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Home My WebLink AboutCT 81-10; Snap-On Tools Lot 26; Drainage Study; 1989-04-25r - Ml9/00 4/25/89 1LW R!I’O, 6/12/89 WD, 7/17j!9 DRAINAGE STUDY LOT 26, C.T. 81-10, MAP NO. 11134 SNAP-ON TOOLS PE 2.89.29 JUL 19 1989 ,@. 3 / CITY OF CARLSBAD p31 P-7. Svvices - .- S&AP- cm rwLs /I//+/h f/zr/89*Iw .- Bfm~N46~ 5/we/t?// .. LOT 2u/, c. iT 8/-/o, ‘MH ND ///3c /vo72-3 f/k //yoR.df KY cm c//I A77LM/S - - N&F-: L&= T/ME & CUN~E~~~r/Qn//~UKur/o/r/ (0) Of 5 /WA&773 /V/NOV&#, AS o/mz7tw /Ty r/m “f L.fKLsk#D Lv.u/~~k/~~ uEi?Aflmm/- S7zfi I’XIR AND ASSOCIATES +Gll Manchaster Ava suite 107 E?si?iias, CA 92024 - - - - - - 5NW- u/v pur 5 ////t’l’/dU j’/Z5/d9 f&w 4 ,** = c Lv” KAHR AND ASSOCIATES 4401 Manchaster Ave. Suk4 107 Ensinim. CA OWZJ - - - - _- - - - - - - - -~ - - - - - ~RUKOFF COEFFICIENTS (RATIORAL METHOD) L.UD USE Undeveluped Residential: Rural Single Family >!ulti-Units Nobile Homes .(:) Commercial (2) SOTES : !I) (2) . Coefficient, C Soil Group I:l) 8 C a c .- .35 .40 .dj !I . 50 .3@ .40 .45 .45 . 70 .jj .40 .ii .4s .SD .i3 .50 .6!l .-C .50 .Sj ..3 L- .75 .a!-! 25 .80 .85 .9D .Pj 2 0 Cbtain soil group from maps on file with the Department of Sanitat:d:l and Flood Control. Where actual conditions deviate significantly from the tabulated imperviousness values of 80% or 90%, the values given for coefficient C, may be revised by multiplying 80% or 90% by the ratio of act,ual imperviousness to the tabulated imperviousness. However, in no case’ shall the final coefficient be less than 0.50. For example: Conslrler commercial property on D soil group. Actual imperviousness = jO$ Tabulated imperviousness = 80”. Revised C = $$ X 0.85 = 0.55 I(AHR AND ASS5ClAlES 44ci Mancheste:Aua suite 107 Enchl;as,CA82024 ,lPPESUIX I\ ‘1 j.c 9. L L 9. b ?” c -ii& . c 4 \ fiu 4 ‘;: 2. .x co I . z 5 2. L 3 a9 .C 4’ z .7 .1 -2 I5 .6 .5 ._ P $ g .3 a c v) vl .z % iz z z .I I I I I I i I I I I I I I INTIXITY-DU,~TIOi'l DESIGN CHART ~i~r~;,rrli[~l~t~-nimnmr;mrmrr- i~-~4;:mrm;:l’lri~ 1. It/l-i I 1 Equation: I I = 7.44 P6 D 1 G= 10 15 20 30 40 50 1 2 3 4 5.6 , I I From precipitation maps determine 6 hr. and 24 hr. amounts for the selected frequenc:r. These maps are printed in the County Hydrology Manual (10, 50 and 100 yr. maps included in th: Design and Procedure Manual). Directions for Application: 1) 2) 3) 4) 5) Adjust 6 hr. precipitation (if necessary) so that it is within the range of 45% to 65% of the 24 hr. precipitation. (Rot nPPlicable to Desert) Plot 6 hr. precipitation on the right side of the chart. Draw a line through the point parallel to the plotted lines. This line is the intensity-duration curve for the location being analyzed. Application Form: 0) Selected Frequency /dd yr. 1) p6 = 2.8 in., P24= A:0 , *P6 = LX* - 2) Adjusted *P6= 2.8 '24 in1 3) t,= min. 4) I= in/hr. *Not Applicable to Desert Region KAltFl CND ASSOCIATES 44Gl MancheeterAyg slilto 107 Encinitas, CAWj24 I I I I I I I I I I I I I I I I COUItTY OF SAN DIiGO DEFART~IwT OF SA~~ITATION z FLOOD COIITROL p~~-Jp~$/gj=p;,j Ii%!-VEM 6-MB.& 45 30’ I---l 118’ 45’ 30’ I I I I I I I I I I I I I I I COWITY OF S/V1 DIECO DEPARTMIJT OF SANITATION 8. FLOOD COilTROL 30' 15’ “;h ~;;&$s, l?mAw-, ’ ,I \ _- 161;41b/y 1 -: -. 3 ‘,I L ‘I II I I- - -- -- - p . -, ,P C~’ Prep. ..i h” U.S. DEPARTIIIITN 1’ OF C0.2IMI~RCE f 1 G ., F z ic 30' -1. J- ] I ?I 1111” 41, ’ 30’ 15’ 117” I,$ I :: .lll’ I 5 ’ I II," - - - - - . 1 ;Tff PLJ -*.b+=. 6 Pr * 2.8/h JOB TITLE: .yLpo.2?&9--~ STORM SEWER DE TIME OF CONCENTRATION (IJF~IMPROVED~ - . ‘KAHR mm ASSOC Overland flow Jdilin Total InletTime Min. 4401 MANCHESTER AVENUE, SI HE/; /4t.-,, CraSXJ EN(.,,“,TAs,$* 92024 ph: (6,s m Type p’lcr: -~@‘3~h%+F’3fl3~.+~%/ Roughness Coefficient n = 8. ON DATE: Minimum Velocity at Design Flow: v = f.ps. WK. BY OAT -1 -1 It It -- -- i- i- I I , ,, , ,, ,i, ,i, C 2. 4 :: s E Iii ~“r/z”c4n-# d”S,M : %rpr ‘6 ‘Cd. /ub-7 M ,, “TN a-/ ‘c5:WC7 ‘y/f 24 ‘.sPc;b. ‘aru c,rar 7YA ‘A F7w.wD,,,A/ cm& SHT. IOF/z - - - - - - - - - - - - - - 3%4~- 4d 7iw s ////37/m Tf/z5/39 L1.w KAHR At25 A%CC:.ATZ 4401 tvlalX?!i%kr AY$, Sui!e 107 Encinitas, CA 52024 PC84f /p - - - - - - - - .- - - - - m4/44b- .qt@y,~ LQi-2.6, G % 8/-/O, H4Fz60 ///?/ skJ//--oA/ pur 5 ////sy/~o f/+5/8,+ afu 4,&90T c<,* : 0.95 @A3 YSO.o,, -o,!fJ- o,~r / =3.2 cs .z) i 2.6,: &E 5’w? ;9’CMd /P&$7- CU4,‘77’/4U5 b/f.d.&- = &lT q 5 U, 7 L (a t y / ‘/‘, A-2 C/T Of &‘df S&D snAm4&J trs/b/v cx/mLz, d/m- /y, /987 t-a, Pg. 35, /nF7,4k7. p. A. ~SnPG. 3 PhVCh‘28) 4 ,m- c /,A * 0.95 [a.83 /54JD~y~d. 55 = 3.9 c/s GO/m? .%!#pi i /: 7 % ; j/ (hum .&m7Q = L? 32 ; fa CUUM+Y OfSd/v o/&v Qf--w#u AN/ pAucmul@ MdzvUffL , 0 c/T ‘$5 tLJ, d/m4k7~~ /r- D /ST- I% /2 An7CHfaJ q -p.7++@ 3/1 3..9.~.7L(o.33f0.32/ L -10.63 c (6 “/@ALL ‘2) = //. ~3 ; I/SE/Z ‘p/L ‘23 / . c&f5 /WE77 PG. 9 Qf /L KAHR AF15 AStCCi,+iES ~::;i :~~a;lch:~:li.; abbe. L:.:,. ii)-: c--: ..“..: ,-,: “.‘,-‘< I., - - - - - - - - ~- - 8.0 INTERCEPTION CAPACITY OF INLETS IN SAG LOCATIONS Inlets in sag locations operate as weirs under low head conditions and as orifices at greater depths. Orifice flow begins at depths dependent on the grate size, the curb opening height, or the slot width of the inlet, as the case may be. At depths between those at which weir flow definitely prevails and those at which orifice flow prevails, flow is in a transition stage. At these depths, control is ill-defined and flow may fluctuate between weir and orifice control. Design procedures adopted for this Circular are based on a conservative approach to estimating the capacity of inlets in sump locations. The efficiency of inlets in passing debris is critical in sag locations because all runoff which enters the sag must be passed through the inlet. Total or partial clogging of inlets in these locations can result in hazardous ponded conditions. Grate inlets alone are not recommended for use in sag locations because of the tendencies of grates to become clogged. Combination inlets or curb-opening inlets are recommended for use in these locations. 8.1 Grate Inlets A grate inlet in a sag location operates as a weir to depths dependent on the bar configuration and size of the grate and as an orifice at greater depths. Grates of larger dimension and grates with more open area, i.e., with less space occupied by lateral and longitudinal bars, will operate as weirs to greater depths than smaller grates or grates with less open area. The capacity of grate inlets operating as weirs is: --+ Qi = CwPdl” (17) where: P = perimeter of the grate in ft (m) disregarding bars and the side against the curb CW = 3.0 (1.66 for SI) The capacity of a grate inlet operating as an orifice is: Qi = CoA(2gd)0’5 (18) where: Co where: Co = orifice coefficient = orifice coefficient = 0.67 = 0.67 A = clear opening area of the grate, ft* (m*) A = clear opening area of the grate, ft* (m*) g = 32.16 ft/s* (9.80 m/s*) g = 32.16 ft/s* (9.80 m/s*) 69 KAHR Ah’D A.i5?,7;>-:~~ 4401 fpET;p .+?. ‘2, 1 Enc!nlias, CA 82024 . - - - - - - - - - - STANDARD DES IGN CRITER IA 4. INLETS _ 35 A. 1 8. C. 0. E. F. G. Curb inlets at a sump condition should be designated for ,tw ~~.CFS per lineal foot of opening when. headwater may rise to the top of curb. Curb inlets on 8 continuous grade should be designed based on the following equation: 0 = 0.7 L (a + y) 312 Where y z depth of flow in approach gutter in feet a = depth of depression of flow line at inlet in feet. L : length of clear opening in feet Q z flow in CFS Grated inlets should be avoided when possible. When necessary, the design should be based on the Bureau of Public Roads Nomographs (non known 8s the Federal Highway Administration). All grated inlets shall be bicycle proof. All catch basins shall have an access hole in the top unless access through the grate section satisfactory to the City Engineer is provided. Catch basins/curb inlets’ shall be located so as to eliminate, whenever possible, cross gutters. Catch basins/curb inlets shall not be located within ten-feet (10’) of any curb return or driveway. Minimum connector pipe shall be 18”. Flow through inlets may be used on. the upper reach of drainage systems when pipe sire is 24” or less and open channel flow characteristics exist. -~- - 5 . STORM DRAINS A. Minimum pipe slope shall be .005 l.51) unless otherwise approved by the City Engineer. @WRAlh:D kSSCC,PTis 4401 ?m,cl,2;;,i ,kve. .&it* 1 :: j %cinit~zs, CA $23.:~ . _- - - - - - - - - - - RESIDENTIAL SlPEFT ONE SIDE CLlLY I .::I -& -I x : ~: j -.‘,: -_..~. I 2 DISCHARGE (C F S.) EXAMPLE: 9.’ Givenl Q.= IO‘ Ki;tiR AND RSSCC~RTES S = 2.5% Chart gives: Depth = 0.4, Velocity = 4.4 tps. 4401 ManchesterAvfj. hi!3 107 Encinihs, CA 92C24 I - c - SAN DIEGO COUNTY DEPARTMENT OF SPECIAL DISTR!CT SERVICES DESIGN MANUAL GUTTER AND ROADWAY DISCHARGE-VELOCITY CKCRT Appf+J”ED fi..// ,!&&j?;~;~$Y ( 3ATE d3d? I A?PEMCIX X-3 /% /2 df /‘z