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Home My WebLink AboutCDP 2017-0064; SLOWIK ADU; LIMITED DRAINAGE STUDY; 2019-07-15 LIMITED DRAINAGE STUDY SLOWIK RESIDENCE 3960 Sunnyhill Road Carlsbad, California CDP2017-0064 DWG 518-2A/GR2019-0019 Date 7-15-19 Prepared By: ENGINEERING DESIGN GROUP Erin Rist, RCE 65122 2121 Montiel Road San Marcos, California 92069 2121 Montiel Road, San Marcos, CA 92069 760 8397302 PROJECT DESCRIPTION The subject property is located at 3960 Sunnyhill Road, Carlsbad, California. The property is approximately 0.54 acres currently developed with an existing single-family residence. Additional improvements onsite include paved driveway, flatwork, site retaining walls and other associated landscape improvement. The rear portion of the property ascends from the generally flat building pad approximately 13 feet at a 2:1 slope, to a relatively flat area at the top of the slope. PROJECT SCOPE The proposed new scope of work consists of an addition of a proposed second dwelling unit and detached garage at the rear portion of the existing property. In addition to the second dwelling unit and garage, a new driveway and retaining walls are proposed to extend the existing driveway to the new ADU/garage. BASIN DESCRIPTION AND FLOW PATTERNS The subject site has been divided into two Basins, as more specifically described below. Basin DMA1: Basin DMA1 includes the second dwelling unit, detached garage and the covered patio and courtyard in the area of the ADU. The proposed development will include downspouts that will be directed to flow to proposed new private area drain system. The new area drain system will flow to the front yard, where it will dissipate in the large grass area of the front yard. Basin DMA2: Basin DMA2 includes the proposed new driveway and parking areas along the north side of the new improvements. A combination of permeable pavers and concrete driveway are proposed in these areas. Runoff will be collected by new grated inlets, and trench drains and routed to private area drains. Private area drains will tie to new drains associated with DMA 1, will flow to the front yard, where it will dissipate in the large grass area of the front yard. Basin OFFSITE REAR: Basin Offsite Rear consists of limited offsite drainage from sloped areas to the east of the property. Offsite drainage will be captured in concrete brow ditches behind proposed retaining walls and routed to new private area drain systems and drained across landscape areas at the front of the property for dissipation. CONCLUSIONS: Runoff from rear yard improvements will be directed to flow across grassy landscape areas at the front of the property for additional dissipation. It is our opinion in the increase in total runoff of 15%, dissipated at landscape areas, is considered negligible. SLOWIK RESIDENCE3960 Sunnyhill Rd, CarlsbadPRELIMINARY HYDROLOGY CALCULATIONSC(composite) C=0.90 x % impervious surfaces + Cp x (1‐%impervious)RATIONAL METHOD FOR TRIBUTARY < 0.5 SQ MILEQ = CIAI (in/hr) - 100 YR6.85=7.44 P6 D^(-0.645)P62.6I (in/hr) - 50 YR6.06=7.44 P6 D^(-0.645)P62.30SOIL TYPE BHYDROLOGIC & HYDRAULIC DESIGNBASIN NO. TOTAL AREA (sf)TOTAL AREA (ac)IMPERV AREA (sf)AREA IMPERV (ac)% IMPAREA PERV (sf)AREA PERV (ac)C T Q100 (cfs)PRE-DEVELOPMENT ONSITEDMA 1 4,170 0.10 - 0.00 0.00 4,170 0.10 0.25 5 0.16DMA 23,020 0.07 - 0.00 0.00 3,020 0.07 0.25 5 0.12SUBTOTAL 7,190 - Subtotal Q Pre 0.28OFFSITE - REAR 4,440 0.10 - 0.00 0.00 4,440 0.10 0.25 5 0.17SUBTOTAL 11,630 - Subtotal Q Off 0.28 TOTAL SITE AREA RUNOFF27,435 0.63 7,220 0.17 0.26 20,215 0.46 0.49 2.13POST DEVELOPMENT ONSITEDMA 14,170 0.10 3,170 0.07 0.76 1,000 0.02 0.77 5 0.50DMA 23,020 0.07 900 0.02 0.30 2,120 0.05 0.51 5 0.24OFFSITE REAR4,440 0.10 0.00 0.00 0.00 4,440 0.10 0.25 5 0.17SUBTOTAL 11,630 4,070 3,120 Subtotal Q Post0.75TOTAL SITE AREA RUNOFF27,435 0.63 11,305 0.26 0.41 16,130 0.37 0.58 2.49delta Q 0.35 HYDROLOGY PRE- DEVELOPMENTBasin DRAINAGE SUMMARY TABLE lmpef11ious Area (ac) Q (cfs) Area (ac) DMA 1 0.10 0 0.16 DMA 2 0.07 lEGEND ----------0 0.12 OFFS/TE REAR 0.10 PROJECT BOUNDARY --HYDROLOGY SUB-BASIN TOTAL I ✓ I 0 0.17 0.63 0.17 2.13 I ----------FLOW DIRECTION ~ 1/,/PEJ?v,ous BLDG SURFACE ~ CONCRETE SURFACE _SIT£ PLAN -~ 40 60 sr!h-~ ;:;;:s;;;;;;;. ,,-nY ~y---,i<o'oY "' r.; ~ 4),,-55).,, '<!-'i \ ,l'l-'o ___ , • • . • . . . ,.-~:-~i' _ __./ • .. •. A •.... . ••• . ".... , ,..._,_1'._..--··"-_,. :·/:•:tit·•~· .. :;.•• ·• . .'.. ;:·· ,.. 111~t~~~-f~1~N:~i~}r~'. -~ ,,,. . :-<·. ·.:. ~ · .... 4 .. TOTAL ' '>77 .d~ I.O O C' (' C' C'\/ ...._,. ...._,. .......... ,'-.;. . N 1'. N ...._,. ::---. C',j ~ ...._,. ~ '-~ I.O -~, / ~" ~;:: ~ ~ -.....'-.;.. ' . (' ~!-. -C\/ C\/ ·,'-'--:::--.. '-.;.. '--'-OFFS/TE HYDROLOGY PRE- DEVELOPMENT' ' ' /; 0' I -----------PROJECT BOUNDARY D FLOW DIREcnoN HYDROLOGY BASIN C:;j PRP. BLDG SURFACE:-~ IMPERVIOUS ~ PRP. CONC/AC PAVING ~ (E) AC PAVING lil[] PRP. PE, I RVlous COBBLE/PAVERs I ~ ~ , +oo.o \ "'-/ / x:iY ,,,,,. ~,., ~ ";5 ~r.:: \ / ,,.. ,,..l, . ◄ . . . ... . ·• .. . ·.: .. :· ~-..... : _;·. · .. _ ... ·· .. · ... . .. · ..... ·. 5) ____ )J,'j ~ <:>11 ___. i<:>'oJ <£ ~ <!!_cri -.~ :·I;_.•.:• , .> _i~• ••.•·:> • •4 --:--.-.~ •.::4~<: ./:•: .. ;~ .:. • ,• • . • ."ll : . ·;..··}f~:ci:n~ff---~ffl{i~ TOTAL HYDROLOGY 100 4. 52.6 0.57 2.6 5 6.9 10.0 9.0 8.0 7.0 :5 0 ~ 0) .c 6.0 5.0 4.0 3.0 2.0 g1.o ~09 ·~o.a ~0.7 0.6 0.5 0.4 0.3 0.2 0.1 r-... ' ..... i-....r---I""", r,.. ' .... ........ ' ' .... ' ..... ,1 ..... ' ,, ""' ,, 'r-... I"""~ .... . ' r,.., .... r-... I' ""' 'r--.... , r-.... . ' ,, r-... r-...., r..~ ' .... , r-... '""' ' 5 6 7 8 9 10 ~ r--""" ,"i-, ... ~ ... ~ ... , ... ,, .... ~ .. ........ ... ... ~ ...... ... ~ ...... '~ . ... ',, ", .. ... ~ ...... ... r-......... .... ~ '~ ',, ...... ... ~ ... , r-..... ..... r..~ ... ~ ...... .. ...... 15 20 30 Minutes I r- ~ ~ r- ~ ~ r- 40 50 Duration EQUATION I = 7.44 Ps D-0.645 I = Intensity (in/hr) p6 = 6-Hour Precipitation (in) D = Duration (min) ', ' .... ,1 .... ' ~ ... ~ ... '~ 1, i"or,,. ... .... ~ " i"or,,. r-'~ 1, ... I', ~ ... '~ r,,.~ r-.r,,. ... r-~ ', r-,1', ~ ~ I', r- .... , ", r- .... r-1', ~ ,. '~ l""r-r- ... "r-.r-. ~ ~ 1,.., ~ ', ... '~ ~ 2 3 4 Hours r- r- ~ ~ ~ r- ~ 5 6 O') ::r: 0 !,; '1J al C') 6.0 -g 5.5 ~ 5.0 g ~-5 '§' C') 4.0 ffi 3.5 !!:- 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Template Directions for Application: (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) p6 = ---in., P24 = ---.~ = ---%(2) 24 (c) Adjusted p6<2l = ___ in . (d) Ix= ___ min. (e) I = __ in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. P6 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 Duration I I I I I I I I I I 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 :~:~~ 10 1.68 2.53 3.37 4.21 5.05 5.90 6.74 7.58 8.42 9.27 15 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 1.24 1.66 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98 --4-0 0.69 1.03 1.38 1.72 2.07 2.41 2.76_ 3.10 3.45 3.79 4.13 50 0.60 0.90 1.19 1.49 1.79 2.09 2.39 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 ~ 90 0.41 0.61 0.82 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45 120 0.34 0.51 0.68 0.85 1.02 1.19 1.36 1.53 1.70 1.87 2.04 -----;so 0.29 0.44 0.59 0.73 ffl 1.03 1.18 1.32 1.47 1.62 1.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 1.57 240 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 F IG U R E ~ SITE 33d09’26.96” ; 117d19’18.97” I I b -. __ "' H-t----H-+-+-+++++-<c..++:~c++-+-+-+-1---+__,__,__,___,__,--l-Ll::-,~-H 4-+ -1--+++ +--l-+--1-1 H4 -+-1--+-1-+-1-+-LL' "tt--t-t-tt-lt+-t-t+-H-l-:ia-l-t+-H-t+-t-+++++-+:~++++-1-++++++l-~-++++++-1-++--I-I--I--I I b .. ~ ~ :r f ., ., County of San Diego Hydrology Manual 33• • Rainfall lsopluvials 100 Year Runfall Event -6 Houn I --------lsopluviel 0nches) I ~l=R=+=+++t1=1=1=+=++=~tt:/::1~j::titttt:Jj=t±±tt:I-U'\~ tt--t+-t-t+++l--l--l-+++l-++1--1--1---l-l-..j.__j__U--I-W-U J_J..,.,.,.. ~:.. I 8 I A 3l!"SO: I I ~ ~ 321'30' ~ "' ! f$ :r I I ... ., I I ! "' ::= I I .,; :-~----+; ,-••'f---t;i,-~ I +N ~~'1i,7~~ I ••• ~~-"J t,' •• ... I • ~"'°--""~- ,. "\ »-......... -,-~-... a-i,,g .... _. _..,. __ .. __ _ _ __,.,INOOG. TNI,...,...,., ___ ,. ___ _ -..-i,,..._ __ t+-t-+-t!H-t-+-11-t-t---,.-,.-,+1-H+1o,++++-t-t-t...,...:;::++--++-1I 3 0 3 MIies ~ SITE '1 .,.. R~⇒+++=~~⇒=++tth~⇒:t0tttt~⇒~~$~MQijttFttNft;:r_~i=l:]m~~m=1:+tt:r:~:tt~~~iimj:'j;t..t:W_;iJ~~ttm±±±tL1-+±i++-,--H---,I 32'45' 45' County of San Diego Hydrology Manual • ' Rainfal/ Isopluvia/s 100 Year Rainfall Event -24 Hours I ········ l&0pluvisl (inches) I ~ S1'tiGIS We H:i.vt San Diego Cm·crc<l! 50 4.32.3 0.53 2.3 5 6.1 10.0 9.0 8.0 7.0 :5 0 ~ 0) .c 6.0 5.0 4.0 3.0 2.0 g1.o ~09 ·~o.a ~0.7 0.6 0.5 0.4 0.3 0.2 0.1 r-... ' ..... i-....r---I""", r,.. ' .... ........ ' ' .... ' ..... ,1 ..... ' ,, ""' ,, 'r-... I"""~ .... . ' r,.., .... r-... I' ""' 'r--.... , r-.... . ' ,, r-... r-...., r..~ ' .... , r-... '""' ' 5 6 7 8 9 10 ~ r--""" ,"i-, ... ~ ... ~ ... , ... ,, .... ~ .. ........ ... ... ~ ...... ... ~ ...... '~ . ... ',, ", .. ... ~ ...... ... r-......... .... ~ '~ ',, ...... ... ~ ... , r-..... ..... r..~ ... ~ ...... .. ...... 15 20 30 Minutes I r- ~ ~ r- ~ ~ r- 40 50 Duration EQUATION I = 7.44 Ps D-0.645 I = Intensity (in/hr) p6 = 6-Hour Precipitation (in) D = Duration (min) ', ' .... ,1 .... ' ~ ... ~ ... '~ 1, i"or,,. ... .... ~ " i"or,,. r-'~ 1, ... I', ~ ... '~ r,,.~ r-.r,,. ... r-~ ', r-,1', ~ ~ I', r- .... , ", r- .... r-1', ~ ,. '~ l""r-r- ... "r-.r-. ~ ~ 1,.., ~ ', ... '~ ~ 2 3 4 Hours r- r- ~ ~ ~ r- ~ 5 6 O') ::r: 0 !,; '1J al C') 6.0 -g 5.5 ~ 5.0 g ~-5 '§' C') 4.0 ffi 3.5 !!:- 3.0 2.5 2.0 1.5 1.0 Intensity-Duration Design Chart -Template Directions for Application: (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) p6 = ---in., P24 = ---.~ = ---%(2) 24 (c) Adjusted p6<2l = ___ in . (d) Ix= ___ min. (e) I = __ in./hr. Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. P6 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 Duration I I I I I I I I I I 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 :~:~~ 10 1.68 2.53 3.37 4.21 5.05 5.90 6.74 7.58 8.42 9.27 15 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 1.24 1.66 2.07 2.49 2.90 3.32 3.73 4.15 4.56 4.98 --4-0 0.69 1.03 1.38 1.72 2.07 2.41 2.76_ 3.10 3.45 3.79 4.13 50 0.60 0.90 1.19 1.49 1.79 2.09 2.39 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 ~ 90 0.41 0.61 0.82 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45 120 0.34 0.51 0.68 0.85 1.02 1.19 1.36 1.53 1.70 1.87 2.04 -----;so 0.29 0.44 0.59 0.73 ffl 1.03 1.18 1.32 1.47 1.62 1.76 180 0.26 0.39 0.52 0.65 0.78 0.91 1.04 1.18 1.31 1.44 1.57 240 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 F IG U R E ~ SITE 33d04’07.67” ; 117d05’38.30”I ~--t-~+-+-'-I +++ I I tttttt++-1+dL---l-cd111 1 1 1 1 FF f:-t-+T_,_r----t-t--+t-+1+1+--1----:un_,_l.,~ i i T i I L L 1-t~ ' I ~ L ~J•3• i I I I ~ I I I ,d ~!l ,.,_ ~c._J_ I I I .-+- I ~ U_ ,.,. f I II I 1 T I I --r- T I 1 io r "' ..,.. I I I Tl I CJundrty of San Diego y ology Manual • Rainfall Isapluvials 50 Year Rainfall 3 0 ~-3 MIies _; SITE I I b "' b ~ f ~ f $! I J J ~ ~ to County of San Diego Hydrology Manual • ' SO Year Rainfall Event-24 Hours I --------lsopluvisl (inches) I SITE 32• ' 32•3a Legend County of San Diego Hydrology Manual • Soil Hydrologic Groups Soil Groups D GroupA -Gn,upB D Groupe D GroupD LJ Undetem1ined LJ Data Unavailable ~ San Diego County Hydrology Manual Date June 2003 Table 3-1 Section: Page: RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" Soil Type NRCS Elements County Elements %IMPER A B Undisturbed Natural Terrain (Natural) Permanent Open Space O* 0.20 0.25 Low Density Residential (LDR) Residential, 1.0 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 Medium Density 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 0.51 Medium Density Residential (MDR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MDR) Residential, 14.5 DU/A or less 50 0.55 0.58 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 0.76 077 Commercial/Industrial (N. Com) Neighborhood Commercial 80 0.76 0.77 Commercial/Industrial (G. Com) General Commercial 85 0.80 0.80 Commercial/Industrial (O.P. Com) Office Professional/Commercial 90 0.83 0.84 Commercial/Industrial (Limited L) Limited Industrial 90 0.83 0.84 Commercial/Industrial (General L) General Industrial 95 0.87 0.87 C 0.30 0.36 0.42 0.45 0.48 0.54 0.57 0.60 0.69 078 0.78 0.81 0.84 0.84 0.87 3 6 of26 D 0.35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0 71 0.79 0.79 0.82 0.85 0.85 0.87 *The values associated with 0% impervious may be used for direct calculation of the runoff coefficient 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 area is located in Cleveland National Forest). DU/A= dwelling units per acre NRCS = National Resources Conservation Service 3-6 85th Percentile Precipitation /sopluvial Map Rain/all in Inches DRAFT 6127/01 -SanGIS llH,,wS.,,,~c.-.,,! .... ,,._ .. ~ , .. , .. ,..,_,..__,.. __ c-,,i,-~,,._,."'_"""-_,•_._ I ' I -\. ' . ,_ 1, I ' -> n 0 C z ·•---l -< HYDRAULICS POST DEVELOPMENT HYDRAULICSLabel Solve For Friction MethodRoughness CoefficientChannel Slope (ft/ft)Normal Depth (ft)Diameter (ft)Discharge (ft³/s)Flow Area (ft²)Wetted Perimeter (ft)Hydraulic Radius (ft)Critical Depth (ft)Percent Full (%)Critical Slope (ft/ft)Velocity (ft/s)Velocity Head (ft)Specific Energy (ft)Froude NumberMaximum Discharge (ft³/s)Discharge FulSlope Full (ft/fFlow TypeDMA 2 Full Flow Capacity Manning Formula 0.01 0.02 0.33 0.33 0.34 0.09 1.04 0.08 0.311000.017284 0.25 0.58 0 0.37 0.34 0.02 SubCriticalDMA 1 Full Flow Capacity Manning Formula 0.01 0 0 0.33 1 0.09 1.04 0.1 0.33100.000.24185 14.1 3.08 3.4 0 1.300 1.2 0.25 SubCritical3 IN FFC Full Flow Capacity Manning Formula 0.01 0 0 0.33 0 0.09 1.04 0.1 0.31100.000.01728 4.0 0.25 0.6 0 0.370 0.34 0.02 SubCriticalLabel Solve For Friction MethodRoughness CoefficientChannel Slope (ft/ft)Normal Depth (ft)Left Side Slope (ft/ft (H:V))Right Side Slope (ft/ft (H:V))Discharge (ft³/s)Flow Area (ft²)Wetted Perimeter (ft)Top Width (ft)Critical Depth (ft)Critical Slope (ft/ft)Velocity (ft/s)Velocity Head (ft)Specific Energy (ft)Froude NumberFlow TypeOffsite Drainage ChannelNormal Depth Manning Formula 0.0 0 0 1.50 2 0.25 0.10 0.9 0.770.280 2.6 0.1 0.4 1 SupercriticalRock SwaleNormal Depth Manning Formula 0.069 0 0 2.00 2 0.25 0.11 1.1 0.960.250 2.2 0.07 0.3 1 SupercriticalLabel Solve For Discharge (ft³/s) Spread (ft)Gutter Width (ft)Gutter Cross Slope (ft/ft)Road Cross Slope (ft/ft)Grate Width (ft)Grate Length (ft)Local Depression (in)Local Depression Width (ft)Clogging (%) Depth (ft)Gutter Depression (ft)Total Depression (ft)Open Grate Area (ft²)Active Grate Weir Length (ft)Grate Inlet In Sag ‐Spread 0.5 3.23 5 0.02 0.022 2 4 4 0 0 0 0.33 2.4 6Label Solve For Discharge (ft³/s) Spread (ft)Gutter Width (ft)Gutter Cross Slope (ft/ft)Road Cross Slope (ft/ft)Slot Width (ft)Slot Length (ft)Local Depression (in)Local Depression Width (ft)Gutter Depression (ft)Total Depression (ft)Open Slot Area (ft²)Slotted Drain InletSpread 0.25 0.98 0.5 0.02 0.02 0.5 10 0.5 1.5 0 0.04 5