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HomeMy WebLinkAboutSite Utility StudyD. Site Utility Study so • • • • • Terrazas MAJOR USE SPECIAL PERMIT SITE UTILITY STUDY PREPARED FOR B&B Developments, L.L.C. by: KIMLEY-HORN AND ASSOCIATES, INC. 420 LINCOLN ROAD, SUITE 353 MIAMI BEACH, FL 33139 APRIL 2004 Kimley-Horn and Associates, Inc. • • • Terrazas Site Utility Study Terrazas MAJOR USE SPECIAL PERMIT SITE UTILITY STUDY PREPARED FOR B&B Developments, L.L.C. by: KIMLEY-HORN AND ASSOCIATES, INC. 420 LINCOLN ROAD, SUITE 353 MIAMI BEACH, FL 33139 APRIL 2004 Page 1 • • • Terrazas Site Utility Study Introduction The Terrazas project consists of two high rise multi -family residential towers constructed on a 6 story parking garage structure on approximately 2.11 +/- acres of land located at 1861 N.W. South River Drive, in the City of Miami, Miami -Dade County, Florida (see site location map -Fig 1). The largest of the two towers will be a proposed 27 story building, while the second tower will stand 20 stories tall. The development will consist of a total of 324 residential apartments units, and approximately 522 parking spaces. Table 1, shown below depicts the details of the proposed project. Table 1: Project Summary Residential Pedestal 32 48,658 Tower 1 198 238,631 Tower 2 94 92,143 Total 324 379,432 Parking 522 Two significant existing site conditions present challenges within the proposed development. First, the design will accommodate an approximate 11-foot change in the existing site grade from the front of the property adjacent to N.W. South River Drive, to the frontage of the Miami River. Secondly, the existing 15-foot diameter red silk cotton tree, a 4-foot diameter oak, and over a dozen royal palms currently existing onsite, which are to remain or be relocated onsite to enhance the proposed development. Terra7A s Site Utility Study Page 2 • • • Figurel: Site Location Map r1/ � u 0 v 1 TH Si• N 1 1-- v ,71 z Terrazas Site Utility Study 0 z NW 1 BTH TE ___�- I --......_ INW i 8STH iNW i s''H `P' ! W ', 7iH ST ,—..---ram'-..�--- 0 z 0 NW 16TH ST NW 1 STH ST k N"41t1 ST SIR 836 HY NW 9TH} S7»-��---�_-_ - iF T v STH TE �E 0 n ` N O Z O 0 z 1 m PROPOSED PROJECT VER DR A cc NW I ST It w 1 9TH S. lz 4TH ST R/V vW sT T... NW 8TH S[La. 1., wt t 7 T 1—I Page 3 • • • I. Drainage Existing Drainage Presently, the site is developed with a 24,008 S.F, 1-4 story abandoned hospital facility and parking lot. The existing facility, which lies on the west side of the subject site, will be demolished for the purposes of the proposed development. There is an existing drainage system on -site, which will be removed and replaced by a new storm water management system (see Proposed Drainage System). An off -site drainage system could not be identified from the site visit. Due to the large difference in grade elevations from the south side of the property to the north side of the property, it appears that a portion of the on -site drainage run-off may currently be sheet flowing into the Miami River. Proposed Drainage System The drainage system for the proposed development will consist of drainage wells and exfiltration trench, if possible, to facilitate on -site disposal of storm water runoff. The 5- year design storm event will be used to design the storm water management system, in accordance with Section D-4, "Water Control", of Part 2 of the Miami -Dade County Public Works Manual. Based on preliminary calculations, it is anticipated that two (2) 24" drainage wells will provide sufficient capacity to dispose of the design 5-year 24-hour storm water runoff generated by the proposed development. Preliminary drainage computations for the project areas are provided in Attachment "A" 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. Terrazas Site Utility Study Page 4 • • II. 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 3. Table 3: Existing Water Mains N.W. South River Dr. N.W. 19th Ave. and N.W. 18th Ave. 8" D.1. N.W. 18th Ct. Running North through the property from N.W. South River Dr. 8" D.1. In accordance with MDWASD criteria, the owner will most likely be required to construct a new 12-inch ductile iron (DI) water main along the frontage of the property on N.W. South River Drive_ The proposed 12-inch water main will likely be connected to the nearest 12-inch water main or larger. A water main of said diameter, lying within the vicinity of the project area, could not be identified from the MDWASD water atlas sheet. A final determination of the points of connection and requirements will not be provided by MDWASD until a Water and Sewer Agreement is requested by the owner. Water service meters will be installed by MDWASD forces at owner's expense. See Attachment "B" for a copy of the MDWASD water atlas sheet for the project area. Terrazas Site Utility Study Page 5 III. Sanitary Sewer Collection System Table 4 depicts the sanitary sewer mains owned and operated by Miami -Dade Water and Sewer Department (MDWASD), within the vicinity of the project. Table 4: Existing Sanitary Sewer Mains Lr�eavzr Btween e Sant Sewei r klan s L) N.W. South River Dr. N.W. 19th Ave. and N.W. 18th Ave. 8" Gravity Main A copy of the MDWASD Sewer Atlas sheet has been attached (Attachment B). The proposed on -site sanitary sewer system for the property can probably be connected to the existing public gravity main. A letter of availability and further coordination with MDWASD is recommended to verify the proposed sanitary sewer service connection points and requirements for this project. MDWASD may require upgrades to the sanitary sewer system and the receiving pump station, but this can not be determined without a request for a water and sewer agreement. The flows from the existing MDWASD sanitary sewage mains on NW South River Dr. and NW 18th Pl. are received by MDWASD Regional Pump Station #71. As of February 18, 2004, this pump station is operating under capacity as established by the USEPA, but was placed under a moratorium on February 18, 2004 (see Attachment "C" Pump Station Monthly Information). However, according to Miami -Dade County DERM's analysis the moratorium has since been corrected and approved. A final determination regarding the status of the existing transmission system and the need for possible improvements to the existing regional pumping and/or transmission systems will not be made until a Miami - Dade County DERM Sanitary Sewage System Capacity Certification Letter is issued. Terrazas Site Utility Study Page 6 • • An existing private sanitary sewer system, composed of a lift station with a force main to gravity main connection, is located within the property and appears to connect to the existing public gravity system along N.W. South River Drive. Unfortunately, current code no longer allows force main connections to gravity lines, therefore the existing private system may have to be demolished. The flows created by this project have been determined and are shown in Table 5. Terrazas Site Utility Study Table 5: Water & Sewer Flow Generation Apartment 324 units 200 gpd per unit 64,800 Total Anticipated Flow 64,800 gpd Page 7 o • • 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 service will be provided either by private hauling companies and/or 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 6. Terrazas Site Utility Study Table 6: Solid Waste Generation Apartment 324 units 51bs/unit/day 0.810 Total Anticipated Solid Waste Generated 0.810 Page 8 • • • Terrazas Site Utility Study Attachment A Preliminary Drainage Well Calculations Page 9 • • Terrazas City of Miami, Florida DRAINAGE CALCULATIONS: "DRAINAGE WELLS" (MASS DIAGRAM —.DERM CRITERIA) 1. Site Data: A. Average October Water Table Elevation = B. County Flood Criteria Elevation = C. F.I.R.M. Base Flood Elevation = D. Average Road Crown Elevation = E. Average Existing Onsite Grade Elevation F. Proposed lowest inlet grate elevation = 2. Total Contributing Drainage Area (A) : A. Impervious Areas: a) Asphalt and concrete pavement = b) Roof areas + 1/3 NE building comer = Total Impervious Area (A) B. Pervious areas: a) Green Areas = 3, Weighted Runoff Coefficient (C): Runoff Coefficient Impervious (CI) Runoff Coefficient Pervious (C2) C=[(A1 x C1) + (A2 x C2)) / A; C= C x A= Total Contributing Area; C x A= NGVD (Mean High Tide elev. per MLW Bay Datum) NGVD (County Flood Criteria Map, see Appendix A) NGVD (Map No. 12025C01805, see Apx. A) NGVD NGVD NGVD 2.534 Acres ;6 Acres Acres 2.337 Acres (92%) Acres (8%) 0.853 2.16 Acres 4. Time required to generate one inch of runoff (per DERM Water Control Section D-4) Rainfall Intensity (I) = 308.5 / [(48.6 x F0.11) + t (0.5895 + F )] Frequency (F) 5 ; years - Frequency Curve Q = CIA, V = Qt; V(1 in) = Qt(1 in), t(1 in.) = Time to generate 1 inch of runoff V(1'tn.) = CIAt(1 in.) 1" x A = CIAt(1 in,) ; Solving for t{1 no, to in.) = 1" / (IC) Time to Generate one inch of run-off t(in) = 11.78 Min. Time to reach the inlet (tc.) 10 Q{i Min. Total Time required to generate 1 in of runoff = 21.78 Min. OrainCalcs BASIN • • • 5. Cumulative Runoff (Inflow Mass Diagram) 8 10 15 21.78 30 40 50 60 90 120 180 (See.); 480 600 900 1307 1800 2400 3000 3600 5400 7200 10800 CxA• (acres) 2.162 2.162 2.162 2.162 2.162 2.162 2.162 2.162 2.162 2.162 2.162 6.405 6.166 5.641 5.057 4.493 3.956 3.534 3.193 2.477 2.023 1.480 13.85 13.33 12.20 10.94 9.72 8.56 7.64 6.91 5.36 4.37 3.20 AcevrtiuIato . Storm' Runoff 6,648 8,000 10,978 14,290 17,488 20,532 22,927 24,859 28,922 31,496 34,573 6. Drainage Well Design Discharge Rate: Based on well discharge rate of: GPM/1t. Head ra„y ♦ aY Me ,;�,y„ leacllosa due e I5 �t �'��' f Soh ester ✓ ,::, :✓ �'";� ,a eadr�p igy �. `.*, t ✓„ s '� ell Disclarge 1 `* +�Y -✓ 'k eH Struc r �zt et to s S�s 4tructt_ire-;. Storngc Volume ' ✓baweS ..,r C}..._ 1 ' ....?t...., ca�%z � �a �✓; �.. > .� n YY k. ✓:: to {C �, ?. ;'r�: W dt fi ., „- i' k .:..,_( DW-1 11.65 3.00 1.61 7.04 10.98 �( 225.28 DW-2 11.60 3.00 1.61 6.99 10.90 , 223.68 Well Discharge Rate (CFS){ 21.88 7. Detention Time: Total Storage (CF)448.96 The drainage well structure must be designed to detain runoff for a minimum of 90 seconds prior to discharge. Qd = Design Runoff Rate (CFS) _ Vd = Detention Volume (CF) = Qd x 90 sec. _ Vdl = Detention Volume Per Well (CF) = W = Width of Well Structure (ft.) L = Length of Well Structure (ft.) = 10.94 CFS 984.19 CF 492.09 CF 4.0 ft. 8.0ft. H, ,;o, is the minimum depth required from the top of well casing to the floor of the well box to achieve 90 second detention time: Hm;n. (ft.) = Vdu / (W x L) = 15.40 ft. Top of Well Casing Elev. = 3.00 Elevation at Floor of Well Box (NGVD) = Top of Well Casing Elev. - Hm;B, _ -12.40 • • 8. Excess storm water runoff excluding well structure storage: 8 10 15 21.78 30 40 50 60 90 120 180 .(Sec.) > - 480 600 900 1,306.77 1800 2400 3000 3600 5400 7200 10800 21.88 21.88 21.88 21.88 21.88 21.88 21.88 21.88 21.88 21.88 21.88 Accumulated Well .. Discharge Volume ( 10,504 13,130 19,695 28,596 39,389 52,519 65,648 78,778 118,167 157,556 236,334 Accumulated • Storm llunoff 6,648 8,000 10,978 14,290 17,488 20,532 22,927 24,859 28,922 31,496 34,573 Total C3verflow.; Vo1Lirne -3,856 -5,129 -8,716 -14,306 -21,901 -31,986 -42,722 -53,919 -89,245 -126,060 -201,761 9. Excess storm water runoff including well structure storage: Safety Factor ✓ h' a - cii2riiilateft 4Ve11 . A cumulated S e71 D sc is e ` "1'oi d erflow stot l7 1inoft •�' ri7 turf - Volume= y Volume' Y t 8 480 6,648 449 10,504 -4,304.94 10 600 8,000 449 13,130 -5,578.38 15 900 10,978 449 19,695 -9,165.11 21,78 1,306.77 14,290 449 28,596 -14,754.68 30 1800 17,488 449 39,389 -22,349.53 40 2400 20,532 449 52,519 -32,435.33 50 3000 22,927 449 65,648 -43,170.77 60 3600 24,859 449 78,778 -54,367.94 90 5400 28,922 449 118,167 -89,693.81 120 7200 31,496 449 157,556 -126,508.85 180 10800 34,573 449 236,334 -202,210.01 2.00% Safety Factor 2.07% 1 4 Ty 0 NW 16TH TE NW 16TH ST NW 15TH ST T NW NW 17TH ST PROPOSED PROJECT %ram: v R DR NW 11 T NW 10 H ST IGmlay-Horn and Assodaies, Inc. 420 Lincoln Rood Suite 353 Miami Beads, Florida 33139 Phone: 305-673-2025 Fax: 305-673-4882 S NW 16 NW 14TH NW 1 CD TE z-T NW 1 T f NW NW 8TH TE TERRAZZA 1861 NW S. RIVER DR. LOCATION MAP • 11111111 Klmley-Ham and Associates, Inc. 420 Lincoln Road Suite 353 Miami Beach, Florida 33139 Phone: 305-673-2025 Fax: 305-673-4882 TERRAZZA FLOOD CRITERIA MAP • • Kimley-Hom and Associates, Inc. 420 Lincoln Rood Suite 353 Miami Beach, Florida 33139 Phone: 305-673-2025 Fax: 305-673-4882 TERRAZZA FIRM. FLOOD INSURANCE RATE MAP Kimley-Horn and Associates, Inc. INN 420 Lincoln Road Suite 353 Miami Beach, Florida 33139 Phone: 305-673-2025 Fax: 305-673-4882 TERRAZZA 1861 NW South River Drive City of Miami,FI AVERAGE OCTOBER GROUND WATER LEVEL 1960-75 • Attachment B Existing Utility Records 1L fli • Attachment C Pump Station Monthly Information o AY K. 19. Z UU4 3 ; 1 1 NM Pump. Station Monthly Information Station..30 -0071 Atlas Pg..E13 M=AMI DADE WATER & SEWER DEPARTMENT Addr ..1, 07 0 NW 20 AVE Sec--Township-Range 34-53-41 Genr. ET clock.Y Telm.X #Purnps. 2 •UXflP Type.B Stn Class.L Speed.1 ilrspwr.- Res flow(gpd) Plans.. 350 Plats.. 0 Extens. 0 prof Napot 6.24 hrs 6.23 hrs 6.23 hrs % Cap 62.40 62.30 62.30 Date Mo . NAPOT Avg Daily Flows 01/14/2004 4.14 4.14 12/10/2003 5.00 5.00 0.00 1.1/12/2003 6.1.7 6.17 0.00 10/08/2003 8.61 8.61 0.00 09/10/2003 5.39 5.39 0.00 08/13/2003 4.83 4.83 0.00 07/09/2003 6.55 6.55 0.00 signature.. GOLD/M Station I<m>provem.ent GOLD/S GOLD/D <D>ownstream Station G©LD/G Codes & Cata<g>ories GOLD/T • 0.00 J. u r U <....r1 Rev e Moratorium .. 1 APPROVED AND CORRECTED Moratorium effective since 02/18/2004 Yearly NAPOT (hrs) Stn Gross Capacity(gpd) . Station Reduction Factor Stn Net Cap Certif(9pd) Stan Net Capacity(gpd) .. , _ Indicated Flows (gpd) 6 .2: 576,001 1.0( 576,00( 149,521 Rgd # Comments F1g Imp Y 2 CM to AC, work certified. RN Y 2 Y 2 2 Y 2 Y 2 Y 2 Sign Date..02/18/2004 11:51:04.31 <S>tati0n Inform. GOLD/iJ <U>pstream Stati GOLD/P <P>u p Inforrati Sewer Cex'<t>ification