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HomeMy WebLinkAboutSite Utility StudyPARK PLACE II MAJOR USE SPECIAL PERMIT SITE UTILITY STUDY Prepared for: Rilea Group Prepared by: Bermello, Ajamil & Partners February 1, 2005 • PARK PLACE II . SITE UTILITY STUDY 1. DRAINAGE A. Drainage Area • o The site is located west and adjacent to Brickell Avenue, east of the alley between South Miami Avenue and Brickell Avenue, and on the north side of SE 15th Road. It consists on one parcel of approximately 2.46 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 and the FDOT presently maintain a roadway drainage system in all three streets surrounding the area. The site is presently fully developed. The existing roadway system there, 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 four 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 • • Table 1 Sample Drainage Calculations (Phase 2 only) Runoff Generations 1. Total Area a. Impervious b. Pervious 2. Average Runoff Coefficient 3. Design Storm 4. Time of Concentration 5. Rainfall Intensity 6. Peak Runoff (Q) - C,A 2.46 Acres 95% or 0.95 Acres 5% or 0.05 Acres (.95) (.9) + (.05) (.3) = 0.87 5 years 10.00 min 6.10 in/hr (.87) (6.10) (2.46) = 13.06 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 welt 1,500 gpm = 3.34 CFS (Peak runoff) (Flow per well) 13.06 CFS 3.34 CFS Provide 4 - 24" diameter wells Detention Tank: Providing 1 % minute detention time of storage in tank. = 3.90 Wells 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 4 tanks, each one with the following interior dimensions: 5' (width) x 5' (height) x 12' (length) = 300 ft3 Page 3 • • o Provide 4 tanks with 300 ft3 volume each II. WATER DISTRIBUTION The Miami -Dade Water and Sewer Department owns and operates one 12" Water Main located on SE 15th Road. The water connections to serve the buildings will be done from the existing 12" water line. The connections will consist of fire protection line, domestic water supply system 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 Office Area 524,300 sf @ 10gpd/100 sf 52,430 gpd III. SANITARY SEWER The Miami Dade Water and Sewer Department owns and operates a 10" gravity sewer system running along the alley bordering Park Place Phase I and by the east side of the subject property. It is anticipated that multiple gravity sewer laterals connecting to this 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) 52,430 gpd Average Flow 36.40 gpm Peak Flow (36 x 3.5) 126 gpm 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 Page 4 • • • 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 estimated daily volume of solid waste generated is shown in Table 4, below. Table 4 Solid Waste Generation Office Building 524,300 sf @ 6 ppd/1000 sf 3,146 Ibs Page 5