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Home My WebLink AboutPD 2023-0004; HILLSIDE PATIO HOMES SLOPE REPAIR; DRAINAGE REPORT; 2024-06-15Office: 858.451.0713 Email: dianed3@cox.net, wjdeberry@cox.net Cell: 858.472.2783 www.deberryeng.com '(%(55<(1*,1((5,1*$662&,$7(6,1& 2OG:LQHU\&RXUW3RZD\&DOLIRUQLD DRAINAGE REPORT HILLSIDE PATIO HOMES 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Carlsbad, California Lot 489 US 55 & 56 Carlsbad Tract 72-20 Unit 3 Lot 492 US 130 & 131 Carlsbad Tract 72-20 Unit 3 in the City of Carlsbad County of San Diego APN: 223-200-16-55, 223-200-16-56, 223-200-32-26, 223-200-32-27 Project ID: PD 2023 – 0004 PeUPLt ID: GR 2023- 0005 (DWG 541-5A) December 22, 2022 Updated 7-1-2023 Updated 11-15-2023 PROJECT APPLICANT: Price, Moore, Curry Walker PROJECT CONTACT: DeBerry Engineering Associates, Inc. William DeBerry (858) 451-0713 DeBerryEng@gmail.com Updated1-25-2024 Updated 5-1-2024 8SGDWHG '(%(55<(1*,1((5,1*$662&,$7(6,1& Office: 858.451.0713 Email: dianed3@cox.net, DeBerryEng@gmail.com Cell: 858.472.2783 www.deberryeng.com 2OG:LQHU\&RXUW3RZD\&DOLIRUQLD -XQH 2024 SUBJECT: Drainage Report PROJECT: 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Carlsbad, California As a part of this slope repair project, a representative of DeBerry Engineering Associates, Inc. has conducted an investigation of slope failure of the above project over the period of time from approximately April 2020 through September 2021. As a part of that investigation, a drainage study to evaluate the anticipated drainage flow on the slope repair was conducted. The drainage report is prepared in accordance with the San Diego County Hydrology Manual, June 2003 and City of Carlsbad Engineering Standards 2022. The following report is understood to be an expression of professional opinion by this engineer, which is based on his knowledge, information and belief of the conditions noted at the time of the investigation. As such, it consists of neither a guarantee nor a warranty, expressed or implied as to the condition of the property or possible defects which may not have been apparent at the time of the investigation. This report is provided solely for the exclusive use of the above noted client. If either party becomes involved in litigation arising as a result of the contents of this report, both parties agree to mediation through the Better Business Bureau. We appreciate this opportunity to be of Professional Service to you in this matter. If you have any questions regarding this report please contact us. Respectfully Submitted, DeBerry Engineering Associates William J. DeBerry, R.C.E. #34545 :LOOLDP-'H%HUU\NO. 34545EXPIRES 09/30/25 OFESSIONA E M J DEBE R RY CIVI L FCALI F O E P R WILLI A EO William J DeBerry '(%(55<(1*,1((5,1*$662&,$7(6,1& 17708 Old Winery Court, Poway, California 92064 Office: 858.451.0713 Email: dianed3@cox.net, wjdeberry@cox.net Cell: 858.472.2783 www.deberryeng.com TABLE OF CONTENTS PURPOSE AND SCOPE: …………………………………………………..…………..… 1 PROJECT DESCRIPTION: …………………………………………………………….… 1 DESIGN METHODOLOGY: ……………………………………………………………… 2 DECLARATION OF RESPONSIBLE CHARGE: ………………………………………. 2 DRAINAGE CALCULATION: ……………………………………………………………...3-5 VICINITY MAP: ……………………………………………………………………………. 6 DRAINAGE AREA MAP: ……………………………………………………………….….7 APPENDIX Office: 858.451.0713 Email: dianed3@cox.net, DeBerryEng@gmail.com Cell: 858.472.2783 www.deberryeng.com 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Page 1 PURPOSE AND SCOPE: The properties involved are more particularly referred to as Lot 489 US 55 & 56 Carlsbad Tract 72-20 Unit 3 and Lot 492 US 130 & 131 Carlsbad Tract 72-20 Unit 3, in the City of Carlsbad, County of San Diego. APNs 252-200-16-55, 223-200-16-56, 223-200-32-26, 223- 200-32-27. It was indicated that there had been a slope failure on the slope between the Price and Moore properties at the base of the slope and the Curry and Walker properties at the top of the slope on April 10, 2020. The primary purpose of this limited Hydrology Study Report is to identify drainage at the repaired slope areas at the rear of the properties to assess the run- off potential at the rear of the property. This project does not increase the run-off from the site. PROJECT DESCRIPTION: The subject slope consists of graded topography from a subdivision constructed approximately1980. Prior to development the natural topography consisted of a slope with a down to a generally flat plane area at La Costa Ave. The slope has a gradient of approximately 2:1 (H:V). Grading consisted of cutting house pads at the top of the slope on Dorado Pl and the base of the slope at Vivienda Cir. There was a concrete drainage swale near the upper portion of the slope which was damaged in the slide. The scope of the project is to re-construct the slope between the Price -Moor and the Curry Walker properties with a reinforced concrete retaining wall with concrete pier supports at the toe of the slope and re construction of the slope and damaged concrete drainage swale. CLEAN WATER ACT: This project is not required to obtain approval from the Regional Water quality Control Board under the Federal Clean Water Act. Section 401 of the CWA states: Any applicant for a Federal license or permit to conduct any activity including, but not limited to, the construction or operation of facilities, which may result in any discharge into the navigable waters, shall provide the licensing or permitting agency a certification from the State in which the discharge originates. This minor grading for a slope repair does not include the construction of operation of facilities which may result in any discharge into the navigable waters. Section 404 of the Clean Water Act (CWA) establishes a program to regulate the discharge of dredged or fill material into waters of the United States, including wetlands. Activities in waters of the United States regulated under this program include fill for development, water resource projects (such as dams and levees), infrastructure development (such as highways and airports) and mining projects. This minor grading for a slope repair does not include discharge of dredged or fill material into waters of the United States, including wetlands. DESIGN METHODOLOGY: This study was conducted utilizing the Rational Method, (RM) formula for the calculation of the maximum run-off rate from a given rainfall for intersecting sub basins. It has particular application in urban storm drainage, where it is used to estimate peak run-off rates from small urban and rural watersheds for the design of storm drains and small drainage structures. 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Page 2 Office: 858.451.0713 Email: dianed3@cox.net, DeBerryEng@gmail.com Cell: 858.472.2783 www.deberryeng.com Methodology and Data for this report is obtained from the San Diego County Hydrology Manual, June 2003 and City of Carlsbad Engineering Standards 2022. This study is conducted to determine the peak run-off from the repaired site area based upon the 100 year rainfall event, The 100 year rainfall peak run-off determination is used for the permanent drainage facilities on the site. The flow calculations are computed from each of two drainage areas. Area A at the top of the slope behind the Curry-Walker properties to the concrete drainage swale. Area B from the concrete drainage swale to the retaining wall and drain at the rear of the Price-Moore properties. The calculations indicate that the flow rate from the drain outlet from the rear slope is: A Q100=0.09 Cubic feet per second B Q100=0.15 Cubic feet per second, DECLARATION OF RESPONSIBLE CHARGE I hereby declare that I am the Engineer of work for this project, that I have exercised responsible charge over the design of the project as defined in section 6703 of the business and professions code and the design is consistent with current design William J. DeBerry, R.C.E. #34545 -XQH, 2024 ::LOOLDP-'H%HUU\ NO. 34545EXPIRES 09/30/25 OFESSIONA E M J DEBE R R Y CIVI L FCALI F O E P R WILLI A EO William J DeBerry DeBerry Engineering Associates Project: Job #: By: wjd Phone (858) 451-0713 Date: June 15, 2024 Page: 1 of 3 Project: Client Subject: Drainage Calculations Calculated By: William DeBerry C 34545 Land use Residential Per Design Manual Conc Time Tc Soils Group D Drainage Area Intensity Water Course Dist Per Fig 3.3 Q = CIA A 7.02 16 5.25 100 year event, 6hr P6 2.75 B 5.41 36 7.87 Run-off Coefficient C 0.52 Per Table 3-1 Concentration timeTc= 12.00 min I (intensity) A 7.02 in/hr Per Appendix B I (intensity)B 5.41 in/hr Drainage Area sf ac Q100 A 2139.00 0.05 0.18 Cu. Ft per sec B 3462.00 0.08 0.29 Cu. Ft per sec FLOW FROM FLOW TO TOTAL Q100 V100 A DRAIN SWALE 0.18 1.08 Ft per sec B RETAINING WALL 0.29 1.75 Ft per sec Carlsbad, California 92009 Price, Moore, Walker and Curry 3311 & 3313 Dorado 3325 & 3327 Vivienda 3325 & 3327 Vivienda CALCULATIONS DRAINAGE CALCULATION for HYDROLOGY ANALYSIS DESIGN CRITERIA: SAN DIEGO COUNTY HYDROLOGY MANUAL MODIFIED RATIONAL METHOD FLOW Check the Capacity of the Concrete Drainage Swale Use Manning's Formula: Q=K/n *R^(2/3) * S^(1/2) Q= Flow in cf/sec D= depth of water= 8 in = 0.66 ft d= Diameter of channel = 36" K= 1.486 Plan Checker s= slope of channel = 0.017 n= roughness coefficient = 0.016 for concrete lined channel from Civil Engineering Handbook, table 19 Section 4-77 Channel is a circular with depth D = 8" and d = 12" Q= 4.27 cf/sec 1.08 Ft per sec Q100 @ concrete = 0.12 0.18<4.27 OK The concrete swale discharges Thus this drainage ditch will more than handle Q100 to the existing which discharges to a public street drainage way Check the Capacity of the Concrete Drainage V ditch at the retaining wall Use Manning's Formula: Q=K/n * D8/3s1/2 Q= Flow in cf/sec D= depth of water 0.66 ft K= 1.74from Civil Engineering Handbook, table 20 Section 4-79 s= slope of channel = 0.017 n= roughness coefficient = 0.016 for concrete lined channel from Civil Engineering Handbook, table 19 Section 4-77 Channel is a V shaped with depth D = 12" and w 30" Q= 2.37 0.29<2.37 OK cf/sec Thus this drainage ditch will more than handle Q100 Check the Required Size of the Atrium Drain Inlet at the end of the V ditch Flow into a 6" drain inlet at 0.017 % slope Calculation to size sd outlet pipe Flow to Outlet Pipe= 0.29 CuFt / sec Use Manning Equation: Diameter of Drain Inlet (ft)= [3.208*(n/Kn)*(Qp/So^0.5)]^3/8 n= 0.016 Manning's roughness coefficient Kn= 1.49 Constant Qp= 0.29 CuFt/sec Design discharge So 0.017 % Local Slope to Pipe d= 0.38 ft Drain Inlet size= 4.6 inches 6" inlet is OK 1' + / - a 6" 3" MIN 3' min J DRAIN TO MATCH EXISTING 1 1/2" x 1 1/2" 17GAGE STUCCO NETTING.CONCRETE WITH 3" 2500 PSI, 6" 12" min SDRSD D 75 TYPE D MODIFIED 3" 2500 PSI CONCRETE WITH 1 1/2" X 1 1/2" 17 GAGE STUCCO NETTING 30" +/- 12" MIN 6" 6" RETAINING WALL CONCRETE DITCH PER SDSRD D75 TYPE A3 Page 3 of 3 Check the Required Size of the Drain Outlet Pipe and Sump Pump Calculation to size sd outlet pipe Flow to Outlet Pipe=0.29 CuFt / sec 131 Gal/min Capacity of 3" pipe with .003 roughness is 0.202 cfs 0.202 < 0.29 use 4" pipe SPBS Series Sump Pump Battery Backup 10 EC 67 gpm along with the 6' x 2' sump will handle most of the peak flow. The excess flow will come out of the top of the sump without damaging the property. This is rare occurrence 7RFRPSOHWHO\FRYHUDOO\HDUHYHQWVZRXOGUHTXLUHWRRODUJHRIDSXPSZKLFKZRXOGQRW EHIHDVLEOHIRUDUHVLGHQWLDOLQVWDOODWLRQ 266 260262 268 270272274 276 278 260 270 270 280 272274 280276278 282284 288 288 286 280 266 268270272274 276 280 3327 Vivienda CirEXISTING SINGLE FAMILY RESIDENCE 3325 Vivienda CirEXISTING SINGLE FAMILY RESIDENCE 280.5 F L 268266264262 262264266268270272 274276278280 Rem o v e S l i d e S o i l TW 261.5BW 258.0 TW 261.5BW 258.0 TW 261.0BW 257.5 TW 262.5BW 258.0 TW 261.0BW 257.5 TW 261.5BW 258.0 282 284286288 D/5 3329 Vivienda Cir 3323 Vivienda Cir EXISTING SINGLE FAMILY RESIDENCE EXISTING SINGLE FAMILY RESIDENCE 2:1 S L O P E Section A Section B Section B 1/4 2/4 3" TRIPLE WALL HDPE DRAIN PI PE2.5 % SLOPE TO DISCHARGE TO GUTTERIE 252.6' 1/4 LAWN A R E A N O H ARDSCAP E 2:1 S L O P E EXISTING RETAINING WALL TO REMAIN TOP OF SLOPE288' 288' 289 . 5(P) P A T I O 290 . 0 290.2 5 288 . 0 290.0 290 . 5 (P) P A T I O (P) PA T I O FG 255'FL 249.9 FG 255'FL 250' FG 255'FL 249.7' FG 255'FL 249' FG 255'FL 249.65' FG 255'FL 249.5' FG 255'FL 249.4' FG 255'FL 249.2' 1 3 4 1 1 1 3 3 2 4 4 5 IE 253.7 Sump Sump Pump Float Switch Steel Cover 72" +/- Out flow Two pump system. Main pump hard wired to house power,secondary pump with batteryback-up in case of power loss Grade Level LITTLE GIANTSump/Battery Back-UpSystem: 1/3 (Primary) HP Cast Iron (Primary)Plastic(Secondary) Item 48ZJ79 Mfr. Model 506411 SUMP PIT24"Corrugated HDPE Pipe with cover 72" deep 3" TRIPLE WALL HDPE DRAIN PIPE2.5 % SLOPE TO DISCHARGE TO GUTTER FL 25 5 . 0 FL 251.5 12" FL 255.1 Sump is Fiberglass GB-24 X 072-100 with 5/32" wall and floor thickness By AK Industries Inc or Similar 5/32" fiberglass 5/3 2 " f i b e r g l a s s 5/3 2 " f i b e r g l a s s SPBS Series Sump Pump Battery Backup10EC Flow/Capacity in liters Per Minute 40 80 120 160 200 240 f7 10 20 30 40 so 60 Flow/Capacity in US Gallons Per Minute 2500 3360 6EC lOEC Head GPM (LPM) GPM (LPM) GPM (LPM) GPM (LPM) 0' 42 (159) 53 (200 6) 5' 29 (109.8) 39 (147.6) 53 (200.6) 67 (253.6) 10' 20 (75.7) 24 (90.8) 50 (189.3) 57 (215.8) 15' 13 (49.2) 42 (159) 54 (204.4) 20' 34 (128.7) 47 (177.9) 30' 28 (106) 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Page 6 Office: 858.451.0713 Email: dianed3@cox.net, DeBerryEng@gmail.com Cell: 858.472.2783 www.deberryeng.com SAN T A F E CITY OF ENCINITAS OCEAN PACIFIC BL V D LA COSTA AVE RA N C H O R E A L C I T Y O F C A R L S B A D CANNON PALOMAR C A R L S B A D A V I A R A PKW Y . AIRPO R T CITY OF OCEANSIDE I N T E R S T A T E 5 HIGHWAY 78 RD. EL CAM I N O ROA D CITY OF VISTA ROAD ALGA ROAD MARCOSCITY OFSAN SCALENOT TON VICINITY MAP C O L L E G E B L . CO L L E G E BLV D . XSITE SITE 3325 &3327 Vivienda Cir 3311 & 3313 Dorado Pl Page 7 Office: 858.451.0713 Email: dianed3@cox.net, DeBerryEng@gmail.com Cell: 858.472.2783 www.deberryeng.com DRAINAGE AREAS 2 6 6 26 0262 26 8 2 7 0 27 2 27 4 27 6 2 7 8 26 0 2 7 0 27 0 28 0 27 2 27 4 28 0 27 6 27 8 28 2 2 8 4 28 8 2 8 8 28 6 2 8 0 266 268 270 272 274 276 280 282 3311 Dorado Pl EXISTING SINGLE FAMILY RESIDENCE 3313 Dorado Pl EXISTING SINGLE FAMILY RESIDENCE 3327 Vivienda Cir EXISTING SINGLE FAMILY RESIDENCE 3327 Vivienda Cir EXISTING SINGLE FAMILY RESIDENCE 280 . 5 F L 284 26 8 2 6 626 426 2 26 2 26 4 26 6 26 8 27 0 27 2 27 4 27 6 28 0 28 0 Remove Slide Solil Re m o v e S l i d e S o l i l TW 261.5BW 258.0 TW 261.5BW 258.0 TW 261.0BW 257.5 TW 262.5BW 258.0 TW 261.0BW 257.5 TW 261.5BW 258.0 0510 10 20 AREA B NO R T H AREA A Q= 0.18 ft per secV= 1.08 ft per sec Q= 0.29 ft per secV= 1.75 ft per sec --- $SSHQGL[ San Diego County Hydrology Manual Date: June 2003 Table 3-1 Section: Page: RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil T e NRCS Eleme.nts County Elements ¾IMPER. A B Undisnirbed Nantral Terrain (Natural) Permanent Open Space O* 0.20 0.25 Low Density Residential (LDR) Residential, LO DU/A or less 10 0.27 0.32 Low Density Residential (LDR) Residential, 2.0 DU/A or less 20 0.34 0.38 Low Density Residential (LDR) Residential, 2.9 DU/A or less 25 0.38 0.41 MediUlll De.nsity Residential (MDR) Residential, 4 .3 DU/A or less 30 0.41 0.45 Medium Density Residential (MDR) Residential, 7.3 DU/A or less 40 0.48 051 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 054 MediUlll Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 058 High Density Residential (HDR) Residential, 24.0 DU/A or less 65 0.66 0.67 High Density Residential (HDR) Residential, 43.0 DU/A or less 80 0.76 0.77 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Comme.rcial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited I.) Lintited Industrial 90 0.83 0.84 Commercial/Industrial (General I.) General Industrial 95 0.87 0.87 3 6 of 26 C D 0.30 0.35 0.36 0.41 0.42 0.46 0.45 0.49 0.48 0.52 054 0.57 057 0.60 0.60 0.63 0.69 0.71 0.78 0.79 0.78 0.79 0.81 0.82 0.84 0.85 0.84 0.85 0.87 0.87 *The values associated with 0% in1pervious may be used for direct calculation of the mnoff coefficient as described in Section 3.1.2 (representing the pervious mnoff coefficient, Cp, for the soil type), or for areas that will remain undisntrbed in perpetuity. Justification must be given that the area will remain nanual forever (e.g., the area is located in Cleveland National Forest). DU/A = dwelling units per acre NRCS = National Resources Conservation Service 3-6 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 0.5 0.4 0.3 0.2 0.1 ' '' -.... ' .... I'-.. ' '' ' ....... ~ ' r-.. • ' ' .... i-. .... r,.. .... r-.... r- ' r-.. .... ' i-.,.... . ' "', ~~' r-.. ... -·, ... ~ ' ~ ~ ·, "' ... ~ ~ ... ' . ' ' ... i-. "'~ ~ I',. ..... ...... i-., ~, .... ~ r-..' ..... I= 3.2 in/hr r-~, ~ ... ' ' '"' ~ ... ' .... ...... .... ~ ~~ r-.. .... ' .... ,, ' ...... ~, i--... ' 'r-'r-~~ le= 20 min I I I I I I 11 11111111 . 5 6 7 8 9 10 1S 20 30 Minutes ~ I ~ ~ I ~ 40 50 Duration EQUATION I = 7.44 P5 o-0·645 I = Intensity (in/hr) P5 = 6-Hour Precipitation (in) D = Duration (min) ~ ..... i-. ... i-. .... "', . ' i-.' r-r,. ' ' ' ~ ' ' i-.' .... r-r-~ • ~ ' ' r-r,. ~~ ~ ~ ' r-, r..., r..., r-"' ~ ~ . ' ' ' r- -i.... ....... I'-. ' -~ . I', "', ~ 'r,. ~ ' r-' I ' ~ 'r,, r..., ' t--, ~ 2 3 4 Hours - S 6 '?' I ~ "O al (') 601 5.5 c: 5.0 g 4.5 5' (') 4.0 16 3.5 .!!!.. 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart • Example Directions for Appllcatlon: (1) From precipitation maps determine 6 hr and 24 hr amounts for the selected frequency. These maps are included in the County Hydrology Manual (10, 50, and 100 yr maps included in the Design and Procedure Manual). (2) Adjust 6 hr precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr precipitation (not applicaple to Desert). (3) Plot 6 hr precipitation on the right side of the chart. (4) Draw a line through the point parallel to the plotted lines . (5) This line is the intensity-duration curve for the location being analyzed. Application Form: (a) Selected frequency~ year p (b) Ps = _3_ in, P24 = ~ 'P 6 = ~ %(2) 24 (c) Adjusted p6<2> = _3_ in. (d) lx = ~ min. (e) I = -11.._ in./hr . Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. PS 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 Duration" I I -r--, I ,--,--,--, 7 I 5 2.63_ 3.95 5.27 6.59 7.90 9.22 10.54 11.86 13.17 14.49 15.81 --7 2.12 3.18 4.24 5.30 6.36 7.42 8.48 9.54 10.60 11.66 12.72 10 1.68 2.53 ~3.3?_ _i.21 5.05 5.90 6.74 7.58 8.42 ~7 10.11 --,5 1.30 1.95 2.59 3.24 3.89 4.54 5.19 5.84 6.49 7.13 7.78 20 1.08 1.62 2.15 2.69 3.23 3.77 4.31 4.85 5.39 _5.93 6.46 25 0.93 1.40 1.87 2.33 2.80 3.27 3.73 4.20 4.67 5.13 5.60 30 0.83_ .1,_2~ j,_66_ _2~0L ._2.49 2.90 3.32 3.73 4.15 4.56 4.98_ ~ 0.69 1.03 1.38 1.72 2.07 2.41 2.76 3.10 3.45 3.79 4.13 so 0.60 0.90 1.19 1.49 1.79 '2.09 2.3f 2.69 2.98 3.28 3.58 60 0.53 0.80 1.06 1.33 1.59 1.86 2.12 2.39 2.65 2.92 3.18 90 0.41 0.61 -0.82 I.Of T.23· 1.43 7.63 1.84 2.04 -2.25-'2.45 120 0.34 0.51 _0.5!! 0.85 1.02 1.19 1.36 1.53 1.70 1.87 2.04 150 0.29-o.« 0.59 0.73· 0.88 1.03 1.18 1.32 1..47 1.62-"T.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 1.57 24() 0.22 0.33 0.43 0.54 0.65 0.76 0.87 0.98 1.08 1.19 1.30 300 0.19 0.28 0.38 0.47 0.56 0.66 0.75 0.85 0.94 1.03 1.13 360 0.17 0.25 0.33 0.42 0.50 0.58 0.67 0.75 0.84 0.92 1.00 I-w w LL z w (.) z < I-(/) cS w Cl) a::: :::> 0 (.) a::: w .... < :s: 2.50% slope 2.0 -+------l-'-111' 100 l--_J1~-5q ~==::1;:~~~~- 0 EXAMPLE: Given: Watercourse Distance (D) = 70 Feet Slope (s) = 1.3 % Runoff Coefficient (C) = 0.41 Overland Flow Time (T} = 9.5 Minutes SOURCE: Airport Drainage, Federal Aviation Administration, 1965 T = 1.8(1 .1-C)VD 3lfs 20 10 (/) w I- :::> z ~ z w ~ I- :s: 0 ...J LL 0 z < ...J a: w > 0 FIGU R E Rational Formula -Overland Time of Flow Nomograph 3-3 FLOW WITH A FREE SURFACE ~77 Manning proposed the following val f • uc O c m the Chezy 1 .486r~6 c =---n (15 1) . thr ~me coeffi cient of roughn ci,s used in the carlic G •1 , 11 1~ d b H . r angu1 let-Kutter fo «hr\ \'lllurs of 11 prepare • Y orton 3 are given in Table 19. r- n111l~- 19 f{o RroN's VAL ES OF n TO BE UsEo WITH TLI E M F f\l!l,E '· ' ANNINO ORM ULA Surface Best Good Fair Bad -- . .0-1'(! ~ewer pipe ........ • • .............. {0.010} 0.013 • I 1i1 ' 0.011 0.015 0.017 . C1n-da,· drainage tile ................. 0.011 0.012 • 0.014 • 0.017 l ,1ni0l . • . k ·1 d bnc-kwor .......................... 0.011 0.012 0.013 • 0.015 F~'i:{ in cement mortar; brick sewers ........ 0.012 0.013 0.015 * 0.0 17 x~; cement surfaces ...................... 0.010 0.011 0.012 0.013 L°fnieni m~rtar surfaces ..............•..... 0.011 0.012 0.013 • 0.015 ·0ncret e p1 pe: .. • . • • • • • • • · • • • • . . . . . . . . • • • . 0.012 0.013 0.015 • 0.01 6 l\(lOO~taVe p1pe .. · . · • • • • • • • •••••••••••••• 0.010 0.011 0.012 0.013 p18nk Burnes: Planed . . . · · · · · · · · · • • • • • • • • • •••••••••• 0.010 0.012 • 0.013 0.014 [nolaned ............................... 0.011 0.013 • 0.014 0.015 \Yiih battens .........................•. 0.012 0.015 • 0.016 Concrete-lined channels .................... 0.012 0.014 • 0.016 * 0.018 Lement-rubble surface ..................... 0.017 0.020 0.025 0.030 Dry-rubb le surface ......................... 0.025 0.030 0.033 0.035 Dressed-ashlar surface ..................... 0.013 0.014 0.015 0.017 ::emicircular metal flumes, smooth ........... 0.011 0.012 0.013 0.01 5 corrugated. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0225 0.025 0.0275 0.030 Canals and ditches: l:ar h • h d ·r 0.017 0.020 0.0225 • 0.025 1 , straig t an uru orm ............... P~k cuts, smooth and uniform ........... 0.025 0.030 0.033 * 0.035 \\p~ed and irregular ................. -• 0.035 0.040 0.045 D mdrn~ sl uggish canals .................• 0.0225 0.025 * 0.0275 0.030 (; redge earth channels .................. 0 .025 0.0275 • 0.030 0.033 anals with rough stony beds weeds on ~tt!tnks ........ · ........ '. .......... 0.025 0.030 0.035 • 0.040 ~at I tom, rubble sides ..........•.••• 0.028 0.030 * 0.033 • 0.035 • 1 ur~ stream ~hannels: . • ~lt:an, straight bank full stage, no nfts or 0.025 0.0275 0.030 0.033 2 8 eep pools . . . . . . . . '. . . . . . . . . . . . . . . . • • • i \\~_me _as 1, but some weeds and stones ••• 0.030 0.033 0.035 0.040 4. S inding, some pools and shoals, clean ... 0.033 0.035 0.040 0.0-15 • slame as 3, lower stages more ineffective 0.045 0.050 0.055 ope and • ' 0.040 5. Sam sections ...............•••••• G S e as 3, some weeds and stones• ...... 0.035 0.040 0.045 0.050 • ame 0.045 0.050 0.055 0.060 7. SI .as 4, stony sections ........•••••• ....,.uthggish river reaches rather weedy or 0.070 0.080 8 1 ver d ' 0.050 0.060 . Very Y eep pools . . . . . . . . • • • • • • • • • • 0.075 0.100 0.125 0.150 weedy reaches ............ • • • • • • • • v. ijlul:6 --comrnonlv uPod in d pq-ianiDK•