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Home My WebLink AboutSW6220604_Design Calculations_20220926COMPUTATIONS FOR NCDEQ SW PERMIT SUBMITTAL: VEGETATED CONVEYANCES AND VELOCITY CHECKS AT DISCHARGE LOCATIONS TO WETLANDS ROCK OUTLET PROTECTION HARRINGTON PLACE RESIDENTIAL DEVELOPMENT KNIGHT ROAD HARNETT COUNTY, NORTH CAROLINA JUNE 22, 2022 *REV 9-26-2022* Prepared by: J THOMAS ENGINEERING, INC. a� E CIVIL ENGINEERING & PLANNING 143 Charlotte Avenue, Suite 104" Sanford, North Carolina 27330 919-777-6010 phone www.jthomasengineering.com License No. C-3389 COMPUTATIONS FOR VEGETATED CONVEYANCES AND VELOCITY CHECK AT DISCHARGE LOCATIONS HARRINGTON PLACE RESIDENTIAL DEVELOPMENT 22-Jun-22 (REV 9-26-2022) Location Swale No. (for reference to NCDEQ Low Density Supplement EZ) Start STA 10055 ..........................................1...... 10056 ..........................................:...... 11050 ..........................................1...... 10727 ..........................................:...... 11235 ..........................................1...... 11216 ..........................................:...... 11400 ..........................................1...... 11400 ..........................................:...... 11705 ..........................................1...... 11705 ..........................................:...... 11730 ..........................................1...... 11800 ..........................................:...... 11800 ..........................................1...... 20055 ..........................................:...... 20060 20263 ..........................................:...... 20313 20443 ..........................................:...... 20550 20729 ..........................................:...... 20950 ................................................ 20997 ..........................................:...... SP Ditch 04 i 30023 ..........................................:...... 30700 30260 ..........................................:...... 30700 SP Ditch 02 ................................................ 40023 40023 ..........................................:...... 40730 50023 ..........................................:...... 50575 50575 ..........................................:...... SP Ditch 03 i aded• Knight• Rd. Ditch aded Knight Rd Ditch .................................................. aded Kniaht Rd Ditch End STA 10600 ...................... 10727 11191 ...................... 111.6 11400 ...................... 11400 11705 ...................... 11705 11730 ...................... 11730 11800 ...................... 11908 11908 ...................... .20241 20263 ...................... .20288 20443 ...................... 20950 20683 ...................... 20950 20997 21100 30700 30800 ...................... 30700 30760 40730 ....................... 40285 40835 ....................... 50575 50690 of culvert ..................... of culvert Road Side (R / L)..... L ........................... .......... _ R ........... L ........................... .......... _ R ........... L ........................... .......... _ R ........... L ........................... .......... _ R ........... L ........................... .......... _ R ........... L ........................... ........................... ............ R ........................... ............ ............ R ........................... .......... _ R ........... R ........................... ............ R ........... L ........................... ............ E............ L ........................... N/A ........................... ............ E............ L ........................... .......... _ R ........... R ........................... N/A ........................... ............ R ........... L ........................... ............ R ........... L ........................... .......... _ R ........... N/A Area Incremental Da :Total ............................................. acres acn 0.50 i 0.5 2.30 2.3 ............................................. 0.10 i 0.1 2.80 2.8 ............................................. 0.10 i 0.4 2.00 5.0 ............................................. 0.30 i 0.3 3.00 3.0 0.05 i 0.0 0.30 0.3 ............................................. 0.05 i 02 020 02 ............................................. 5.30 i 5.3 0.30i 0.3 ............................................. 1.30 i 1.3 0.30i 0.3 ............................................. 120 i 12 5.50i 5.5 ............................................. 0.10 i 0.1 020 02 ............................................. Evaluation Sum CA Tc 0.05 ................................................................... i 025 0.13 0.05 ...............................:.................................... 0.05 0.03 0.00 i 16.80 6.97 1.50 ...............................;.................................... 1.50 0.75 020 i 1.70 0.89 0.30 .................................................................... 0.30 0.15 0.10 i 0.40 020 020 .................................................................... 0.60 028 1.50 i 1.60 0.65 0.50 .................................................................... 0.50 025 020 i 1.80 0.75 1.40 .................................................................... 1.80 0.88 020 i 020 0.14 020 .................................................................... 2.00 0.98 020 i 2.40 ................... 120 0.10 ...............................;.................................... 0.10 0.04 0.00 ...............................:..................... i 320 121 ............... 0.00 i 4.80 1.97 1 Conveyance Specified Pipe 1 Velocity Conveyance Design 10-year € 10-year Conveyance Upstm Downstm € Slope Conveyance € Conveyance Roughness Bottom Dia. or Bottom: Normal € at Normal Flow Time € Time € Intensity € Discharge; Length € Invert € Invert € (Longitudinal) Side Slope Material Coefficient Width Width Depth € Depth Designer Comments (min) min 1 in/hr I CFS ft Elev I Elev 1 ft/ft X:1 n ft in ift fps 0.0 5.0 1 7.9 1 2.0 1 545 1 371101 365.00 1 0.011 i4.0 iGrass 1 0.05 i0 i0 i 0.5 1 2.0 BUA = 5850 (ROAD) + 0 (L 0.0 5.0 ................................................1............................I........................................................................................................................ 7.9 7.3 671 € 372.10 € 365.60 € 0.010 !.........................................1..... 4.0 Grass 0.03 0 0 0.8 € 2.7 BUA = 7100 ROAD + 17500 0.0 5.0 € 7.9 0.4 141 € 369.40 € 366.00 € 0.024 4.0 Grass 0.07 2 0 i 0.2 € 0.8 - + (ROAD) BUA = 1410 ROAD 0 L 0.0 ......................................................................................1.................................................................................................................................................................1..... 5.0 7.9 8.8 439 € 372.10 € 368.30 € 0.009 4.0 Grass ............ 0.03 .... .... 2 ........ ....... 0 .......... .......... 0.7 € 2.6 BUA = 4390 ROAD + 15750 0.0 5.0 € 7.9 1.4 165 € 370.00 € 368.00 € 0.012 4.0 Grass 0.05 0 0 i 0.5 € 1.2 - + (ROAD) BUA = 1650 ROAD 0 LO 0.0 5.0 ................................................1............................I........................................................................................................................ « 7.9 15.8 184 € 370.00 € 368.10 € 0.010 !.........................................1..................................I........ 4.0 Grass 0.03 .......................... 2 ........... ....... 0 ............................................................... 0.9 3.2 BUA = 1840 ROAD + 7000 L 0.0 5.0 1 7.9 0.9 305 1 373.80 1 370.00 1 0.012 4.0 Grass 0.07 0 0 i 0.5 1 1.0 +....... (ROAD) BUA = 3050 ROAD 0 L 0.0 5.0 ................................................1............................I........................................................................................................................ 7.9 9.5 305 € 373.80 € 370.00 € 0.012 !.........................................1..... 4.0 Grass 0.03 2 0 0.7 € 3.0 BUA = 3050 ROAD + 10500 0.0 5.0 € 7.9 0.2 25 € 373.80 € 371.00 € 0.112 4.0 Grass 0.07 0 0 i 0.2 € 1.4 - + (ROAD) BUA = 250 ROAD 0 L 0.0 .............................................................................................................1.................................................................................................................................................................1..................................I........ 5.0 7.9 0.7 25 € 373.80 € 372.00 € 0.072 4.0 Grass 0.07 ... 0 ........ ....... 0 ........... ......... 0.3 .. 1.6 ................. BUA = 250 ROAD + 0 L 0.0 5.0 1 7.9 1.4 70 1 375.00 1 371.00 1 0.057 4.0 Grass 0.05 0 0 i 0.4 1 2.3 BUA = 700 ROAD 0 LOT: (ROAD) 0.0 5.0 ................................................1............................I........................................................................................................................ 7.9 1.1 150 € 376.50 € 375.00 € 0.010 !.........................................1..... 4.0 Grass 0.07 0 0 0.6 € 0.9 BUA = 2500 ROAD + 2000 0.0 5.0 7.9 16.7 150 € 376.50 € 375.00 € 0.010 4.0 Grass 0.03 0 0 1.1 3.3 - + BUA - 2500 ROAD 7000 (ROAD) 0.0 € ..................................................................................1............................I.................................................................................................................................................................1..................................I.................................I............ 5.0 € 7.9 « 0.9 186 € 359.70 € 357.60 € 0.011 4.0 Grass 0.07 0 ....... 0 ..... .......... .......... 0.5 .....................,........................... € 0.9 .. BUA - 2500 ROAD + 0 L .......................................5................�...........5... 0.0 5.0 7.9 4.1 203 € 360.10 € 357.90 € 0.011 4.0 Grass 0.03 0 0 0.7 € 2.4 - + BUA - 2600 ROAD 7000 0.0 ................................................................................1............................I.................................................................................................................................................................1..... 5.0 7.9 1.7 25 € 360.10 € 358.80 € 0.052 4.0 Grass ............ 0.05 .... .... 0 ....... ....... 0 .......... .......... 0.4 € 2.3 ................. BUA - 2600 ROAD + 3500 0.0 5.0 7.9 3.8 130 € 361.30 € 358.80 € 0.019 4.0 Grass 0.03 2 0 0.4 € 2.8 - + BUA = 1300 ROAD 10500 ( ) 0.0 5.0 ................................................1............................I........................................................................................................................ 7.9 17.4 507 € 361.30 € 356.60 € 0.009 !.........................................1..... 4.0 Grass 0.03 0 0 1.2 € 3.2 BUA = 5070 ROAD + 38500 0.0 5.0 € 7.9 0.4 133 € 360.50 € 35920 € 0.010 4.0 Grass 0.07 0 0 i 0.4 € 0.7 - + (ROAD) BUA = 2500 ROAD 0 L 0.0 € ...............................................................................................................1.................................................................................................................................................................1..................................I.................................I............ 5.0 € 7.9 0.8 221 € 358.80 € 356.50 € 0.010 4.0 Grass 0.07 0 ....... 0 .......... .......... 0.5 € 0.8 ................. BUA = 2210 ROAD + 0 L 0.0 1 5.0 € 7.9 1 1.0 i 47 € 356.60 € 35320 € 0.072 i 4.0 Grass 1 i 0.07 i 0 i 0 i 0.4 € 1.8 . - + BUA - 470 ROAD 0 LOT: (ROAD) 0.0 1 5.0 ............................................................1.................................................................................................................................................................1..................................I.................................I............ 1 7.9 « 0.2 . 103 1 357.00 1 35320 1 0.037 4.0 Grass 0.07 0 ......... ....... 0 ........................................,........................... 0.2 1 0.9 BUA = 1030 ROAD + 0 L ...................�...............)...........�.. 0.0 € 5.0 ........................r.........................,............5 7.9 € € 55.0 i ...............................................,....................,.....3 100 1 35320 352.70 1 0.005 i 3.0 Grass € i 0.03 i 3 36 i i 1.8 1 3.6 BUA = 30270 (ROAD) + 8400( 0.0 ................................................................................1............................I.................................................................................................................................................................1..... 5.0 7.9 5.9 677 1 359.70 1 341.60 € 0.027 4.0 Grass ............ 0.03 .... .... 2 ....... ....... 0 .......... .......... 0.4 € 3.6 .. ........... BUA - 7000 ROAD + 7000 0.0 5.0 € 7.9 7.0 115 € 341.60 € 340.00 € 0.014 4.0 Grass 0.03 2 0 i 0.6 € 2.9 - + (ROAD) BUA = 2600 ROAD 1750 LC 0.0 € 5.0 € 7.9 1 « 1.2 ............................I........................................................................................................................!.........................................1..................................I.................................I............ . 440 € 350.40 € 341.60 € 0.020 4.0 Grass 0.05 0 ....... ........... ....... 0 ......................,........................... .......... .......... 0.5 € 1.5 BUA - 4400 ROAD + 0 L .......................................5................�...........5... 0.0 5.0 € 7.9 1.6 70 € 341.60 1 34020 € 0.020 4.0 Grass 0.05 0 0 i 0.5 € 1.6 - + BUA = 700 ROAD 0 LOT: ( ) 0.0 5.0 7.9 2.2 90 € 34020 € 336.00 € 0.047 4.0 Grass 0.05 0 0 0.5 € 2.4 BUA = #27 0.0 5.0 7.9 1 5.1 707 : 358.70 336.90 1 0.031 4.0 Grass 0.03 0 0 i 0.6 1 3.6 BUA = 7070 (ROAD) + 7000 (LC 0.0 .............................................................................................................1.................................................................................................................................................................1..... 5.0 7.9 2.0 262 € 358.80 € 350.70 € 0.031 4.0 Grass ............ 0.05 .... .... 0 ........ ....... 0 .......... .......... 0.5 € 2.0 .. BUA - 2620 ROAD + 1750 0.0 5.0 € 7.9 5.9 170 € 336.90 € 333.50 € 0.020 4.0 Grass 0.03 0 0 i 0.7 € 3.2 - + (ROAD) BUA - 3050 ROAD 0 LOT 0.0 € ..................................................................................1............................I.................................................................................................................................................................1..................................I.................................I............ 5.0 € 7.9 7.0 552 € 367.70 € 355.00 € 0.023 4.0 Grass 0.03 0 ....... 0 ........... ......... 0.7 € 3.6 .. BUA = 5520 ROAD + 10500 L ....................... 0.0 5.0 € 7.9 1.1 170 € 355.00 € 352.00 € 0.018 4.0 Grass 0.07 0 0 i 0.5 € 1.0 - + BUA = 4000 ROAD 0 L (ROAD) 0.0 € 5.0 ............................................................I.................................................................................................................................................................1..................................I.................................I............ € 7.9 « 7.7 . 130 € 355.00 € 352.00 € 0.023 4.0 Grass 0.03 0 ....... 0 ..... ........... ......... 0.7 .................,........................... .. .. € 3.7 .. BUA = 2250 ROAD + 0 LOT ......................................... ........................�...........�........ 0.0 € 5.0 ........................_.........................;...........9.................................................;................0 7.9 € € 9.5 i 180 1 352.00 1 351.00 1 0.006 i 4.0 Grass € i 0.03 i 0 0 i i 1 €2.3 BUA = #33 + #34 0.0 1 ...............................................................................................................1.................................................................................................................................................................1..................................I.................................I............ 5.0 1 7.9 « 0.3 . 70 1 ;..........................;.........................................;.........................................;..................................,.................................,.................................,.............................................................;.......................................................................................................................... 36720 1 365.60 1 0.023 4.0 Grass 0.07 0 ....... 0 ............0..........,........0 ........... ......... 0.3 1 0.9 .. ....................................................................0.(...............)...........(... BUA = 1 ROAD + 0 L 4.0 5.0 ......................_f.......................................................................................;....................;......... 1 7.9 9.6 70 1 365.00 364.00 1 0.014 4.0 Grass 0.03 0 0 i 0.9 1 3.3 BUA = 500 (ROAD) + 0 (LOTS) + #1 .... .... 5.0 5.0 7.9 15.6 70 € 357.60 € 35720 € 0.006 4.0 Grass 0.03 0 0 1.2 € 2.7 1 BUA = 5500 (ROAD) + 0 (LOTS) + #1 ocity Check for disharges to wetlands ..................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... low 24" culvert STA 11730 ...........................................................................................................................................................................................................................................................................................1......................_'_.........................'_..............................................................'_....................'_.................................... 19.4 0.020 Flat Apron Rock Outlet_ 0.07 144 0.7 2.0 low S ecial Ditch 01 P........................................................................................................................................................................................................................I.......................................I.....................1........................................................................... 8.3 ... .. ........................... ............ 0.064 ................... ...... ..... Flat Apron 1 .................. Rock Outlet 0.07 .... ... .......................... 144 ......... ........ 0.2 1 2.0 low Special Ditch 02 ..................................................................................................................................................................................................................................................................................................................................................................................................2................................................................................................................................................................................................................................................................................................................................................................. i 2.2 i € € € € € € € 0.047 i Flat Apron 1 Rock Outlet 0.07 i i 72 i0.2 1 1.5 low Roadside Ditch 30031-30190 RT ........................................................................................................................................................................................................................................I.......................................I.....................1........................................................................... 8.2 ... .. ........................... ............ 0.036 ................... ...... ...... Flat Apron € ............ _ Rock Outlet 0.07 .... ... .......................... 144 ......... ........ 0.3 € 1.9 low Roadside Ditch 4002340285 RT ...................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... i 2.0 i € € € € i € € € 0.031 i Flat Apron € Rock Outlet 0.07 i i 72 _ 0.2 € i 1.3 low Roadside Ditch 40730-40835 LT ........................................................................................................................................................................................................................................I.......................................I.....................1........................................................................... 5.9 ... .. ........................... ............ 0.020 ................... ...... ..... Flat Apron € ............ _ Rock Outlet 0.07 .... ... .......................... 72 ......... ........ 0.5 € 1.7 low Special Ditch 03 ....................................................................................................................................................................................................................................................................................................;................................. 9.5 ...................... _:..................... ...... ........................... _ ............ 0.006 _ ................... _ ...... .............. ..... Flat Apron 1 ...................................... _ Rock Outlet ........................ _ 0.07 .... ............... _ .......................... 72 _ .................. ...... 0.9 1 _ ........ _ 1.3 .. ....... le of Special Ditch 04 55.0 0.005 Level Discharge I Grass 0.03 600 0.5 € 2.0 1v4 E7-rHVA:> � Ffza.p-7 /V L L a!oslo.�-' 4fv.v-r/r-o`. In - 'N W tt.) .S $-x I ! 6 ��.�► G' 1L V C ST�-rle) V]a 7r `�o-s ® L x 3, " 1 f 5- F-T/ ['L)z V eYtT 1 I1 + ara - ~ v oa, J? CID p.A L. k L = K 3G = /e F (f tAss 6 e),,o, 1_.4p -Z-a w ! x 2 t t ifcA-*,. s A IC.i -e L r (f L Ida" cR` n r ��o = • 3 S LID L-:-. 't r �L�151Y. ` sue, E 8 tv, m r Vj 0 'y Z use t � E. ^ 4-' , `s ,� � i- T" P-IO06"T 7 Tif C,- 1 �� Vi, p 5.V rps NOAA Atlas 14, Volume 2, Version 3 FORT BRAGG WATER PLANT Station ID: 31-3168 Location name: Spring Lake, North Carolina, USA* Latitude: 35.1778*, Longitude:-79.0239° Elevation: .0 Elevation (station metadata): 160 ft** m` *source: ESRI Maps ** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES G.M. Bonnin, D. Martin, B. Lin, T. Parzybok, M.Yekta, and D. Riley NOAA, National Weather Service, Silver Spring, Maryland PF tabular I PF graphical I Maps & aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches/hour Duration Average recurrence interval (years) 1 �� 2 5 10 25 50 100 200 500 1000 5.22 6.16 7.16 7.91 8.78 9.40 9.97 10.5 11.1 11.6 5-min (4.69-5.84) 1 (5.53-6.90) 1 (6.44-8.03) 11 (7.10-8.83) 11 (7.85-9.80) 1 (8.40-10.5) 1 (8.86-11.1) 1 (9.29-11.7) 11 (9.74-12.3) (10.1-12.9) 4.16 4.92 5.74 6.32 7.00 7.48 7.93 8.32 8.80 9.13 10-min (3.74-4.67) 1 (4.43-5.51) 1 (5.17-6.43) 11 (5.68-7.07) 11 (6.26-7.81) 1 (6.68-8.33) 1 (7.04-8.81) 1 (7.36-9.25) 11 (7.70-9.77) 11 (7.95-10.1) 3.47 4.12 4.84 5.33 5.91 6.32 6.68 7.00 7.38 7.64 15-min (3.12-3.89) 1 (3.71-4.62) 1 (4.36-5.42) 11 (4.79-5.96) 11 (5.29-6.60) 1 (5.64-7.04) 1 (5.93-7.43) 1 (6.19-7.78) 11 (6.47-8.20) 11 (6.66-8.48) 2.38 2.85 3.44 3.86 4.38 4.76 5.12 5.45 5.87 6.19 30-min (214-2.67) 1 (2.56-3.19) 1 (3.09-3.85) 11 (3.47-4.32) 11 (3.92-4.89) 1 (4.25-5.30) 1 (4.54-5.69) 1 (4.82-6.05) 11 (5.15-6.52) 11 (5.39-6.87) 1.48 1.79 2.20 2.52 2.92 3.22 3.52 3.82 4.21 4.52 60-min (1.33-1.66) 1 (1.61-2.00) 1 (1.98-2.47) 11 (2.26-2.81) 11 (2.61-3.26) 1 (2.88-3.59) (3.13-3.92) (3.38-4.25) (3.69-4.68) (3.93-5.01) 0.868 1.05 1.32 1.52 1.78 1.99 2.20 2.41 2.68 2.90 2-hr (0.774-0.984) (0.940-1.19) 1 (1.17-1.49) 11 (1.35-1.71) 11 (1.58-2.01) 1 (1.75-2.24) (1.93-2.48) (2.10-2.71) (2.31-3.02) (2.48-3.26) 0.615 0.743 0.934 1.09 1.29 1.46 1.62 1.80 2.04 2.24 3-hr (0.549-0.697) (0.665-0.842) (0.835-1.06) (0.967-1.23) (1.14-1.45) 1 (1.28-1.64) 1 (1.42-1.83) 1 (1.56-2.03) 11 (1.75-2.30) 11 (1.89-2.51) 0.367 0.445 0.559 0.651 0.776 0.878 0.984 1.10 1.25 1.37 6-hr (0.333-0.409) (0.403-0.494) (0.506-0.620) (0.587-0.721) (0.695-0.859) (0.781-0.971) (0.867-1.09) (0.956-1.20) (1.08-1.37) 11 (1.17-1.51) 0.216 0.261 0.330 0.386 0.464 0.528 0.595 0.666 0.768 0.850 12-hr (0.195-0.239) (0.237-0.289) (0.299-0.366) (0.348-0.427) (0.414-0.511) (0.468-0.581) (0.523-0.653) (0.579-0.730) (0.658-0.841) (0.719-0.929) 0.128 0.154 0.195 0.227 0.271 0.306 0.342 0.379 0.430 0.471 24-hr (0.119-0.138) (0.144-0.167) (0.181-0.210) (0.210-0.244) (0.250-0.292) (0.281-0.329) (0.314-0.368) (0.347-0.408) (0.392-0.463) (0.427-0.507) 0.074 0.089 0.112 0.130 0.154 0.174 0.194 0.215 0.243 0.265 2{iay (0.069-0.080) (0.083-0.096) (0.105-0.120) (0.121-0.139) (0.143-0.166) (0.161-0.187) (0.179-0.208) (0.197-0.231) (0.222-0.261) (0.241-0.286) 0.053 0.063 0.079 0.091 0.108 0.121 0.135 0.149 0.169 0.184 3{iay (0.049-0.056) (0.059-0.068) (0.073-0.084) (0.085-0.097) (0.100-0.115) (0.112-0.130) (0.125-0.144) (0.137-0.160) (0.155-0.181) (0.168-0.197) 0.042 0.050 0.062 0.071 0.085 0.095 0.106 0.117 0.132 0.144 4{iay (0.039-0.044) (0.047-0.053) (0.058-0.066) (0.067-0.076) (0.079-0.090) (0.088-0.101) (0.098-0.112) (0.107-0.124) (0.121-0.140) (0.131-0.153) 0.028 0.033 0.040 0.046 0.054 0.061 0.067 0.074 0.083 0.090 7{iay (0.026-0.029) (0.031-0.035) (0.038-0.043) (0.043-0.049) (0.050-0.058) (0.056-0.065) (0.062-0.072) (0.068-0.079) (0.076-0.089) (0.083-0.097) 0.022 0.026 0.032 0.036 0.042 0.046 0.051 0.055 0.061 0.066 10-da (0.021-0.023) (0.025-0.028) (0.030-0.034) (0.034-0.038) (0.039-0.044) (0.043-0.049) (0.047-0.054) (0.051-0.059) (0.057-0.065) (0.061-0.071) 0.015 0.018 0.021 0.023 0.027 0.029 0.032 0.035 0.039 0.042 20-da (0.014-0.016) (0.016-0.019) (0.019-0.022) (0.022-0.025) (0.025-0.029) (0.027-0.031) (0.030-0.034) (0.032-0.037) (0.036-0.041) (0.038-0.045) 0.012 0.014 0.017 0.019 0.021 0.023 0.025 0.027 0.029 0.031 30-da (0.012-0.013) (0.014-0.015) (0.016-0.018) (0.018-0.020) (0.020-0.023) (0.022-0.025) (0.023-0.027) (0.025-0.029) (0.027-0.031) (0.029-0.033) 0.010 0.012 0.014 0.015 0.017 0.018 0.020 0.021 0.023 0.024 45-da (0.010-0.011) (0.011-0.013) (0.013-0.015) (0.014-0.016) (0.016-0.018) (0.017-0.020) (0.019-0.021) (0.020-0.022) (0.021-0.024) (0.022-0.026) 0.009 0.011 0.012 0.014 0.015 0.016 0.017 0.018 0.020 0.021 60-da (0.009-0.010) (0.010-0.012) (0.012-0.013) (0.013-0.014) (0.014-0.016) (0.015-0.017) (0.016-0.018) (0.017-0.019) (0.018-0.021) (0.019-0.022) Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (for a given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information.