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HomeMy WebLinkAboutIII.Tab.3 Site Utility Study.TAB 3 RELATED LOFTS III MAJOR USE SPECIAL PERMIT SITE UTILITY STUDY Prepared for: The Related Group of Florida Prepared by: Consulting Engineering and Science, Inc. December 20, 2006 1. General A. Project Location and Size: The subject property is located along the east side of N.E. 2nd Avenue, bounded on the south by N.E. 2nd Street and on the north by N.E. 3rd Street, in the City of Miami. The site, with a net lot area of 28,541 square feet, or 0.66 acres, has approximately 300 feet of frontage along N.E. 2nd Avenue; approximately 90 feet of frontage along N.E. 2th Street; and, approximately 100 feet of frontage along N.E. 3rd Street. The land on which the project is proposed consists of Lots 11, 12 and 14; and, a portion of Lot 13 in Block 100 of NORTH CITY OF MIAMI, accordingly to the plat thereof as recorded in Plat Book B at Page 41 of the Public Records of Miami -Dade County, Florida. The site is currently occupied by two 2-story and one 3-story retail/office buildings. B. The proposed project build -out will be as follows: Residential: 495 units Retail 13,374 s.f. Net Lot Area 28,541 s.f., or 0.66 acres Gross Lot Area 43,750 s.f., or 1.00 acres Construction will consist of a 32-story workforce housing condominium building. Retail space will be developed within the ground floor level fronting N.E. 2nd Avenue, N.E. 2nd Street and N.E. 3rd Street. 2. Drainage A. Drainage Area Upon development, 100 per cent of the site will be impervious. Stormwater runoff will consist of rainfall from the building roofs, driveways, walks and one-third of the vertical building surface. The coefficient of run-off is calculated as follows: 100% (impervious) X 0.90 = 0.90 Overall coefficient = 0.90 B. Existing Storm Drainage System: Runoff from the site is currently directed to a number of catch basins located towards the easterly portion of the project site from which the runoff is directed to underground seepage trench/exfiltration trenches. There appears to be no evidence of drainage problems or prolonged standing water on the site or in the adjacent streets. C. Proposed Storm Drainage System: The storm drainage system to serve this project will be designed to fully contain the 5-year 1-day storm event on - site, as required to comply with the applicable requirements of the Miami -Dade County Department of Environmental Resources Management (DERM). It is anticipated that the stormwater disposal system will include two (2) 24" drainage wells. See supporting calculations, in Table 1. Runoff will be collected through a system of catch basins and conveyed by pipes to the well locations. Runoff from driving surfaces such as the service driveway will be diverted through baffled pollution control structures which will capture the oils and greases prior to flowing into the wells. Table 1 Preliminary Drainage. Calculations 1. Total Net Area 0.66 Acres a. Impervious Roof/Driveways/Walks 0.66 Acres 1/3 Vert. Bldg. Surface 1.83 Acres 2.49 Acres b. Pervious 0.00 Acres c. Adjusted Contributing Area 2.49 Acres 2. Average Runoff Coefficient 2.49(0.9) 2.49 = 0.90 3. Design Storm 5 years 4. Time of Concentration 15 minutes -2- 5. Rainfall Intensity 5.50 in/hr 6. Peak Runoff (Q = CiA) (0.90)(5.50)(2.49) = 12.33 cfs 7. Direct Runoff (Q = CiA) (0.90)(5.50)(0.66) 3.27 cfs Assume each 24-inch diameter drainage well has a capacity of 1,000 gpm per foot of head; and, using 3.0 feet of available head: Well Capacity = 1,000 gpm x 3.0 feet = 3,000 gpm per well = 6.68 cfs per well No. Wells = Peak Runoff = 12.33 cfs = 1.85 wells Well Capacity 6.68 cfs Provide 2 - 24" diameter Drainage Wells Detention Tank: Provide 1.5 minutes of Direct Runoff detention time for storage in the detention tank: Volume of tank required to handle 3.27 cfs for 1.5 min: 3.27 cfs x 1.5 min = 294 cubic feet (cf) Provide two (2) tanks with the following interior dimensions: 2 X 4'-0" (width) x 8'-6" (length) x 4'-6" (depth) = 306 cf 3. Water Distribution The Miami Dade Water and Sewer Department owns and operates 12-inch water mains in N.E. 2nd Street and N.E. 3rd Street; and, two (2) 12-inch water mains in N.E. 2nd Avenue fronting the property. An existing 4-inch water main running through the site will need to be removed. The water and fire connections for this project will be made from the 12-inch water main in either N.E. 2nd Street or N.E. 3rd Street. The connections will consist of a fire line service, domestic water service and cooling tower water service. No on -site water wells are planned for this project. The calculations for anticipated water usage required for this project are shown below, in Table 2. -3- Table 2 Water Usage Residential Condominiums/Apartments: 495 units @ 200 gpd/unit = 99,000 gpd Retail: 13,374 sf @ 5 gpd/100 sf = 669 gpd Total = 99,669 gpd 4. Sanitary Sewer The Miami -Dade Water and Sewer Department owns and operates 10-inch gravity sewer mains in N.E. 2nd Street and N.E. 3rd Street; and, an 8-inch gravity sewer main in N.E. 2nd Avenue fronting the property. It is anticipated that one or two gravity sewer connections to one or two of these sewer mains will be utilized to serve this project. No pump station will be required to serve the project. Anticipated sewage flow calculations are shown below, in Table 3. Table 3 Sewage Flow Calculations Average Daily Flow (Table 2) = 99,669 gpd Average Daily Flow = 69.2 gpm Peak Flow (69.2 x 2.0) = 138.4 gpm 5. Solid Waste Generation Solid waste generated by this project will be collected in standardized on -site containers for refuse and recyclable waste. Regular service will be provided by either private hauling companies and/or the City of Miami Solid Waste Department. Both will transport the waste to Miami -Dade County's Disposal or Recycling facilities. The projected daily volumes of solid waste generation are shown below, in Table 4. Table 4 Solid Waste Generation Residential Apartments: Solid Waste Retail: Solid Waste Total 495 units x 1.42 tons/unit/year 703 tons/year 1.93 tons/day 3;860 lbs/day 13,374 sf @ 3.08 lbs/sf/year 41,192 lbs/year 113 lbs/day 3,973 lbs/day