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HomeMy WebLinkAboutMS 01-02; CALAVERA HILLS PHASE II; PRELIMINARY HYDROLOGY STUDY FOR CALAVERA HILLS PHASE II; 2000-01-21PRELIMINARY HYDROLOGY STUDY FOR CALA VERA HILLS PHASE II Prepared By: ODAY CONSULTANTS 5900 Pasteur Court, Suite 100 Carlsbad, California 92008 (760)931-7700 January 21, 2000 (P -2406 George O'Da$v (9 RCE 32014 Prepared By: Registration Expires 12/31/00 Checked By: GO ,,h_c 0)—O__ This preliminary drainage report has been prepared for the intial review of the tentative maps by the City of Carlsbad. The following references were used Hydrology Manual. County of San Diego, Dated January 1985 City of Carlsbad standards for design & Construction of public works improvements In the City of Carlsbad, dated April 20, 1993 HYDROLOGY CALCULATIONS The hydrological analysis utilized to calculate the storm runoff for the 100 year storm event was the Rational Method (Q = C * I * A). Q = Runoff (cfs), C = Runoff coefficient, 'A = Rainfall intensity (inches/hour) A = Area (acres) Tc = Time of Concentration (Initial, overland, street gutter or pipe). Determination of Runoff Coefficient The runoff coefficient (C) is based on the soil group of the drainage basin. Runoff coefficients are also dependent on the proposed land use of each basin. Coefficients for this project were based from the County of San Diego Hydrology Manual. Determination of Intensity Rainfall intensity (I) is a function of the six-hour precipitation measure and the time of concentration for the drainage basin, as defined by the County of San Diego Hydrology Manual Determination of Areas The area (A) of each drainage basin was determined from the drainage area map. The drainage sub-basins have been based on the ultimate anticipated land use. Hydrology Calculations A summary of hydrology calculations for the developed conditions is listed in Exhibit. Exhibit "A" San Diego County Soil Classification Map Exhibit "B" San Diego County Runoff Coefficients Exhibit "C" Thomas Brother's Map - Location of Site Exhibit "D" 100-year, 24 Hour Precipitation Exhibit "E" 100-year, 6 Hour Precipitation Exhibit "F" Intensity - Duration Design Chart Exhibit "G" Urban Areas Overland Time of Flow Curves Exhibit "H" Gutter and Roadway Discharge - Velocity Chart Exhibit "I" Nomograph for Time of Concentration for Natural Watershed Exhibit "J" 400-Scale City of Carlsbad Topographic Map with Project Plotted Exhibit "K" 100-Scale Composite of the Tentative Maps - Villages U, W, X, Y, K, L-2, and R Exhibit "L" 40-Scale Composite of the Tentative Maps - Villages H W:MSOFFICEWINWORD\981020\Drainage.std . . AL4Vg,4.. N,i... r,m'. 4PeA,'t,'AG .. ... . . . . . . ••. 55 ,ec 7/114/ (oi6,zleele 7) . 1L.. _____ . •• /-i .•. 5 .,'IB . • • S •••.. ••• I 10,5.5r /4/ • • • 04 • S • 3,.. •• •• L6. 1 . 3..•. . /•. .. c4.. S z9 •. s • . •.• •• • !-• i •. • 79 .••• L-Z • •- .. ••• , I .ô7 . . ••.• • H0 2ôO. . .•. • 55 • . 55'. • 5 • -H O.9c . . • • I 0,7 0 /37 /3 3 .10. 4 .19, I 2 4LA V4 91415 r rP1. 4 (Ac,) ;' a,s- W-Z i :0155 Z3 ; ,5c. 23,9 w-4 ;o.cc 035 5_. • . . cl,4q o • 5_. .. 01155 91513 015 • • • • . a4q • K-. 3 23' Ito K8 25 . K-'? , :. /.•/,. ,1/'5: f,O K-il dill L- _i' . .. .-..--- Q1 o(Cf5 J,•. .•I '4/49E&4. //fL S 7:4.. PeWMI PM/dAG - ..I. NACRE-S) '.55.. . .. . /I oz /116. P42 13 2,4w /15 .. 0.3 . 2,3' /4 1.4. a.59 /7/ . /4 .'1O. Q.S•. %. /8... . 3o2 0. c 4.39. IC' a4 /Z. . .13.. • . • . . H . .. • . . . ... .• . . . .•. • • . . . . . . . • . . • • Ji • . . . •.. . sl oI . • •.. .* 0/ • 2/V • . /. O'/ / Z • • co Jr4 • •• . O/ 9s'0• . . (1' • ... of r/ 'O • c.h ... 12 . / • • . • . . • 2'/ • • • . • ki 0/ 1.eaH .. 'Q 4Q Z7 Val /. . • O 18D 55•0 2 V' . . . If Jc"E 5O • . • . . 5 , -'I i70Tb ccc \ Fa 1-2 U L D2 3b 0 _ _ _ / -I- - TI erd Ricl -- 1.11 J'./Yi (HDONDA( ,.HESTNU1\, Liç CA i L S B A D / >1 - .• . -• .. . . . Moun Mount Mar Ev Po t s EKb TABLE 2 RUNOFF COEFFICIENTS (RATIONAL METHOD) DEVELOPED AREAS (URBAN) Coefficient,C Soil Group (1) Land Use A B C D Residential: Single Family .1+0 .1+5 .50 .55 Multi-Units .1+5 .50 .60 .70, Mobile homes .1+5 .50 .55 .65 Rural (lots greater than 1/2 acre) .30 .35 .1+0 .45 Commercial (2) .70 .75 .80 .85 80% Impervious I ndustr i a 1 (2) .85 .90 95 90% Impervious NOTES: Soil Group mars are available at the offices of the Department of Public Works. (2)where actual conditions deviate significantly from the tabulated impervious- ness values of 80% or 90%, the values given for coefficient C, may be revised by multiplying 80% or 907. 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 0 soil group. Actual imperviousness = 50% Tabulated imperviousness = 80% Revised C =2 x 0.85 =O-53 80 IV-A-9 APPENDIX IX-B Rev. 5/81 I— A =~rl /1 107 ::7:!!!Kl 1, 21 VISTA w TA RD D10"f 35 — 16o - 31 WY EBM r 2 - - J ROLLING H! 4 I t I !WESLEY huN VISTA /.-- sl / CARLSBAD ST— X A t\I si ( r' 4 EL AWSO 12 AV Ilk t 1127 06T*Isl) 1-1 12200o 0 DESIGNED BY: HA. DRAWN BY: J-5, DATE: NOV. 1999 AS SHOWN PROJECT MGR.G O'D CONSULT N T S :L O 5900 Pasteur Court Suite 100 Civil Engineering Planning ENGINEER OF WORK Carlsbad, California 92008 Processing 760-931-7700 Fax 760-931-8680 Surveying DATE GEORGE O'DAY RCE: 32014 0doy0dayconsuftontscom -I 7 + + + + + + + + / + I I % ( : I \ / 0 711 I \\\ + + + + + 00 ---- 7 /'--'I- - - I -, ..- .- _ - - -- -- - -- V - - •- I - V VT It-. / ,.;-.7 + V VVV VVV : V :V V - -V - !:V: V: V :- ,V :V: :-V - - - - - ))): ) I •: V: + + -- - - - - - - - - --------------------- ----------------------- 77 CL to 131-4 0 - - I tb V - V - + - -- + CD FO ml - - - - - - I CO CIO LW - ""S'1H 1111111 JI]I]111II1IIII F - ]I HIlL Jr r j if UJIJLL mu 1 II r UU 11111 rh ILl Jfl-1 lumltr ILl I 11t lilt flil 1Jun11 LIIII -if - I -r + 0' 25' 100' 50' 200' SCALE: 1 = 100' Ou 2Ut) SCALE: 1" = 100' / S I / \ 7 ( ± 24 200 N + / 1 / 1 •a"', / / / 7' --:- — •H ''AJ:"j' 277 - —f ->--- /1/ / -t ---•- - .17,f 7 - - - -. -- --- - ---- - - - / 1 1 / - - • - •" ( .' - - 47/ INN momin '-- G:\SDSK\PROJ\981020\DWG\CALA.VERA\982OZZ29.DWG 12-16-99 11947 p EST