HomeMy WebLinkAboutSite Utility Study•
•
•
ONYX 2
MAJOR USE SPECIAL PERMIT
SITE UTILITY STUDY
Prepared for:
02, LLC
Prepared by:
Bermello, Ajamil & Partners, Inc.
June 7, 2004
. 1. DRAINAGE
•
A. Drainage Area
The site is located east of Biscayne Blvd., west of NE Bayshore Drive, on the
north side and south side of NE 28th Street. The site consists of two parcels, one
located on the north side of NE 28th Street, of approximately 0.78 acres, and one
parcel on the south side of NE 28th Street, of approximately 0.39 acres. It
consists of a total of f1.17 acres.
After development, approximately 95% of the site will be impervious areas and
approximately 5% of the site will remain as pervious areas. The storm water
discharge will consist primarily of building roofs, driveways and landscape areas
run-off. The coefficient of run-off is arrived at as follows:
0.95 (impervious) x 0.90 =
+0.05 (pervious) x 0.30
overall coefficient
B. Existing Drainage System
0.855
0.015
0.87
The City of Miami presently maintains a roadway drainage system in both side
streets. The site is presently fully developed. The existing roadway system
appears to be of sufficient capacity to handle the present conditions.
C. Proposed Drainage System
The primary drainage system of this building will consist of drainage wells which
will allow the stormwater runoff to be fully contained on -site. No off -site runoff is
expected from this building. It is anticipated that three drainage wells will be
sufficient to handle the runoff (See Table 1 for drainage calculations).
The stormwater will be collected thru a system of catch basin inlets and
transported by pipes to the well locations. The wells will allow the stormwater to
flow into the Biscayne Aquifer. The wells will be designed to handle the
stormwater runoff and tested for capacity as they are installed.
Runoff from driving surfaces such as driveways and parking areas will be
diverted thru detention structures which will capture the oils and greases prior to
flowing into the wells.
Page 2
•
•
•
Runoff Generations
1. Total Area
a. Impervious
b. Pervious
Table 1
Sample Drainage Calculations
(Phase 1 only)
1.17 Acres
95% or 0.95 Acres
5% or 0.05 Acres
2. Average Runoff Coefficient (.95) (.9) + (.05) (.3) = 0.87
3. Design Storm 5years
4. Time of Concentration 10.00 min
5. Rainfall Intensity 6.10 in/hr
6. Peak Runoff (Q) - C;A (.87) (6.10) (1.17) = 6.21 CFS
Assume each 24" diameter drainage well flows at 750 gpm per foot of head -
using 2 feet of head:
2 x 750 gpm = 1,500 gpm per well
1,500 gpm = 3.34 CFS
(Peak runoff) 6,21 CFS = 1.85 Wells
(Flow per well) 3.34 CFS
Provide 3 - 24" diameter wells
Detention Tank:
Providing 11/2 minute detention time of storage in tank.
Volume of tank required to handle 1,500 gpm for 1,5 min.
1,500 gpm x 1.5 min = 2,250 gal/tank or 300 ft3 each
Provide 3 tanks, each one with the following interior dimensions:
5' (width) x 5' (height) x 12' (length) = 300 ft3
Provide 3 tanks with 300 ft3 volume each
Page 3
•
II. WATER DISTRIBUTION
The Miami Dade Water and Sewer Department owns and operates two 2" water mains
located on NE 28th Street. This project proposes to design and construct a new 12"
water main extension tying in to an existing 16" water main at Biscayne Boulevard and
extending it along NE 28th Street to the east end of the subject property.
The water connections to serve the buildings will be done from the proposed 12" water
main. The connections will consist of fire line supply, domestic water and irrigation
water. No on -site wells are planned for this project,
The calculations for anticipated water volumes required for this project are shown
below, in Table 2.
Table 2
Water Volumes
ResidentialApartments
117 units @ 200gpdfunit 23,400 gpd
III. SANITARY SEWER
The Miami Dade Water and Sewer Department owns and operates a 10" gravity sewer
system along NE 28th Street, fronting the subject property. It is anticipated that multiple
gravity sewer laterals connecting to the existing 10" gravity sewer main will be sufficient
to serve this project. No pump station will be built on -site to serve the project. Table 3,
below, shows the anticipated sewage flow calculations.
Table 3
Sewage Flows
Average Flow (from Table 2) 23,400 gpd
Average Flow 16.25 gpm
Peak Flow (16 x 3.5) 57 gpm
Page 4
• IV. SOLID WASTE GENERATION
Solid waste generated by this project will be collected in standardized on -site containers
for refuse and recyclables. Regular pick-up service will be provided by either private
hauling companies and/or The City of Miami Solid Waste Department, which will
transport the waste to Metro -Dade County's Disposal or Recycling facilities.
The projected daily volumes of solid waste generation are shown in Table 4, below.
•
•
Table 4
Solid Waste Generation
Residential Apartments
(117 units @ 1.42 tons/units x 2,000 Ibs/ton)/365 days 910 Ibs
U:\TALIAIW0RD\Engineeringlon}nclonyx2siteUtility.doc
Page 5