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HomeMy WebLinkAbout2002 - Responses to Request for Additional InformationSt. John's River Water Management District Application No. 40 -061- 68172 -3 RAI #2 Responses For arf OF SEBAS,TIAN HOME OF PEUCAN ISLAND Sebastian Municipal Airport T- Hangar Development / Access Roads Prepared by; THE LPA GROUP INCORPORATED September 20, 2002 'LFALTHE LPA CROUP INCORPORATED Transportation Consultants 4503 WOODLAND CORPORATE BOULEVARD, SUITE 400 ■ TAMPA, FLORIDA 33614 111813-889-3892 ■ FAX 813 -889 -3893 September 20, 2002 Ms. Karen Garrett -Kraus Ms. Leigh Stewart St. Johns River Water Management District 525 Community College Parkway S.E. Palm Bay, FL 32909 (321) 984 -4940 Subject: Sebastian Municipal Airport T- Hangar Development/Access Roads Application No. 40 -061- 68172 -3 Dear Ms. Garrett -Kraus and Ms. Stewart: In response to the Request for Additional Information (RAI) for the referenced project, we offer the following responses. Please see the attachments for supporting documentation. Wetland Comment: 1. It has been determined that the proposed stormwater pond adjacent to the existing wetland and wetland area to be restored will have a drawdown effect on the wetland. Please be advised that this is considered a wetland impact. Please demonstrate that the wetland hydrology will not be impacted or provide additional mitigation. [section 12.2.2.4, 12.2.7, A.H.] An additional parcel of mitigation is proposed to offset the potential drawdown effect of the adjacent stormwater pond, as well as serve as mitigation for the small restoration area proposed on -site. This mitigation replaces the on -site restoration area discussed in response no. 7, (RAI Responses letter dated 14- AUG-02). With the purchase of this additional parcel, no ors -site mitigation or restoration will occur on the Airport. This parcel ( #261) is adjacent to the two parcels ( #260, #350) offered for mitigation for the roadway impacts associated with this permit application. Based on a review of the aerial map of the mitigation property and a field visit conducted on August 28, 2002, Parcel 261 appears to be entirely wetland. The wetland would be described as a shrub marsh with scattered magnolias, bay trees, and wax myrtle. Ground cover included lyonia, hat pins, and other grasses. On the date of the site visit there was standing water present in the wetland. It is connected to a larger forested bay swamp to the northwest. Roadside ditchlunderdrain system, general comments: ATLANTA ■ BATON ROUGE ■ CHARLESTON ■ CHARLOTTE ■ CHICAGO ■ COLUMBIA ■ GREENSBORO ■ GULFPORT ■ JACKSONVILLE KNOXVILLE LITTLE ROCK ■ MOBILE ■ ORLANDO ■ RALEIGH ■ RICHMOND ■ SARASOTA ■ TALLAHASSEE ■ TAMPA ■ WEST PALM BEACH Ms. Garrett-Kraus and Ms. Stewart, Page 2 1. Please show the proposed elevation of the ditch bottom on the plan and profiles. Show the underdrain in the pavement cross- section and note where applicable. [40C -4.301 (1) F.A.C.] p^ This information has been added to the plans. Note sheet C2.1 of the Roadway plans for a table of underdrain lengths and sizes in the typical section. 2. Please provide justification for the permeability rate of 1 ft/hr used in the underdrain calculations. The geotechnical report indicates k values in the range of 1.33 -1.35 ft/day. [40C- 42.026 (2) F.A.C.] Per discussions with Leigh Stewart (SJRWMD) it was agreed upon that the K value of 1 foot per hour can be used. Clean sand (FDOT 904 -2 for Type V underdrains) is to be used to replace the native soil between the top of the backfill material and the bottom of the pond or ditch (as detailed on Sheet C4.2 of the T- Hangars and C5.1 of the roadway). Section 10 +70 to 15 +30: 1. What is to prevent the roadside ditch from outfalling to the Roseland Road swale? [40C -4.301 (1) F.A.C.] At station 10 +50 ditch blocks have been added to the plans on both sides of the road. 2. The inverts of CO -1 and CO -2 are shown to be at elevation 10.35 feet. The cross- section indicates the depth from the bottom of the ditch to the invert of the pipe to be 2.58 feet (2' native soil + 3" gravel + 4" pipe). This would dictate an invert at elevation 9.77 feet. [40C- 42.026 (2) F.A.C.] The inverts of CO -1 and CO -2 have been revised, but changed to 9.68' due to the pipe diameter increase to 5 inches. Inverts at JB -1 and JB -2 have been changed and the pipe slope to 0.1 percent. 3. The ditch block is called out at elevation 14.0 feet on sheet C5.1, however; the treatment volume is retained at elevation 12.65 feet per the stage storage chart and the underdrain calculations are based on the ditch block at elevation 12.65 feet. Please clarify. 140C- 42.026 (2) F.A.C.] - Ditch blocks DB -1 and DB -2 have been revised to show an elevation of 12.65 at the top. Section 20 +50 to 26 +50: 1. Please show the stations on the bottom of the profile on sheet C5.2 and the location of the cross culverts in the profile. [40C -4.301 (1) F.A.C.] The stations and the location of the cross culverts have been added to the profile on sheet C5.2 Ms. Garrett -Kraus and Ms. Stewart, Page 3 2. The inverts of CO -3 and CO -4 are shown to be at elevation 8.50 feet. The cross - section indicates the depth from the bottom of the ditch to the invert of the pipe to be 2.58 feet (2' native soil + 3" gravel + 4" pipe). This would dictate an invert at elevation 7.92 feet. [40C- 42.026 (2) F.A.C.] The inverts of CO -3 and CO -4 have been revised, but changed to 7.75' due to the pipe diameter increase to 6 inches. Inverts at JB -1 and JB -2 have been changed and the pipe slope to 0.1 percent.. 3. Sheet C2.1 shows MES 7 and MES 8 at an invert elevation of 9.50 feet, however; the ditch bottom is indicated at elevation 10.5 feet. Please clarify. [40C -4.301 (1) F.A.C.] On Sheet C2.1 the inverts for MES 7 and MES 8 have been revised to elevation 10.5 feet. 4. Inlet H -1 (existing type "H" inlet) has a grate elevation of 10.5 feet. Is this grate to be adjusted? If not, how will the treatment volume in this section be retained? [40C- 42.026 (2) F.A.C.] The grate elevation to Inlet H -1 (existing type "H" inlet) and H -2 have been revised and are now 13.5 feet. Section 60 +00 to 66 +40: 1. Please show the swale contours and elevations on the plan view. [40C -4.301 (1) F.A.C.] This information has been added to the plans. 2. The inverts of CO -5 and CO -6 are shown to be at elevation 14.8 feet. The cross- section indicates the depth from the bottom of the ditch to the invert of the pipe to be 2.58 feet (2' native soil + 3" gravel + 4" pipe). This would dictate an invert at elevation 12.22 feet. [40C- 42.026 (2) F.A.C.] The inverts of CO -5 and CO -6 have been revised, but changed to 14.13' due to the pipe diameter increase to 5 inches. Underdrain inverts at C -1 have been �- changed to 13.68 and the pipe slope has been revised to 0.1 percent. Section 72 +00 to 77 +92: 1. Please show the swale contours and elevations on the plan view. [40C -4.301 (1) F.A.C.] This information has been added to the plans. 2. The inverts of CO -7 and CO -8 are shown to be at elevation 14.28 feet. The cross - section indicates the depth from the bottom of the ditch to the invert of the pipe to be 2.58 feet (2' native soil + 3" gravel + 4" pipe). This would dictate an invert at elevation 13.70 feet. [40C- 42.026 (2) F.A.C.] Ms. Garrett -Kraus and Ms. Stewart, Page 4 The inverts of CO -7 and CO -8 have been revised, but changed to 15.61' due to the pipe diameter increase to 5 inches (18.2' ditch bottom elev. - 2' of clean sand - 5" PERF pipe -3" gravel = 15.61'). Underdrain inverts at C -2 have been changed to 15.3 and the pipe slope to 0.1 percent. 3. The "UNDER DRAIN DESIGN OF THE TREATMENT FACILITY" page is missing for this section of roadway, please include. [40C- 42.026 (2) F.A.C.] This has been added to the documentation. T- Hangar Site: 1. Please provide a node -link diagram. Additional comments, if any, will be forthcoming upon receipt and review of the diagram. [40C -4.301 (1) F.A.C.] A node -link diagram has been added to the stormwater document for the existing and proposed condition.. 2. The maximum stage for N -4 is 14.29 and 15.31 feet for the mean annual and the 25- year events, respectively. As such, overflow will occur at MES 6 and enter the roadside system. Please review. [40C -4.301 (1) F.A.C.] West of IVIES-6 the ditch block elevation has been raised to 15.3' and the ditch regarded to contain runoff up to an elevation of 15.3 feet. 3. The not to the cleanout for the underdrain system is not legible. Please clarify. [40C -4.301 (1) F.A.C.] Full size plans have been submitted. 4. Please indicate the length and inverts of the underdrain system in the retention area. [40C- 42.026 (2) F.A.C.] This information has been added to the plans. 5. Please provide a full size plan of the T- hangar site, sheet C2.1 and a full set of final plans. [40C -4.301 (1) F.A.C.] Please see plan sheet C2.1. Three full -sized copies have been provided. Three sets of half -sized Final T- Hangar Plans are also included. Please note that architectural, electrical, mechanical, etc. sheets that are unrelated to environmental permitting issues have not been included. Summary: We have included (attached) the following: + Three copies of the Revised Drainage Report and Calculations with Node Diagram Ms. Garrett -Kraus and Ms. Stewart, Page 5 • Three half -sized copies Revised Road Plans (note: only the sheets that have been revised are included) • Three Full -sized copies of the T- Hangar drawing C2.1 • Three half -sized copies of the T- Hangar drawings relevant to drainage /permitting It has been a pleasure working with you on the review portion of the Application process. We hope that the responses listed above answer all of your questions. If not, please feel free to call me in the Orlando office at 407 -306 -0200 if you need anything. We look �- forward to completing the permitting process with you both. Sincerely, THE LPA GWUP INCOR RATED t2 C. Jansen, P Project Engineer cc: Jason Milewski, City of Sebastian (wlattach) Jean Strickland, SEI Andy Padgett, LPA (w/attach) °— Mohsen Mohammadi, LPA File: (TA412007.2j) DRAINAGE REPORT AND COMPUTATIONS - REVISED FOR RAI NO.2 DATED SEPTEMBER 11, 2002 (Resubmitted September 20, 2002) PAR DATED SEPTEMBER 11, 2002 MR (Resubmitted September 20, 2002) ON TABLE OF CONTENTS am APPENDIX OR on EXISTING CONDITIONS DRAINAGE MAP DM -1 PROPOSED CONDITIONS DRAINAGE MAP DM -2 FDOT 1 DAY PRECIPITATION DEPTH DATA UNDERDRAIN DESIGN & PERFORMANCE CRITERIA 12 -1 METHODOLOGY & DESIGN EXAMPLE FOR UNDERDRAIN SYSTEMS 27 -1 w w Chester A. Padgett, Jr. P.E. No. 46675 The LPA Group Incorporated 450' ) Woodland Corporate Blvd., Suite 400 Tampa, FL 33614 (813) 889 -3892 (Office) PAGE EXISTING CONDITION I PROPOSED CONDITION 3 DITCH DESIGN 6 STORMWATER TREATMENT VOLUME & UNDERDRAIN DESIGN 10 TABLES FOR PEAK DISCHARGE RATE OF 21 PRE VERSUS POST DEVELOPED CONDITION BASIN B -2 ADICPR MODEL AND OUTPUT 23 — EAST AIRPORT DR. & RUNWAY RD. ADICPR MODEL AND OUTPUT 42 am APPENDIX OR on EXISTING CONDITIONS DRAINAGE MAP DM -1 PROPOSED CONDITIONS DRAINAGE MAP DM -2 FDOT 1 DAY PRECIPITATION DEPTH DATA UNDERDRAIN DESIGN & PERFORMANCE CRITERIA 12 -1 METHODOLOGY & DESIGN EXAMPLE FOR UNDERDRAIN SYSTEMS 27 -1 w w Chester A. Padgett, Jr. P.E. No. 46675 The LPA Group Incorporated 450' ) Woodland Corporate Blvd., Suite 400 Tampa, FL 33614 (813) 889 -3892 (Office) Appendix — Existing Condition The Sebastian Airport is located in Indian River County and is owned and operated by the City of Sebastian. Overall the airport is 616 acres in area and has several soil types represented on the site: Immokalee. Myakka, Arents and Urban. The SCS Soil Survey of Indian River County considers both Immokalee and Myakka B/D soils. A soil in the B/D hydrological group is considered a B when the site is artificially drained and a D when the soil has not been drained. Arents and Urban soils are considered to be artificially created by the development of land. For the portion of the airport within this project only the Immokalee and Myakka were encountered. Included is the geotechnical report that supports the findings of the soil survey. A SHWT for .� this area according to this report will vary between 1 -3.5 feet below existing grade. As can be seen by the Existing Condition Drainage Map included with this report the airport is divided into three major basins which all drain through cross - drains under Rosaland Road and into Sebastian Creek. The basin being most impacted by this project is Basin B. In this particular basin, B -1, drains the in -field area, N -1, between the runways and taxiway and then is — conveyed via a 30" RCP to basin B -2. Runoff collects in a depressional area (N -2) of this basin and then pops -off into a 36" RCP that carries the stormwater to the Sebastian Creek (N -3). In the area of Airport Drive East and Runway Road East runoff is carried to a canal that parallel the airport's east and south boundary lines. From the airport property the canal continues and parallels Main Street and eventually discharges into Collier Creek. which flows into the Sebastian Creek South Prong. At this time there is a gravel /limerick road that connects Airport Drive East to the East end of runway 9 -27. no am we so M am on M we M .. Computation of Existing Curve Number (CN): Basin B -I Description Area ac. CN Paved Runway/Taxiway 11.4 gg Open Space (grass cover > 75 %) 31.8 80 Totals 43.2 Composite CN: 3661.6/ 43.2 = 84.8 Basin B -2 Description Area ac, CN Paved Runway /Taxiwav 3.68 9$ Open Space (grass cover > 75 %) 38.03 80 Central Airport Dr. (gravel) 0.18 S5 Totals 42.0 Composite CN: 3418.3/42 = 81.4 Existing Condition for Airport Drive East (STA 60 + 00 to 66 + 40): Area x CN 1119.2 2542.4 3661.6 Area x CN 360.6 3042.4 1.5.3 3418.3 Description Area (Ac.4 CN Area x CN Paved Road w/ Open Ditch 0.19 9; 17.9 Open Space (grass cover > 75 %) 0.69 80 55.1 Totals 0.88 73.0 Composite CN: 73!0,88 = 83.0 Existing Condition for Runway Road East (STA 72 + 00 to 77 + 92): Description Area (ac.) CN Open Space (grass cover > 75 %) 0.82 80 2 no Proposed Condition In Basin B the improvements proposed are a T- Hangar facility and access roads. All of the improvements will occur in basin B -2 as can be seen on the Proposed Basin Map included with this report. The majority of the T- Hangar site (B -4) will be directed into a storm water facility (N -4) and the pond will outfall into a junction manhole where the existing 30" RCP (PIPE -1) will be extended by a 29" x 45" ERCP that will maintain the connection between basins B -1 and B -2. That portion of this site directed to the pond will be treated and attenuated there. The remainder of the site will be treated in the ditches running adjacent to the access road. Airport Drive West. No additional attenuation will be done in Basin B due to the removal of a portion of runway 9 -27 in basin B -1. A portion of runway 9 -27, approximately 232 acres. is to be removed when it is rehabilitated/resurfaced. At that time the width will be reduced from 150' wide to 75 feet. The amount of pavement to be removed at that time will off set the new pavement for the new access roads and enough of the T- hangar site that only 0.81 acres will be required to be attenuated. °^ For Airport Drive East and Runway Road East the treatment and attenuation will be done in the ditches paralleling the proposed road. Runoff will leave through the ditches and drain into the ditch described in the existing conditionas paralleling the East and South property lines. Computation of Proposed Curve dumber (CN): Basin B -1 _ Description Area ac. CN Area x CN Paved Rumva%-'Taxiway 9.1 98 891.8 Open Space (grass cover> 75 %) 34.1 80 2728.0 7_s.0 Totals 43.2 3619.8 Composite CN: 3619.8/ 43.2 = 83.8 oft Basin B -2 Description Area (ac.) CN Paved Runway /Taxiway 2.81 98 Open Space (grass cover > 75 %) 23.72 80 Paved Road w/ Curbing 0.73 93 Totals 27.26 Composite CN: 2240.9 27.3 = 82? no Area x CN 275.4 1897.6 67.9 2240.9 3 Basin B -4 - T- Hangar & Stormwater Pond Description Area (ac.) Paved Taxiway /Building 2.01 Pond TOB 0.30 Open Space (grass cover > 75 %) 1.36 Totals 3.67 Composite CN: 330.0/3.67 = 89.9 Basin B -6 - Paved Road w/ Curbing Sta 15 +30 to 20 +50, Paved Road w/ Ditch Sta 20 +50 to 30 +00 (Lt.), -. & Paved Road w/ Ditch Sta 40 +00 to 45 +50 (Lt. & Rt.) Description Area ac. Paved Road w/ Curbing 0.33 Paved Road w/ Ditch 1.41 Totals 1.74 Composite CN: 163.5 / 1.74 = 94.0 Basin B -7 - Paved Road w/ Ditch Sta 20 +50 to 26 +50 (Rt.), & Paved Road w/ Ditch Sta 50 +30 to 54 +75 (Rt.) Description Area ac, Paved Road Nv/ Ditch 0.72 Paved Taxiway 0.;� Open Space (grass cover > 75 %) 3.65 Totals 4.89 Composite CN: 410.0 / 4.89 = 83.9 Basin B -8 - Paved Road w/ Ditch Sta 26 +50 to 30 +00 (Rt.), & Paved Road w/ Ditch Sta 50 +30 to 54 +75 (Lt.) Description Area ac. _ Paved Road w/ Ditch 0.55 Paved Taxiway /Building 0.63 Open Space (grass cover > 75 %) 3.26 Totals 4.44 Composite CN: 373.7 / 4.44 = 84.2 CN Area x CN 98 197.0 80 24.0 80 109.0 330.0 CN Area x CN 98 32.3 93 131.2 163.5 CN Area x CN 93 67.0 98 51.0 80 292.0 410.0 CN Area x CN 93 51.2 98 61.7 80 260.8 373.7 4 Airport Drive East (STA 60 + 00 to 66 + 40): Description Area (ac.) CN Paved Road w/ Open Ditch 0.88 9; Runway Road East (STA 72 + 00 to 77 + 92): Description Area ac. CN Paved Road w/ Open Ditch 0.82 9; 5 qMM MR -� Ditch Design Basin within ROW bet. Stations 10 +70 to 15 +30: Description Area Rational Cocf. Pavement 0.26 ac. 0.95 Open Space 0.37 ac. 0.25 Total Area 0.63 ac. C,, = (0.26 x 0.951+ (0.37 x 0.25) = 0.54 0.63 Q = CIA = 0.54 x 7.4 in/hr x 0.63ac. = 2.52 cfs Discharge rate for each side of the road would be the previously computed Q divided by 2, which would equal 1.26 cfs. Project Description Worksheet Trapezoidal Channel — I ., Flow Flement Trapezoidal Channel Method Mannina's ForMUla Solve For Channel Depth - Input Data Nlannina s 0.030 Coefficient Slope 0.0001 ft/ft 00 Left Side Slope 3.00 H '^ V Right Side Slope 5.00 H V Bottom Width 8.?0 ft Discharge 1.26 cfs we MR 6 ^ Results ,M, Depth 0.47 ft Flow Area 4.7 W Wetted 12.09 ft ^ Perimeter Channel Top Width 1196 ft Critical 0.09 ft — Depth Channel Depth Critical Slope 0.029889 ft/ft Velocity 0.27 ft/s — velocity 1.1 e -3 ft Head Specific 0.47 ft ^ Energy Froude 0.07 Number ^ Flow Type SubcriticaI ^ Basin within ROW bet. Stations 15 +30 to 30 +00(Lt.) and 40 +40 to 45 +00 (Rt. & Lt.) (Length = 1930 LF): Description Area Rational Coe% Pavement 0.69 ac. 0.91 Open Space 0.96 ac. 0?; Total Area 1.65 ac. C „= 0.69x 0.95) +(0.96x0.25)= 0.54 1.65 Q = CIA = 0.54 x 7.4 in/hr x 1.65 ac. = 6.6 cfs Project Description ^ Worksheet Trapezoidal Channel — 1 Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth M ow 7 OR ON Basic; within ROW bet. Stations 15+30 to 30 +00(Rt.) & 50 +50 to 54 +75 (Rt. & Lt.) (Length = 1895LF): Description Area Rational Coef. Pavement 0.67 ac. 0.95 Open Space 0.93 ac. 0.25 Total Area 1.60 ac. C„ = 0.67 x 0.95) + (0.93 x 0.25) = 0.54 1.60 Q = CIA = 0.54 x 7.4 in/hrx I.60 ac. = 6.4cfs No 8 Input Data Manning's 0.030 Coefficient Slope 0.0001 ft/ft 00 Left Side SIope 3.00 H : V Right Side Slope 5.00 H V - Bottom Width 5.00 ft Discharge 6.60 cfs �- Results Depth 1.38 f[ Flow Area 14.5 ft- Wetted 16.38 ft Perimeter Top Width 16.02 ft Critical 0.34 ft Depth Critical SIope 0.02029 ft /ft 6 Velocity- 0.46 ft/s Velocity 3.23e -3 ft '^ Head Specific 1.38 ft Energy Froude 0.08 Number Flow Type Subcritic al Basic; within ROW bet. Stations 15+30 to 30 +00(Rt.) & 50 +50 to 54 +75 (Rt. & Lt.) (Length = 1895LF): Description Area Rational Coef. Pavement 0.67 ac. 0.95 Open Space 0.93 ac. 0.25 Total Area 1.60 ac. C„ = 0.67 x 0.95) + (0.93 x 0.25) = 0.54 1.60 Q = CIA = 0.54 x 7.4 in/hrx I.60 ac. = 6.4cfs No 8 Project Description Input Data .� Worksheet Trapezoidal Manning's Channel — 1 Flow Element Trapezoidal Channel Method Manning's Formula Solve For Channel Depth 9 Input Data Manning's 0.030 Coefficient Slope 0.0001 ft/ft 00 Left Side Slope 33.00 H : V Right Side Slope 5.00 H V Bottom Width 5.00 ft Discharge 6.40 cfs Results Depth 1336 ft Flo,,y Area 14.1 ft' ^, \Vetted 16.21 ft Perimeter Top Width 1-5.85 ft Critical 0.34 ft Depth Critical Slope 0.020.10 ft/ft •, 1 Velocity 0.13 ft/s Velocity 3.18e -3 ft -� Head Specific 1.36 ft Energy Froude 0.08 Number Flory Type Subcritic al 9 REQUIRED STORMWATER TREATMENT VOLUMES Volume Provided in Pond: South T- Hangar Impervious Area: Volume Required: 2.01 acres x (1.75 " /12 ") = 0.293 ac -ft Volume Provided in Ditches Adjacent to Nest Access Rd. (Sta. 20 +50 to 26 +50): Impervious Area for Parking West of T- Hangar: Volume Required: 0.4 acres x (1.75 " /12 ") = 00583 ac -ft West & Central Access Road Bet. Stations 15 +30 to 30 +00 (Lt) & 40 +00 TO 45 +50 (Rt & Lt): Volume Required: [(550 LF x 25') + (1470 LF x 12.5')] x (1.75 " /12 ") = 4.685 of = 0.1076 ac -ft Taxiway Dr. West Between Stations 15 +30 to 30+00 (Rt) & 50 +00 to 54 +75 (Rt & Lt): Volume Required: [ (1470 LF x 12.5') + (475 LF x 21')] (1.75''112 ") = 4134 cf = 0.0949 ac -ft Total Volume Required: 0.058' ) ac -ft + 0.1076 ac -ft + 0.0949 ac -ft = 0.2608 ac -ft Volume Required per side: 0.1304 ac -ft Volume Provided per side: 0.1334 ac -t[ West Access Road Between Stations 10 +70 to 15 +30 (Rt & Lt): 460 LF x 25' x (1.75'.112 ") = 1677 cf = 0.0385 ac -ft Volume Required per side: 0.0193 ac-ft i Volume Provided per side: 0.028 ac -ft M 10 Airport Dr. East (STA 60 + 00 to 66 + 40): Volume Required: 640 LF x 21' x (1.75'112 ") = 1960 cf = 0.0450 ac -ft Volume Required per side: 0.0225 ac -ft Volume Provided per side: 0.0274 ac -ft Runway Road East (STA 72 + 00 to 77 + 92): Volume Required: 592 LF x 21' x (1.75°'/12'') = 18 13 ) cf = 0.0416 ac -ft �. Volume Required per side: 0.0208 ac -ft Volume Provided per side: 0.0252 ac -ft All stormwater is being treated by using an underdrain system below the bottom of the facility. The underdrain was designed using the Design and Performance Criteria in Section 12 and the Methodology and Design Example in Section 27 of the SJRWMD Applicant's Handbook. am an no M 11 U A v_ M QI N 4 II cn O i" II E Z W g O 7 0 m c � � OJ v E E m z 3 `o U A Fm c In ea I� m 07 Q N m a N r C4 04 N w A lz w 7 A w Ch J Q Q r O O N O m O 4 O vOS O tOD a m Q PQ1 O m o 7 O O o O O O C Q O a a 4i 0 a UJ II U aW tD [D O a N v v Y J 7 7 m v m m v1 Ci N r� CID v O co N U') i d CTI m ? J N to co r N N m In v > If Y% W WlLil CD a v O n co u) SD m N L s co to � w m m CID 1- N 1°n W W J N N m m Cl) Q tD to yy Q C) 7 Z 4 O J H H u J Z A w a0 N ^ 41 ID cc) N m m ° M N 61 2¢ o w o COD Q Q ono o C3 o W w o Q Q o o a o o Q n O U Q Z J Z N O O ? a co O O O N n iD V .- N 6 m Q ^ 6 Ur ['} D� c� 4 cq J w w IX ¢ m N tD N O m Q m n m e tf7 D1 -T m sn LO Ln a w L) rr+� Z 2 O m cf It N C co tD IT N 'o C co co to to LID W J O cc Q v] CD n qj M O N Fm c In ea I� m 07 Q N m a N r C4 04 N w A lz r� 0.5 in/hr �3 UNDER DRAIN DESIGN OF TREATMENT FACILITY BETWEEN STATION 10+70 AND 15 +30 PER SIDE Parameters Given: Desired depth of the treatment volume in the basin (DTFI) = 0.3 feet Desired basin freeboard (DFe) = 0.7 feet .� minimum pipe diameter (Dia) = 5 inches gravel envelope on each side of the drainage pipes (D, ©) = 3 inches Drawdown of Groundwater Table below Basin Bottom (r) = 6 inches Minimum distance between basin bottom and top of the gravel envelope (m + r) = 2 feet Depth from natural ground to impermeable barrier (D) = 5 feet Area of basin (measured from top of treatment volume) (AeT)= 3422 sq. ft. Maximum top dimension of basin perpendicular to drainage laterals = 13 feet Permeability Rate of the Soil (K) = 1 Ndhr. Slope of laterals = 0.1 % Roughness Coefficient (n) = 0.015 Safety factor= 2 Distance of top of basin in the direction parallel to the laterals, h. (Dp"R) = 460.0 feet Distance of top of basin in the direction perpendicular to the laterals, ft. (DpER) = 13 feet Capacity of 4' drain with slope = 0.002 & n = 0.015 (Qc): 0.092 cfs DESCRIPTION OF CALCULATION EQUATION Step 1. Calculate the required drain spacing. Depth to the drain line from natural ground surface (d) d = DTR + DFe + (m +() + Do + (DIa/2) 3.46 feet Height of drain above impermeable layer, Egn.27 -4 (a) a = D - d 1.54 feet Depth to water table after drawdown (c) c = DTR + DFe + r 1.50 feet Ht. of water table above drain (after drawdown) measured at the midpoint bet. laterals, ft., Eqn. 27 -3 (m) m = d - c 1.96 feet Drainage Coef. (q) from Eqn. 27.2 with •r t = 36 hr to incorporate safety factor of 2 q = Gt 0.04 ft/hr Spacing (S) determined from Eqn 27 -1 S = ((4 x K x (rrF + 2 x a x m)) /q) "2 30.79 feet Determine the number of laterals (N), Eqn, 27 -9 N > DpER/S OA2 Step 2. Calculate the length of the laterals. ., Use Equation 27 -11 with A97 = ATr to determine Dp„R DpAg = ATjDpER 26123 feet Find the length of each lateral (L) from Eqn. 27 -8 1-? D¢„R - S 232.44 feet Step 3. Size the drainage laterals. The flow per lateral (Q,, is found from Equation 27 -12 Q, _ (q x S (L + S /2)) / CF 0.0883 M" Accretion per 100 feet (Acc); Acc = Q,/ (L1100 ft) 0.0380 Distance (in 100 -foot sections) down gradient that a drain would be adequate (LA): LA = Oc 1 Acc 2.4215 r� 0.5 in/hr �3 VOLUME TREATED IN DITCH BETWEEN STATION 20+54 AND 26 +50 PER SIDE r UNDER DRAIN DESIGN OF TREATMENT FACILITY BETWEEN STATION 24+50 AND 26 +50 PER SIDE ,. Parameters Given: Desired depth of the treatment volume in the basin (DTR) = 0.75 feet Desired basin freeboard (DFa) = 1 feet minimum pipe diameter (pia) = 6 inches gravel envelope on each side of the drainage pipes (Do) = 3 inches Drawdown of Groundwater Table below Basin Bottom (r) = 6 inches Minimum distance between basin bottom and top of the gravel envelope (m + r) = 2 feet Depth from natural ground to impermeable barrier (D) = 5 feet Area of basin (measured from top of treatment volume) (Ar)= 8424 sq. ft. Maximum top dimension of basin perpendicular to drainage laterals = 20 feet Permeability Rate of the Soil (K) = 1 ft./hr. Slope of laterals = 0.1 % Roughness Coefficient (n) = 0.015 Safety factor = 2 Distance of top of basin in the direction parallel to the laterals, ft. (DP,w) = 600.0 feet Distance of top of basin in the direction perpendicular to the laterals, ft. (DPER) = 20 feet Capacity of 4' drain with slope = 0.002 & n = 0.015 (Oc): 0.155 cfs DESCRIPTION OF CALCULATION EQUATION Step 1. Calculate the required drain spacing. Depth to the drain line from natural ground surface (d) d = DTR + DFa + (m +r) + Do + (Diaf2) 4.25 feet Height of drain above impermeable layer, Egn.27 -4 (a) a = D - d 0.75 feet Depth to water table after drawdown (c) c = DTR + DF® + r 2.25 feet Ht. of water table above drain (after drawdown) measured at the midpoint bet. laterals, ft,. Eqn. 27.3 (m) m = d - c 2.00 feet Drainage Coef. (q) from Eqn. 27 -2 with -� t = 36 hr to incorporate safety factor of 2 q = Gt 0.06 ft/hr Spacing (S) determined from Eqn 27.1 S = ((4 x K x (m" + 2 x a x m)) /q) "2 21.17 feet Determine the number of laterals (N), Eqn. 27.9 N > DPER/S 0.94 Step 2. Calculate the length of the laterals. .. Use Equation 27 -11 with A3; = ATLto determine Dp,w DpAA = A- L/DPER 421.20 feet Find the length of each lateral (L) from Eqn. 27 -8 L? OPAA - S 400.03 feet Step 3. Size the drainage laterals. The flow per lateral (0„ is found from Equation 27 -12 0, = (q x S (L + S!2)) / CF 0.1509 Accretion per 100 feet (Acc) ACC = Or (L7100 ft) 0.0377 Distance (in 100 -toot sections) down gradient that a drain would be adequate (La }: Lx = Oc 1 Acc 4.1094 0.75 irdhr IS VOLUME TREATED IN DITCH BETWEEN STATION 60 *00 AND 66+40 PER SIDE UNDER DRAIN DESIGN OF TREATMENT FACILITY BETWEEN STATION 60+00 AND 66 +40 PER SIDE Parameters Given: Desired depth of the treatment volume in the basin (DT) = 0.3 feet Desired basin freeboard (DFB) = 1.7 feet minimum pipe diameter (Dia) = 5 inches gravel envelope on each side of the drainage pipes (Do) = 3 inches Drawdown of Groundwater Table below Basin Bottom (r) = 6 inches Minimum distance between basin bottom and top of the gravel envelope (m + r) = 2 feet Depth from natural ground to impermeable barrier (D) = 5 feet Area of basin (measured from top of treatment volume) (A$T)= 4752 sq. ft. Maximum top dimension of basin perpendicular to drainage laterals = 15 feet Permeability Rate of the Soil (K) = 1 ft./hr. Slope of laterals = 0.15 % Roughness Coefficient (n) = 0.015 Safety factor = 2 Distance of top of basin in the direction parallel to the laterals, ft. (DpkR) = 640.0 feet Distance of top of basin in the direction perpendicular to the laterals, ft. (DPEp) = 15 feet Capacity of 4" drain with slope = 0.002 & n = 0.015 (Qc): 0.115 cfs DESCRIPTION OF CALCULATION EQUATION Step 1. Calculate the required drain spacing. Depth to the drain line from natural ground surface (d) d = DTa + DFs + (m +r) + Do + (Diaf2) 4.46 feet Height of drain above impermeable layer, Egn.27 -4 (a) a = D - d 0.54 feet Depth to water table after drawdown (c) c = DTa + DFe + r 2.50 feet Ht. of water table above drain (after drawdown) measured at the midpoint bet. laterals, ft., Eqn. 27.3 (m) m = d - c 1.96 feet Drainage Coel. (q) from Eqn. 27.2 with t = 36 hr to incorporate safety factor of 2 q = clt 0.07 ft/hr 0.8333 irvhr Spacing (S) determined from Eqn 27 -1 S = ((4 x K x (m' + 2 x a x m))/q)"2 18.52 Determine the number of laterals (N), Eqn. 27 -9 N > DPER/S 0.81 Step 2. Calculate the length of the laterals. Use Equation 27 -11 with AeT = Anto determine Dp n Da„a = ATL /DaER +w 316.80 feet Find the length of each lateral (L) from Eqn, 27 -8 L? DP„A - S 298.28 feet Step 3. Size the drainage laterals. The flow per lateral (Q,i is found from Equation 27.12 Q, � (q x 5 (L + S /2)) 1 CF 0.1099 Accretion per 100 feet (Acc): Acc = Qr/ (LA 00 ft) 0,0368 Distance (in 100 -foot sections) down gradient that a drain would be adequate (L,J: La = Qc I Acc 3.1216 17 X W CL �c m M1 M1 z Q �O G N M1 z O H Q V) Z w w � ut m t) a D 2 D ua 4 It] x .0%t1Y 7 J O 1s UNDER DRAIN DESIGN OF TREATMENT FACILITY BETWEEN STATION 72 +00 AND 77 +90 PER SIDE a no 0.4333 in/hr 19 Parameters Given: Desired depth of the treatment volume in the basin (DTR) = 0.3 feet Desired basin freeboard (DFs) = 0.5 feet minimum pipe diameter (Dia) = 5 inches gravel envelope on each side of the drainage pipes (Do) = 3 inches Drawdown of Groundwater Table below Basin Bottom (r) = 6 inches Minimum distance between basin bottom and top of the gravel envelope (m + r) = 2 feet Depth from natural ground to impermeable barrier (D) = 5 feet Area of basin (measured from top of treatment volume) (APT )= 4382 sq. ft. Maximum top dimension of basin perpendicular to drainage laterals = 15 feet Permeability Rate of the Sort (K) = 1 ft./hr, Slope of laterals = 0.1 /Q Roughness Coefficient (n) = 0.015 Safety factor = 2 Distance of top of basin in the direction parallel to the laterals, ft. (OpAo = 590.0 feet Distance of top of basin in the direction perpendicular to the laterals, ft. (DPER) = 15 feet w, Capacity of 4' drain with slope = 0.002 & n = 0.015 (Qc): 0.092 cfs DESCRIPTION OF CALCULATION EQUATION Step 1. Calculate the required drain spacing. Depth to the drain line from natural ground surface (d) d = DTR + OFe + (m+r) + Da + (Dial2) 3.26 feet Height of drain above impermeable layer, Egn.27 -4 (a) a = D - d 1.74 feet �. Depth to water table after drawdown (c) C = OTR + DFB + r 1.30 feet Ht, of water table above drain (after drawdown) measured at the midpoint bet. laterals, ft., Erin. 27 -3 (m) m = d - c 1.96 feet Drainage Coef. (q) from Eqn. 27 -2 with ++ 1 = 36 hr to incorporate safety factor of 2 q = all 0.04 ftltmr Spacing (S) determined from Eqn 27 -1 S = ((4 x K x (m2 + 2 x a x m)) /q) "7 34.35 feet Determine the number of laterals (N), Eqn. 27 -9 N > DPERIS 0,44 Step 2. Calculate the length of the laterals. ... Use Equation 27 -11 with APT = ATL to determine DpAp DpAFr = ATLIDPER 292.13 feet Find the length of each lateral (L) from Eqn. 27.8 La Dpm - S 257.78 feet Step 3. Size the drainage laterals. The flow per lateral (0„ is lound from Equation 27.12 O, = (q x S (L + S12)) / CF 0.0949 Accretion per 100 feet (Acc): Acc y 0,1 (Ul00 it) 00368 Distance (in 100 -foot sections) down gradient that a drain would be adequate (LA): LA = Q,1 Acc 2,5027 a no 0.4333 in/hr 19 OEM UNDER DRAIN DESIGN OF TREATMENT FACILITY FOR T- HANGAR STORMWATER POND Parameters Given: Desired depth of the treatment volume in the basin (DTR) = 0.13 feet Desired basin freeboard (DFB) = 1 feet minimum pipe diameter (Dia) = 4 inches gravel envelope on each side of the drainage pipes (DO) = 3 inches Drawdown of Groundwater Table below Basin Bottom (r) = 6 inches Minimum distance between basin bottom and top of the gravel envelope (m + r) = 2 feet Depth from natural ground to impermeable barrier (D) = 5 feet Area of basin (measured from top of treatment volume) (ABT)= 14131 sq. ft. Maximum top dimension of basin perpendicular to drainage laterals = 150 feet Permeability Rate of the Soil (K) = 1 ft./hr. Slope of laterals = 0.1 % Roughness Coefficient (n) = 0.015 feet Safety factor = 2 feet Distance of top of basin in the direction parallel to the laterals, R. (DPAR) = 102.0 feet Distance of top of basin in the direction perpendicular to the laterals, ft. (DPER) = 150 feet Capacity of 4' drain with slope = 0.002 & n = 0.015 (oc): 0.054 cfs DESCRIPTION OF CALCULATION EQUATION Step 1. Calculate the required drain spacing. Depth to the drain fine from natural ground surface (d) d = DTR + DFB + (m +r) + Du + (Dia/2) 422 feet Height of drain above impermeable layer, Egn.27 -4 (a) a = D - d 0.78 feet Depth to water table after drawdown (c) c = DTR + DFB + r 2.30 feet Ht_ of water table above drain (after drawdown) measured at the midpoint bet. laterals, R., Eqn. 27 -3 (m) m = d - c 1.92 feet Drainage Coef. (q) from Eqn. 27 -2 with I = 36 hr to incorporate safety factor of 2 q = c/t 0.06 ft/hr 0.7667 in /hr Spacing (S) determined from Eqn 27 -1 S = ((4 x K x (mz + 2 x a x m)) /q)12 20.45 feet Determine the number of laterals (N), Eqn. 27 -9 N Z DPERIS 7.34 Step 2. Calculate the length of the laterals. Use Equation 27.11 with AB- = AT t to determine DPAR DPAR = ATL /DPER 94.21 feet Find the length of each iateraf (L) from Eqn. 27 -8 L a DPAR - S 73.76 feet Step 3. Size the drainage laterals. The flow per lateral (Q„ is found from Equation 27 -12 Q, = (q x S (L + S12)) / CF 0.0305 Accretion per 100 feet (Ace): Ace = Q,/ (1-1100 ft) 0.0413 Distance (in 100 -foot sections) down gradient that a drain would be adequate (LA): LA = Qc f Ace 1,3071 4° no MODELLING OF PRE AND POST- DEVELOPED CONDITION No an W. =4 ADICPR 2.2 was used to model the pre- and post- condition. Referring to the included Drainage Basin Maps the premise for the two models can be identified. The model associated with the T- hangars and access road differs from what was discussed earlier in the Proposed Condition section of the report in that more attenuation was necessary than just for the 0.81 acres of increased imperviousness. As can be seen attenuation was necessary along the east and west side of the access road and in the in -field area of basin B -1. Below the table indicates the out come of the model and its concurrence with the post — developed discharge peak rate not being increased over pre - condition for Node N -2, which is the node prior to leaving the site. PEAK STAGE & DISCHARGE FROM BASIN B -2 EXISTING PROPOSED Description Stage (ft) Discharge (cfs) Stage (ft) Discharge (cfs) Average -24 hr 7.00 27.04 6.74 22.74 25 yr -24 hr 8.21 47.74 8.14 46.55 PEAK STAGE & DISCHARGE FROM AIRPORT DR. EAST EXISTING PROPOSED Description Stage (ft) Discharge (cfs) Stage (ft) Discharge (cfs) Average -24 hr 0.71 17.91 0.45 25 yr -24 hr 1.61 18.55 0.97 PEAK STAGE & DISCHARGE FROM RUNWAY RD. EAST EXISTING PROPOSED Description Stage (ft) Discharge (cfs) Stage (ft) Discharge (cfs) Average -24 hr 0.67 19.2 1 0.72 25 yr -24 hr 1.60 19.68 1 1.91 Review of the last table indicates that the proposed run -off from Runway Road East is increased over the pre - developed condition. Since the basins from Runway Road East and Access Drive East both outfall into the same ditch the results For each basin has been added together and shown in the next table. By adding the results of the two basins it can be shown that the post - developed run -off has not been increased over the pre - developed condition. 21 PEAK STAGE & DISCHARGE FROM THE COMBINED BASINS EXISTING PROPOSED Description Stage (ft) Discharge (cfs) Stage (ft) Discharge (cfs) Average -24 hr 1.38 1.17 25 yr -24 hr 3.21 2.8$ 22 THE LPA GROUP INCORPORATED 10008 N. Dale Mabry Highway Suite 202 TAMPA, FLORIDA 33618 (813) 960 -8366 JOB TA '-41 -2605 SHEET NO OF �j O CALCULATED BY— CHECKED BY DATE er.n; F c.tq T c. 3 ;3 5-,1-4sa.�e 5�4�e A�ec,. C� s -2 A c eo. = Lk Z oc . A/ o Al2- '\'3. cx. QC O►-rQ. 5 t%mt-� u,,ce.. ' - f%'4. 13. S 5$6 L,Nr, —30U Rel ' ( -304) G mss.. •n C3 -Z- S �L)C fie.. ( R -Z) S tw E `fit cec. @ e-"z .Z3 Advanced illtvi,'Ullli +l,iko (Ta"nul & 1'Un"J I,od In,J (1cpH V,r 2.20) CopyrighL 1495, 5truamline Technologies, Inc. SEBASTIAN AIRPORT EXISTING CONDITION FOR HAK I N B -; * * *A A. AA +A Node Max 11num Co((pdi i s a n s AAAAAAAAAAAAA+ A A A A 4 A k A A A A A k A******************** * * * * *k * ** *k * * * * * * * * ** * * ** * * * * ** (Tinge units - hours) Sim Max Time mdx :csdgo Warning M "x 1011" M.,x Aurfar.e Max Time Max Inflow Max Time Max Outflow Nam- C1,"diLluns (JI ) sIdy n (II) :Moon (I1 ) Area (sl:) Inflow (cis) Outflow (cis) *. * Node Name: N -1 Group: BASE -------------------------------- AVERAGE 24.00 15.28 19.00 - 0.0119 475599.99 12.25 90.58 9.07 1.83 25YR24HR 24.00 16.30 19.00 - 0.0119 748635.40 12.25 195.78 6.70 1.83 * ** Node Name: N -2 Group: BASE AVERAGE 13.41 7.00 15.00 0.0048 136819.46 12.50 56.48 13.47 27.04 25YR24HR 13.72 8.21 15.00 0.0048 234911.20 12.50 127.30 13.72 47.74 * ** Node Name: N -3 Group: BASE AVERAGE 0.00 3.20 5.00 0.0000 0.00 13.47 27.04 0.00 0.00 25YR24HR 0.00 3.20 5.00 0.0000 0.00 13.72 47.74 0.00 0.00 6/5/2002 3 :57 PNI on Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) (11 am Copyright 1995, Streamline Technologies, Inc. EXISTING CONDITION FOR ACCESS RD & T- HANGARS ** r r* r r r* Input Report Basin E of Rosaland, r] of Taxiway, S of Airport Dr r. 25 -- - - - - -- Class: Node------------------------------ Name: N -1 Base Flow(cfs): 0 Init Stage(ft): 13.5 Group: BASE Warn Stage(ft): 19 Comment: Stage(ft) Area(ac) 13.5 0 18 27.6 -- - - - - -- Class: Node-------------------------------------------------------------- Name: N -2 Base Flow(cfs): 0 Init Stage(ft): 5.3 Group: BASE Warn Stage(ft): 15 Comment: Stage(ft) Area(ac) 5.3 0 14 16.1 -- - - - - -- Class: Node-------------------------------------------------------------- Name: N -3 Base Flow(cfs): 0 Init Stage(ft): 3.2 Group: BASE Warn Stage(ft): 5 Comment: Time(hrs) Stage(ft) 0 3.2 30 3.2 -- - - - - -- Class: Basin------------------------------------------------------- - - - - -- ,,,, Basin: B--1 Node: N -1 Status: On Site Type: SCS Unit Hydr Group: BASE Unit Hydrograph: UH323 Peak Factor: 323 Rainfall File: SCSIII Storm Duration(hrs): 24 Rainfall Amount(in): 5 Area(ac): 43.2 Concentration Time(min): 18 Curve #: 84.8 Time Shift(hrs): 0 DCIAM : 0 Infield bet. Taxiway & Runway 2 & 4 .. --- -- - - -- Class: Basin------------------------------------------------------------ Basin: B -2 Node: N -2 Status: On Site Type: SCS Unit Hydr Group: BASE Unit Hydrograph: LH323 Peak Factor: 323 Rainfall File: SCSIII Storm Duration(hrs): 24 Rainfall Amount(in): 5 Area(ac): 42 Concentration Time(min): 40 ,,. Curve #: 81.4 Time Shift(hrs): 0 DCIA( %): 0 Basin E of Rosaland, r] of Taxiway, S of Airport Dr r. 25 am Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [2] Copyright 1995, Streamline Technologies, Inc. ... EXISTING CONDITION FOR ACCESS RD & T- HANGARS *wwwwwwwww Input Report * w* wwwwwwwwwwwwwwwwwwwwww *rw *wwww *wwwwwwwwwww ** *www *w * *w -- - - - - -- Class: Drop Structure----------------------------------------------------- Name: 30" From Node: N -1 Length(ft): 560 Group: BASE To Node: N -2 Count: 1 Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 30 30 Rise(in): 30 30 �* Invert(ft): 9.6 9.59 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 Downstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 ..,, * ** Weir 1 of 2 for Drop Structure 30" * ** [TABLE] Count: 2 Bottom Clip(in): 0 Type: Mavis Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 18 Invert(ft): 13.5 �w Rise(in): 18 Control Elev(ft): 13.5 * ** Weir 2 of 2 for Drop Structure 30" * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 48 Invert(ft): 15 Rise(in): 36 Control Elev(ft): 15 on 26 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2,20) [31 Copyright 1995, Streamline Technologies, Inc. EXISTING CONDITION FOR ACCESS RD & T- HANGARS * * * * * * * * ** Input Report * * * * * * * * *rr * * * * * ** err***** * * * * *x * * * * *r* * * * * * * * * *r * * * * * * ** -- - - - - -- Class: Drop Structure--------------------------------------------------- Name: 36" From Node: N -2 Length(ft): 70 Group: BASE To Node: N -3 Count: 1 Outlet Cntri Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular .r UPSTREAM DOWNSTREAM Span(in): 36 36 Rise(in): 36 36 .� Invert(ft): 4.5 4.09 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 Downstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 no * ** Weir 1 of 2 for Drop Structure 36" * ** [TABLE] Count: 2 Bottom Clip(ft): 0 Type: Mavis Top Clip(ft): 0 Flow: Both Weir Discharge Coef: 3 an Geometry: Trapezoidal Orifice Discharge Coef: 0.6 Bottom Width(ft): 0 Invert(ft): 5.3 Left Side Slope(h /v): 65 Control Elev(ft): 5.3 '~ Right Side Slope(h /v): 8.75 StructOpeningDim(ft): 3.5 * ** Weir 2 of 2 for Drop Structure 36" * ** [TABLE] ,r Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 err Span(in): 48 Invert(ft): 15 Rise(in): 36 Control Elev(ft): 15 4W no 27 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [4] Copyright 1995, Streamline Technologies, Inc. 0-0 EXISTING CONDITION FOR ACCESS RD & T- HANGARS ..R * * * * * * * ** Input Report ********** arr* er**** r*+ r*** * * * * * * * * * * * * * * * * * * * *tr * * * * * * * ** -- - - - - -- Class: Simulation ------------------------------------------------------- Y:\ AIRPORTS \SEBAST- 1 \ADICPR \PROPOSED \AVER Execution: Both Header: SEBASTIAN AIRPORT EXISTING CONDITION FOR BASIN B -2 ma` --------- HYDRAULICS----------------------- - - - - -- HYDROLOGY--------------- - --- -- Max Delta Z (ft): 1 Delta Z Factor: 0.05 Override Defaults: Yes Time Step Optimizer: 10 Storm Dur(hrs): 24 Drop Structure Optimizer: 10 Rain Amount(in): 5 Sim Start Time(hrs); 0 Rainfall File: SCSIII Sim End Time(hrs): 30 Min Calc Time(sec): 0.1 Max Calc Time(sec): 0.5 To Hour: PInc(min): To Hour: PInc(min): 30 15 24 15 -- - - - - -- -GROUP SELECTIONS--------------------------------- + BASE [06/04/02] -- - - - - -- Class: Simulation ------------------------------------------------------- *� Y: \AIRPORTS \SEBAST- -1 \ADICPR \PROPOSED \25YR Execution: Both Header: SEBASTIAN AIRPORT EXISTING CONDITION FOR BASIN B -2 --------- HYDRAULICS _- °-- ------------------------ HYDROLOGY -------------------- Max Delta Z (ft): 1 Delta Z Factor: 0.05 Override Defaults: Yes Time Step Optimizer: 10 Storm Dur(hrs): 24 Drop Structure Optimizer: 10 Rain Amount(in): 9.3 Sim Start Time(hrs): 0 Rainfall File: SCSIII Sim End Time(hrs): 30 Min Calc Time(sec): 0.1 Max Calc Time(sec): 0.5 To Hour: PInc(min): To Hour: PInc(min): 30 15 24 15 -- - - - - -- -GROUP SELECTIONS ---------------------------------------------------- + BASE [06/04/02] e., AM no 28 THE LPA GROUP INCORPORATED " 10048 N. Dale Mabry Highway Suite 202 TAMPA, FLORIDA 33618 (813) 960 -8366 m" pm 0. ©o F SHEET NO. OF CALCULATED BY DATE CHECKED BY DATE crni c Node- N -1 I No &e N4 6 -A 5_e 4 vn O Po '-a 50 I- t9'° QtiCQ `r F��� g �� sL-�& 6.5' 0 S°—cq;p- Am. -- A= 3.�7 mac. CN -X9.9 I$.© VLe 12.5' 031`1 -�(= tQw;ti.s.• � 6 5$0 $4sCY. 6 -$ A 4.44 4c . t = 151 firr: kt��„ I Aj Y O 3 Z' 50 I- t9'° QtiCQ 6 6, , nn 8 A= 4.13 t c.C. CN .. 5 5 2't" tZCP �9 "`x ►�5" ERCe Ie0 LF None K-7 S.3 0 1=k' 1(..\ Q.Q-. CS, -2- CN = 4ct 3 \ "j S S am Ac E Y O 3 Z' 6 6, , nn 8 A= 4.13 t c.C. CN .. 5 5 2't" tZCP �9 "`x ►�5" ERCe Ie0 LF None K-7 S.3 0 1=k' 1(..\ Q.Q-. CS, -2- CN = 4ct 3 \ "j S pr — I.74 4c. pffi LT2wl «sh�mY a 'Z? Seb o.S{.,�•� Cam. C N -3; O 3 Z' pr — I.74 4c. pffi LT2wl «sh�mY a 'Z? W I I I I I I ! I I I I I I 1 I 1 I I Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [1] Copyright 1995, Streamline Technologies, Inc. SEBASTIAN ACCESS ROAD t, T- HANGAR I MPROVEMI HT.,: RESULTS UF ANALYSIS FOR STORM EVENTS: AVERfiW & PWR -2= SCSIII * * * * * * * A A A Node Ma x i m um Comp a r i s o n s A A A A • A A A t A A A A A A A A A A A A * * *� * * * * (Time units - hours) Sim Max Time Max s aqe Velarninq Max Doll" Max Surface Max Time Max Inflow Max Time Max Outflow Name --------------------------------------------------------------------------------------------------------------------- Conditions (ft) Stage (to : t.aq" (U) Area WE) Inflow (cfs) Outflow (cfs) * ** Node Name: N -1 Group: BASE AVERAGE 24.00 15.31 11.00 0.0002 482424.87 12.25 88.13 16.07 1.70 25YR24HR 14.23 16.00 21.00 0.0002 669217.68 12.25 153.39 14.23 19.92 * ** Node Name: N -2 Group: BASE AVERAGE 13.74 6.74 15.00 0.0002 116391.77 12.50 40.62 13.74 22.74 25YR24HR 14.50 8.1.4 15.00 0.0003 229240.62 12,56 124.36 14.49 46.55 * * * Node Name; : N -3 Group: BASE AVERAGE 0.00 3,20 5.00 0.0000 0.00 13.74 22.74 0.00 0.00 25YR24HR 0.00 3.20 5.00 0.0000 0.00 14.49 46.55 0.00 0.00 * ** Node Name: N -4 Group: BASE AVERAGE 13.20 14.29 16.00 0,0002 19800.27 12.25 9.40 13.20 1.72 25YR24HR 12.57 15.31 1+.00 0.0004 23211.83 12.25 18.86 12.57 10.76 * ** Node Name: N -5 Group: BASE AVERAGE 13.31 8.10 17.00 0.0005 442.21 13.44 3.17 13,24 3.34 25YR24HR 12.57 1039 17.00 0.0066 259.86 14.22 23.60 14.23 23.60 * ** Node Name: N -6 Group: BASE AVERAGE: 13.26 13.30 10.00 0.0003 18971.43 12.50 3.09 13.26 1.58 25YR24HR 12.52 13.30 10.00 0.0001 18986.89 12.50 5.95 12.50 5.93 * ** Node Name: N -7 Group: BASE AVERAGE: 13.25 13.30 15.00 0,0004 19013.34 12.48 11.83 13.25 5.66 25YR24HR 12.59 13,36 15.00 0.0004 19264.23 12,29 22.91 12.27 20.78 * ** Node Name: N -8 Group: BASE AVERAGE 12.57 14.41 17,00 - 0.0081 947,60 12.50 6.30 12.48 9,31 25YR24HR 12.73 15.76 17.00 - 0.0081 4359.65 12.50 13.81 12,73 11.76 * ** Node Name: N -9 Group: BASE. AVERAGE 13.31 8.63 17.00 0.0026 608.90 13.25 8.88 13.31 8.53 25YR24HR 12.57 10.54 11.00 0.0158 216.67 12.57 32.15 12.57 32.15 I No no an 91 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) (1] Copyright 1995, Streamline Technologies, Inc. we BASIN HYDROLOGY Basin Summary - AVERAGE Basin Name: B -1 B -2 B -4 B -6 3 -8 Group Name: BASE BASE BASE BASE BASE Node Name: N -1 N -2 N -4 N -6 N -8 ?ydrograph Tyne: UH UH UH UH UH Unit Hydrograph: UH323 UH323 UH323 UH323 UH323 Peaking Factor: 323.00 323.00 323.00 323.00 323.00 Spec Time Inc (min): 2,40 5.33 2,00 5.33 5.33 +� Comp Time Inc (min): 2.40 5.33 2.00 5.33 5.33 Rainfall File: SCSIII SCSIII SCSIII SCSIII SCSIII Rainfall Amount (in): 5.00 5.00 5.00 5.00 5.00 Storm Duration (hr): 24.00 24.00 24.00 24,00 24.00 Status: ONSITE ONSITE ONSITE ONSITE ONSITE Time of Conc. (min): 18.00 40.00 15.00 40.00 40.00 Lag Time (hr): 0.00 0.00 0,00 0100 0.00 Area (acres): 43.20 27.30 3.67 1.74 4.44 w� Vol of Unit Hyd (in): 1.00 1.00 1.00 1.00 1.00 Curve Numher: 83.80 82,20 89.90 94.00 84.20 ^CIA H) : 0,00 0.00 0.00 0.00 0.00 --me Max ;• -_ '2.32 12,53 12.3u �2.qa 12.53 __Dw Max _5 _ -.24 36.66 9.50 3.04 6.32 3.25 3.10 3.87 1.31 3.29 �'w 1GLL ;10034 307136 31523 27222 53046 aq Has-'. Name: -7 _ -�;_ Name: Br.SE Name: N -7 'yz+rograpr. _,:p =: UH ". �-; 323 Baking F _- _. 33.00 .,, 'cec Time _n.: _:s; . 4.00 Tome Time inc _n', . 4.00 SCSIII 24.00 St�-_-:3: CNSITE Time of C nZ. m.... 30.00 -ag Time _,. 0.00 .� Area ( acres): 4.89 !o_ o Uni~ H d in ?. 1.00 23.90 D --A ( 1 . 0 . 00 -4.-ie Max rhrs'i, 12,40 iow Max 8.14 Runoff Vol =e (1n) . 3.26 Runozz Volume (C f): 57905 an 91 w" Node Hyde . _Je_. UH uni _ - H323 Peak_-.: _._____. 323.00 M Spey _..._ 4.00 Comp . _..._ _.._ Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [11 Copyright 1995, Streamline Technologies, Inc. .. -. 24.00 S _aces: ONSITE Time of -Jn::. cmi . . 30.00 M Lag Time ^.l 0.00 BASIN HYDROLOGY 4.89 Basin Summary -------------------------------------------------------------------------- - 25YR24HR - - - - -- DC TA Basin Name: B -1 B -2 B -4 S -6 B -8 Group Name: BASE BASE BASE BASE BASE 130295 Node Name:. N -1 N -2 N -4 N -6 N -8 Hydrograph Type: UH UH UH UH UH Unit Hydrograph: UH323 UH323 UH323 UH323 UH323 Peaking Factor: 323.00 323.00 323.00 323.00 323.00 Spec Time Inc (min): 2.40 5.33 2.00 5.33 5.33 Comp Time Inc (min): 2.40 5.33 2.00 5.33 5.33 Rainfall File: SCSIII SCSIII SCSIII SCSIII SCSIII Rainfall Amount (in): 9.30 9.30 9.30 9.30 9.30 Storm Duration (hr): 24.00 24.00 24.00 24.00 24.00 Status: ONSITE ONSITE ONSITE ONSITE ONSITE Time of Conc. (min): 18.00 40.00 15.00 40.00 40.00 Lag Time (hr): 0.00 0.00 0.00 0.00 0.00 r.� Area (acres): 43.20 27.30 3.67 1.74 4.44 Vol of "'.._ = Hyd ; in) : 1.00 1 . 00 1.00 1.00 1.00 83.80 82.20 89.90 94.00 84.20 DC =.= 0.00 0.00 0.00 0.00 0.00 .w Time Max 12.32 12.53 12.27 12.44 12.53 82.67 19.03 5.97 13. "- -.33 7.13 8.09 8.58 7.33 1 =_1x27 706529 107630 54188 118902 Node Hyde . _Je_. UH uni _ - H323 Peak_-.: _._____. 323.00 M Spey _..._ 4.00 Comp . _..._ _.._ ._. , . 4.00 Rained_'_ ..1 =: SCSIII 9.30 Storm __ .. -. 24.00 S _aces: ONSITE Time of -Jn::. cmi . . 30.00 M Lag Time ^.l 0.00 Area a' =_ =s; 4.89 33.90 DC TA n.00 Time'. : rs 12.43 _OW .. .. 3 R:uno i _ "; me 7.34 Runof t Vol•sme ( c=) : 130295 on 3Z Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. * # * * * * * * ** Input Report * xar** r**** r**** r* r * *+rr * *r * *r * * * * * * * * * * * *r *rrrx *# -- - - - - -- Class: Node------------------------------------------------------------- Name: N -1 Base Flow(cfs): 0 Init Stage(ft): 13.5 Group: BASE Warn Stage(ft): 21 Comment: am Stage(ft) Area(ac) 13.5 0 18 27.6 -- - - - - -- Class: Node-------------------------------------------------------- - - - - -- "' Name: N -2 Base Flow(cfs): 0 Init Stage(ft): 5.3 Group: BASE Warn Stage(ft): 15 Comment: Stage(ft) Area(ac) 5.3 0.0001 14 16.1 -- - - - - -- Class: Node-------------------------------------------------------- - - - - -- Name: N -3 Base Flow(cfs): 0 Init Stage(ft): 3.2 Group: BASE Warn Stage(ft): 5 Comment: Time(hrs) Stage(ft) 0 3.2 30 3.2 - - - - -- Class: Node------------------------------------------------------------- Name: N -4 Base Flow(cfs): 0 Init Stage(ft): 12.5 Group: BASE Warn Stage(ft): 16 Comment: Stage(ft) Area(ac) 12.5 0.319 14 0.432 15.5 0.549 -- - - - - -- Class: Node-------------------------------------------------------------- Name: N -5 Base Flow(cfs): 0 Init Stage(ft): 8 Group: BASE Warn Stage(ft): 17 'i Comment: Stage(ft) Area(ac) [Manhole, Flat Floor] 8 0.0003 15.8 0.0003 33 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) (2] Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. NOR * * * * * * * * ** Input Report *********** r** r* rrr* w * * *a * * * * * * * * * * * * * * * * *x * * * * * * * ** -- - - - - -- Class: Node-------------------------------------------------------------- Name: N -6 Base Flow(cfs): 0 Init Stage(ft): 10.5 Group: BASE Warn Stage(ft): 15 Comment: Stage(ft) Area(ac) 10.5 0.1102 11 0.165 11.5 0.2231 12 0.281 12.5 0.3397 13 0.3992 13.5 0.4593 -- - - - - -- Class: Node ------------------------------------------------------------- Name: N -7 Base Flow(cfs): 0 Init Stage(ft): 10.5 Group: BASE Warn Stage(ft): 15 Comment: Stage(ft) Area(ac) 10.5 0.1102 0" 11 0.165 11.5 0.2231 12 0.281 12.5 0.3397 13 0.3992 13.5 0.4593 -- - - - - -- Class: Node------------------------------------ Name: N -8 Base F= ow(cfs): 0 Init Stage(ft): 14 •* Group: BASE Warn Stage(ft): 17 Comment: Stage(ft) Volume(af) Bottom Area(ac): 0.0074 14 0 14.5 0.00744 15 0.0186 15.5 0.05888 16 0.10971 16.5 0.15186 -- - - - - -- Class: Node ------------------------------------------------------------- Name: N -9 Base Flow(cfs): 0 Init Stage(ft): 7.5 Group: BASE Warn Stage(ft): 15 Comment: Stage(ft) Area(ac) [Manhole, Flat Floor] 7.5 0.0003 13.5 0.0003 ^1 on 34 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [3] ,m Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. * *w * *wwwww Input Report ***** wrwwwww* ww** r* w** wrw *w *wwww * * * * *w *w *w *w *zwwwwww *www we No 35 - -- Class: P ---------------------- --------------------------- - - - - -- Name: PIPE -5 From Node: N -5 Length(ft): 250 Group: BASE To Node: N -9 Count: 1 wo UPSTREAM DOWNSTREAM Equation: Average K Geometry: Circular Circular Flow: Both Span(in): 36 36 Entrance Loss Coef: 0.5 MR Rise(in): 36 36 Exit Loss Coef: 0 Invert(ft): S 7.5 Bend Loss Coef: 0 Manning's N: 0.013 0.013 Outlet Cntrl Spec: Use do or tw Top Clip(in): 0 0 Inlet Cntrl Spec: Use do Bottom Clip(in): 0 0 Stabilizer Option: None Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 ., Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 -- - - - - -- Class: Pipe------------------------------------------------------------- Name: PIPE -6 From Node: N -6 Length(ft): 70 Group: BASE To Node: N -7 Count: 2 UPSTREAM DOWNSTREAM Equation: Average K Geometry: Circular Circular Flow: Both Span(in): 24 24 Entrance Loss Coef: 0.5 Rise(in): 24 24 Exit Loss Coef: 0 Invert(ft): 10.5 10.5 Bend Loss Coef: 0 Manning's N: 0.013 0.013 Outlet Cntrl Spec: Use do or tw Top Clip(in): 0 0 Inlet Cntrl Spec: Use do Bottom Clip(in): 0 0 Stabilizer Option: None Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: ,,. Circular Concrete: Square edge w/ headwall 1 1 we No 35 Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 me M 36 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [4] Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. ..-------- Class: Pipe------------------------------------------------------------- Name: PIPE-8 From Node: N -8 Length(ft): 50 Group: BASE To Node: N -7 Count: 1 UPSTREAM DOWNSTREAM Equation: Average K Geometry: Circular Circular Flow: Both Span(in): 18 18 Entrance Loss Coef: 0.5 Rise(in): 18 18 Exit Loss Coef: 0 Invert(ft): 13 12.5 Bend Loss Coef: 0 Manning's N: 0.013 0.013 Outlet Cntrl Spec: Use do or tw Top Clip(in): 0 0 Inlet Cntrl Spec: Use do Bottom Clip(in): 0 0 Stabilizer Option: None Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 -- - - - - -- Class: Pipe------------------------------------------------------------- Name: PIPE -9 From Node: N -9 Length(ft): 100 Grout): BASE To Node: N -2 Count: 1 UPSTREAM DOWNSTREAM Equation: Average K Geometry: Circular Circular Flow: Both Span(in): 36 36 Entrance Loss Coef: 0.5 Rise(in): 36 36 Exit Loss Coef: 0 Invert(ft): 7.5 7.2 Bend Loss Coef: 0 Manning's N: 0.013 0.013 Outlet Cntrl Spec: Use do or tw Top Clip(in): 0 0 Inlet Cntrl Spec: Use do Bottom Clip(in): 0 0 Stabilizer Option: None Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 me M 36 am Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [5] Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. * * * * *r ** ** Input Report ****** tt* vr*** r* x** rrr**** * * * * * *r * * * * *r * *t * * * * *rt * * *r * *r* -- - - - - -- Class: Drop Structure--------------------------------------------------- Name: CONTROLI From Node: N -1 Length(ft): 580 Group: BASE To Node: N -5 Count: 1 .. Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 30 30 Rise(in): 30 30 Invert(ft): 9.6 9.59 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 * ** Weir 1 of 2 for Drop Structure CONTROLI * ** (TABLE] ^„ Count: 1 Bottom Clip(in): 0 Type: Mavis Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 3 Invert(ft): 13.5 Rise(in): 30 Control Elev(ft): 13.5 * ** Weir 2 of 2 for Drop Structure CONTROLI * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 172 Invert(ft): 16 Rise(in): 99999 Control Elev(ft): 16 4W 37 an Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [6] Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. * * ** * * * * ** Input Report -- - - - - -- Class: Drop Structure -------------------------------------------------- Name: CONTROL2 From Node: N -2 Length(ft): 70 Group: BASE To Node: N -3 Count: 1 .� Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 36 36 ^' Rise(in) : 36 36 Invert(ft): 4.5 4.09 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 �a Downstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 Weir 1 of 1 for D Count: 1 Type: Mavis Flow: Both Geometry: Trapezoidal Bottom Width(ft): Left Side Slope(h /v): Right Side Slope(h /v): ma Am .. rap Structure CONTROL2 * ** [TABLE] Bottom C1ip(ft): 0 Top Clip(ft): 0 Weir Discharge Coef: 3 orifice Discharge Coef: 0.6 0 Invert(ft): 5.3 65 Control Elev(ft): 5.3 8.75 StructOpeningDim(ft): 9999 ■e 38 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [7] .� Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. * * * * * * * * ** Input Report -- - - - - -- Class: Drop Structure--------------------------------------------- - - ---- Name: CONTROL4 From Node: N -4 Length(ft): 55 Group: BASE To Node: N -5 Count: 1 Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 24 24 Rise(in): 24 24 Invert(ft): 10 9.6 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 Downstream FHWA Inlet Edge Description: Circular Concrete: Groove end w/ headwall 1 2 rr * ** Weir 1 of 2 for Drop Structure CONTROL4 * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Mavis Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 7 Invert(ft): 13.3 Rise(in): 24 Control Elev(ft): 13.3 * ** Weir 2 of 2 for Drop Structure CONTROL4 * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 172 Invert(ft): 15.3 Rise(in): 9999 Control Elev(ft): 15.3 so an 39 MR Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [8] no Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. M * * * * * * * * ** Input Report rr****** r**************** * * * * * * * * * * * * * *r * *t * *rr *rt * * * * ** -- - - - - -- Class: Drop Structure--------------------------------------------------- Name: CONTROL6 From Node: N -6 Length(ft): 2 Group: BASE To Node: N -2 Count: 1 •• Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 18 18 .. Rise(in): 18 18 Invert(ft): 7.65 7.5 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 ,. * ** Weir 1 of 2 for Drop Structure CONTROL6 * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Mavis Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 .. Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 3 Invert(ft): 11.25 Rise(in): 11 Control Elev(ft): 11.25 * ** Weir 2 of 2 for Drop Structure CONTROL6 * ** [TABLE] Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 144 Invert(ft): 13.3 Rise(in): 99999 Control Elev(ft): 13.3 .. W 40 Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) (9] .., Copyright 1995, Streamline Technologies, Inc. PROPOSED CONDITION OF T- HANGAR & ACCESS RD EXT. wn ww * * * * * * ** Input Report wwwww* r**** trw* wwwwwwwwwwwwwwwww *ww *w * * *r * * * *wwr * *w *rwww� -- - - - - -- Class: Drop Structure--------------------------------------------------- Name: CONTROL? From Node: N -7 Length(ft): 2 Group: BASE To Node: N -9 Count: 1 .. Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 18 18 Rise(in): 18 18 Invert(ft): 7.65 7.5 Manning`s N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both r Exit Loss Coef: 0 Equation: Aver Conveyance Upstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 .� Downstream FHWA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 * ** Weir 1 of 2 for Drop Structure CONTROL7 * ** (TABLE] Count: 1 Bottom Clip(in): 0 Type: Mavis Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 *+ Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 3 Invert(ft): 11.25 Rise(in): 11 Control Elev(ft): 11.25 * ** Weir 2 of 2 for Drop Structure CONTROL? * ** (TABLE) Count: 1 Bottom Clip(in): 0 Type: Horiz Top Clip(in): 0 Flow: Both Weir Discharge Coef: 3 Geometry: Rectangular Orifice Discharge Coef: 0.6 Span(in): 144 Invert(ft): 13.3 Rise(in): 99999 Control Elev(ft): 13.3 41 1 ! 1 1 1 1 1 1 1 I 1 I 1 I ! 1 1 1 1 Advanced Interconnected Channel & Pond Ruur:ing (ICPR Ver 2.20) [1] Copyright 1995, Streamline Te +_-hnologies, Inc:. * * * * * * 'A- A A A Node Maximum C:ompa r i sons A' k # A A F l A l l A A A A k A A A 'k A * k * #' * 'F' (Time units - hours) Sim Max Time Max Stagtr Warning Max Delta Max Surface Max Time Max Inflow Max Time Max Outflow Name Conditions (tf) Stage (fl) :,taye (ft) Area (sf) Inflow (cfs) Outflow (cfs) *** Node Name: N -DRIVE Group: BASE ---------------------------- AVERAGE 15.41 17.91 20.[i(,) O.ODUp 18018.30 12.25 2.98 15.41 0.45 25YR24HR 15.29 18.')_) 20.uii 0.0001 24900.42 12.25 5.93 15.29 0.97 *** Node Name: N -ROAD Group. BASE AVERAGE 13.71 19.21 21.mi 0.000U 14868.04 12.25 2.81 13.71 0.72 25YR24€fR 13.311 19.68 21.00 0.0001 19479.79 12.25 5.63 13.34 1.91 k* Node: Name: OUTFALL Group: BASE AVERAGE 15.00 16.00 20.00 0.0000 0.00 14.09 1.13 0.00 0.00 25YR24Hit 15.00 16.00 20.i)r) ().0000 0.00 13.48 2.82 0.00 0.00 mom on Y..._..< <+ Basin .-.:".ary - �3'_R24HR - *+ +. -.-- -- - -- -_e- w <t + +�n Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [1] Copyright 1995, Streamline Technologies, Inc. E2S= BASE * * * ** * * * ** Basin Summary - AVERAGE B1 -DRIVE N -ROAD Basin Name: EX -ROAD EX -DRIVE PR -ROAD PR -DRIVE UH Group 'Name: BASE BASE BASE BASE Node Name: N -ROAD N -DRIVE N -ROAD N -DRIVE UH323 Hydrograph Type: UH UH UH UH 323.00 323.00 ,., Sc � :ime Inc (mi_, __•__ i =.36 1.33 Unit Hydrograph: UH323 UH323 UH323 UH323 1.33 Peaking Factor: 323.00 323.00 323.00 323.00 SCSIII Spec Time Inc (min): 10.13 11.86 1.33 1.33 9.30 Comp Time Inc (min): 10.13 11.87 1.33 1.33 2-1.00 Rainfall File: SCSIII SCSIII SCSIII SCSIII ONSITE Rainfall Amount (in): 5.00 5.00 5.00 5.00 �+ Storm Duration (hr): 24.00 24.00 24.00 24.00 0.00 Status: ONSITE ONSITE ONSITE ONSITE 0.82 Time of Conc. (min):. 76.00 89.00 10.00 10.00 1.00 Lag Time (hr): 0.00 0.00 0.00 0.00 93.00 Area (acres): 0.82 0.88 0.82 0.88 0.00 Vol of Unit Hyd (in): 1.00 1.00 1.00 1.00 12.24 Curve Number: 80.00 83.00 93.00 93.00 4.82 DCIA (�): 0.00 0.00 0.00 0.00 Time Max (hrs): 12.84 13.05 12.24 12.24 8.46 Flow Max (cfs): 0.67 0.71 2.50 2.68 25275 Runoff Volume (in). 2.89 3.17 4.20 4.20 Runoff' Volume (cf1: 3613 10135 12501 13416 Y..._..< <+ Basin .-.:".ary - �3'_R24HR - *+ +. -.-- -- - -- -_e- w <t + +�n Bas_.. `:wme: v.. -:,SAD -EX-DRIVE _ :: -ROAD PR -DRIVE BASE E2S= BASE :; J N -?.OAD B1 -DRIVE N -ROAD N -DRIVE dr= raph Type: UH UH UH UH Unit Hydrograph: 7X 323 UH323 UH323 UH323 Factor: 3L-_.00 323.00 323.00 323.00 ,., Sc � :ime Inc (mi_, __•__ i =.36 1.33 1.33 mp -'me Inc (rn_:,. 1? 11.37 1.33 1.33 Rainfall File: S'_SIII SCSIII SCSIII SCSIII A c : : , 3+' 9.30 9.30 9.30 24.00 2-1.00 24.00 `a.'.s: 7 iSITE ONSITE ONSITE ONSITE Tim= f Conc. (min.;: r.00 89.00 10.00 10.00 1,ag T 1me (hr) : .. 00 0.00 0.00 0.00 Area 'acres): -.82 0.88 0.82 0.88 Vol of ?nit Hyd (in): 1.00 1.00 1.00 1.00 Curve Number: 60.00 83.00 93.00 93.00 DCTA ;: °.00 ).00 0.00 0.00 1me ?a : hrs) . !--,34 13.05 12.24 12.21 ='_Dw ',lax (cfs) : 1.60 1.61 4.82 5.17 .� Runoff Volume (in): 6.85 7.22 8.46 8.46 Runoff Volume (cf): 20404 23075 25275 27017 OR 43 an ON me Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [1] Copyright 1995, Streamline Technologies, Inc. # + +w + * + + *+ Input Report AM -- - - - - -- Class: Node--------------------------------------------------- Name: N -DRIVE Base Flow(cfs): 0 Init Stage(ft): 16.8 Group: BASE Warn Stage(ft): 20 Comment: Stage(ft) Area(ac) 16.8 0.1469 17 0.1944 17.2 0.2422 17.4 0.2901 17.6 0.3383 17.8 0.3868 .� 18 0.4355 18.2 0.4844 18.4 0.5335 �., 18.6 0.5829 -- - - - - -- Class: Node ------------------------------------------------------------- �;ame: N -RGz_D Base Flow(cfs): 0 !nit S_age(ft): 18.26 Group: BASE Warn Stage(ft): 21 Comment: we _s. -- -- ' -- Name: JUT = --- ?ase Flow(cfs). 0 T.-,it_ S-age(rt). 14 Group: BASE Warn Stage(ft): 20 Time,hrs) S:a:1e'f=) Q _ 3. AM i Advanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [2) 4UN Copyright 1995, Streamline Technologies, Inc. am Input Report* r < * *tt * * + *f * * *�r�a + # *� + *t * *rW ** -- - - - - -- Class: Drop Structure--------------------------------------------------- Name: CONTROLI From Node: N -ROAD Length(ft): 100 Group: BASE To Node: OUTFALL Count: 1 .. Outlet Cntrl Spec: Use do or tw Inlet Cntrl Spec: Use do Upstream Geometry: Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span(in): 24 24 i Rise(in): 24 24 Invert(ft): 15 14 Manning's N: 0.013 0.013 Top Clip(in): 0 0 Bottom Clip(in): 0 0 Entrance Loss Coef: 0.5 Flow: Both Exit Loss Coef: 0 Equation: Aver Conveyance Upstream _ WA Inlet Edge Description: Circular Concrete: Square edge w/ headwall 1 1 Downstream ::TWA Inlet Edge Description: Circular Ccncre,-e: Sc,-:are edge wl headwall 1 1 pie__ _ v' I i.__ ^c S __ _ c _Ere r.DN.rrR' _ _ [TABLE, aunt: 1 Bottom Too _ Discha_ -- 18.68 ice, L Cont_.,_ Elev(rt}. 18.63 45 PM am -Avanced Interconnected Channel & Pond Routing (ICPR Ver 2.20) [3) Copyright 1995, Streamline Technologies, Inc. so Input Report W= am IMIN -------- Class: Dron Structure --------------------------------------------------- Name: CONTROL2 From Node: N-DRIVE Length(ft): 25 Group: BASE To Node: OUTFALL Count: 1 Outlet Cntrl S-_e-_: Use dc or tw Inlet Cntrl Spec: Use do Upstream Geom=------;. Circular Downstream Geometry: Circular UPSTREAM DOWNSTREAM Span."in): 24 24 Risek'in): 24 24 Inverlutft): 16 15 Manning's N: 0.013 0.013 Top Clip (in): 0 0 Bottom Clin(`n) : 0 0 Entrance Loss --oef; 0.5 Flow: Both me Exit Loss Coef: 0 Equation: Aver Conveyance Upstream :nIet Edge Description: Cirz--:1ar Co7,.z:rste: Groove end w/ headwall 1 2 Downs7_ream - inlet Edge Description: end wl headwall 2 CONTROL2 "a3,- 7 Count I 50-_ --om clip ( -in, : ID Tyne: op Clip(in): 0 --low: C), �_charge Coe4: 3 S narge C-3ef: 7 17 _' R_'se;in Control Elev(f--,: 17.2 W= am IMIN - Appendix D a x m i n a ti i 0 P i v 'o n i 0 i a a c 0 0 1 O �_ 1 Z-"G DDV,=. I :L I x L L :DDZ=„L :1,VxZ4 Hoevro XXXX—XX)( dVW 3E)VNIVIIO NOLLICINOO CIBSOdOUd SNISVS 3E)VNIVUO N3SNVr 'N INQZNVS '8 l-L30(]Vd 'V sn U ! - 'HOV3E rfWd iS3M -u . � W 'VdMYt • VIDSVElys �A OWM�O 18 - DN -HSUWtl . NU DS H3'V3E FULWI•IV -znlBCPt- I ;A= / PN 'OMErLKU'* -35 'V;GMM33--ll 'O7VDI10 3H '21OIIVH3 •33 'M0IS713SWO • Vo 'ViNY-U V SiNV.LYtMZ) NUIVIBOcENYU dnouo VdI 3HJL VOIHOI-q Nvlisvgas i8odaiv wdoiNnVY NVUSV99S GNVM NVOMETIO 2WOH a Aw .00 -, X \N "I ' --� � X, LL ol N 17 L"7 93BOV i7L =v SR ERRIM it NO al -jjCp—[] 4c T: ". . ........ .. . zi f. 51501 n N3SNVr 'N INQZNVS '8 l-L30(]Vd 'V sn U ! - 'HOV3E rfWd iS3M -u . � W 'VdMYt • VIDSVElys �A OWM�O 18 - DN -HSUWtl . NU DS H3'V3E FULWI•IV -znlBCPt- I ;A= / PN 'OMErLKU'* -35 'V;GMM33--ll 'O7VDI10 3H '21OIIVH3 •33 'M0IS713SWO • Vo 'ViNY-U V SiNV.LYtMZ) NUIVIBOcENYU dnouo VdI 3HJL VOIHOI-q Nvlisvgas i8odaiv wdoiNnVY NVUSV99S GNVM NVOMETIO 2WOH a Aw .00 -, X \N "I ' --� � X, LL ol N 17 L"7 93BOV i7L =v SR ERRIM it NO al 4c T: ". N3SNVr 'N INQZNVS '8 l-L30(]Vd 'V sn U ! - 'HOV3E rfWd iS3M -u . � W 'VdMYt • VIDSVElys �A OWM�O 18 - DN -HSUWtl . NU DS H3'V3E FULWI•IV -znlBCPt- I ;A= / PN 'OMErLKU'* -35 'V;GMM33--ll 'O7VDI10 3H '21OIIVH3 •33 'M0IS713SWO • Vo 'ViNY-U V SiNV.LYtMZ) NUIVIBOcENYU dnouo VdI 3HJL VOIHOI-q Nvlisvgas i8odaiv wdoiNnVY NVUSV99S GNVM NVOMETIO 2WOH a Aw .00 -, X \N "I ' --� � X, LL ol N 17 L"7 93BOV i7L =v SR ERRIM it NO al sopuenbai.1 jue k-W L Pue -OS '-SZ '-Q L '-S ' -E jol ejeq yldaQ uoijejidioaad AEQ -L 119611 AlaJYSJaH :a2u8jalad 1 6 MaA sZ 11 6 8 �'~ 1l at 1 oil, 5 1 f at s'c J"A s 8' s'9 �II 9 r Lll 41 ► of 6 ti 11 It . . 11 -` zo •' B � at i 6, , JeaA tts S °5 leeA Z 9► i rr, sayoul ul sinoiu40 t4lddea Ila 96;0 V8 a6ud e sw-o o-SZ9 Y y jenueyy eoeuieJp uojlelaodsueJl jo ,uauiliwa{3 epuol j 'S3unC]300dd —Z 3YV 12,0 Underdrain Design and Performance Criteria 12.1 Description Stotmwater underdrain systems consist of a dry basin underlain with perforated drainage pipe which collects and conveys stotmwater following percolation from the basin through suitable soil. Underdrain system are generally used where high water table conditions dictate that recovery of the stormwater treatment volume cannot be achieved by natural percolation (i.e, retention systems) and suitable outfall conditions exist to convey flows from the underdrain system to receiving waters. Schematics of a typical underdrain system are shown in Figures 12 -1 and 12 -2. Underdrain systems are intended to control both the water table elevation over the entire area of the treatment basin and provide for the drawdown of the treatment volume. Underdrains are utilized where the soil penreability is adequate to recover the treatment volume sincetheon -site soils overlay theperforated drainage pipes. Underdrain systems provide excellent removal of stormwater pollutants. Substantial amounts of suspended solids, oxygrn demanding materials, heavy metals, bacteria, some —� varieties of pesticides and nutrients such as phosphorus are removed as runoff percolates through the vegetation and soil profile. Then are several desim and performance criteria which must be met in order fora underdrain system to meet the rule regtdrements. The underdrain vile criteria are described below. 12.2 Treatment Volume The first Hush of runoff should be detained in a dry detention basin and percolated through the soil. For discharges to Class Ill receiving water bodies, the role specifies either of tine following treatment volunes: (a) Off -line retention of the first one -half inch of runoff or 1.25 inches of runoff from the impervious area, whichever is greater, or (b) On -fine rent ion of an adds Tonal one half inch of runoff from the drainage area over that volume specified foroff- -line treatment. For direct discharges to Class 1, Class II, OFWs, or Class III waters which are approved, conditionally approved. restricted, or conditionally restricted for shellfish harvesting the applicant should provide retention foreither of the following: (a) At least an additional fifty percent of the applicable treatment volume specified for off - line retention in (a). above. Off -line retention must be provided forat least the first one- half inch cat runoff or 1.25 inches of runoff from the impervious area, whichever is greater, of the total amount of runoff required to be treated. 12 -1 (SAH — 10/3/95) we (b) On -line retention of the runoff from the three -y ear, one -hour storm or an additional fifty percent of the treatment volurne specified in (b), above, whichever is greater. M 12.3 Recovery Time am The system should be designed to provide for the drawdown of the appropriate treatment volune specified in section 12.2 within 72 hours following a storm event. The treatment volume is recovered by percolation through the soil with subsequent transport through the underdrain pipes. The system should only contain standing water within 72 hours of a .M storm event. The pipe system configuration (e.g, pipe size, depth, pipe spacing, and pipe inflow capacity) of the underdrain system must be designed to achieve the recovery time requirement. Underdesign of the system will result in reduced hydraulic capacity. This, in turn, will result in a reduction in storage between subsequent rainfall events and an -� associated decrease in the annual average volume of stonnwater treated resulting in a reduction of pollutant removal (Livingston et al. 1988). Such circurnstances also reduce the aesthetic value of the system and may promote mosquito production. A detailed methodology with design exam les for calculating retention basin recovery is presented in section 27. The benefits of gravel envelopes around perforated pipes are discussed in section 25. r. 12.4 Safety Factor The underdrain system trust be designed with a safety factor of at least two unless the applicant aflii-matively demonstrates based on plans, test results, cakulations or other information that a lower safety factor is appropriate for the specific site conditions. Exan>ples of how to apply this factor include but are not limited to the following": (a) Reducinathedesi t percolation rate by half (b) Designin = fortherequired drawdown within 36 hours instead of 72 IIOLl1S. 12.5 Underdrain Media To provide proper treatment of the runoff, at least two feet of indigenous soil must be between the bottom of the basin storing the treatment voltune and the outside of the underdrain pipes (orgravel envelope as applicable). i MR 12 -2 (SAH - 10/3/95) am am 12.6 Filter Fabric MR Underdrain systems should utilize filter Fabric or other means to pre�ent the soil from no move into and clogging perforated pipe. 12.7 Inspection andCleanout forts To facilitate maintenance of the underdrain system, capped and sealed inspection and cleanout ports which extend to thesurface of the ground should be provided, at a minimum, at the following locations for each drainage pipe: (a) The tertninus (b) At every 400 feet or every bend of 45 or more degrees, whichever is shorter. 12.8 Basin Stabilization The underdrain basin should be stabilized with permanent vegetative cover and should contain standing water only immediately following a rainfall event. 12,9 References .,„ LiN-aaa—ston, E, H.. E. N1 cCarron, J. Cox, F. Sanzone. 1948. The Flotid a Land Devc4opnzent _11(ttrirctl: .4 Guide to Sound Land and Wato- Management. Florida Department of Environmental Regulat'on, Nonpoint Source NI anag'ement Section, Tallahassee, Florida. ON Oft am ., 12 -3 (SAH - 10/3/95) rI 4"'q_ EF ll o iii Q p Q 0 4. P 0 z 0 S Z Z C :s > 0 7' -'E'7 i CL > c LLJ Figure 12-1. Cross-.,ection of Underdrain System (N.T.S.) 12-4 (SAH - 10/3/95) Tf ICJ l51 C top of ncldr) Botlnrn of Basin To Outlet �I� 27.0 Methodology and Design Example for Underdrain Systems 27.1 Spacing Underdrain Laterals Optimum drain spacing for drainage laterals is influenced by soil permeability, drain depth, water table elevation desired after installation of the system, and site characteristics. The following procedure used to design underdrain systems are lariply based on techniques used to design agricultural subsurface drainage systems. The procedures in this section are adapted from Livingston et al.( 1988). U nderdrain spacing can be determined by the "ellipse equation" which is expressed as (SCS 1973): S = 4K(1712 + ?am) (27 -1) where: S = Drain spacing (ft) K = Permeability rate of the soil (fr /hr) 1rr = Height of water table above drain (after drawdown) measured at the midpoint between laterals (f) a = Height of drain above impermeable layer (ft) q = Drainage coefficient (ft/k-) Refer to Figure 27 -1 for an illustration of the variables used in the ellipse equation. ThedrainaQe coefficient (q) is the rate of water removal to obtain the required 72 -hour recovery of the treatment voltnne and to lower the free wetter surface a specified depth below the basin bottom. In theellipse equation, thedrainage coefficient (q) is expressed in thesame units as the permeability (K). The drain coefficient (q) can be expressed as (Livingston et al. 1988): c' q r (27 -2) t where: c = Depth fromtheground surface to water table (after drawdown) (ft) t = Recovery time (hr) Based on Figure 27 -1, the heig-Pub of the water table above the dram (err) is given by: in = d - c (27 -3) where: el = Depth to drainage pipe from the natural ground surface elevation (ft) The height of the drain above the impermeable barrier (a) is: u = D - d (27 -4) where: D = Depth to impermeable laver from the natural 21-ound surface elevation (ft) 27- 1 (S H - 10/3/95) MR A, .. When there is no impermeable barrier present, the depth to the impermeable layer (D) should be assumed at a depth equal to twice thedrain depth (c). The ellipse equation is based on steady state conditions and the assumption that ground water inflow from outside the area is slight. For this reason the use of the ellipse equation should be limited to conditions in which: (a) The hydraulic gradient of the undisturbed water table is one percent (4.01 feet per foot) or less. Under these conditions there is likely to be very little ground water flow or movement from outside the sv stem. (b) The siteis underlain by a impermeable barrier at relatively shallow depths (twice the depth of thedrain (d) or less) which restricts vertical flow and forces the percolating water to flow horizontally toward thedrain. (c) A gravel envelope surrounds the perforated drainage pipes so that flow restrictions into the drain are minimized. (d) The height of drain above impermeable layer (a) is less than or equal to the depth to the drainage pipe(ci). 27.2 Length of Underdrain Required and Basin Dimensions It is desirable to keep both the bottom and sides of the detention area dry. To maintain a dry basin bottom, the District recommends the distance between the basin bottom and water table after drawdow n be at least 6 inches (see Figun-e 27 -1). hlaintaininer ? 6 inches will ensure that the floor of the basin is above the t-attnd water table cap Mary zone. If the side slope and shape of the detention basin are known, it is possible to determine the dimensions of the basin and the exact lenah of draw pipe needed. The area (AL) served by each lateral in a rectangular basin is given by (see Figttre 27-2); .4L = S (L + S) (27 -5) where: AL = Area served by each lateral (f") L � Length of lateral (ft) 27- 2 (SAH - 10/3/95) MR MR MR we s am an MR Ad, MR f . s s 1 X `t V1 --- --��'f •"y \ \ \N i y[ u I w � S l ' W y �• � I r f } Ei21 ure ?7- 1. Cross-section of Underdrain System Illustrating Variables Used in the Ellipse Equation (N.T.S.) 27- 3 (SAH - 10/3/95) d3 UA - I �- ; i j J 4 Fi"Lire 27-2. Top View of Underdrain System Illustratinu, Variables Used in the Ellipse Equation (N.T.S,) 27- 4 (SAH - 10/3/95) on ,., The total area served by all the laterals (ArL) is: ATL = AL N (27 -6) where: N = Number of laterals The top area of the detention basin (ABT) can be expressed as: ,48T = DPAR DPER (27-7) where: .4BT = Top area of the detention basin (,la=) DPAR = Distance of top of basin in the direction parallel to the laterals (Jt) DPER = Distance of top of basin in the direction perpendicular to the laterals (ft) Setting thetotal areaserved by the laterals (ArL) so that it is equal to the area of the detention basin as treasured from the top of bank dimensions (ABT), will ensure that both the bottom and sides of the basin remain dry between stony events. In this case the criteria for the lateral spacings and the top dimensions of the basin are determined as follows: Lateral Length : L + S >_ DPAR (27 -8) Lateral Spacing: S () ? DP-PR (27 -9) Lateral Side ©ffset Distance: Offset <_ S (27 -10) Top Area: DP.gR fDPERI < A,.,_ (27 -11) Given the lateral spacing (S) and two of the three variables L. DPAR. or DPER, the designer can solve fortheunknown variable usinY_ theequations in this section. An erannple problem for designing an underdrain system is given in section 27.5. 27.3 Drain Size Mft The discharge from a drain may be found by the following formula (SCS 1973): MR yS(L + S) O = CF j (27 -12) wheile: L),. = Relief drain discharge (c.-A) S = Drain spacing (ji) L Drain lengh (1 6 q = Drainage coetlicient i in hr) .,s CF = Conversion factor= 432 (X) 27- 5 (SAH - 16/3/95) MR Subsurface drains ordinarily are not desitmed to flow under pressure. The hydraulic gradient is considered to be parallel with the grade line of the underdrain. The flow in the dram is considered to be open - channel flow. Thesizeconduit required fora given capacity is dependent on the hydraulic gradient and the roughness coefficient (n) of the drain. Commonly used materials have it values rangng fromabout 0.011 for good quality smooth plastic pipe to about 0.025 For corrugated metal. When determiningthe size ofdrain required for a particular situation then valueoftheproduct to be used must be known. This information will normally be available from the manufacturer. The diameter pipe required for a given capacity, hydraulic gradient, and four different n values may be detennined from Figures 27 -3, 27 -4, 27 -5, and 27 -6. The area to the right of the broken line in the charts indicates conditions where the velocity of flow is expected to be less than 2.0 ft /sec. Lower velocities may present a p roblern with siltation in areas of fine soils. 27.4 Sizing of Drains Within the System The previous discussion on dram size deals with the problem of selecting the proper size for a drain at a specific point in the stormwater system. In drainage systems with laterals and mains, the variation of flow within a single line may be great enough to warrant changing size in the line. This is often the case in long drains or systern with numerous laterals. The examp le problem in section 27.5 illustrates a method for such a design. 27.5 Example Design Calculations for Underdrai n S vstems Given: Desired depth of the treatment volume in the bas in = 3 feet Desired basin freeboard = 1 ft .. 4 " mininlUrn pipe diameter 3'" gravel envelope on each side of the drainage pipes Cvl inimurm distance between basin bottom and top of the gravel envelope = 2 feet = ,nr fi r .� Depth from natural ground to impermeable barrier= 7.5 feet Area of basin (measured From top of treatment volume) = 7260 ft' Nlaxnnurn top dimension of basin perpendicular to drainage laterals = 30 feet K = 1.0 ftihr Slope of laterals = 0?11 o x = 0.015 Safety factor = 2.0 "T" shaped drainage network (similar to Figure 27 -2) an ObJective: Desim an underdrain system to lower the water level to a level 6" below the basin bottorn within 72 hours. 0 A 27- 6 (SAH - 10/3/95) M M Desizat Calculations: Step 1. Calculate the required dram spacing. .. First determine the depth to the drain line from natural round surface (d) from the Following relationship: Depth to thedrabi linefrom = Depth oftreatment voltane in the basin + depth of natural ground surjirce (d) freeboard +depth of'.soil bettwett basDt floor and envelope + depth ofgravel envelope + drain radars d = 3 ft + 1 ft + 2 ft + 3 in — 2 in = 6.42. ft 12 inifl 12 in /# Determine the height of the drain above the impermeable layer (a) by utilizing Equation 27 -4: a = D - d = 7.5 - 6.42 = 1.08_ ft Depth to wato• table after- drattdown (c) = treatment voltune depth + freeboard depth + r c= 3_J1- Ifi- 6 i = 4.5ft 12 in /ft From Equation 27 -3: in = d - c= 6.42fi-4.5.1t= 1.92.ft Determine the drainage coefficient (q) froth Equation 27 -2 with t = 36 lu-s to incorporate a safety factor of 2 ( i.e.. 72i2 = 36): q = c = 4.5 ft = 0.125 ft1ir = 1.5 inilu t 36 hr Thespacing(S) is detennined from Equation 27 -1: EMBED Equat ion.2 Determine the numl-er of laterals (N) utilizing Equation 27 -9: N? 3011 > l.5 15.8.f} Sind the laterals should be located no farther than S2 from the top of the basin. use two laterals spa,-rd 15 ft apart and located 5 ft inside the top of basin. The two laterals will be connected to a amain line with an outlet pipeintcssectingat thetnidpoint ofthemain line. 27- 7 (SAH - 10/3/95) Step 2. Calculate the length of the laterals. Use Equation 27 -11 w•ith,48T- ATL: DPAR = 7 -2601r — 242 ft 30 ft Find the length of each lateral (L) from Equation 27 -8: L = 242 ft - l 5 fi = 227ft Step 3. Size the drainage laterals. The flow per lateral (Or) is found from Equation 27 -12: O, _ (1.5 inch /ht) 15.,tt 227ft + 15, 1 = 0.122 cfs 2 / 43200 _ From Figre 27 -5 with slope = 0.002 and n = 0.015, the capacity of a 4" pipe is 0.074 cfs. Since this is less than the flow rate that each lateral must convey, a 4" drain will not be sufficient for the entire leng3h of the lateral and the size will have to be increased. Start the design process at the Lipper end of the drain using a minimum size of 4 inches. First, compute the distance that the drain would carry the flow on the assumed grade, The accretion per 100 would be: 0.122 cfs = 0.054 cfs 227. fr /100, /i Thedistance (in 100 -foot sections) down gradient that a 4" drain would be adequate is: no 0.074 c s = 1.38 (100 -foot sections of 4" pipe) 0.054 cfs The4" drain pipe is adequate for 135 feet of line. Continue these calculations for the next size pipe (5 -inch) which has a maxinum capacity of 0.13 cfs (from Figure 27 -5). 0.13 c s = 2.42 (100 -foot sections of 5" pipe) 0.055 cfs The 5" drain would be adequate for 242 feet. Of this 242 feet, 138 would be 4" drain: and the remaining 104 feet would be 5" pipe. Since the total lengh required for each lateral is 227 feet, the an amount of 5" drain needed is: 227, ft - 138.6 = 89/i of 5 " drub? per lateral M In surnr1><u-%, each lateral should contain I38 ft of 4" drain and 81) tt of 5" dram, although pra�xiral applicatirnts might consider 5" drain fortheentire 227 ft. 27- 8 (SAH - 10/3/95) e Step 4. Size the main and outlet lines. Assume the outlet intersects the main line at the midpoint. With only two laterals in the system, the main will not intersect any other laterals before reaching the outlet. Therefore, a 5" drain 10 feet in lengh on either side of the outlet will be sufficient for the main line. Flow, in the outlet = 0.122 cf per lato -al x 2 laterals = 0.244 efs From Figure 27 -5, with slope = 0.002 and n = 0.015; a flow of 0.244 cfs is greater than the capacity of a 6" but less than the capacity of a 8" dram. Therefore, use 8" drain for the outlet. 27.6 References Livingston, E.H., E. McCarron, J. Cox, P. Sanzone. 1988. The Florida Land Devdopment Uanual: .4 Guide to Sound Land and Water- Management. Florida Department of Environmental Regulation, Nonpoint Source Management Section, Tallahassee; Florida. Natural Resources Conservation Service (SCS). 1973. Drainage ol'Agz•iculawal Lancis. Water Information Center, Port Washington, New York Ow ., 27- 9 (SAH - 10/3/95) i ^..0 17 . c z i.ci y • z. -- _ _ . a '-1 L . i.IY G F1l-'EB1't -27-3. Dtain Capacity Chart - "Il" -- II.01 1 (Source (_ SL).\ -SC S) Source: Lip inumon el al.. 1988 27 -10 1S -2,kF - 10;'3/95) ................ 1.0 0.80 0.06 Fitiore 27-4. SubNurface Drain Capacli,, Chan - "n" — 0.01 (SoUrce USDA-S•S) SOLII-Ce: Livingston et al., I 27-11 (SAH 10/31/95) (puclas InA 1004 31qn:)) 'kjLj.)vjv,j Ct Q 0 11 el P -4 ID (I V3 ,1 (puclas InA 1004 31qn:)) 'kjLj.)vjv,j Ct Q 0 11 el P -4 ID (I V3 ft (J Ln V) ON M PI LL- 'Mel, 0 Jill iA ft (J Ln V) ON M PI LL- 'Mel, 0 iA 11W 11 N 'n ft (J Ln V) ON M PI LL- omm m c c c a 4 4. Ol 2.0 O Y. LIO. 7, 771 C. 6o 0.40 0.30 0. ca Fluure 27-5. Subsurface Drain Capacity Chart -'°n" 0.015 (Source USDA-SCS) SOLII-CC: Lix Inuston ei al.• 1985 27-12 (SAH - 10/3/95) -4 Z-- F, 7 7- �7 c c c a 4 4. Ol 2.0 O Y. LIO. 7, 771 C. 6o 0.40 0.30 0. ca Fluure 27-5. Subsurface Drain Capacity Chart -'°n" 0.015 (Source USDA-SCS) SOLII-CC: Lix Inuston ei al.• 1985 27-12 (SAH - 10/3/95)