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HomeMy WebLinkAboutCT 74-21; Drainage Study Lots 23 & 38, Loker Avenue; Drainage Study Lots 23 & 38, Loker Avenue; 1996-10-22DRAINAGE STUDY LOTS 23 and 38, C.T. 74-21, MAP NO. 10372 LOKER AVENUE, CARLSBAD, CA LINCOLN PROPERTY COMPANY C KAHR AND ASSOCIATES 5600 AVENIDAENCINAS, SUITE 104 CARLSBAD, CA 92008 (619)438-5620 CHARLES S. KAHR R.C.E. 23907 REGISTRATION EXPIRES 12/31/97 DATE C 0 NOTES FOR HYDROLOGY CALCULATIONS METHODOLOGY FOR WATERSHEDS OF LESS THAN 0.5 SQUARE MILE (320 AC.), USE THE RATIONAL METHOD PER THE COUNTY OF SAN DIEGO DESIGN AND PROCEDURE MANUAL, OCT. 1985 ED., WHERE Q = CIA. SEE PAGE 10 ATTACHED FOR CALCULATIONS. RUNOFF COEFFICIENT - C LAND USE FOR SUBJECT SITE IS INDUSTRIAL; USE AN ASSUMED WORST CASE CONDITION WHERE ON-SITE SOILS CONSIST OF SOIL GROUP T>'. PER APPENDIX IX OF DESIGN AND PROCEDURE MANUAL (SEE PAGE 3), C = 0.95 FOR MAJOR EARTHEN LANDSCAPE AREAS CONSISTING OF LIGHTLY VEGETATED SILTY SAND, PER SEEYLE ENGINEERING DESIGN MANUAL (SEE PAGE 4), C = 0.4 FOR WEIGHTED 'C' VALUES AT INDIVIDUAL BASINS, SEE PAGE 5. STORM FREQUENCY/INTENSITY -1 THE STORM DRAIN SYSTEM SHALL CARRY THE 10 YEAR FREQUENCY 6 HOUR STORM UNDERGROUND. USE THE INTENSITY/DURATION DESIGN CHART IN CONJUNCTION WITH THE 10 YEAR 6-HOUR AND 24-HOUR PRECIPITATION MAPS PER APPENDICES XI-A, XI-C, AND XI-F OF THE DESIGN AND PROCEDURE MANUAL. (SEE PAGES 6-8).WHERE P6 = 1.8, Iio= 7.44(1.8XD)*645 = 13.39(Dy°645 NOTE: USE TIME OF CONCENTRATION (DURATION, D) OF 5 MINUTES MINIMUM AS SET FORTH IN THE CITY OF CARLSBAD MASTER DRAINAGE AND STORM WATER QUALITY MANAGEMENT PLAN DATED 3/94. © c DRAINAGE BASIN AREA - A THE DRAINAGE BASIN AREAS, IN ACRES, ARE INDICATED ON THE ATTACHED 1" = 80' DRAINAGE AREA MAP; SEE PAGE 9. EXISTING CONDITIONS THE EXISTING STORM DRAIN SYSTEM WAS CONSTRUCTED IN APPROXIMATELY 1987 PER CITY OF CARLSBAD DRAWING NO. 218-5. THIS SYSTEM PROVIDES AN EXISTING 18" R.C.P. LATERAL TO THE SUBJECT SITE, DICTATING THE USE OF 18" MINIMUM DIAMETER STORM DRAIN CONDUIT UPSTREAM (ON-SITE). SUMMARY THE USE OF 18" MAXIMUM STORM DRAIN WILL HANDLE THE 10-YEAR FREQUENCY DESIGN STORM, WITH THE HYDRAULIC GRADE LINE REMAINING BELOW FINISH SURFACE. DURING 50-YEAR AND 100-YEAR FREQUENCY STORMS WATER WILL BACK UP AND BE CONTAINED WITHIN THE LOADING DOCK AREAS ALONG THE SOUTHERLY SIDE OF THE PROPOSED BUILDING AT NODES Al, A2, AND A3, WHICH ARE 4 FEET BELOW THE PROPOSED SLOPING FINISH FLOOR ELEVATION. IF THESE AREAS FILL, OVERFLOW WILL EXIT THESE DETENTION AREAS UPON ATTAINING AN ELEVATION OF 2.1 FEET BELOW FINISH FLOOR ELEVATION. THIS SURFACE FLOW WILL THEN BE DIRECTED WESTERLY AND NORTHERLY THROUGH THE PROPOSED PARKING AREA WHILE MAINTAINING A MINIMUM OF 1.2 FEET OF FREEBOARD TO THE PROPOSED FINISH FLOOR. FLOW WILL CONTINUE NORTHERLY, WHERE IT WILL RE-ENTER THE STORM DRAIN SYSTEM VIA THE DOWNSTREAM INLET STRUCTURE AT THE END OF THE PROPOSED NPDES GRASS LINED DITCH.. RUNOFF COEFFICIENTS (RATIONAL METHOD) LAND USE Undeveloped Residential: Rural Coefficient. C Soil Group (1) A JJ C .30 .35 .40 .30 .40 D .45 .43 .C Single Family Multi-Units Mobile Homes (2) Commercial (2) 80% Impervious Industrial (2) 90% Impervious 40 45 45 70 .45 .50 .50 .75 .50 .60 .55 .80 .55 .70 .65 .35 ,80 ,85 .90 NOTES: (1) Obtain soil group from maps on file with the Department of Sanitation and Flood Control. (2) 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 actual imperviousness to the tabulated imperviousness. However, in no case shall the final coefficient be less than 0.50. For example: Consider commercial property on D soil group. Actual imperviousness = 50% Tabulated imperviousness = 80% Revised C 80 X 0.85 = 0. 53 APPENDIX 'X DRAINAGE— RUNOFF—2 Q°ACL RATIONAL FORMULA (Logical approach'). Q =» R UNOFF «• Pe.ok discharge of waters/>ed in cubic feef per second (c.f.s.) dtse to max/mum sforrrr crsstsrnecf . 3&e fs'gx.jWo/=} Pg. Id-O/ (l/jtser//y /O — 25years). /A **AfCa of n/orders h GO//n crcres. C ^Coefficient- of resnoff, TO&/& B t>eJow(Mecrstsre. o/Vosses «/</e fa /rrf/'/frarfort, ere.). t » Intensity afrcrfnfa/J in Jnches pernoi/r framed on concenrraf/'or? rfm&,5ee fg./Q-C Corrcen/rc-fJon tfrrte.* time regis/rea" far rain fatttng- at ,-nosr re/note point" to reach discharge ooi'nf. Oyncesjfra-f/on t/me rnatf /rtc/itde Oyerfond f~/otv t/'/rre, r~fg. H, Pa. I8-OI ona1 Pa, 18-05, 18-O6, /d-69 and (8-7f. TABLE A-COMPUTAT1ON FORM FOR RATIONAL FORMULA. LOCATION STREET FIRST ST. MAIM RD. . " " FROM A & C TO 5 C D A INCRE- MENT /.a /.9 2.0 ToTAl /.a 3.7 5.7 C .44 .50 .50 TIM£ OF FLOW -M IN. TO INLET 16.5 IN CHAN NEL 0.3 2.5 I.Q. TIME OF CONC 16.5 16.8 /Z3 u 1*. 3.3 3.7 3.5 Q CJfy. 3.0 &Q iao DESIGN CHAM- MEL OR, PIPE SIZE 15' D-Z Zl" SIOPE ft. pcrff. .ooa .Oil .007 n .015 .030 .0/5 CAPA- CITY FUU. C.f.6. ^.6 /2.0 //./ V ft.per sec. 3.9 2.8 4.5 P RO F I L E LENcrHft. 60 420 460 FALL fh 0.45 4. 62 3.36 OTHER LOSSES ft. + O O 2?0 |WV. CLtV. UPPER END 82.00 81.52 74.70 INV. ELEV. LOWER END 5A52 76.90 70.34 *yVo/e that the sequence of design as fn example, Fig. Jt Pg. 18-01 trtvo/ves trfaf assumjot' for?& //7 d'eferm/n/rrg *• "rfcr// //7 TABLE PL \/A 1 1 I F *=i OF <~ Rt/r^of/' i.Lj VMLUtO Ur C.- &J/MFALL &UP»F3AC1ES» K.oor*S , j/oy fa ms+ol . PAVEMBHTS Concrete or Sypfra/t-. . &/f t/rrt/rrot/s Mocaa^etfrj, open ar/rcf c/oaca* fyp&. <$ro\s&I, frofn Cfeo/7 orref /oc3G fo cfoe/et/ <rrr^" C'OfrtjooC'f'.R.ff.. YAXOS GAXTH St/XfAC£S COAffOS/TJ? JAJS-AS SAM£)t from esrriforrrt gt-a/rt S/2&, /to fines, ro »vc// graded, sorrr9 cfay orjf/f. i jto^/tf, from ^afic/y or arave/fy to c/cry&y. GSZAVei., from c/eorr ora\se/ trncf graye/ sar/<f /n ix-rures, no a///- or c/oy /o Mffb c/0y or jJ/f Corrfcrrr. C/.AY", -from coarac. sone/y or jf/ry -fo pure cot/ofcJo/ c/ays. Barei/'aAf Vcaeiafion Dens* Veqefafion Bo-re i/'ahf Vegetation Dense yeaetaffon Bore 1/aAf Veaetat/on Dense Vcoeta+'ian j&cr/'e L/aAf y<eaeSatSo/i Dense feae/atian City, bus/ness areas. CV/4/, c/ense resta"e/tft'a/ trreers, vor.ti a A /o So// tra</ Veattrar/ort . Suburban rGsfc/enf/a/ areas. . » •• >t Aura/ DJsfr/cSs, » » • ParAs, e?o/f Courses, etc., » „ * VALUE. PROPOSED MIN. O-9O 0.90 O.70 0.25 o.lo 0.15. o./oj O.O5 0-20 0. IO O.O5 0.25 o.)5 0.10 0.30 o. 2oO'ie 0.60 O.SO 0.35 O.JO O.IO MAV 1.00 I.OO o.9o O.70 o. So«**•^ 0.60 0.45 o.3S 0.65 0.50 0.4O 0.7S 0.60 O.SO 0.7S 0.65 0.55 0.25 0.3S VAI.UK B.-T OTHBR. AUTHORITY MIN. O.70 0.«J5 0.70 0.15 0.10 kp.Ol ^b.Ol O.OI O.IO 0. IO O.IO 0.6O o;ao 0.25 O.IO O.O5 MAX. 0.95 I.OO 0.90 0.30 O.JO O.S5 0.99 0.55 • O.7O O.70 O.70 0-95 O.GO O.4O 0-25 0.25 ft, of "c "for car/A surfaces are further var/erf Ay c/eorce carrJoercf/ari, se/s-/iycc /rregt//**rfft/ ana' s/ooe, by character of se/Aso//f one/ At/ presence of frosf or f/o*z<sa'* anotv or- ice. (D &ryanL# Ku/chttng, fie/aort, Ao-cAi Bay Sewerage jQ/lSr/c/; Boston, /9O9. <D Me feoff anof £c/c/y, Amer/con ^eweragv Pracf/c:<z, /32Q. (3) USG.C/ at/ C/fy of Boston, reported by Metca/f .< of D<z/ro/f; reportetJ by C/'v/Y ' ' C ' o. s / o./ ? a. 85 Q./7 c 6 ' $7 .?? 1.83 i./7 6.77 0.7? 0.07 3.7 / 0./3 0. 77 6.79 a. #7 0.9f o. 4- 0.9S 6.23 2/7 OINTENSITY-DUJV\ DESIGN CHART I « 7.44 P • ill I. l.-lri.l l_M.-M"rnS f llTi i -.645 ) Intensity (Jn./Hr.) 6 Hr. Precipitation (In.) Duration (Min.) O Directions for Application: 1) From precipitation maps determine 6 hr. and 24 hr. amounts for the selected frequency. These maps are printed in the County Hydroloc Manual (10, 50 and 100 yr. maps included in t Design and Procedure Manual). 2) Adjust 6 hr. precipitation (if necessary) so that it 1s within the range of 45% to 65% of the 24 hr. precipitation. (Not applicable 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 foi the location being analyzed. Application Form: 0) Selected Frequency yr. P6S Jn., P24= 3.2 . Pg %* 2) Adjusted *Pg= / 3) tc = min. 4) I = In/hr. 24 in. *Not Applicable to Desert Region 10 15 20 30 40 50 1 4 5 6 70 (t (0 (X COOn m 2!O o O O COUNTY OF SAN DIEGO DEPARTMENT OF SANITATION 6- FLOOD CONTROL 10-YEAR 6-HOUEj PRECIPITATION •IB— IS6PLUVIALS OF 10-YEAR PRECIPITATION IN TENTHS OF AN INCH-^VilMJOC^-XVSV. >\V '1 V. ~ \ i n t -^ »M I *•»»• -•W^te .IOSPIIERIC ADMINISTRATION VDROLOGY. NATIONAL WEATHER SERVICE Prtpilred by U.S. DEPARTMENT OF COMMERCE NATIONAL OCEANIC AND AT* SPECIAL STUDIES BRANCH. OFFICE OF 30 in 0) oo o COUNTY OF SAN DIEGO . DEPARTMENT OF SANITATION FLOOD CONTROL 33* m oi—ix x Prep U.S. DEPARTMEh NATIONAL OCEANIC AND AT SPECIAL STUDIES BRANCH. OFFICE OF I o 10-YEAR 24-HOUR PRECIPITATION ISOPLUVIALS )F 10-YEAR 24-HOUR O PRECIPITATION IN EMTHS OF AN IfiCM 30 110 __ ^POJOUAR AJSPOKF ROAD SCALED 1" = 2/2//K o JOB TITLE: twwA/ /****ry C* STORM SEWER DESIGN *^ / •> DPS RY <^5/f Designationtreet£. t-_l o A EX. '«»" e> c D - ^*^J ^ D^ _o 'S. 0OT <U 0 1* A I A2* /4 ^> /A *•/" A5^TA^; r>*?; a; Af e.\ C2 Dl C2 - ^ A* A3 J\*+ A5^ ^"A^; ( &•?) As C2 C3- DATE=Incremental Afea.A(Acres)^./ /-3 /X0 — 0.^ ;,&?- /^ 2,3 /J . .. /6/2///?&Runoff Coefficient^^»T ^?^ ^ff/ — Ortf, £>.<} 0,77 o,*(* 0,8(>Product,Area x CoefficientI-"7? l.i* 0.71 — 0.5? \M Lib \.CI.S 0,^5 I ProductArea x Coefficientl--r<f ?^l 1--7-Z 3.^2 5,W \0fO^@ 1 ' 1 (& LI 8 0.<i5 LOCATIOjvh County 5XA/ £>/£&& RUNOFF COEFFICIENTS: Land use //i/^3^-S//P/^zl Weighted Coefficient _sff /*£ ^"Duration, Min.(Time of Concentr.)3" 5.7% b.oo (o.^S b.W ? f g- - ..Rainfall Intensity,!Inch /Hour+,-7+ t.tf *,2} 3,^-7 3.tb +.-?? w/- H-.-Ti- ca U 3 »K. O W 2,fr6 '5,7!? IS.7P 5/.Vf 27,/7 5.SO ^.39 ^5Z? •2 c<v VX.& \KM ml 3(77,55" /** ^3.3 7?^ ¥3.7V /7A6/ - 0 a O ex a ;»" if" i ,* * o i *j w to" IS" if" c(UO a)a. a. JO (O I^C? O.'a'O o,*o 0*0 •3^00 2M *.3V 7,<?<P I,V-2 \ o u. "o .c "a.<u0 loc> 10V too too 100 too 5-7% 4-7^7 $o"/0 10 ' RAINFALL CURVES: Source <£»«*>, ;L Of s~- >},**, « ' Freauencv / £> Y<»nr<; TIME OF CONCENTRATION ( IMPROVED) Gutter Time Min. Total COa. "5_o /f-S'o 7,/fr *,** #,*8 y?^3 /5.3S /J.7? /fe?/ Z3f 2 a> E 0 u. f^ "7^^ <*.?* $ /$ \0 0.58 :0,c?3 ?)*'l *^" P ~ / ff TIME OF CONCENTRATION (UNIMPRO\/Fr^^ PIPE: Inlet Time Min. <_ £ •oo<o X "o _0 ^ i . ! 1 1 I 1>i #¥7£ A^y^ /,o^? L6.0 9.-5i? y-77< c ^ o c 4o?.?4 +**;& «*.+i {6*62. to/ ft, ifro.53. +0:30 to?. 2 a tails' "D O ¥0X72 +*+.& -tat'f 4*/.3L (4».7ti Gfl^mo *e/,8& &<*.//) U'tJi) Overland Ro Total InletTi Tvoe /fX Roughness Cc Minimum Vel Design Flow c•o o« Xx: « o JJ -0 > iZ o 2 c • i - o b.'1* •'-' , • . • . ' W Min me Min >efficie ocity c : V = rrt n = <?, <0// it f.D.s' l^\ c Wi.98 »io.y *0<*.l» W8.W H03.fi ^#7 <K)$.97 • ,.-r_ ' ' •-'. ' o w>.v ^Hft.^ ***.*<? WJ-? 4<a,?7 L+CV.70 Ho-bS7 ^"•- :• jt.w O £ CC '* T . •?.-•>; " -iv; /X/ir 'j+'sas.a. ryss's',*.?. • ^"zw^Mtfr fx/sr: ry/>f j's.aca. 24 "*24 "' £• &• 3££ ASffYf 7M>£-'6-/' C.S. ;• */a/A/ £jr/sr: 7Y/=f, '/* '• ... /*»"*/^V.^ J^"«f A4OV£ • •' '• • SHT. _ OF _