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Home My WebLink AboutIII. Tab 3. Site Utility Study• • 234-242 NE 79th STREET MIAMI, FLORIDA 33138 SITE UTILITY STUDY STE PROJECT NO.04.2879 APRIL 2005 PREPARED FOR: BISCAYNE HOUSING GROUP, INC. THE CARLISLE GROUP 2950 SW 27th AVENUE, SUITE 200 MIAMI, FLORIDA 33133 PREPARED BY: SUN -TECH ENGINEERING, INC. 1600 WEST OAKLAND PARK BOULEVARD FORT LAUDERDALE, FLORIDA 33311 954-777-3123 954-777-3114 (fax) wwwsuntech@sithtecheng.com • Villa Patricia Site t- Biscayne dousing Group INTRODUCTION :iiity St April 2 y The project site is located at 234-242 NE 79th Street, Miami, Florida 33138 and has a net lot area of 2.44 acres. An elderly residential community is proposed consisting of two apartment buildings, having a total of 340 units, and a four level parking garage. Construction is proposed in two phases. Phase 1 consists of a 13 story apartment building having 180 units and the parking garage. Phase Il consists of a 16 story, 160 unit apartment building. Driveway connections are proposed onto NE 78th Street and NE 79th Street. NE 79th Street is a state road which will require a driveway connection peiinit as well as a drainage connection pet mit from the Florida Department of Transportation. ll. DRAINAGE SYSTEM General Runoff Characteristics The proposed site does not include a lake or an offsite drainage connection so all stormwater runoff must be collected and stored within seepage trenches and/or a retention area. The drainage system must be designed to accommodate the traditional runoff generated from the horizontal surfaces, and in addition Miami -Dade DERM requires that for high rise buildings, the proposed drainage system also take into account .runoff from one-third of the largest vertical building face for the 5 year-24 hour storm event. For the vertical runoff calculations, the most critical runoff will be generated when the rain/wind is out of the east/west direction, exposing the broadest building faces to the rain. Preliminary drainage calculations are shown in Exhibit A. Site Coverage Data Horizontal Areas ARE'A(ac.) PERCENT Building 0.44 18.0% Paved (Garage & on grade Parking & Roads) 1.02 41.6% Sidewalk 0.18 7.5% Green (Landscaping) 0.80 32.9% TOTAL 2.44 100° o Vertical Areas (1/3 of the buildingface) 13 Story Building (1 /3 x 120' x 198') 0.18 16 Story Building (1/3 x 147' x 149') 0.17 Parkin Garage (1/3 x 32' x 1211) 0_03 TOTAL 0.38 TOTAL 1MPERVIOUS AREA (including veriicai areas) 2.02 72®/a PERVIOUS AREA 0.80 28% TOTAL RUNOFF AREA 2.82 100% Page 2 of 5 • • Villa Patricia ity Study iscayue ousing Group April 2005 Permit Criteria South Florida Water ?Management District (SFWMD) Per the above site coverage data, this project qualifies for a 'No Notice General Permit for Activities in Uplands' in accordance with the SFWMD Permit Information Manual, Volume IV, Section 40E-400.315. Miami -.Dade County Dept. of Environmental Resources Manage (DERM) in accordance with Section D-4 of the Miami -Dade Public Works Manual, the drainage system must be designed to store the required water quality treatment volume or the runoff generated from the 5 year-1 hour storm event, which ever is greater. The minimum parking grade must be above the 5 year-1 hour storm elevation. These calculations are shown on Exhibit A. Note: DERM requests that the drainage systems for the parking levels below roof, not subject to direct runoff, be kept separate from the site drainage. n Florida De al orient of Transportation (FDOT) Since this project is adjacent to a state road (NE 79th Street), a drainage connection permit is required. Critical pei,nit criteria requires all on -site runoff generated from the 100 year-1 hour stout) event, equaling 5.1 inches, must be contained on -site without discharging into the FDOT right-of-way. Minimum Grade Criteria Parking Lot/Road Grade- Min. of: 5 year-1 hour storm elevation 'h foot below back of sidewalk grade. Minimum Perimeter Grade- 100 year-1 hour storm elevation Finished Floor Elevation- Min. of: 100 year-72 hour storm elevation 8" above crown of City Rd. FEMA Base Flood Elevation(See exhibit B) Project Discharge This project does not have any opportunities for an offsite drainage connection unless a drainage well is permitted. As stated above, the perimeter grade must be designed to retain the volume of stointwater runoff generated from the 100 year- 1 hour stoinm event. Under storm events greater than the 100 year- 1 hour storm event, the surface water elevation will rise above the perimeter grade and sheet flow offsite into the adjacent streets. If drainage wells are permitted at this location, the drainage system can be designed to store the required water quality treatment volume and then discharge any additional runoff directly into the drainage well. Page 3 of 5 • Villa Patricia Biscayne housing Group Site Utility Study April 2005 Drainage Wells Drainage Wells are regulated by the Department of Environmental Protection and the main limiting criteria permitting their use is such that the well casing shall penetrate a zone containing a minimum of 10,000 mg/L Total Dissolved Solids (TDS). As a rule of thumb, the closer the project site is to the ocean, bay or saltwater canal, there is a greater probability of meeting the TDS criteria due to the high level of salinity. Given the proximity of the project site to the nearest salt-waterbody, according to an official in the Water Control Section of DER.M and a local well drilling contractor, there is a good probability that the subject property will qualify for a drainage well. The only way to know for certain is by having a test hole drilled and tested. 111. WATER DISTRIBUTION SYSTEM Miami -Dade Water and Sewer Department owns and operates the public water mains in this area. The existing water mains adjacent to the project are as follows: NE 2na Avenue- Ten (10) inch NE 78`h Street- Two (2) inch NE 79n1 Street- Six -teen (16) inch. Pursuant to the "Letter of Water and Sewer Availability" from MD-WASD dated February 8, 2005, water service and fire service connections shall be from the ten (10) inch water main on NE 2" a Avenue. A contribution fee shall be paid to the County, in lieu of upsizing the two (2) inch main to a twelve (12) inch, the amount of thirty dollars ($30.00) per linear foot of the owner's property directly abutting NE 78th Street. The estimated average daily water consumption from this project is 34,407 gallons per day (gpd), as calculated in Exhibit C. IV. SANITARY SEWER SYSTEM MD-WASD owns and operates a sixteen (16) inch gravity sewer interceptor main on NE 79th Street and ten (10) inch gravity sewer mains located on NE 2n"a Avenue and NE 78th Street, adjacent to the project site. Pursuant to the "Letter of Water and Sewer Availability", connections to any of these mains are allowed, provided there is adequate depth and no conflicts with existing infrastructure. The estimated average daily sewage flow from this project is 34,407gpd, as calculated in Exhibit C. Page 4 of 5 • Villa Patricia 'Biscayne .lousing Group V SOLID WASTE MANAGEMENT Site 1rltihty Study April 2005 On -Site receptacles for refuse and recyclables are proposed within each of the buildings_ Regular pick-up service shall be provided by either the City of Miami Solid Waste Department and/or an approved private hauling company. Page 5 of 5 SUN -TECH ENGINEERING, INC. DATE: 4128105 1600 W. OAKLAND PARK BLVD_ REV: FORT L AUDERDALE, FL 33311 BY: `,NCL EXHIBIT A PRELIMINARY DRAINAGE CALCULATIONS FOR VILLA PATRC LAND USE BREAKDOWN LAND USE AREA PERCENT BUILDING 0.44 PARKING & GARAGE 1.02 SIDEWALK 0.18 GREEN 0.80 POND BANK 0,00 POND BOT, 0.00 18.0% 41.6% 7.5% 32.9% 0% 0% TOTAL 2.44 100% VERTICAL BUILDING FACES BUILDING WIDTH HEIGHT 1/3 x AREA (AC.) Phase I (13 story) Phase II (16 story) Parking Garage 198 149 121 120 147 32 0.18 0.17 0.03 TOTAL 0.38 • TOTAL RUNOFF AREAS* LAND TYPE AREA PERCENT IMPERVIOUS PERVIOUS 2.02 0.80 72% 28% TOTAL 2.82 100% *Includes vertical building faces. Design Storm Rainfall Amounts Storm Frequency Rainfall fn.) 1 hr 24 hr 72 hr 5 year 100 year 32 5.1 6.50 11.00 N/A 14.95 Soil Storage Calculation A. Total Pervious Area = 0.80 acres B. Depth to Water Table = 4.0 feet C. From SFWMD Permit Information Manual, Vol_ IV, Figure E-1, For 'Developed/Compacted Sandy Soils°, the Cumulative Available Soil Storage is: Sp = 8.18 inches D. Site Soil Storage = Sp x (Pervious Area/Total Area) 2.69 inches E. Curve Number (CN) = 1000/( Soil Storage + 10) = 78.82 F. Rational Method Coefficient (C) = (.25 x pervious area + .95 x Impervious Area)/ Total Area = 0.75 Water Quntity_Ca{culations A. Calculate the Runoff in Inches_ (Rainfall - 0.2 x Soi! Storage)? / (Rainfall + 0,8 x Soil Storage) 05yr-1 hour' Q5yr-1 day= Q1OOyr-1hour` 010Oyr-3day= 1.32 4.11 2.87 12.15 inches inches inches inches B. Calculate the Runoff Volume V= Q x Total Runoff Area (1 ft / 12 V5yr-1 hour= V5yr-1 day:: V1OOyr-1 hour= ViCijyr_3day= 0.31 0.97 0.68 2.86 ac-ft ac-ft ac-ft ac-ft Water Quality al' in) RUNOFF VOLUME TO BE STORED/EXFILTRATED BELOW THE FINISHED GRADE FOR THE FOLLOWING: MINIMUM PAVEMENT GRADE MINIMUM PERIMETER GRADE MINIMUM FINISHED FLOOR ELEVATION no ve A. Compute the first inch of runoff from the entire site. 1 inch x Total Area x (1 ft / 12 in) 0.20 ac-ft B. Compute 2.5 inches times the percentage of imperviousness. C. a. b. c. Site Area (SA), for water quality pervious/impervious calculations only SA= Total Area - (roof + fake) 2.00 Acres Impervious Area (IA), for water quality pervious/impervious calculations only IA= Site Area(SA) Pervious Area 1.2017447 Acres Percentage of imperviousness for water quality %imp= (IA / SA) x 100% 59.95 % d. For 2.5 inches times percentage of imperviousness 2.5 inches x %imp 1.50 inches e. Compute volume required for quality detention inches to be treated x (total - lake) x (1 ft / 12 in) 0.31 ac-ft (CONTROLS) Since 2.5 inches times the percentage of impervious is greater than the first inch of runoff over the entire site, the volume to be treated is: Volume to be treated = 0.31 ac-ft D. Since this is a commercial project, 0.5 in. dry detention/retention Pre-treatment must be provided. However, since the project is 100% retention and does not have any wet retention areas, the dry pre-treatment volume will be provided. EXHIBIT B NE 7C , Si NE cc.r'. ;E ZONE X NE 77NP ST tar EP3TH 67TH ST APPkOXIMA C. SC Al`t 5-DO 0 500 FEE NATIONAL FLOOD INSURANCE PROGRAM FIRM FLOOD INSURANCE RATE MAP DADE COUNTY, FLORIDA AND INCORPORATED AREAS PANEL 181 Of 625 (SEE MAP MPEx FOR PANEL,. NOT PR,P,EO) CONTAINS: UNiY 0Jt0ER PANEL oN ine Tvs na product IrtforrnaPPP MAP NUMBER 12025COi81 J ,' TMAI' !?I=VIsr--o MARCil 2, 991 SUN -TECH ENGINEERING, iNC. 1600 W. OAKLAND PARK BLVD. FORT LAUDERDALE, FL 33311 DATE 4/28/05 REV.: BY: VVCL EXHIBIT C ESTIMATED FLOW OF WATER & WASTEWATER FOR VILLA PATRICIA AVERAGE DAILY FLOW FLOW(gpd) TOTAL TYPE OF USE PER UNIT FLOW(apd) 340 Residential Apartments(1 bedroom with 750 SF or less) 100 34,000 Retail & Office Space (2,715 S.F.) 0.15 407 AVERAGE DAILY FLOW = 34,407 gpd - 0.034 mgd ESTIMATED PEAK FLOW POPULATION (P) = NO. UNITS x 1.5 PEOPLE/UNIT x 1/1000 = 0.510 (THOUSANDS) PEAKING FACTOR= (18 + P1r2) / (4 + P1' ) 4.0 PEAK FLOW = ADF X PEAKING FACTOR = 136,589 gpd 0.137 mgd Notes: 1. gpd = gallons per day 2. mgd = millon gallons per day 3. No industrial wastewater is anticipated to be generated. •