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HomeMy WebLinkAboutSite Utility Study• o • PREMIERE TOWERS BRICKELL VILLAGE MAJOR USE SPECIAL PERMIT SITE UTILITY STUDY Prepared for: BAP DEVELOPMENT, INC. Prepared by: Bermello, Ajamil & Partners, Inc. September 7, 2004 • • • DRAINAGE A. Drainage Area The site is located at the northwest corner of the intersection of S Miami Avenue and SE 9th Street. The site consists of seven conjoining parcels, consisting of a total property area of 1.38 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 adjacent streets. The site is partially vacant and partially consists of older residential/office buildings that will be demolished. 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. Table 1 Page 2 • • • Runoff Generations 1. Total Area a. Impervious b. Pervious Sample Drainage Calculations (Phase 1 only) 1.38 Acres 95% or 0.95 Acres 5% or 0.05 Acres 2. Average Runoff Coefficient (.95) (.9) + (.05) (.3) = 0.87 3. Design Storm 5 years 4. Time of Concentration 10.00 min 5. Rainfall Intensity 6.10 in/hr 6. Peak Runoff (Q) - CA (87) (6.10) (1.38) = 7.35 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) (Flow per well) 7.35 CFS 3.34 CFS 2.2 Wells Provide 3 - 24" diameter wells Detention Tank: Providing 11/2 minute (90 seconds) 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 (WASD) will own and operate a 12" water main located on SE 9th Street fronting the subject project which is currently under construction by the development on the south side of SE 9th street. It is anticipated that this watermain will be conveyed to WASD before the start of construction. 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 Residential Apartments: 560 units @ 200gpd/unit 112,000 gpd Retail / Shopping: 21,000 SF @ 5 gpd/100 SF 1,050 gpd TOTAL: 113,050 gpd III. SANITARY SEWER The Miami Dade Water and Sewer Department owns and operates two 6" gravity sewer mains along SE 9th Street, fronting the subject property and a 10"gravity sewer main at the intersection of SW 1st Avenue and SE 9th Street. This project proposes to design and construct a new 10" gravity sewer main to replace one of the 6" gravity sewer mains located on SE 9th Street. The proposed 10" main will tie into the 10" gravity sewer system at the intersection of SW 1st Avenue and SE 9th Street and extend east along SE 9th Street to the eastern end of the developers' property. It is anticipated that multiple gravity sewer laterals connecting to the proposed 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) 113,050 gpd Average Flow 78.5 gpm Peak Flow (13.2 x 3.5) 275 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: (560 units @ 1.42 tons/units x 2,000 lbslton)/365 days 4,357 lbs Page 5