D. SITE UTILITY STUDY

Transcription

1 D. SITE UTILITY STUDY MIADOCS

2 5220 BISCAYNE BOULEVARD MAJOR USE SPECIAL PERMlT!$ITE UTILJTY STUDY z"lmpamm Societe L &t -pation Fimm, Inc.

3 Site Utility Study Introduction 5220 Biscayne Boulevard is a proposed mixed-use development to be located on /- acres in the City of Miami, Miami-Dade County, Florida. It is located between NE 52"* Terrace and NE 52nd Street, along N. Federal Highway on the West and Biscayne Blvd on the East. (See Attachment "A" Maps). Currently, the site is occupied by a three story residential tower and an asphalt parking lot. All existing on-site facilities will be demolished as a part of this project. The proposed 5220 Biscayne Boulevard project will include an 11 story residential tower and a parlung garage to serve the tower. A total of 177 residential apartment units, 10,500 S.F. of commercial space and approximately 312 parking spaces will be constructed for this development. A tabular breakdown of the project details is depicted in Table 1- "Project Summary" below. Occupancy Table 1: Project Summary I Residential I ,705 / Commercial Parking Units 3 12 spaces Floor Area (sf) 10,500 I Total I 1 175,205 I 5220 Biscayne Boulevard Site Utility Study Page I

4 I. Drainage Relative to the aforementioned project, the following information shall be used during the storm water management design and site grading. Flood Criteria: The proposed project site grade elevations will be designed to meet flood criteria according to Federal State, Miami-Dade County and City of Miami standards as follows: 1. The subject property is located in PANEL 181 of COMMUNITY-PANEL NUMBER 12025C0181 J of the Flood Insurance Rate Map (FIRM). According to the National Flood Insurance Program, the project is in Zone X. As such the project area has been determined to be outside 500 years floodplain. 2. Miami-Dade County Flood Criteria elevation is estimated to be 5.0 ft. NGVD. This will be used to determine proposed minimum grade elevations. 3. The average October ground water table elevation is estimated to be 2.0 ft. NGVD. This elevation will be used to compute drainage well capacity and roadway base clearance. (Source: Dade County Department of Environmental Resource Management & Miami-Dade County Public Works Manual, Volume I1 - Design Standard Detail WC 2-2). Existing Drainage Based on site observations and other available information, there is a drainage system currently serving the existing building and asphalt parking lot. This existing drainage system will be demolished and a new stormwater management system will be constructed to retain the runoff generated by the proposed improvements, as required by code (see "Proposed Drainage System" below) Biscayne Boulevard Site Utility Study

5 Prouosed Drainage System The drainage system for the proposed development will consist of a combination of drainage wells and exfiltration trench, to facilitate on-site disposal of storm water runoff., In accordance with Section D-4, "Water Control", of Part 2 of the Miami-Dade County Public Works Manual, the 5-year 24-hour design storm event will be used to design the new storm water management system. Based on preliminary calculations, it is anticipated that three (3) 24" drainage wells will provide sufficient capacity to dispose of the storm water runoff generated by the proposed development. Preliminary drainage computations for the project areas are provided in Attachment B "Preliminary Drainage Well Calculations", which includes the basis for design. The final drainage design for the project should be in conformance with the requirements of the Miami-Dade County DERM Water Control Section, Florida Department of Environmental Protection, and other local, state and federal regulatory agencies having jurisdiction over the project. 11. Water Distribution System The water mains owned and operated by the Miami-Dade Water and Sewer Department (MDWASD) in the vicinity of the project are shown in the Table Biscayne Boulevard Site Utility Study Page 3

6 Table 2: Existing Water Mains (Per MDWASD Water Atlas Sheet) Location Biscayne Boulevard Between N.E. 53rd Street and N.E. 52nd Street Water Main(s) 8" I Federal Highway I N.E. 53rd Street and N.E. 52nd Street / 8" and 12" I Per MDWASD Water Atlas, an existing 8-inch water main fronts the property along Federal Highway. A 12-inch water main extends along a small portion of the site on Federal Highway. There is also an 8-inch water main within the right-of-way of Biscayne Boulevard. In accordance with Miami-Dade Water and Sewer Department (MDWASD) criteria, the developer may be required to extend the existing 12-inch water main southerly along Federal Highway, so that it fronts the entire length of the Western boundaries of the property. A final determination of this and the required points of connection will not be provided by MDWASD until a Water and Sewer Agreement is requested by the owner and/or the Hydraulic Analysis undertaken by MDWASD is completed. Water service meters will be installed by MDWASD forces at owner's expense. A copy of the MDWASD water atlas sheet for the project area has been included in Attachment " C for a 111. Sanitary Sewer Collection System Table 3 depicts the sanitary sewer mains owned and operated by Miami-Dade Water and Sewer Department (MDWASD), within the vicinity of the project Biscaync Boulevard Site Utility Study Page 4

7 Table 3: Existing Sanitary Sewer Mains (Per MDWASD Sewer Atlas Sheet) I Location Between I Federal Highway 1 NE. 53. Street and N.E. 52nd Street Sanitary Sewer Main(s) I 36" Force Main 1 48" B 8" Gravity line The proposed on-site sanitary sewer system for the property may be connected to either of the existing mains along Federal Highway; provided that the line has sufficient capacity to handle the additional flows contributed by the proposed project. MDWASD may also require upgrades to the sanitary sewer system. However, final determinations on these issues cannot be made until the necessary coordination has been completed with MDWASD. A letter of availability is recommended to verify the proposed sanitary sewer service connection points and requirements for this project. As is the case with the water service connections, public improvement requirements for sanitary sewer services will not be provided by MDWASD until a Water and Sewer Agreement is requested by the owner. The flows from sanitary sewer mains are received by MDWASD Regional Pump Station #2, which is located at 925 Biscayne Boulevard. Pump Station No. 2 is currently operating at an average yearly NAPOT of 2.89 hourslday, and is presently not under any type of moratorium (see attachedpump station report). It is not anticipated that any improvements to the regional pumping andlor transmission systems will be required to connect the proposed project. However, a final determination regarding the status of the existing transmission system and the need for possible improvements will not be made until construction plans are submitted to the Miami-Dade County DERM Wastewater Section and a Sanitary Sewage System Capacity Certification Letter is issued Biscayne Boulevard Site Utility Study Page 5

8 The additional flows created by this project have been determined and are shown in Table 4 below. Table 4: Water & Sewer Flow Generation 1 Apartment units gpd per unit I 35,400 I Retail 10,500 sf 5 gpd per loosf 525 Total Antici~ated Flow 35,925 epd IV. Solid Waste Generation Solid waste generated by this project will be collected in standard on-site containers for refuse and recyclables. Regular pick-up services will be provided either by private hauling companies andlor by the City of Miami Solid Waste Department, who will transport the waste to Miami-Dade County's or private disposal and recycling facilities. The volumes of solid waste projected to be generated by the project are shown in Table 5. Table 5: Solid Waste Generation Type of Occupancy Phase I Quantity Usage Rate Total Solid Waste Generated (Tonmav) Apartment 177 units 5lbs/unit/day 0.44 Retail 10,500 sf 61bs11000 sflday 0.03 I Total Anticipated Solid Waste Generated ( Biscayne Boulevard Site Utility Study Page 6

9 Attachment A Maps 5220 Biscayne Boulevard Site Utility Study

10 I Uichigan Ave Suite 400 Miomi Beach, Florida Kimley-Horn and Associates, Jthc Phone: =Lwx "---"-" -&7-T-?:& *-- Fax: ~ BISCAYNE BOULEVARD AVERAGEOCTOBERGROUND WATER LEVEL

11 ' 0-0 rn 1691 Michigan Avenue Suite 400 Miomi Beoch, Florido Kimley-Horn and Associates, Inc. Phone: ~-?z ~Y-T-?:&-L Fox: BICAYNE BOULEVARD CITY OF MIAMI, FLORIDA FLOOD CRITERIA MAP

12 1 I691 Michigan Avenue Suile 400 Miomi Beach, Florido BISCAYNE BOULEVARD Kimley-Horn and Associates, Inc. Phone: FLOOD CRITERIA MAP Fax:

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14 Attachment B Preliminary Drainage Well Calculations 5220 Biscayne Boulevard Site Utility Study

15 DRAINAGE CALCULATIONS: I DRAINAGE WELLS I I (MASS DIAGRAM - DERM CRITERIA) I 1. Site Data: 5220 BISCAYNE BOULEVARD City of Miami, Florida A. Average October Water Table Elevation = 2.00 NGVD B. County Hood Criteria Elevation = 5.00 NGVD (County Flood Cntena Map, see Appendix A) C. F.I.R.M. or FEMA Base Flood Elevation = n/a Zone X (Map No 12025C0181J, see Append~x A) D. Average Crown Road Elevation = 12.M NGVD E Average Existing Ons~te Grade Elevation = NGVD F. Proposed drainage inlet grate elevation = NGVD 2. Total Contributing Drainage Area (A): 2.16 Acres A. Impervious Areas: a) Asphalt and concrete pavement = 0.80 Acres 1.31 Acres b) Roof areas NE buildmg comer = -- Total Impervious Area (Al) = Acres (98%) B. Pervious areas: a) Green Areas = 0.05 Acres (2%) 3. Weighted Runoff Coefficient (C): Runoff Coefficient Impervious (Cl) = 0.90 Runoff Coefficient Pervious (C2) = 0.30 C = [(Al x C1) + (A2 x C2)] I A; C = 0.89 C x A = Total Contributing Area; C x A = 1.91 Acres 4. Time required to generate one inch of runoff (per DERM Water Control Section D-4) Q = CIA, V = Qt; V,, Rainfall Intensity (I) = I [(48.6 x fl 11) + t ( F ~~)] Frequency (F) = 3 years - Frequency Curve = Qt(l in,). t(, in,) = Time to generate 1 inch of runoff V(I in.) = CIAt(l in.) I" x A = CIAt,, ; Solving for I,,,,,, t,,,,, = 1" I (IC) Time to Generate one inch of run-off t(in) = Min. Time to reach the inlet (tc.) = Min. Total Time reauired to generate 1 in of runoff: = Min. VISTA BISCAYNE DRAINAGE WELLS Altechmnl B x15

16 5. Cumulative Runoff (Inflow Mass Diagram) - I (inches) Accumulated Runoff CFS) ,084 9,721 12,443 15,485 18,180 20,300 22, , , , Drainage Well Design Discharge Rate: Based on well d~scharge rate of 400 GPMIft. Head Lowcst Inlet Ott. Water Headloss due to Higher SG Well Slsucture Well Discharge Rate (CFS)( Total Storage (CWI Detention Time: The drainage well structure must be designed to detain runoff for a minimum of 90 seconds prior lo discharge. Q, =Design Runoff Rate (CPS) = 9.76 CFS V, =Detention Volume (CF) = Qd x 90 sec. = CF V,, =Detention Volume Per Well (CF') = CF W =Width of Well Structure (ft.) = 7.0 ft. L = Length of Well Suucture (ft.) = 12.0 fl. H,. is the minimum depth required from the top of well casing to the floor of the well box to achieve 90 second detention time: Hmin (ft.) = V,, / ( W x L) = 3.50 ft. Top of Well Casing Elev. = Elevation at Floor of Well Box (NGVD) = Top of Well Casing Elev. - H,;,. = 7.00

17 8. Excess slonn water runoff excluding well structure storage: Well Discharge Rate (CFS) kccumulate Well Discharge Volume (CF) 10,652 13,316 19,973 28,284 39,947 53,262 66,578 79, , ,679 'otal Ovemou Volume (cn -4,766-6,232-10,253-15,842-24, ,278-57, Safety Factor- 9. Excess storm water runoff including well structure storage: Volume Volume Safety Factor-

18 Attachment C Existing Utility Records 5220 Biscayne Boulevard Site Utility Study

19 rn M~chigon Avenue Suite 400 Miami, Florido fimley-hom and Associates, Inc. Phone: FOX: 305-t BISCAYNE BOULEVARD MDWASD SEWER ATLAS SHEET

20 m Michigan Avenue Suite 400 Miomi. Florido Kimley-Hom and Associates, Inc. Phone FOX: BISCAYNE BOULEVARD MDWASD WATER ATLAS SHEET E-11

21 5220 Biscayiie Boulevard Site Utility Study Attachment D Pump Station Monthly Information

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