HomeMy WebLinkAboutTab 3 - Site Utility Study•
2222 BISCAYNE BOULEVARD
MAJOR USE SPECIAL PERMIT
SITE UTILITY STUDY
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Prepared for:
Grouper Financial, Inc.
Prepared by:
Consulting Engineering and Science, Inc.
June 30, 2006
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1. General
A. Project Location and Size:
The project is located along the west side of Biscayne Boulevard in
the City of Miami; bounded on the north by N.B. 23rd Street;
bounded on the west by N.E. 2nd Avenue; and, bounded on the south
by N.E. 22nd Street. The site has a gross lot area of 223,653
square feet, or 5.13 acres; and, a net lot area of 161,885 square
feet, or 3.72 acres, The site has approximately 312 feet of
frontage along Biscayne Boulevard; approximately 488 feet of
frontage along N.E. 23rd Street; approximately 312 feet of frontage
along N.E. 2nd Avenue; and, approximately 488 feet of frontage
along N.E. 22nd Street.
The land on which the project is proposed consists of a single
parcel of land, identified as Miami -Dade County tax folio numbers
01-3230--062-0010. A legal description of the property is as
follows:
A portion of Tract A of TERRANOVA BISCAYNE, according to
the plat thereof, as recorded in Plat Book 150, at Page
14, of the Public Records of Miami ---Dade County, Florida.
The eastern portion of the site is presently occupied by a 2-story
office building (18,280 sf) and a 7-story office building (44,037
sf) interconnected by a covered breezeway; and, a 2-story parking
structure. The western portion of the site is presently vacant.
B. The proposed project build -out will be as follows:
Office.
62,317 sf (Existing)
430,477 sf (Proposed)
492,794 sf
Net Lot Area 161,885 sf, or 3.72 acres
Gross Lot Area 223,653 sf, or 5.13 acres
It is intended that the existing structures within the eastern
portion of the site will remain; and, a new office condominium
tower of 28 stories will be constructed on the western portion of
the site.
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2. Drainage
Drainage Area
Upon development, the site will include two (2) drainage sub -
basins. The eastern sub -basin, containing 1.97 acres, will be
approximately 66 per cent impervious and approximately 34 per
cent pervious. The western sub -basin, containing 1.75 acres,
will be approximately 80 per cent impervious and approximately
20 per cent pervious. Stormwater runoff will consist of
rainfall from the building roofs, driveways, walkways,
landscape areas and one-third of the vertical building
surfaces.
The coefficient of runoff is calculated as follows:
Eastern Sub -basin:
66 . 0% (impervious) X 0.90
34.0% (pervious) x 0.20
Overall coefficient
Western Sub -basin:
80.0% (impervious) X 0.90
20.0% (pervious) x 0.20
Overall coefficient
B. Existing Storm Drainage System
0.59
0.07
0.66
0.72
0.04
0.76
In the eastern portion of the site that is developed, runoff
is currently directed to a number of catch basins located in
and around the open spaces between structures from which the
runoff is directed to underground seepage trench/exfiltration
trenches. There are no existing drainage facilities located
in the western portion of the site.
C. Proposed Storm Drainage System
The storm drainage system to serve this project will be
designed to direct the 5-year 1-day storm event to on -site
retention/exfiitration systems and to contain the 25-year 3-
day storm event on -site, as required to comply with the
applicable requirements of the Miami -Dade County Department of
Environmental Resources Management (DEFJ4). It is anticipated
that the existing storm drainage system in the eastern portion
of the site will remain. It is further anticipated that the
stormwater disposal system for the western portion of the site
will include four (4) 24" drainage wells. See supporting
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calculations in Table 1. Runoff will be collected through a
system of catch basins and conveyed by pipes to the well
locations.
Runoff from driving surfaces such as driveways and walkways
will be diverted through baffled pollution control structures
which will capture the oils and greases prior to flowing into
the wells.
Table 1
Preliminary Drainage Calculations
Eastern Portion of the Site:
Total Net Area 1.97 Acres
a. Impervious
Roof/Driveways/Walks 1.30 Acres
1/3 Vert. Bldg. Surface 0.14 Acres
Total 1.44 Acres
b. Pervious 0.67 Acres
c. Adjusted Contributing Area 2.11 Acres
2. Adjusted Runoff Coefficient 1.44(0.9)-1- 0.67(0.2)
2.11
= 0.68
3. Design Storm 5 years
4. Time of Concentration 15 minutes
5. Rainfall Intensity 5.50 in/hr
6. Peak Runoff (Q) = CiA (0.68)(5.50)(2.11)
7.89 cfs
Existing drainage facilities to remain.
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Western Portion of the Site:
€. Total Net Area 1.75 Acres
a. Impervious
Roof/Driveways/Walks 1.40 Acres
1/3 Vert. Bldg. Surface 3.06 Acres
Total 4.46 Acres
b. Pervious 0.35 Acres
c. Adjusted Contributing Area 4.81 Acres
2 Adjusted Runoff Coefficient 4.46(0.9)+ 0.35(0.2)
4.81
= 0.85
3. Design Storm 5 years
4. Time of Concentration_ 15 minutes
5. Rainfall Intensity 5.50 in/hr
6. Peak Runoff (Q) = CiA (0.85)(5.50)(4.81)
= 22.49 cfs
Assume each 24-inch diameter drainage well has a capacity of 1,000
gpm per foot of head; and, using 2.5 feet of available head:
Well Capacity = 1,000 gpm x 2.5 feet = 2,500 gpm per well
= 5.57 cfs per well
No. Wells = Peak Runoff = 22.49 cfs = 4.03 wells
Well Capacity 5.57 cfs
Provide four (4) - 24" diameter Drainage Wells
Detention Tanks: Provide 1.5 minutes of detention time of
storage in detention tanks:
Volume of tanks required to handle 22.49 cfs for 1.5 min:
= 22.49 cfs x 1.5 min x 60 sec/min = 2,024 cubic feet (cf)
Provide four (4) tanks (one with each well) with the following
approximate interior dimensions:
4 times 6'-S" (width) x 15'-3" (length) x 5' (depth) = 2,034 cf
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Water Distribution
The project is located in the water service area of the Miami -
Dade Water and Sewer Department (WASD). There is an existing
16-inch water main in Biscayne Boulevard; and, existing 12-
inch water mains in N.E. 23rd Street, N.E. 2nd Avenue and N. Eo
22nd Street. These existing water .mains are capable of
providing the required domestic and fire flow required for
this project; and, as such, it is not anticipated that WASD or
the Fire Department will require off --site water system
improvements to serve this project.
Existing water and fire service connections to those buildings
to remain shall remain as is. The water and fire service
connections to the new portion of the project will be made
from the adjacent existing water mains. The connections will
consist of domestic water services, fire line services and
cooling tower/irrigation water service, as applicable. No on -
site water wells are planned for this project.
The calculations for anticipated water usage required for this
project are shown below, in Table 2.
Table 2
Water Usage
Existing Offices;
62,317 sf @ 10 gpd/100 sf .... 6,232 gpd
Proposed Offices:
430,477 sf @ 10 gpd/100 sf = 43,048 gpd
Total _ 49,280 gpd
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4. Sanitary Sewer
The project is located in the sewer service area of the Miami -
Dade Water and Sewer Department (WASD). WASD currently has 8-
inch gravity sewer mains fronting the property in Biscayne
Boulevard, N.E. 23rd Street and N.E. 22nd Street; and, has a
10-inch gravity sewer main fronting the property in N.E. 2nd
Avenue. Thee existing sewer mains appear to have adequate
capacity to serve this project. Flow from this project will
be directed to WASD pump station PS-02 which currently has
sufficient available capacity to serve this project.
Therefore, it is anticipated that no new pump station will be
required to serve this project.
Existing sewer laterals serving those buildings to remain
shall remain as is. It is anticipated that new sewer laterals
will be installed from the adjacent existing gravity sewer
mains to serve the new portion of the project.
Anticipated sewage flow calculations are shown below, in Table
3.
Table 3
Sewage Flow Calculations
Average Daily Flow (Table 2) = 49,280 gpd
Average Daily Flow = 34.2 gpm
Peak Flow (34,2 x 2.0) = 68.4 gpm
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5e Solid Waste Generation
Solid waste generated by this project will be collected in
standardized on -site containers for refuse and recyclable
waste. Regular service will be provided by either private
hauling companies and/or the City of Miami Solid Waste
Department. Both will transport the waste to Miami -Dade
County's Disposal or Recycling facilities.
The projected daily volumes of solid waste generation are
shown below, in Table 4.
Table 4
Solid Waste Generation
Existing Office:
Solid Waste = 62,317 sf x 3.08 lbs/sf/year
191,936 lbs/year = 96 tons/year
= 526 lbs/day
Proposed Office:
Solid Waste = 430,477 sf x 3.08 lbs/sf/year
1,325,869 lbs/year = 663 tons/year
3,633 lbs/day
Total _ 4,159 lbs/day
The project is located in the water and sewer service area of the
Miami Dade Water and Sewer Department (WASH).
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