813 acres. Residential land uses
comprise over 65 percent of the study area. The remaining land consists of mostly wetlands,
forest, commercial, and transportation, communications, and utilities. Table 5 provides the
complete statistics of land use within the study area.
Table 5 Land Use within the Study Area
:W_
FP
Low Density Residential
77
4.3%
Medium Density Residential
936
51.6%
High Density Residential
172
9.5%
Commercial and Institutional
102
5.6%
Open Land
4
0.2%
Forest
108
5.9%
Water
40
2.2%
Wetlands
302
16.7%
Transportation, Communications, and Utilities
72
4.0%
Total
1,813
100.0%
Smith 2-11
Figure 6
Smith Land Use Map
Gee Creek Flood Study
City of Winter Springs
Section 2 • Data Collection and Review
2.3.2 Soils Data
The soils coverage for the study area was obtained from MRCS and is shown on Figure 7. The
area is mainly comprised of Type A/D, Type A soils, and Urban Land. The Urban Land
classification does not have an associated hydrologic soil group and generally represents the
residential communities within the study area. Type A soils are well -drained with a low runoff
potential and constitute nearly 22 percent of the study area. Type A/D soils are very poorly
drained and are most prevalent in the low-lying wetland areas. Table 6 provides the complete
statistics of soil hydrologic groups within the study area.
Table 6 Soil Hydrologic Groups within the Study Area
2.3.3 Hydrologic Gage Data (Precipitation, Flow, Stage)
Hydrologic gage data near the study area were reviewed to summarize peak stages, flows, and
cumulative rainfall associated with Hurricane Irma. Hurricane Irma made landfall in southwest
Florida near Marco Island on September 10, 2017 as a Category 3 storm. It continued on a north-
northwest path through west Florida. At its closest point, the eye of Irma was about 65 miles west
of the Gee Creek study area, although the rain bands fully encompassed the east -west extents of
the state.
The closest SJRWMD rainfall gage to the study area is Station 09992839, located 3.2 miles
southeast of SR 434 at Gee Creek. According to the data recorded at this gage, the area
experienced 11.02 inches of rain on September 10. This closely resembles the FEMA FIS 100-
year/24-hour rainfall estimate of 11.3 inches. According to Station 09992839, only about 0.3
inches of rain fell on the following day of September 11. As shown on Figure 8, the rainfall from
Hurricane Irma was not evenly distributed throughout the day; over a third of the rain fell
between 11 a.m. and 3 p.m. Data from a NOAA station at the Sanford Airport, 6.5 miles northeast
of Gee Creek, was also reviewed, but it had several data gaps and thus was not included in this
analysis. City staff indicated the rainfall experienced in the study area was closer to about 14
inches based on measurements taken at a local police station.
Smith 2-13
Type A
392
21.6%
Type A/D
795
43.9%
Type B/D
34
1.9%
Type C/D
16
0.9%
Water
26
1.4%
Urban Land
550
30.3%
Total
11813
100.0%
2.3.3 Hydrologic Gage Data (Precipitation, Flow, Stage)
Hydrologic gage data near the study area were reviewed to summarize peak stages, flows, and
cumulative rainfall associated with Hurricane Irma. Hurricane Irma made landfall in southwest
Florida near Marco Island on September 10, 2017 as a Category 3 storm. It continued on a north-
northwest path through west Florida. At its closest point, the eye of Irma was about 65 miles west
of the Gee Creek study area, although the rain bands fully encompassed the east -west extents of
the state.
The closest SJRWMD rainfall gage to the study area is Station 09992839, located 3.2 miles
southeast of SR 434 at Gee Creek. According to the data recorded at this gage, the area
experienced 11.02 inches of rain on September 10. This closely resembles the FEMA FIS 100-
year/24-hour rainfall estimate of 11.3 inches. According to Station 09992839, only about 0.3
inches of rain fell on the following day of September 11. As shown on Figure 8, the rainfall from
Hurricane Irma was not evenly distributed throughout the day; over a third of the rain fell
between 11 a.m. and 3 p.m. Data from a NOAA station at the Sanford Airport, 6.5 miles northeast
of Gee Creek, was also reviewed, but it had several data gaps and thus was not included in this
analysis. City staff indicated the rainfall experienced in the study area was closer to about 14
inches based on measurements taken at a local police station.
Smith 2-13
Figure 7
Smith Soils Map
Gee Creek Flood Study
City of Winter Springs
12.00
10.00
U
v 0.00
FC 6.00
�4
N
4.00
2.00
0.00
Section 2 • Data Collection and Review
SJRWMD Gage 09992839 - September 10th Cumulative Rainfall
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
c-1 c-1 r-1 c-1 c-1 r-1
Figure 8
Hurricane Irma Cumulative Rainfall Data
USGS Gage 02234400, Gee Creek Near Longwood, FL, is located at SR 434 and Gee Creek and has
collected data since 1972. This gage collects mean daily discharge data, reported in cubic feet per
second (cfs), and stream water level data, reported as feet NAVD 88. On September 11, the mean
stage and discharge estimated at this site peaked at approximately 15.6 feet and 765 cfs,
respectively. These values are the highest of all data collected for this gage's period of record.
Data reported for September 10 and 11 is noted by USGS as estimated, potentially due to loss of
power and other storm -related incidents that may have affected the data collection. Graphs of the
stage and flow data from the USGS gage are provided on Figures 9 and 10 and have been
compared to the FEMA FIS and 1996 100-year/24-hour model results.
Smith 2-15
Section 2 • Data Collection and Review
18
16
a
14
Q 12
(a
� 10
00 8
Q
z
6
P=
0
September 2017 - USGS Gage 02234400 (SR 434 over Gee Creek)
*t 15.6
--*-- USGS Gage
1996 Model (11.4 inches, For
Comparison Only)
FEMA FIS (11.3 inches, For
Comparison Only)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
O O O O O O O O O O O O O O O O O O O O O
Figure 9
Gee Creek at SR 434 Stage Data for Hurricane Irma
2-16 Smith
Section 2 • Data Collection and Review
September 2017 - USGS Gage 02234400 (SR 434 over Gee Creek)
1500
1400
1300
1200
v
1100
>
1000
0 900
c
v 800
Figure 10
Gee Creek at SR 434 Discharge Data for Hurricane Irma
Gage data at Lake Jesup, SJRWMD Gage 01410650 were reviewed to determine the impact of
tailwater conditions in Lake Jesup on the Gee Creek system. According to the gage, Lake Jesup did
not peak until September 24, 2017, 14 days after Hurricane Irma passed through Central Florida.
Lake Jesup peaked at approximately 7 feet NAVD, nearly 2 feet below the FEMA FIS 100 -year Still-
water stage. Lake Jesup slowly receded over the remainder of 2017, recovering to its pre -Irma
stage on December 26, 2017. The hydrograph of the SR 434 gage has been compared to the Lake
Jesup hydrograph, as shown on Figure 11, to assess the tailwater influence. SR 434 over Gee
Creek is located about 4,500 feet upstream of the Gee Creek confluence with Lake Jesup.
Smith 2-17
Section 2 • Data Collection and Review
14
Comparison of September 2017 Stages at SR 434 and Lake Jesup
8
Q
z
6
I=
Fj
0
--*--SJRWMD Gage 01410650 (Lake
Jesup)
FEMA FIS (For Comparison
Only)
--*--USGS Gage 02234400 (SR 434)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
N N N N N N N N N N N N N N N N N N N N N N N N N N N N N N
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
O O O O O O O O O O O O O O O O O O O O O
Figure 11
Lake Jesup and Gee Creek Stage Data for Hurricane Irma
The graph on Figure 11 indicates that the main cause of flooding along Gee Creek may not be
dependent on tailwater conditions of Lake Jesup. Residents in the study area reported that the
residential and street flooding occurred during and immediately after Hurricane Irma, not several
weeks later. Thus, it is anticipated that the main cause of flooding is due to lack of capacity in the
creek itself to convey high flows.
2.4 Field Reconnaissance
On January 17 and 23, 2018, CDM Smith performed site visits to evaluate conveyance of Gee
Creek within the study area. With the exception of some densely vegetated stretches, nearly the
entire creek was walked within the study area. CDM Smith focused on determining where
obstructions, such as downed trees or constrictions, could have impacted the creek's ability to
convey floodwaters during rainfall events. Overall, the creek and its associated cross drains were
found to have several potential deficiencies that could limit capacity and therefore, conveyance.
2-18 Smith
Section 2 • Data Collection and Review
There were several trees that blocked the main channel of Gee Creek, most notably throughout
Hacienda Village (Figure 12), just downstream of Shore Road (Figure 13), and along the Church
on 434 property (Figure 14). A wire fence traverses the creek behind (north) of a residential
Figure 12 Creek blockage in Hacienda Village
Figure 14 Creek blockage on Church on 434 Property
p
a
-
r,.
Figure 15 Bank erosion downstream of Murphy Road
Smith
Figure 13 Creek blockage downstream of Shore Road
property located at 80 Holiday Lane. This fence
had accumulated some debris such as
branches and vegetation which limits the
channel capacity. Without removal or
maintenance of this fence, it is anticipated it
will continue to become clogged with debris,
potentially affecting upstream stages.
Sedimentation and bank erosion was also
observed to be a significant issue in sections of
the creek. There were several stretches of the
creek where the banks had near vertical walls
from erosion and washout. Specifically, Gee
Creek between Murphy Road and Moss Road
(Figure 15), along Hacienda Village (Figure
16), and between Shore Road and Alton Road
had the most serious erosion.
2-19
Section 2 • Data Collection and Review
Figure 16 Bank erosion within Hacienda Village
Figure 18 Moss Road cross -drain blockage
Figure 19 Hayes Road cross -drain blockage
2-20
Figure 17 Edgemon Ave cross -drain blockage
Additionally, four cross drains had major
sediment deposit creating a reduction in flow
capacity. The cross drain at Edgemon Avenue
(Figure 17) had one of the three barrels about
75 percent blocked with sediment. At Moss
Road (Figure 18) one of the two barrels was
essentially fully blocked with sediment. The
cross drain under Hayes Road (Figure 19) is a
single barrel that was estimated at 35 percent
sediment blockage. At Alton Road (Figure 20),
one of the three barrels was nearly fully
blocked with sediment. Table 7 summarizes
the cross drains' estimated combined percent
blockage for all pipes at each crossing.
Figure 20 Alton Road cross -drain blockage
Smith
Section 2 • Data Collection and Review
Table 7 Sediment Buildup in Major Cross -Drains
Number ElEffirossing
Location ilktimated
BlockageIrrossing
Percent
1
Murphy Road
< 5%
2
Edgemon Avenue
25%
3
Moss Road
50%
4
Costa Rica Drive
< 5%
5
Hayes Road
35%
6
Shore Road
< 5%
7
Alton Road
30%
8
SR 434/SR 419
0%
9
Cross Seminole Trail
0%
The stretches where the bank washout was observed during field review also corresponds with
the locations where the most cross drain sedimentation was observed. For example, Hayes Road
is located just downstream of Hacienda Village. Therefore, it is presumed that the bank erosion
may be directly contributing to the cross -drain sediment buildup at Hayes Road.
It was also noted that two cross -drains in the downstream -half of the Creek length at Shore Road
and Alton Road are significantly smaller (i.e., less capacity) than the rest of the major crossings in
the City limits. Field measurements indicated that the Shore Road cross -drain consists of three
54 -inch reinforced concrete pipe (RCP) culverts, the combined capacity of which is significantly
less than that of the next upstream crossing at Hayes Road, a 28 -feet wide by 8 -feet high
CON/SPAN®-style bridge culvert. Furthermore, field measurements indicate that the next
downstream culvert at Alton Road, where significant flooding was observed during Hurricane
Irma, is even smaller with three 48 -inch RCP culverts. The inconsistent and regressive condition
of cross -drain capacities in this area of the basin have the potential to contribute to observed
flooding.
The field visit also included a review of some City -owned land where potential BMP storage
alternatives may be implemented. There is unused, City -owned land owned just upstream of
Moss Park and at Buttonwood Avenue. This land was undeveloped as of the February 2018 field
review.
A full log of photographs taken during CDM Smith's field review are provided in Appendix A.
Smith 2-21
Section 2 • Data Collection and Review
This page intentionally left blank.
2-22 Smith
Section 3
Conceptual Alternatives Identification
Following the review of relevant data and field reconnaissance summarized in Section 2, CDM
Smith developed a series of recommendations to address flooding concerns and potentially
mitigate the effects of future significant rainfall events. These improvements are both structural
and non-structural in nature and have been organized and prioritized into the following five
classes:
1. Priority 1- Maintenance: this includes activities such as culvert desilting and removal
of obstructions to restore conveyance capacity within Gee Creek. These are relatively
low-cost measures with minimal permitting burden that are likely to improve flood
control level -of -service within the City's portion of the Gee Creek Basin and are
recommended to be among the first improvements implemented.
2. Priority 2 - Local conveyance improvements: these include small drainage
improvements targeting specific residential complaints and can be expected to provide
relief of nuisance flooding for small storms and can be implemented for relatively low
cost and low permitting burden.
3. Priority 3 - Bank stabilization: As described in Section 2, findings during the field
reconnaissance indicate that bank erosion may be contributing significant volumes of
sediment to Gee Creek and impacting conveyance capacity through accumulation at
Creek ox -bows and at cross -drains. Stabilizing banks through the implementation of
sand -cement rip -rap, gabions, or other appropriate technologies may have direct flood
control benefits by reducing maintenance burden associated with sedimentation that is
occurring downstream of these areas. These projects have ancillary benefits including
improving receiving water quality.
4. Priority 4 - Major conveyance improvements: These include upgrades to existing cross -
drains, specifically those at Alton Road and Shore Road, to remove potential hydraulic
bottlenecks resulting from a decreased conveyance capacity through the existing
culverts as compared to that provided in cross -drains upstream of these crossings.
These are major improvements representing more significant capital outlays and
potential permitting complications.
5. Priority 5 - Storage improvements: These include the construction of stormwater
management facilities on vacant, undeveloped City -owned parcels located in the
upstream portion of the basin. Providing additional storage and attenuation may
mitigate local and downstream flooding issues and provide ancillary benefits for water
quality.
Smith 4-1
Section 3 • Conceptual Alternatives Identification
This section summarizes the proposed improvements and includes figures illustrating conceptual
plan views of each improvement. A summary sheet showing the details of each proposed
improvement are provided in Appendix B. A table of conceptual cost estimates of the
recommendations is provided below with detailed cost breakdowns provided in Appendix C.
It should be noted that no quantitative analysis of the anticipated flood control benefit of any of
the proposed improvements has been performed, and along with these improvements, CDM
Smith recommends an update of the existing H/H modeling in the Gee Creek Basin with
alternatives modeling of these improvements to verify their projected benefit to flood control LOS
in the basin.
3.1 Maintenance
Figure 21 illustrates the locations with identified maintenance needs to restore conveyance
capacity of Gee Creek and its major crossings.
3.1.1 Cross Drain Maintenance
A total of four cross drains have been identified for major maintenance operations. These cross
drains are at Gee Creek crossings at Edgemon Avenue, Moss Road, Hayes Road, and Alton Road
with estimated blockages of 25, 50, 35, and 30 percent, respectively. Cleanout of these structures
at the earliest opportunity is recommended to allow the culverts to provide their full design
capacity. Moving forward, it is recommended that inspection and maintenance of these cross
drains is undertaken as frequently as practicable. The City's National Pollutant Discharge
Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Permit (FLS000038-
04) prescribes an inspection regimen for pipes and culverts of at least 10 percent of the total
number of structures in the City's inventory every year, with all structures being inspected at
least once every 10 years. Given the propensity for significant sediment accumulation at these
crossings, it is recommended that the City prioritize these cross drains for annual inspection, if
possible, and maintain the cross drains as needed to assure proper operation.
Three crossings at Murphy Road, Costa Rica Drive, and Shore Road over Gee Creek had minor
blockages and have been classified as minor maintenance. The Murphy Road and Shore Road
cross drains have minor sediment buildup, and the Costa Rica Drive bridge has some branches
obstructing flow. These three instances were only estimated to reduce the capacity of the
crossings by about 5 percent. As with the aforementioned crossings, inspection and maintenance
of these crossings is recommended be undertaken as frequently as practicable given the
importance of the cross drains to conveyance capacity of the Gee Creek system.
3.1.2 Channel Maintenance
Five general locations within Gee Creek have obstructions that are currently reducing the
channel's flow capacity. Downed trees, that traverse the channel, were observed during the field
review throughout Hacienda Village, downstream of Shore Road, Alton Road, and a power
easement, and throughout Gee Creek adjacent to the First Baptist Church of Winter Springs. At 80
Holiday Lane, a wire fence traverses the creek behind (north) of the residential property. This
fence is recommended for removal so that it does not continue to become clogged with debris,
potentially affecting upstream stages and reducing flow capacity.
3-2 Smith
ALTON A 7
v Down trees
A 5
Gee Creek
--E46
m
0
z
Down trees
Down trees
N
No Name Creek
Legend
N
Study Area Major Crossings - Maintenance Needs 1 inch = 2,000 feet
0 Misc Maintenance 0 Sediment/Debris Cleanout (Major) 0 1,000 2,000
—Streets
GeeCreekCreek Sediment/Debris Cleanout (Minor)
Feet
No Name Creek ® Satisfactory
Smith
Figure 21
Recommended Maintenance Locations
Gee Creek Flood Study
City of Winter Springs
Section 3 • Conceptual Alternatives Identification
3.2 Local Conveyance Improvements
Several localized areas of flooding were reported during Hurricane Irma, especially in the North
Orlando Ranches subdivision at the northern ends of Lido Road, Holiday Lane, and Mockingbird
Lane and at the eastern end of Sailfish Road. For these locations, field reconnaissance revealed a
general lack of positive outfalls for these areas. To improve flood control level -of -service for these
locales, minor conveyance improvements are proposed including the construction of new curb
inlets and storm sewer to connect to existing systems.
Concept C-1 is located on the northern end of Lido Road and includes two new curb inlets
and 15 -inch RCP storm drains to connect to existing storm sewers along Lido Road. The
project also includes the installation of a secondary outfall to an existing drainage ditch
running along the powerlines at the northern boundary of the subdivision to provide relief
for the existing outfall at 109 Lido Road. The project is illustrated on Figure 22.
■ Concept C-2 is located on the northern end of Holiday Lane and Mockingbird Lane and
includes two new curb inlets and 15 -inch storm drains to connect to an existing outfall to
No Name Creek located on Mockingbird Lane. The project is illustrated on Figure 22.
■ Concept C-3 is located on the eastern end of Sailfish Road and includes two new curb inlets
and 15 -inch RCP storm drains to connect to existing storm sewers along Mockingbird Lane.
The project is illustrated on Figure 23.
These projects are anticipated to provide benefits for small storms and nuisance flooding, but
benefits for large events like Hurricane Irma will be limited by tailwater conditions in Gee Creek
and No Name Creek.
3-4 Smith
Figure 22
Smith Improve Local Conveyance - Lido Rd (C-1) & Holiday Ln (C-2)
Gee Creek Flood Study
City of Winter Springs
I •1
01
0
•
�N
-25 LF
p
• • SAILFISH RD Q U
cn
• w
• -285 LF a
z
z
Ir-
W
Legend
• Existing Structures Proposed Structure
N
Existing Culverts O Inlet 1 inch = 150 feet
o Existing Ponds O Manhole 0 75 150
D Parcels Proposed 15" Pipe Feet
=City of Winter Springs Parcel
Smith
Figure 23
Improve Local Conveyance - Sailfish Rd (C-3)
Gee Creek Flood Study
City of Winter Springs
Section 3 • Conceptual Alternatives Identification
3.3 Bank Stabilization
As mentioned previously, significant bank erosion was noted throughout the project area and
may be contributing to the large volumes of sediment accumulating at the major crossings in the
Gee Creek Basin. Reducing this sediment transport may have direct benefits for flood control
level -of -service in the basin. CDM Smith identified three areas of concern for focused
implementation of bank stabilization efforts.
■ Concept B-1 is located along Gee Creek between Murphy Road and Moss Road, where
several areas of significant bank erosion were noted during field reconnaissance. The
project is illustrated on Figure 24. Five segments totaling 710 linear feet (LF) of channel
are identified for bank stabilization improvements on both banks.
Concept B-2 is located along Gee Creek within the Hacienda Village development, where
several areas of significant bank erosion were noted during field reconnaissance. The
project is illustrated on Figure 25. Five segments totaling 1,075 LF of channel are identified
for bank stabilization improvements on both banks.
Concept B-3 is located along Gee Creek between Shore Road and Alton Road, where several
areas of significant bank erosion were noted during field reconnaissance. The project is
illustrated on Figure 26. Three segments totaling 680 LF of channel are identified for bank
stabilization improvements on both banks.
There are several methods for bank stabilization that may be applicable to these stretches of Gee
Creek, including rip -rap, gabion walls, sheet -pile retaining walls, and others. For the purposes of
developing preliminary cost estimates, CDM Smith assumed the use of sand -cement rip -rap,
which has been implemented successfully in the stretch of Gee Creek between Hayes Road and
Shore Road.
3.4 Major Conveyance Upgrades
As mentioned previously, it was noted during field reconnaissance that the crossings at Shore
Road and Alton Road have significantly smaller hydraulic capacities than the other major
crossings of Gee Creek, both upstream and downstream. Table 8 lists the cross-sectional flow
area of the major crossing through the system, and as demonstrated in the Table, the Alton Road
crossing, which flooded during Hurricane Irma, has only 17 percent of the capacity of the Hayes
Road crossing upstream, and 12 percent of the capacity of the SR 434 crossing downstream.
Smith 3-7
N
Z-
0
N
N
fl �
ee
• dee
z
•
�e DOLPHIN RD
5
W BAHAMA RD
cP't—
Ada
a,
Legend N
Bank Stabilization (710 LF) C=I Parcels 1 inch = 250 feet
• Existing Structures =City of Winter Springs Parcel
Existing Culverts 0 125 250 Feet
o Existing Ponds
Smith
Figure 24
Bank Stabilization - Murphy Rd to Moss Rd (B-1)
Gee Creek Flood Study
City of Winter Springs
OPv�O S�
E SR 434
co09-
st
I,
u11 ��'�►�i� � �r'�\111,
Vii.. ►1111 X111. ..__ f. ���� 1!!1/�i. •
Legend N
GeeCreek o Parcels 1 inch = 350 feet
• Existing Structures =City of Winter Springs Parcel 0 175 350
Existing Culverts Bank Stabilization (1,075 LF Total)
o Existing Ponds Existing Retaining Wall (318 LF) Feet
�w
Figure 25
Smith Bank Stabilization - Hacienda Village (B-2)
Gee Creek Flood Study
City of Winter Springs
PEARL -RD
1A V
G% e Creek
ALTON RD
SILVER CRE
EK DR
up
06
•
69
•
f2
O
N fl •
fl •
Legend N
Bank Stabilization (B-3, 680 LF) C=l Parcels 1 inch = 250 feet
Upsize cross drains (U-1) =City of Winter Springs Parcel
• Existing Structures 0 125 250 Feet
Existing Culverts
Figure 26
Smith Bank Stabilization - Shore Rd to Alton Rd (B-3) & Upsize Shore and Alton Crossdrains (U-1)
Gee Creek Flood Study
City of Winter Springs
'- r i -n 3 • Conceptual Alternatives Identification
Table 8 Flow Capacities of Major Crossings of Gee Creek within City of Winter Springs (Upstream to
Downstream)
It is possible that the bottleneck represented by the Alton Road and Shore Road cross -drains
could be contributing to the flooding seen at Alton Road, as well as adversely affecting upstream
flood stages. Upsizing these cross -drains may improve flood control level -of -service in the area
but should be confirmed through H/H modeling.
Figure 26 illustrates the culverts identified for upsizing in proposed Concept U-1. At this time,
CDM Smith cannot provide a recommended size, as detailed H/H modeling will be required to
determine the level -of -service currently provided and identify a feasible alternative. In the
interest of developing a planning -level cost estimate for the City, CDM Smith assumed that both
crossings could feasibly be replaced with triple 4 -foot by 5 -foot concrete box culverts with
minimal modifications to the existing roads, which serves as the basis for the conceptual cost
estimate provided below. However, this is an estimate for planning purposes and any final
recommendations based on detailed modeling may vary.
Upsizing the Shore and Alton Road crossings may carry advanced permitting requirements, as
regulators may interpret the improvements as increasing flows and pollutant loading to the
receiving water (Lake Jesup). Compensatory storage, perhaps from one of the storage
improvements proposed below, may be necessary to facilitate permitting.
3.5 Storage Improvements
In general, there are few City -owned, undeveloped properties within the Gee Creek Basin. Parcel
ownership within the study area (Figure 27) was reviewed to help identify potential
improvement locations not requiring right-of-way acquisition. Most of the study area is privately
owned, residential property. One FDOT parcel with a wet detention pond exists southwest of SR
434 over Gee Creek. It did not appear there was ample room to use this parcel to either expand
the existing pond or excavate a new one. One large City -owned, undeveloped parcel at the
southeast corner of the study area was reviewed but was not a viable option for an improvement
location based on its wetlands coverage and the preliminary topographic data.
Smith 3-11
1 1;4�m 0, 19i'l-'T17-1
anglam
0 4 . . 0 1
-i mi
Murphy Road
Quadruple 12 ft by 4 ft
192
< 5
182
Edgemon Avenue
Triple 12 ft by 4 ft
144
25
108
Moss Road
Double 24 ft by 6.5 ft
312
50
156
Costa Rica Drive
29 ft by ^23 ft
449
< 5
426
Hayes Road
28 ft by 8 ft
224
35
146
Shore Road
Triple 54 -in RCP
48
< 5
45
Alton Road
Triple 48 -in RCP
38
30
26
SR 434/SR 419
Triple 11 ft by 10 ft
330
0
330
It is possible that the bottleneck represented by the Alton Road and Shore Road cross -drains
could be contributing to the flooding seen at Alton Road, as well as adversely affecting upstream
flood stages. Upsizing these cross -drains may improve flood control level -of -service in the area
but should be confirmed through H/H modeling.
Figure 26 illustrates the culverts identified for upsizing in proposed Concept U-1. At this time,
CDM Smith cannot provide a recommended size, as detailed H/H modeling will be required to
determine the level -of -service currently provided and identify a feasible alternative. In the
interest of developing a planning -level cost estimate for the City, CDM Smith assumed that both
crossings could feasibly be replaced with triple 4 -foot by 5 -foot concrete box culverts with
minimal modifications to the existing roads, which serves as the basis for the conceptual cost
estimate provided below. However, this is an estimate for planning purposes and any final
recommendations based on detailed modeling may vary.
Upsizing the Shore and Alton Road crossings may carry advanced permitting requirements, as
regulators may interpret the improvements as increasing flows and pollutant loading to the
receiving water (Lake Jesup). Compensatory storage, perhaps from one of the storage
improvements proposed below, may be necessary to facilitate permitting.
3.5 Storage Improvements
In general, there are few City -owned, undeveloped properties within the Gee Creek Basin. Parcel
ownership within the study area (Figure 27) was reviewed to help identify potential
improvement locations not requiring right-of-way acquisition. Most of the study area is privately
owned, residential property. One FDOT parcel with a wet detention pond exists southwest of SR
434 over Gee Creek. It did not appear there was ample room to use this parcel to either expand
the existing pond or excavate a new one. One large City -owned, undeveloped parcel at the
southeast corner of the study area was reviewed but was not a viable option for an improvement
location based on its wetlands coverage and the preliminary topographic data.
Smith 3-11
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Section 3 • Conceptual Alternatives Identification
County -owned school property exists on the North side of SR 434, but these parcels were nearly
fully developed and were not considered ideal locations for improvement locations due to their
distance from the major problem flooding areas. City -owned properties considered for potential
improvement locations include unused land near Moss Park, land just south of Buttonwood
Avenue, and just west of Murphy Road.
CDM Smith identified four locations in the upstream portion of the basin on which storage
improvements may be considered for implementation to attenuate flood flows and improve
downstream conditions.
■ Concept S-1, the Buttonwood Avenue Stormwater Management Facility, is located in the
western portion of the study area. The residential community located west of Edgemon
Avenue is currently served by storm drains that discharge directly into Gee Creek without
water quality treatment or flood attenuation. This project, adapted from a similar project
proposed by CDM Smith in the 2009 TMDL Master Plan, involves the construction of a 2.3 -
acre stormwater management facility on City -owned property located at the west end of
Buttonwood Avenue as shown on Figure 28. To route stormwater to the proposed facility
from a contributing area of approximately 77 acres, new inlets and over 5,000 LF of storm
sewer is required. The proposed pond will outfall to the Edgemon/Lombardy Road ditch
northeast of the proposed pond. In addition to providing the treatment envisioned in the
TMDL Master Plan, the proposed improvements will limit direct discharges into Gee Creek
and attenuate inflows, thereby potentially reducing flows in downstream stretches of Gee
Creek.
Concept S-2, illustrated on Figure 29, is a proposed 0.9 -acre off-line stormwater
management facility located adjacent to Gee Creek on City -owned land between Murphy
Road and Edgemon Avenue. A low -flow diversion weir and pipe in Gee Creek on the
western end of the project will direct flow into the facility, which will discharge back into
Gee Creek on the eastern end of the project. The goal of this project is to provide additional
storage in the Gee Creek floodplain to attenuate flood flows to improve downstream level -
of -service, while providing ancillary water quality benefits during low -flow periods.
Concept S-3, also shown on Figure 29, is a proposed 0.8 -acre extension of an existing
stormwater management facility located on the south side of Moss Park. The existing
facility primarily serves roadway drainage from Edgemon Road. The outfall control
structure of the existing pond will be reconfigured with a low -flow weir in Gee Creek to
divert flows into the expanded pond, which will discharge back into Gee Creek at the
eastern end of the project. The goal of this project is to provide additional storage in the
Gee Creek floodplain to attenuate flood flows to improve downstream level -of -service,
while providing ancillary water quality benefits during low -flow periods.
Smith 3-13
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Proposed Structures • Existing Structures jv
Control Structure Existing Culverts
End Structure
National Wetlands Inventory 1 inch = 300 feet
OStorage Option S-1
Manhole pParcels 0 75150 300 Feet
Inlet =City of Winter Springs Parcel
Proposed Pipe
Smith
Figure 28
Stormwater Management Facility at Buttonwood Ave (S-1)
Gee Creek Flood Study
City of Winter Springs
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Figure 29
Stormwater Management Facilities near Moss Park (S-2 and S-3)
Gee Creek Flood Study
City of Winter Springs
Section 3 • Conceptual Alternatives Identification
■ Concept S-4, shown on Figure 30, is a proposed, on-line, 3.0 -acre stormwater management
facility on City -owned property located just west of Murphy Road. As illustrated in Figure
21, this area is largely residential and is served by three existing ponds which discharge
into Gee Creek, which meanders between the ponds after crossing into the City from the
adjacent City of Casselberry. The project seeks to "open up" Gee Creek into a wide, flow-
through system on currently undeveloped portions of the City property, with the goal of
providing additional floodplain storage for flow attenuation, as well as providing a basin to
settle out sediment transported from upstream of the City. The eastern end of the project
will include an outfall control structure and emergency overflow. While potentially
providing significant storage, there may be complicated permitting requirements
associated with this concept, including wetland impact mitigation. A detailed wetlands
evaluation would be required to define the extent of existing wetlands and potential
impacts that may need to be mitigated.
3.6 Opinion of Conceptual Capital Costs
CDM Smith has developed opinions of conceptual capital costs for the proposed improvements,
based primarily on FDOT Historic Cost Information and 6 -month statewide moving averages. The
conceptual cost estimates incorporate a 30 percent planning -level contingency and include a 20
to 50 percent allowance for engineering, surveying, and permitting. Cost estimates are provided
in Table 9 below.
Table 9 Opinion of Conceptual Capital Costs
OpinionConcep 1W Description
Capital
Maintenance Identified Maintenance Items $264,000
C-1 Lido Road Local Conveyance $92,000
C-2 Holiday Lane Local Conveyance $189,000
C-3 Sailfish Road Local Conveyance $121,000
B-1 Bank Stabilization — Murphy to Moss $335,000
B-2 Bank Stabilization — Hacienda Village $710,000
B-3 Bank Stabilization —Shore to Alton $450,000
U-1 Shore and Alton Culvert Upsizing $626,000
S-1 Buttonwood Ave SMF $1,761,000
S-2 Murphy/Edgemon SMF $224,000
S-3 Moss Park SM F $197,000
S-4 Murphy Online SMF $639,000
Total $5,608,000
3-16 Smith
�N HAWTHORN
!
_ N CIR
Legend N
OS -4 National Wetlands Inventory 1 inch = 250 feet
• Existing Structures = Parcels
Existing Culverts =City of Winter Springs Parcel 0 125 250 Feet
A Existing Ponds
Figure 30
Smith Online Stormwater Management Facility near Murphy Road (S-4)
Gee Creek Flood Study
City of Winter Springs
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OS -4 National Wetlands Inventory 1 inch = 250 feet
• Existing Structures = Parcels
Existing Culverts =City of Winter Springs Parcel 0 125 250 Feet
A Existing Ponds
Figure 30
Smith Online Stormwater Management Facility near Murphy Road (S-4)
Gee Creek Flood Study
City of Winter Springs
Section 3 • Conceptual Alternatives Identification
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3-18 Smith
Section 4
Summary and Conclusions
Hurricane Irma represented one of the most significant hydraulic events experienced by the City
in its recent history. Reported rainfall accumulations of up to 14 inches over September 10 and
11, 2017 are roughly equivalent to a 100 -year storm, or a rainfall event that has a 1 -percent
chance of occurring in a given year. This volume of rainfall placed an extraordinary demand on
Gee Creek and the stormwater collection and conveyance systems within the Gee Creek Basin.
The low-lying nature of the basin, and development in natural floodplain areas and the loss of
floodplain storage and conveyance in the decades preceding the adoption of floodplain
management ordinances, resulted in the flooding of roads and structures during and after the
event. CDM Smith's review of available data and documentation relevant to the study area
indicate that Gee Creek in its present condition does not have sufficient capacity within its
floodway to convey the runoff of an extreme event like Hurricane Irma within its banks, and that
resulting high stages in Gee Creek may present a tailwater limitation in the many secondary
drainage systems that discharge into the Creek, such as those serving Hacienda Village and the
Lido Road corridor in North Orlando Ranches, resulting in flooding of those systems.
While the improvements proposed in Section 3 may not produce a flood control level -of -service
sufficient to accommodate a storm similar to Hurricane Irma while keeping flood waters out of all
roads and structures in the basin, the conceptual alternatives may have beneficial impacts
including reducing flood stages and reducing the duration of inundation. The identified
maintenance activities will help ensure that the major cross -drains will not inhibit discharge of
flood waters, and obstructions will not diminish the conveyance capacity of Gee Creek. Minor
conveyance improvements such as those proposed in North Orlando Ranches will provide
positive outfalls to primary conveyances and will assist in managing nuisance flooding and
smaller storms. Upgrades to major cross -drains at Shore and Alton Roads will help ensure that
bottlenecks are minimized along the Creek. Finally, storage alternatives such as those proposed in
Section 3.5 will attenuate flood flows by providing some compensation for the historic loss of
storage in Gee Creek's floodplain.
Further investigation is recommended to optimize the flood control benefits that can be provided
by the conceptual alternatives. Updates to the most recent H/H models for the Gee Creek Basin,
which are 22 years old as of the writing of this report, are recommended to increase the
resolution of existing conditions analyses of the primary stormwater management systems in the
basin, as well as provide a quantitative analysis of the conceptual alternatives to determine the
extent to which they can reduce flood stages and flooding durations.
Smith 4-1
Section 4 • Summary and Conclusions
This page intentionally left blank.
4-2 Smith
Smith A-1
Appendix A • Field Reconnaissance Photolog
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A-2 Smith
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Appendix B • Conceptual Alternative Factsheets
This page intentionally left blank.
B-2 Smith
1� {
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Oroposed BMP Type:
Local Conveyance
Receiving Water Body
2994A (Gee Creek)
Oreliminary Size Estimate:
170 LF, 15" Pipe
Identification Numbers:
2981 (Lake Jesup)
\nticipated Flood Control
Improve localized, nuisance flooding
Proposed Improvements:
Professional survey of system to be
3enefit:
only
tied into, detailed calculations to
verify existing system's capacity,
mprovementArea(s):
Lido Road, just north of Temple Way
construction of two new drainage
structures and pipes
Nater Qual. Benefits (Y/N): N
t/W Acquisition:
None; Within R/W
Required O&M:
Infrastructure inspections, debris
removal, and cleanout
:onceptual Cost Estimate:
$92,000
phs:
Photo 1
CDM
Smith
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15
IM
Fu
Oroposed BMP Type: Local Conveyance
Receiving Water Body
2994A (Gee Creek)
Oreliminary Size Estimate: 490 LF, 15" Pipe
Identification Numbers:
2981 (Lake Jesup)
\nticipated Flood Control Improve localized, nuisance flooding
Proposed Improvements:
Professional survey of system to be
3enefit: only
tied into, detailed calculations to
verify existing system's capacity,
mprovementArea(s): Holiday Lane and Mockingbird Lane
construction of four new drainage
structures and pipes
Nater Qual. Benefits (Y/N): N
t/W Acquisition: None; Within R/W
Required O&M:
Infrastructure inspections, debris
removal, and cleanout
:onceptual Cost Estimate: $189,000
Ohotographs:
Nwiw,I,.
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Photo 1
Photo 2
CDM
Smith
4
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Proposed BMP Type:
Local Conveyance
Receiving Water Body
2994A (Gee Creek)
Preliminary Size Estimate:
310 LF, 15" Pipe
Identification Numbers:
2981 (Lake Jesup)
Anticipated Flood Control
Improve localized, nuisance flooding
Proposed Improvements:
Professional survey of system to be
Benefit:
only
tied into, detailed calculations to
verify existing system's capacity,
ImprovementArea(s):
Sailfish Road, east of Mockingbird
construction of two new drainage
Lane
structures and pipes
Water Qual. Benefits (Y/N): N
R/W Acquisition:
None; Within R/W
Required O&M:
Infrastructure inspections, debris
removal, and cleanout
Conceptual Cost Estimate:
$121,000
phs:
Photo 1
Photo 2
Smith
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Proposed BMP Type:
Bank Stabilization
Receiving Water Body
2994A (Gee Creek)
Preliminary Size Estimate:
710 LF (includes both banks)
Identification Numbers:
2981 (Lake Jesup)
Anticipated Flood Control
Improvement of channel and cross
Proposed Improvements:
Construction of bank stabilization
Benefit:
drain capacity
(sand cement bags or gabions) along
Improvement Area(s):
Gee Creek downstream of Murphy
both left and right channels banks at
Road
critical locations
Water Qual. Benefits (Y/N): Y
R/W Acquisition:
None; Within City easement
Required O&M:
Inspection
Conceptual Cost Estimate: $335,000
Photographs:
Photo 1 Photo 2
CDM
Smith
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downstream. Culverts downstream of these limits had significant sedimentation buildup.
Proposed BMP Type: Bank Stabilization Receiving Water Body 2994A (Gee Creek)
Preliminary Size Estimate: 1,075 LF (includes both banks) Identification Numbers: 2981(LakeJesup)
Anticipated Flood Control Improvement of channel and cross Proposed Improvements: Construction of bank stabilization
Benefit: drain capacity (sand cement bags or gabions) along
ImprovementArea(s): Gee Creek within and downstream of both left and right channels banks at
Hacienda Village critical locations
Water Qual. Benefits (Y/N): Y
R/W Acquisition: Possible; City does have drainage Required O&M: Inspection
easement for these limits of the creek
Conceptual Cost Estimate: $710,000
Photographs:
r
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Photo 1 Photo 2 - Existing Retaining Wall
Smith
AIYi u. N❑
Conceptual Cost Estimate: $450,000
Photographs:
Photo 1
Photo 2
Smith
Project Description:
transport downstream. Culverts
downstream of these limits had
significant sedimentation buildup.
Proposed BMP Type:
Bank Stabilization
Receiving Water Body
2994A (Gee Creek)
Preliminary Size Estimate:
680 LF (includes both banks)
Identification Numbers:
2981 (Lake Jesup)
Anticipated Flood Control
Improvement of channel and cross
Proposed Improvements:
Construction of bank stabilization
Benefit:
drain capacity
(sand cement bags or gabions) along
Improvement Area(s):
Gee Creek downstream of Shore
both left and right channels banks at
Road
critical locations
Water Qual. Benefits (Y/N): Y
R/W Acquisition:
None; Within City easement
Required O&M:
Inspection
Conceptual Cost Estimate: $450,000
Photographs:
Photo 1
Photo 2
Smith
I
7,
Proposed BMP Type:
Crossdrain Conveyance
Receiving Water Body
2994A (Gee Creek)
Existing Sizes:
Triple 54" (Alton), Triple 48" (Shore)
Identification Numbers:
2981 (Lake Jesup)
Proposed size to be determined after detailed H&H modeling.
Anticipated Flood Control
Improvement of crossdrain capacity*
Proposed Improvements:
Design level modeling, professional
Benefit:
survey of area within vicinity of Alton
Improvement Area(s):
Gee Creek upstream of Alton Road
and Shore crossdrains, replacement
and Shore Road
of existing crossdrains
Water Qual. Benefits (Y/N):
N
R/W Acquisition:
None; Within R/W
Required O&M:
Infrastructure inspections, debris
removal, and cleanout
Conceptual Cost Estimate:
$626,000
*Potential impacts to the creek
downstream of the upsized crossdrains
to be analyzed with detailed
H&H modeling to be done under a
Future phase.
Photographs:
Photo 1
Photo 2
CDM
Smith
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photo 2
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Oroposed BMP Type:
Storage
Receiving Water Body
2994A (Gee Creek)
Oreliminary Size Estimate:
2.3 ac
Identification Numbers:
2981 (Lake Jesup)
lnticipated Flood Control
Reduction in volume and peak flow to
Proposed Improvements:
Design level modeling, professional
{enefit:
Gee Creek*
wetland survey, construction of wet
detention pond, replumb existing
mprovement Area(s):
Gee Creek downstream of Edgemon
drainage system, construct outfall
Avenue
drainage system
Nater Qual. Benefits (Y/N):
Y
t/W Acquisition:
None; On City property
Required O&M:
Routine mowing, infrastructure
inspections, debris removal, and
:onceptual Cost Estimate:
$1,761,000
cleanout
`Volume and peak flow calculations will need to be quantified through
detailed H&H modeling to
be done under a future phase.
Ohotographs:
Photo 1
Photo 2
CSmith
a rL�
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Y
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IA
-------------
s
r
r
Proposed BMP Type:
Storage
Receiving Water Body
2994A (Gee Creek)
Preliminary Size Estimate:
0.9 ac
Identification Numbers:
2981 (Lake Jesup)
Anticipated Flood Control
Reduction in volume and peak flow
Proposed Improvements:
Design level modeling, professional
Benefit:
to Gee Creek*
wetland survey, construction of wet
detention pond, construct creek
ImprovementArea(s):
Gee Creek downstream of Murphy
diversion structure and outfall
Road
drainage system
Water Qual. Benefits (Y/N): Y
R/W Acquisition:
None; On City property
Required O&M:
Routine mowing, infrastructure
inspections, debris removal, and
Conceptual Cost Estimate:
$224,000
cleanout
*Volume and peak flow calculations
will need to be quantified through detailed H&H modeling to
be done under a future phase.
Photographs:
Photo - Looking west at S-2 location from Edgemon Avenue (Source: Google Streetview)
CDM
Smith
• �6
e
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e
-LN BAHAMAfti7 •�. � � .. ...�.
i
Proposed BMP Type:
Storage
Receiving Water Body
2994A (Gee Creek)
Preliminary Size Estimate:
0.8 ac
Identification Numbers:
2981 (Lake Jesup)
Anticipated Flood Control
Reduction in volume and peak flow
Proposed Improvements:
Design level modeling, professional
Benefit:
to Gee Creek*
wetland survey, expansion of existing
of wet detention pond, construct
Improvement Area(s):
Gee Creek downstream of Edgemon
creek diversion structure and outfall
Avenue
drainage system
Water Qual. Benefits (Y/N):
Y
R/W Acquisition:
None; On City property
Required O&M:
Routine mowing, infrastructure
inspections, debris removal, and
Conceptual Cost Estimate:
$197,000
cleanout
*Volume and peak flow calculations will need to be quantified through detailed H&H modeling to be done under a future phase.
Photographs:
- Looking west at S-3 location from Moss Road (Source: Google Streetview)
CDM
Smith
3 . 0 ac
U'•
Oroposed BMP Type:
Storage
Receiving Water Body
2994A (Gee Creek)
Oreliminary Size Estimate:
3.0 ac
Identification Numbers:
2981 (Lake Jesup)
lnticipated Flood Control
Reduction in volume and peak flow to
Proposed Improvements:
Design level modeling, professional
;enefit:
Gee Creek*
wetland survey, construction of onlin
mprovement Area(s):
Gee Creek downstream of Murphy
flow through system with outfall
Road
control structure
Nater Qual. Benefits (Y/N):
Y
t/W Acquisition:
None; On City property
Required O&M:
Routine mowing, infrastructure
inspections, debris removal,
occasional dredging of sediment, and
:onceptual Cost Estimate:
$639,000
cleanout
Volume and peak flow calculations will need to be quantified through detailed H&H modeling to be done under a future phase
Photo 1
Photo 2
Smith
Smith c-1
Appendix C • Opinions of Conceptual Capital Costs
This page intentionally left blank.
C-2 Smith
Table C-1: Opinion of Conceptual Capital Cost
Maintenance of Major Crossings
Item No. Item Description
1 Mobilization (approx. 10 percent)
2 Traffic Control (approx. 10 percent)
3 Desilting Pipes
4 Channel Excavation
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
Unit
Qty
Unit Cost
Capital Cost
LS
1 $
17,600
$ 17,600
LS
1 $
17,600
$ 17,600
LF
450 $
40
$ 18,000
LF
3,500 $
35
$ 122,500
Subtotal $ 176,000
Contingency: 30% $52,800
Survey, Engineering, and Permitting: 20% $35,200
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 264,000
A Of �� Cost Estimates -Gee Creek.xlsx/Maintenance
4/19/2015
Table C-2: Opinion of Conceptual Capital Cost
Project No. C-1: Improve Local Conveyance - Lido Road
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 5,100
$
5,100
2
Traffic Control (approx. 10 percent)
LS
1
$ 5,100
$
5,100
3
15 -in RCP, Class III
LF
220
$ 100
$
22,000
4
Curb Inlet, Type P-5, <10'
EA
2
$ 4,900
$
9,800
5
Modify Existing Structure
EA
1
$ 3,200
$
3,200
6
Milling Existing Asphalt Pavement, 2" Average Depth
SY
177
$ 3
$
531
7
Optional Base Group 04 (Limerock)
SY
177
$ 12
$
2,124
8
Asphaltic Concrete FC -12.5
TN
20
$ 125
$
2,500
Subtotal $ 51,000
Contingency: 30% $15,300
Survey, Engineering, and Permitting: 50% $25,500
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 92,000
Cost Estimates - Gee Creek.xlsx/C-1
A 2 Of 12
4/19/2015
Table C-3 Opinion of Conceptual Capital Cost
Project No. C-2: Improve Local Conveyance - Holiday Lane
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 10,500
$
10,500
2
Traffic Control (approx. 10 percent)
LS
1
$ 10,500
$
10,500
3
15 -in RCP, Class III
LF
490
$ 100
$
49,000
4
Curb Inlet, Type P-5, <10'
EA
2
$ 4,900
$
9,800
5
Manhole, P-8, <10'
EA
2
$ 3,400
$
6,800
6
Modify Existing Structure
EA
1
$ 3,200
$
3,200
7
Milling Existing Asphalt Pavement, 2" Average Depth
SY
511
$ 3
$
1,533
8
Optional Base Group 04 (Limerock)
SY
511
$ 12
$
6,132
9
Asphaltic Concrete FC -12.5
TN
57
$ 125
$
7,125
Subtotal $ 105,000
Contingency: 30% $31,500
Survey, Engineering, and Permitting: 50% $52,500
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 189,000
Cost Estimates - Gee Creek.xlsx/C-2
A 3 Of 12
4/19/2015
Table C-4: Opinion of Conceptual Capital Cost
Project No. C-3: Improve Local Conveyance - Sailfish Road
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 6,700
$
6,700
2
Traffic Control (approx. 10 percent)
LS
1
$ 6,700
$
6,700
3
15 -in RCP, Class III
LF
310
$ 100
$
31,000
4
Curb Inlet, Type P-5, <10'
EA
2
$ 4,900
$
9,800
5
Modify Existing Structure
EA
1
$ 3,200
$
3,200
6
Milling Existing Asphalt Pavement, 2" Average Depth
SY
324
$ 3
$
972
7
Optional Base Group 04 (Limerock)
SY
324
$ 12
$
3,888
8
Asphaltic Concrete FC -12.5
TN
36
$ 125
$
4,500
Subtotal $ 67,000
Contingency: 30% $20,100
Survey, Engineering, and Permitting: 50% $33,500
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 121,000
Cost Estimates - Gee Creek.xlsx/C-3
A 4 Of 12
4/19/2015
Table C-5: Opinion of Conceptual Capital Cost
Project No. B-1: Bank Stabilization - Murphy Road to Moss Road
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 22,300
$ 22,300
2
Traffic Control (approx. 10 percent)
LS
1
$ 22,300
$ 22,300
3
Rip -rap, sand -cement
CY
270
$ 570
$ 153,900
4
Embankment
CY
1320
$ 9
$ 11,880
5
Sodding
SY
3950
$ 3
$ 11,850
Subtotal $ 223,000
Contingency: 30% $66,900
Survey, Engineering, and Permitting: 20% $44,600
Total Preliminary Engineer's Estimate of Probable Cost $ 335,000
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1000.
Cost Estimates - Gee Creek.xlsx/B-1
A 5 Of 1'
4/19/2015
Table C-6: Opinion of Conceptual Capital Cost
Project No. B-2: Bank Stabilization - Hacienda Village
Item No. Item Description
1 Mobilization (approx. 10 percent)
2 Traffic Control (approx. 10 percent)
3 Rip -rap, sand -cement
4 Embankment
5 Sodding
Unit
Qty
Unit Cost
Capital Cost
LS
1
$
47,300
$
47,300
LS
1
$
47,300
$
47,300
CY
600
$
570
$
342,000
CY
2000
$
9
$
18,000
SY
5980
$
3
$
17,940
Subtotal
$
473,000
Contingency:
Survey, Engineering, and Permitting:
Total Preliminary Engineer's Estimate of Probable Cost
(Rounded to the nearest $1,000)
30% $141,900
20% $94,600
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1000.
$ 710,000
Cost Estimates - Gee Creek.xlsx/B-2
A 6 Of 12
4/19/2015
Table C-7: Opinion of Conceptual Capital Cost
Project No. B-3: Bank Stabilization - Shore Road to Alton Road
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 30,000
$ 30,000
2
Traffic Control (approx. 10 percent)
LS
1
$ 30,000
$ 30,000
3
Rip -rap, sand -cement
CY
380
$ 570
$ 216,600
4
Embankment
CY
1260
$ 9
$ 11,340
5
Sodding
SY
3780
$ 3
$ 11,340
Subtotal $ 300,000
Contingency: 30% $90,000
Survey, Engineering, and Permitting: 20% $60,000
Total Preliminary Engineer's Estimate of Probable Cost $ 450,000
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1000.
Cost Estimates - Gee Creek.xlsx/B-3
A 7 Of 12
4/19/2015
Table C-8: Opinion of Conceptual Capital Cost
Project No. U-1: Upsize Alton Road and Shore Road Crossdrains
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 39,100
$
39,100
2
Traffic Control (approx. 10 percent)
LS
1
$ 39,100
$
39,100
3
Tx 5' RCBC
LF
576
$ 510
$
293,760
10
Milling Existing Asphalt Pavement, 2" Average Depth
SY
641
$ 3
$
1,923
11
Optional Base Group 04 (Limerock)
SY
641
$ 12
$
7,692
12
Asphaltic Concrete FC -12.5
TN
72
$ 125
$
9,000
Subtotal $ 391,000
Contingency: 30% $117,300
Survey, Engineering, and Permitting: 30% $117,300
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2012 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 626,000
Cost Estimates -Gee Creek.xlsx/U-1
A 8 Of 12
4/19/2015
Table C-9: Opinion of Conceptual Capital Cost
Project No. S-1: Stormwater Management Facility at Buttonwood Avenue
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 117,400
$
117,400
2
Traffic Control (approx. 10 percent)
LS
1
$ 117,400
$
117,400
3
Clearing and Grubbing
AC
3
$ 9,600
$
28,800
4
Excavation
CY
38,000
$ 4
$
152,000
5
24 -in RCP, Class III
LF
3,500
$ 70
$
245,000
6
36 -in RCP, Class III
LF
1,800
$ 110
$
198,000
7
Mitered End Section 24"
LF
2
$ 1,550
$
3,100
8
Mitered End Section 36"
LF
1
$ 3,700
$
3,700
9
Ditch Bottom Inlet, Type C, <10'
LS
3
$ 3,000
$
9,000
10
Ditch Bottom Inlet, Type D, <10'
EA
4
$ 3,500
$
14,000
11
Manhole, P-8, <10'
EA
22
$ 3,400
$
74,800
12
Milling Existing Asphalt Pavement, 2" Average Depth
SY
5,127
$ 3
$
15,381
13
Optional Base Group 04 (Limerock)
SY
5,127
$ 12
$
61,524
14
Asphaltic Concrete FC -12.5
TN
729
$ 125
$
91,172
15
Concrete Sidewalk and Driveways
SY
600
$ 55
$
33,000
16
Sodding
SY
3000
$ 3
$
9,000
Subtotal $ 1,174,000
Contingency: 30% $352,200
Survey, Engineering, and Permitting: 20% $234,800
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 1,761,000
Cost Estimates - Gee Creek.xlsx/S-1
A 9 Of 12
4/19/2015
Table C-10: Opinion of Conceptual Capital Cost
Project No. S-2: Stormwater Management Facility near Moss Park
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 12,400
$
12,400
2
Traffic Control (approx. 10 percent)
LS
1
$ 12,400
$
12,400
3
Clearing and Grubbing
AC
1
$ 9,600
$
9,600
4
Excavation
CY
15,000
$ 4
$
60,000
5
24 -in RCP, Class III
LF
200
$ 70
$
14,000
6
Mitered End Section 24"
LF
2
$ 1,550
$
3,100
7
Ditch Bottom Inlet, Type D, <10'
EA
1
$ 3,500
$
3,500
8
Rip -rap, sand -cement
CY
10
$ 570
$
5,700
9
Sodding
SY
1000
$ 3
$
3,000
Subtotal $ 124,000
Contingency: 30% $37,200
Survey, Engineering, and Permitting: 50% $62,000
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 224,000
A 10 Of 1' Cost Estimates - Gee Creek.xlsx/S-2
4/19/2015
Table C-11: Opinion of Conceptual Capital Cost
Project No. S-3: Stormwater Management Facility on Moss Park
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 10,900
$
10,900
2
Traffic Control (approx. 10 percent)
LS
1
$ 10,900
$
10,900
3
Clearing and Grubbing
AC
1
$ 9,600
$
9,600
4
Excavation
CY
12,000
$ 4
$
48,000
5
24 -in RCP, Class III
LF
200
$ 70
$
14,000
6
Mitered End Section 24"
LF
2
$ 1,550
$
3,100
7
Ditch Bottom Inlet, Type D, <10'
EA
1
$ 3,500
$
3,500
8
Rip -rap, sand -cement
CY
10
$ 570
$
5,700
9
Sodding
SY
1000
$ 3
$
3,000
Subtotal $ 109,000
Contingency: 30% $32,700
Survey, Engineering, and Permitting: 50% $54,500
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 197,000
A 11 Of 1' Cost Estimates - Gee Creek.xlsx/S-3
4/19/2015
Table C-12: Opinion of Conceptual Capital Cost
Project No. S-4: Online Stormwater Management Facility near Murphy Road
Item No.
Item Description
Unit
Qty
Unit Cost
Capital Cost
1
Mobilization (approx. 10 percent)
LS
1
$ 35,500
$
35,500
2
Traffic Control (approx. 10 percent)
LS
1
$ 35,500
$
35,500
3
Clearing and Grubbing
AC
4
$ 9,600
$
38,400
4
Excavation
CY
49,000
$ 4
$
196,000
5
Concrete, Class II (for spillway)
CY
80
$ 500
$
40,000
6
Sodding
SY
3000
$ 3
$
9,000
Subtotal $ 355,000
Contingency: 30% $106,500
Survey, Engineering, and Permitting: 50% $177,500
Opinion of Conceptual Capital Cost
(Rounded to the nearest $1,000)
These Opinions of Conceptual Capital Cost:
1. Are in 2018 dollars.
2. Include contractor's overhead, profit, mobilization, and bonding.
3. Do not include potential replacement or rehabilitation of non-stormwater
infrastructure (e.g., water, sewer, reuse, cable, telephone, gas, fiber optic, etc.)
4. Do not include potential land acquisition (unless noted).
5. Do not include any potential hazardous material or groundwater remediation.
6. Do not include any potential wetlands mitigation.
7. Have a 30% contingency.
8. Are rounded to the next highest $1,000.
$ 639,000
A 12 Of 12 Cost Estimates - Gee Creek.x1sx/S-4
4/19/2015
CDM
Smitho
cdmsmith.com