Loading...
HomeMy WebLinkAboutCT 05-19; CARLSBAD MEDICAL VILLAGE; DRAINAGE REPORT; 2006-03-02STORM DRAIN REPORT FOR CARLSBAD MEDICAL VILLAGE Carlsbad, California March 2,2006 CT 05-19 PUD 05-15 SDP 05-13 RECEIVED JUL 2 0 200B ENGINEERING DEPARTMENT Prepared By: PARTNERS Planning and Engineering 15938 Bernardo Center Drive SanDiego, CA92127 (858) 376-3444 Brent C. Moore Registration Expires RCE 59121 6-30-2007 "111 c ..J TABLE OF CONTENTS SITE AND PROJECT DESCRIPTION page 1 METHODOLOGY page 1 EXISTING CONDITIONS page 1 DEVELOPED CONDITIONS page 1 EXISTING RUNOFF ANALYSIS page 1 DEVELOPED RUNOFF ANALYSIS page 3 CHANNEL DESIGN AND ANALYSIS page 3 DETENTION BASIN DESIGN AND ANALYSIS page 3 RESULTS AND CONCLUSIONS page 3 LIST OF FIGURES FIGURE I: VICINITY MAP page 2 FIGURE 2A: EXISTING HYDROLOGY MAP attached FIGURE 2B: PROPOSED HYDROLOGY MAP attached Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5 Appendix 6 LIST OF APPENDICES Runoff Coefficients for Urban Areas Overland Time of Flow Nomograph 100-Year Rainfall Isopluvials Intensity-Duration Design Chart Handbook of Hydraulics Table 7-11 Gutter and Roadway Discharge Velocity Chart SITE AND PROJECT DESCRIPTION: This storm drain report has been prepared as part of the Development Review submittal requirements for the grading and improvements association with the proposed Carlsbad Medical Village. The proposed development includes five (5) office buildings with associated parking, landscaping and hardscape. The project site is currently undeveloped. The project site is located south ofCarlsbad Village Drive and east of Interstate 5. Access to the site occurs off Carlsbad Village Drive. See Figure No. 1 for Vicinity Map. See Figures 2 A and 2B attached at the end ofthis report for the existing and proposed drainage limits. METHODOLOGY This drainage report has been prepared in accordance with current City ofCarlsbad regulations and procedures. All storm water calculations were based on the 100-year storm. The Rational Method was used to compute the anticipated runoff The following references have been used in preparation of this report: (1) San Diego Countv Hydrology Manual, June, 2003. (2) Handbook of Hydraulics, E.F. Brater & H.W. King, 6*'' Ed., 1976. EXISTING CONDITIONS; The project site is currently undeveloped. The runoff from the undeveloped site sheet flows east to west towards the westerly property line and onto the adjacent properties to the west. The runoff from the site ultimately drains to the Pacific Ocean. DEVELOPED CONDITIONS; The proposed development for the Carlsbad Medical Village includes five (5) office buildings with associated parking, landscaping and hardscape. The majority ofthe surface runoff generated on-site as well as a majority of the off-site run-on will be intercepted by either the proposed curb inlet or type 'F' catch basin located near the driveway entrance to the project site. The runoff is then conveyed to the proposed below ground detention facility. The on-site storm drain system will be designed to limit the amount of runoff discharged onto Carlsbad Village Road to 4.0 cfs at any one time. The remainder of the runoff is designed to drain through openings in the proposed site screen wall and onto the adjacent properties to the west. EXISTING RUNOFF ANALYSIS; The runoff from the undeveloped site sheet flows east to west towards the westerly property line and onto the adjacent properties to the west. The runoff from the site ultimately drains to the Pacific Ocean. A runoff coefficient of 0.57 would be appropriate for the existing basin. See the attached calculations. c TO PAC IFIC OCEAN VICINITY MAP NOT TO SCALE DEVELOPED RUNOFF ANALYSIS: All ofthe proposed pipes, inlets and catch basins were designed to intercept and convey the 100-year storm. The runoff coefficients for the site were based on soil group D and the ultimate improvements for the proposed site. CHANNEL DESIGN AND ANALYSIS The proposed trapezoidal grass lined channel within this project was sized using King's Handbook (Ref. 3), Table 7-11. For trapezoidal channels: K' = Qn/[b^(8/3)s'^(l/2)] where K' = Discharge Factor Q = Runoff Discharge (cfs) n = Manning's Coefficient b = Channel Bottom Width (ft) s = Channel Slope (ft/ft) Natural, vegetated lined channels are capable of withstanding erosion for velocities up to 5 fps. DETENTION BASIN DESIGN AND ANALYSIS: The proposed, on-site detention facility was sized utilizing the single-hydrograph method. See the attached calculations for the design procedures utilized with the single-hydrograph method. The on-site detention facility was designed to limit the amount of runoff directed towards Carlsbad Village Road to 4.0 cfs at any one time. RESULTS AND CONCLUSIONS The developed site discharges a total of 1.0 cfs to the adjacent properties to the west and 4.0 cfs to Carlsbad Village Drive. The existing site discharges 9.0 cfs to the properties to the west. The project site design includes below ground culverts to be utilized for storm water detention to reduce post-development runoff to below pre-existing levels. A Storm Water Management Plan will be prepared separately to discuss the impacts the proposed development will have on the storm water quality. $A^i ^ '» y.^ y H-yo (jO \—^/ / ^^s 6^05, oo DM-- f^' Tc^ hH/'l-^)^0 : /.sCf-l- 0,^'/) \fzc>3^^ ^,1/ Ml//^ri^ ^ - "Z'^ '/O B^si^ AZ : A' ^.li'i 1^- CCA-' (<Pr7H)f04lAO^ (n.^lXo^i^^^ O.'fif Tc' ^.*f/^/^+ O'lf^'^' ^>S^M/AP Z/.C/- r,93^^yM^ ^ —^ (^,2A<^-U/^^^ f'y^^'^fOAl CiiAfiJ/^^l^ \ /. ^r^,^'/o y A^yb^ -2:0)0' Zy-f(^)) {^'f'f)''' ^,7Z5f Tr^ f0 5^1,-1 pps - /.rM/A^H)ryj B/^/fi/ A3: A-0,15 firc- CtA= cyf* C^>ez^CoGrAc)' /,o6' Tc,' 1^'^-^ l*>f^^ MJ/i^ Cai^k i><y Hc^d^^i^ l/Gi!^ /61 - (y±^fy)(£^^ ^ ^ ^ F^'vv k^i^-6-^ ry<(i£-€ -i-ti, ^/i'^ o.^-z ^ -^^•^•9'=^ C - O. ^7 tfoc - 7.y 'Trip) ' ''^^ f>«P7 '^^/T^/ • ~ £>nto jQioo^ //5 V Tc ' ^^^^^^ '^"^ I I'h Ree/n "C^TTBiz, / 0^r7^i^A^pisctfTt/^^ U'^t^^tr^ CiA^fiii^T ^ I/'- 2.} ^PS Xc--^>^^^^-^ I^H^^'^' 7^H/<^i^ 7^^^( Z.7)C7.H)'^'^'^^^ 57 52-"^/^^ i —^ — ^—^ . / • {c^PUi^^cit S^sy-'^'S Ai-¥ /A^^4 3hSuJ f3f: A- A-^'£^t AC- 0,^o /V.^rj-f- /^.ffy^9y " ^^^C^ Qioo-C/A ' (o-6/o:>i(?io7 ^'^/If^ )(^.o C^A?I>^ yi<du^ t/>'//rf^e C^iLA^s-U/^/c£> TlUrpr^to^ Ct^A^Aff^i^ \ /IJ ; h^b ^''^ JzyiTfvosi^ '''' \):^(>ilA> ^'1^/0,7-7 sf O'H /^AS"^ ; » ^, A^ C- 0>9olOGo)t 0.97C£^>9o)- €>,So CSA^ (0,ot)(id-6o) C&rO^ )(o^0)- 0,05- J}oc^- 7,'/*-/{z,7)( 5-^0^-^'^^^:^ -7.1}'^1^,1.^ i 1 j 1 ! ! 1 1 i NOTE: i ; Time and Discharge values were obtained using County of San Diego Rational Method Hydrograp h software prepared by Rick Engineering Company copyright 2001. 1 1 ! Detention Basin #1 i TIME DISCHARGE I 0 0 1 175 0.8 350 0.4 7 0.4 : 182 0.9 357 0.4 14 0.4 i 189 1 364 0 21 0.4 ; 196 1 28 0.4 203 1.2 35 0.4 210 1.3 42 0.4 ! 217 1.6 49 0.4 224 1.8 ! 56 0.4 231 2.6 1 63 0.5 238 4.9 i 70 0.5 245 12.2 ! 77 0.5 252 2.1 84 0.5 259 1.4 91 0.5 266 1.1 98 0.5 273 0.9 105 0.5 280 0.8 112 0.5 287 0.7 119 0.6 294 0.7 ! 126 0.6 301 0.6 133 0.6 308 0.6 : 140 0.6 : 315 0.5 147 0.7 322 0.5 154 0.7 329 0.5 161 0.7 336 0.4 : 168 0.8 343 0.4 HYDROGRAPH 14 12 10 (O 8 u. o g O td 6 " ^JM^e-s i/i^i'f^me (Ai2e/ir u/vo^if /:>»^£''*f^^ O'I^M ) —^ 3^so cr ' PZouiD^ ^opir ^S"Pvc^ pipt Toit s-ne^ pi^.rtpps£s __ W/^/fTg^c " l78rl7Cp o)c 0 UiiiiMii'iitrnriiiiiiiiiiiiiiii ^ >^ <^ <^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ 4> ^ ^ ^ ^ # ^ ^fe^ TIME (MIN) 0 I /$ilo^ Ve'rv^T7P/^ c^i^cS CL rUw A^ CfiS 7- Hco-^ APPENDIX San Dicgo County Hydrology Manual Date: June 2003 Section: Page: 3 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil Type NRCS Elements County Elements % IMPER. A B C D Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 ' 0.30 0.35 Low Density Residential (LDR) Residential, 1.0 DU/A or less 10 0.27 0.32 0.36 0.41 Low Density Residential (LDR) Residential. 2.0 DU/A or less 20 0.34 0.38 0.42 0.46 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 0.45 0.49 Medium Density Residential (MDR) Residential, 4.3 DU/A or less 30 0.41 0.45 0.48 0.52 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 0.51 0.54 0.57 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 0.57 0.60 Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 0.60 0.63 High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 0.69 0.71 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 0.78 0.79 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 0.78 0.79 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 0.81 0.82 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (Limited L) Limited Industrial 90 0.83 0.84 0.84 0.85 Commercial/Industrial (General I.) General Industriai 95 0.87 0.87 0.87 0.87 > I *The values associated with 0% impervious may be used for direct calculation of the runoff coefftcient as described in Section 3.1.2 (representing the pervious runoff coefficient, Cp, for the soil type), or for areas that will remain undisturbed in perpetuity. Justification must be given that the area will remain natural forever (e.g., the arca is located in Cleveland National Forest). DU/.A = dwelling units per acre NRCS = National Resources Conservation Service 3-6 EXAMPLE: Given: Watercourse Distance (0) = 70 Feet Slope (s) = 1.3% Runoff Coefficieni (C) = 0.41 Overland Flew Time (T) = 9.5 Minutes SOURCE: /Virport Drainage. Federal Aviation/Vdministration, 1965 1.8(1.1-C)'/D" FIGURE Rational Formula - Overland Time of Fiow Nomograpli 33'3ff 32'3ff County of San Diego Hydrology Manual Rainfall Isopluvials 100 Year Rainfall Event - 6 Hours Isopluvial (inches) ^Gis SanGIS Of tCACHMrWirtAl^fl s 3 0 3 Miles 3 t. Hours Directions for AppHcation: {I) From predpitatior rnaps detemine 6 hr and 24 hr amcunts for Ifie se ected frequency. These maps are included in ttie Counly Hydrology Manual (10.50. and ICO yr maps included in Ihe [)esign arxi Procedtjre Manual). (2) AdjusI 6 hr precipitaticn (if necessary) so ttiat it is vvithin Ihe range of 45% Ic 65% of t^s 2<: hr precipitation (not applicaple to Desert). (3) Plot S hr precipitation on me rigM side cf the chart. (4) Draw a line ttvough tie point parallel to the picttec lines. (5) This line is the intensiby-dtration curve fcr the locaticn being analyzed. AppHcation Fonn: (a) Selected frequency lOO year (b) Pg = tn in., p,^ = .ft = yp^^ (c) Adjusted Pg*^' = in. (d) 1^ = mn. (e) I = in /hr Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. PS 1 1.5 a 2.5 3 3.5 4 4.5 5 5.5 6 [)ura;ion 1 1 1 1 1 1 1 1 1 1 5 263 395 = 27 €59 7 sO 922 IOS4 y Vz 1317 •i 49 1581 7 Z12 3.18 4.24 S.33 6.26 7.42 8.48 9.5* lo.eo •1 f6 12 72 10 1.66 2.S3 3.37 4.21 5.05 S.90 6.74 T.59 8.42 9.27 ID II 15 1.3D 1 95 259 32« 3 69 4 54 519 5 Si 649 7 13 7 7a 20 tos 162 2 ts 2 69 3 23 3 77' 431 485 5 39 5:3 646 2S 093 140 187 233 2 60 3 27 373 4 2) 457 513 sac 30 083 1.24 166 2.07 2 49 290' 3.32 173 4 15 45€ 498 069 103 1 38 1 72 2.0/2 41' 276 313 345 3 7S 4 13 50 063 0 90 1.19 1.49 1.79 2 09 239 269 2.96 3<e 358 SO 0.53 080 106 133 1.69 186 212 23J 265 2:2 318 90 0.41 OS-:8Z 1.02 1.23 1.43 1.63 1.8' 2.» 226 2 45 120 034 OS" C68 cas IM 1-9 136 153 1.70 • S7 2C4 ISO 029 044 :s9 C73 0B8 103 1 ^8 132 1 47 •~ E2 1 76 ISO 0.26 •039' •52 C65 073 091' 104 1 IS 1 31 1 44 1 z> 240 022 033 '43 C54 065 076' 0 87 • 09«' 108 VIS 1 3C 300 0.<9 028 :38 C47 0 56 066 075 085 0.94 1.03 1 13 3S0 0.'7 OiS •33 C.42 0.50 o.se 067 0.75 OB4 0.92 ' CC Intensity-Duration Design Chart - Templats 7-42 H.\XDBOOK OF HYDRAULICS K Table 7-10. Values of K in Formula Q = — D'^sM for n Trapezoidal Channels (Concluded) D =1 depth of water b = bottom width of channel Side slopes of channel, ratio of horizontal to vertical u I Ver- tical K-1 H-l K-1 1-1 lM-1 2-1 2M-1 3-1 4-1 1.81 1.82 1.83 1.84 1.85 .296 .293 .291 .289 .286 .543 .540 .537 .534 .531 .817 .813 .810 .807 .804 1.10 1.09 1.09 1.09 1.08 1.37 1.37 1.37 1.36 1.36 1.90 1.90 1.90 1.89 1.89 2 41 2.41 2.41 2.40 2.40 2.91 2.91 2.90 2.90 2.90 3.40 3.39 3.39 3.39 3.38 4.36 4.36 4.35 4.35 4.34 1.86 1.87 1.88 1.89 1.90 .284 .282 .279 .277 .275 .528 .525 .522 .520 .517 .801 .797 .794 .791 .788 1.08 1.08 1.07 1.07 1.07 1.36 1.35 1.35 1.35 1.34 1.89 1.88 1.88 1.88 1.87 2.40 2.39 2.39 2.39 2.38 2.89 2.89 2.88 2.88 2.88 3.38 3.38 3.37 3.37 3.37 4.34 4.34 4.33 4.33 4.33 1.91 1.92 1.93 1.94 1.95 .273 .270 .268 .266 .264 .514 .512 .509 .506 .504 .785 .782 .779 .776 .774 1.06 1.06 1.06 1.05 1.05 1.34 1.34 1.33 1.33 1.33 1.87 1.87 1.86 1.86 1.86 2.38 2.38 2.37 2.37 2.37 2.87 2.87 2.87 2.86 2.86 3.36 3.36 3.36 3.35 3.35 4.32 4.32 4.32 4.31 4.31 1.96 1.97 1.98 1.99 2.00 .262 .260 .258 .256 .254 .501 .499 .496 .494 .491 .771 .768 .765 .762 .760 1.05 1.04 1.04 1.04 1.04 1.32 1.32 1.32 1.31 1.31 1.85 1.85 1.85 1.84 1.84 2.36 2.36 2,36 2.35 2.35 2.86 2.85 2.85 2.85 2.84 3.35 3.34 3.34 3.34 3.33 4.31 4.30 4.30 4.30 4.29 2.01 2.02 2.03 2.04 2.05 .252 .250 .248 .247 .245 .489 .487 .484 .482 .480 .757 .754 .752 .749 .746 1.03 1.03 1.03 1.02 1.02 1.31 1.30 1.30 1.30 1.30 1.84 1.83 1.83 1.83 1.82 2.35 2.34 2.34 2.34 2.33 2.84 2.84 2.84 2.83 2.83 3.33 3.33 3.32 3.32 3.32 4.29 4.29 4.28 4.28 4.28 2.06 2.07 2.08 2.09 2.10 .243 .241 .239 .237 .236 .477 .475 .473 .471 .469 .744 .741 .739 .736 .734 1.02 1.02 1.01 1.01 1.01 1.29 1.29 1.29 1.28 1.28 1.82 1.82 1.82 1.81 1.81 2.33 2.33 2.33 2.32 2.32 2.83 2.82 2.82 2.82 2.81 3.31 3.31 3.31 3.31 3.30 4.28 4.27 4 27 4.27 4.26 2.11 2.12 2.13 2.14 2.15 .234 .232 .231 .229 .227 .466 .464 .462 .460 .458 .732 .729 .727 .724 .722 1.006 1.004 1.001 .999 .996 1.28 1.28 1.27 1.27 1.27 1.81 1.81 1.80 1.80 1.80 2.32 2.31 2.31 2.31 2.31 2.81 2.81 2.81 2.80 2.80 3.30 3.30 3.29 3.29 3.29 4.26 4.26 4.26 4.25 4.25 2.16 2.17 2.18 2.19 2.20 .226 .224 .223 .221 .219 .456 .454 .452 .450 .448 .720 .718 .715 .713 .711 .994 .991 .989 .987 .984 1.27 1.26 1.26 1.26 1.26 1.79 1.79 1.79 1.79 1.78 2.30 2.30 2.30 2.29 2.29 2.80 2.80 2.79 2.79 2.79 3.29 3.28 3.28 3.28 3.28 4.25 4.24 4.24 4.24 4.24 2.21 2.22 2.23 2.24 2.2; .218 .216 .215 .213 .212 .446 .444 .442 .440 .439 .709 .706 .704 .702 .700 .982 .980 .977 .975 .973 1.25 1.25 1.25 1.25 1.24 1.78 1.78 1.78 1.77 1.77 2.29 2.29 2.28 2.28 2.28 2.78 2.78 2.78 2.78 2.77 3.27 3.27 3.27 3.26 3.26 4.23 4.23 4.23 4.23 4.22 eo .000 .091 .274 .500 .743 1.24 1.74 2.23 2.71 3.67 STEADY UNIFORM FLOW IN OPEN CHANNELS 7-43 K' Table 7-11. Values of K' in Formula Q = - b^i for Trapezoidal Channels D = depth of water 6 = bottom width of channel Side slopes of channel, ratio of horizontal to vertical Ver- tical 01 02 .03 04 05 .06 .07 .08 09 .10 .11 .12 .13 .14 .15 .16 .17 .18 .19 .20 .21 .22 .23 .24 .25 .00068 .00213 .00414 ,00660 .00946 .0127 .0162 .0200 0241 ,0284 0329 ,0376 0425 047ef ,0528 0582 ,0638 .0695 .0753 .0812 .0873 .0934 .0997 .1061 1125 H-l 00068 .00069 ,00215 .00216 .26 .27 .28 .29 .30 .31 .32 .33 .34 .35 119 126 132 .139 .146 .153 .160 .167 .174 .181 .38 .39 .40 .41 .42 .43 .44 .45 .36 .189 .37 .196 203 .211 .218 .226 .233 .241 .248 .256 00419 ,00670 ,00964 0130 0166 ,0206 ,0249 .0294 .0343 .0393 .0446 0502 0559 0619 0680 0744 0809 0876 ,0945 .1015 .1087 .1161 .1236 .131 .139 .147 .155 .163 172 180 189 ,198 ,207 .216 .225 .234 .244 .253 .263 .273 .283 .293 .303 K-1 1-1 00423 ,00679 .00979 .0132 .0170 .0211 .0256 .0304 .0354 .0408 0464 0524 0585 .0650 .0716 .0786 .0857 .0931 .101 109 117 125 133 142 151 160 170 179 189 199 ,209 219 230 .241 .252 263 .274 .286 .297 .309 .321 .334 .346 00069 00217 ,00426 .00685 .00991 .0134 .0173 .0215 .0262 .0311 .0364 ,0420 .0480 .0542 ,0608 0676 ,0748 .0822 .0899 .0979 .106 .115 .124 133 142 152 102 ,172 .:S2 .193 .204 .215 .227 .238 .251 .263 275 .288 .301 .315 .328 .342 .357 .371 .386 00069 00218 00428 lH-1 .00069 00220 ,00433 ,00691 .00700 O1002 .01019 .0136 .0175 .0219 .0267 .0318 .0373 .0431 .0493 .0559 .0627 0700 ,0775 0854 0936 ,1021 .111 120 .130 .140 150 160 171 182 194 305 ,218 ,230 .243 .256 .269 .283 .297 .312 .326 .341 .357 .373 .389 .405 .422 2H-1 .0138 .0180 .0225 .0275 .0329 .0387 .0450 .0516 0587 ,0662 0740 ,0823 ,0910 1001 1096 120 130 141 152 163 175 188 201 214 ,228 242 ,256 271 ,287 303 .319 ,336 ,353 .371 .389 .408 .427 .447 .467 .488 00069 ,00221 ,00436 ,00708 .01033 0141 ,0183 .0231 ,0282 0339 .0400 .0466 .0537 .0612 .0692 .0777 086B 0960 ,1059 ,1163 .127 .139 .150 .163 .176 189 203 ,217 .232 .248 .264 .281 .298 .316 .334 .353 .372 .392 .413 .434 .456 .478 .501 .525 .549 3-1 ,00069 .00070 .00222 .00223 00439 .00716 ,01047 ,0143 .0187 .0236 .0289 .0348 4-1 .0413 0482 0556 0636 ,0721 0811 0907 1008 1115 1227 135 147 160 173 188 202 218 234 250 267 .285 304 ,323 .343 .363 .385 406 ,429 .452 .476 .501 .526 .5.53 .580 .607 .00443 .00723 .01060 0145 0190 ,0240 .0296 .0358 0424 ,0497 ,0575 ,0659 .0749 .0845 .0947 .1055 .1169 .1290 142 155 169 ,184 ,199 ,215 .232 .249 .268 .287 .306 .327 .348 .370 .392 ,416 .440 .465 .491 518 .546 .574 .603 .633 .604 .00070 .00225 .00449 .00736 .01086 .0150 .0197 0250 0310 ,0376 .0448 .0527 .0613 .0706 ,0805 .0912 .1026 .1148 .1277 .1414 .156 171 187 204 222 .241 ,260 .281 .302 .324 .347 .371 .396 .423 .450 478 507 .537 .568 .600 .633 .668 .703 .740 .777 • J ^ w 4^i-^ -^l V A- r t V -1.5'- 5 6 7 8 9 10 Discharge (C.F.S.) EXAMPLE: Given: Qs 10 S°2.5% Chart gives: Depth = 0.4, Velocity = 4.4 f.p.s. SOURCE; San Diego County Department of Special District Services Design Manual 30 40 50 FIGURE Gutter and Roadway Discharge - Velocity Chart