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Home My WebLink About3085; CENTRAL BUSINESS STORM DRAIN; SERVICE AREA HYDROLOGY & HYDRAULICS DOWNSTREAM; 1985-08-07'FRASER & ASSOCIATES.. Consulting Engineers CIVIL. ENGINEERING .' • WATER & WASTEWATER SYSTEMS LAND PLANNING & DESIGN USTUDIES & REPORTS ENVIRONMENTAL ISSUES 0 CONSTRUCTION ASSISTANCE CITY OF CARLSBAD CENTRAL BUSINESS STORM DRAIN PROJECT # 3085 • SERVICE AREA HYDROLOGY & HYDRAULICS DOWNSTREAM OF 17+00 FRASER & ASSOCIATES' G~T. FRASER, ' P A H. FRASER President .E. D.L. JUNG, P.E. Vice-President A Consulting Engineers . . August 7, 1985 I' City of Carlsbad . . 1200 Elm Avenue Carlsbad, CA . 92008. 120-2 I Attention: Mr. D. Gene Donovan, P.E. ' City Engineer I ' Subject: Central Business Storm 'Drain Project No. 3085 Gentlemen: I During a meeting in the office of the City Engineer on July 25, 1985- it was suggested that we should confirm the hydrology of the Central Business Storm Drain and also the hydraulics downstream I of Station 17+00. The reason for concern is the requirement for installing a new catch basin and lateral to serve the adjacent 'properties near this location. It was discussed that prior to I constructing this new facility we should confirm the direction of flow and the estimated quantities of storm water in the 66-inch RCP as well as the overland flows adjacent to this area. Our findings are as follows: A review of the Storm Drain Master Plan prepared by VTN provides no hydrology or, hydraulic data for the recommended facilities. A statement included in the report indicates that all of the technical data was supplied to the City staff in a seperate document. We were unable to locate any of this technical information. There was included, however, in the City files two marked prints denoting the service area. for the Central Business Storm Drain and the subdrainage areas. The area in acres of each subdrainage area is also included on these marked prints. The, data included on these marked prints has been compared with City drainage maps, and the areas for several of the subareas computed. It has been determined from this spot check that the areas of each of the subdrainage areas is sufficiently accurate to utilize in this investigation. The hydrology of the service area has been tabulated in accordance with City standards and all' calculations per- taining thereto are included herein as Appendix A. The service area is as. defined in, the 'Master Drainage Plan and land development in accordance with the City General Plan. FRASER & ASSOCIATES ' 2945 HARDING STREET, SUITE 211, CARLSBAD CALIFORNIA 92008 (619) 434-1794 I Mr. D. Gene Donovan, P.E.. I August 7, 1985 Page The City drainage maps were utilized to compute average slopes for each of the sub-drainageareas. As shown in Appendix A,. it is concluded that the proper flows for design consideration are as follows: I .Q-lo = 215 c.f.s. Q-.50 = 270 c.f.s. 0-100 = 337 c.f.s. I .3. The reach of the 66-inch RCP downstream of Station 5+00 is ...............being constructed ataslope of 4.16 percent. The invert slope of the. 66-inch .RCP. upstream of Station 5+00 is to be I 0.54 percent. The flow downstream of Station 5+00 will be super critical and that the flow upstream of Station 5+00 will be subcritical. The location of the point of concern. I . is. approximately 1,200 feet upstream of Station 5+00,and it is estimated that the flow at this location will be very close to normal depth. I 4. As shown in the calculations included as Appendix B, the hydraulic gradiant in the 66-inch pipe. at Station 17+00 will be at approximate elevation 31.1; and the energy I . gradient will be at an elevation of approximately 33..2 during the computed ten year storm flow. These elevations compare with the proposed inlet to the storm. sewer se.rving I . the properties adjacent to Station 17+00 at elevation 33.3 and a soffit of the 66-inch pipe at elevation 32 6 See sheet 4. of, 7 Appendix B.. ......... . . . .. ... .I. 5. I therefore,conclude that the 66-inch RCP downstream of Station 17+00 has sufficient capacity to serve the tributary areas to ....................the extent of the-calculated-ten-year storm. Also,-that -there is adequate freeboard for the overland flow to enter the storm I sewer at this location. . 6. Hydraulic calculations for the 50 year storm have been computed I . and are also included in Appendix B. These in that the sub-drainage area may be flooded during the calculated 50 year storm flow conditions. . . . . I The service area is comparatively small and therefore, we have chosen tôuse the Rational Method of computing the storm flows, in lieu of utilizing our computer capabilities. Wefee1, however, that the I calculations areproper for this intended purpose. - 1 hope this satisfies your immediate requirements. Please do not FRASER & ASSOCIATES 2945 HARDING STREET, SUITE 211, CARLSBAD, CALIFORNIA 92008 (619) 434-1794. I .. ..,....,.........,....-,...,.---..-.- I / / &'ery V/1 logo o' 1/ / I / / 7 SCALEIN FEET / - ' A - /32 8 - 13 2 - 32 2 o\ ( \ 2 - Af/ \, 8- \ \ 82-13 " ; vs f- 15Z L"1 113,2-17 ' 9 eO 2 \ \\ \132- r7 Pcc, Oceo \ 'I FRASER & ASSOCIATES A Consulting Engineers 2945 HARDING ST., SUITE 211, CARLSBAD, CA 92008 • (619) 434-1794 I I I FRASER & ASSOCIATES Consulting Engineers 2945 HARDING ST., SUITE 211, CARLSBAD, CA 92008 • (619) 434-1794 HYDROLOGY STUDY Project No., I W Sheet —L —of Project TitleC !3ID CB CaIC.by _____ Date______ Subject - Chkd. by1t'1 Date 88 TRACT AREA ~LENGTH (FT) TC EmEm Q10 Q50 Q1 Q1 0 1E Q50 _7 5 Q1 00 NI -_- __ --n- s--- - nP_ KWU MAN Emm Nam • ___ Emu Ewa _-_Iffi Ir Ik&F1 rnw I i i I I I I I I I I I I I I I I I I I I I I .1 I I FRASER & ASSOCIATES HYDROLOGY STUDY 2945 HARDING ST., SUITE 211, CARLSBAD, CA 92008 • (619) 434-1794 A Consulting Engineers Project Title _C1 I'1 P CBO_SP Caic. by Date t/2/ Project No. /2 0 2," Stieet ...Z........t . Subject - Chkd. by _____________________ Date El mommmommummosEa TRACT AREA mom SLPPE LENGTH (FT) (MIN) (MIN) (CFS) Q50 (CFS) 100 (CFS) (CFS) FS) WAM- ME "t OEM IffI low ~fflm, !LW1Ffl1__ - - KM MUM -IITw - i ii z i tri rVIIf1I___ ___19M m, W-ROV74"o -_ CUM __UY _ 71-91m i WON - _________ L I 1J - •• • U U U U WI I U IlL L U I J that It is within the range of 45% to 65% Of the 24 hr. precipitation. (Not applicable to Desert) Plot 6 hr. precipitation on the riq)t side of the chart. Draw a line ts,.oUgh the point parallel to th plotted lines..- This line Is the intensity-duration curve fo the location being analyzed. Application Form: 0) Selected Frequency /0 yr. P67 n.,P244 P24 Adjusted *P in. t• 54 mm. 1 a I05 in/hr. 1.0 *Not Applicable to Desert Region LiJJ llflhllj •• This chart replaces the Intensity- Duration-Frequency curves used since 1965. 4 6 III "I'll "HI — — — — — — — — — IUTENSITY-DUMTIUN DESIGN CHART . 1984 :" 4J}J J] 1111111 Directions for Application 6 HtLIJIII11fl 1) From precipitation maps determine 6 hr. and ,, - r i • Intenstty (In./Hr.) 24 hr. amounts for the selected frequency. I I P6 • 6 Hr. Precipitation (In.) These maps are printed in the County Hydrolo Manual (10, 50 and 100 yr. maps included in Design and Procedure Manual). • . I . D a Duration (Mm .) : - • h. i. ..' lIdfflhiIiifl!ifmrn i 2 hr rarint4-r.n (cnhel't,\ cri II U m I tnt I1 ,uuuuuIuuJ I1J 30 40 50 1 —. — — - — _ '.- ART 1984 DirectionS for Application: From precipitation maps determine 6 hr. and 24 hr. amounts for the selected frequency. These maps are printed In the County Hydroloa Manual (10, 50 and 100 yr. maps included in Design and Procedure Manual). Adjust 6 hr. precipitation (if necesary) so that it Is within the range of 45% to 65% Of the 24 hr. precipitation. ' (Not applicable to Desert) Plot 6 hr. precipitation on the rig)t side of the chart. Draw a line ts..'ough the point parallel to th plotted 'lines. This line Is the intensity-duration curve fo the location being analyzed. Application Form: 0) Selected Frequency 50 yr. 1) P6 225 lfl•I P4 40 , = 56 %* P 24 2) Adjusted *P6= 2.ZS in. 3) t • mm. 4) I i!30 in/hr. INTENSITY-DURATION DESIGN Cl , . - . . . Equation: I "e 7.44 P6 D'645 ' {j I • Intensity (In./Hr.) i I P6 -. 6 Hr, Precipitation (In.) D - Duration (Min..) 4. . •t ' - . - . _j• k . 11f:r • - . . . .• I I I'I - '44 'H - 4111 Ii I I i ii • :j 'J . L 9 -'i I i; '' • • .... a_•! !03 3.5 .; r&!.IJ [I I I' j•'J. Ilir%._. so I Ili' I I ••f _,. I I 'rl F 10. 20 30 40 50' 1 .. '2 3 4 6 This chart replaces the Intensity- , 111 Duration-Frequency curves used since ZS 1n I,uJ. • ' , -.-• - - - - - -. - - - - _• - —. - - - - - g rHTENSITY-DUMTIUN DESIGN CHART 1984. ' .HJLLI L11tTj 1 Equation: I 7.44 p Directions for Application: . - S . 6 D . 1) From precipitation maps determine 6 hr. and too Intensity (In./Hr.) 24 hr. amounts for the selected frequency. 6.Ii S These maps are printed in the County Hydrolo( I fP 6 6 Hr. Precipitation S. Manual (10, 50 and 100 yr. maps included in I uration Min. . . . . . Design and Procedure Manual). D D C) . 4.ST._.S •• I . . 2) AdJust 6 hr. precipitation (ifnecesary) so I -. •Ii• that It is within the range of 45% to 65% of the 24 hr. precipitation. (Not applicable !i • liii •1, : •J I to Desert) 3) Plot 6 hr. precipitation on the right side of the chart ' it IJi 111 rf1 I 'ii , ' 4) Draw a line ts ough the point parallel to th plotted lines.. 10 fill ii 1111 1Ijii L1 0 5) This line Is t10fl curve 60 bei ng analyzed . l'!i11 .1 11 H' 15.5 iIi 0 - ; ' 'i: ,: jj • 1i Application Form 3.5 nml 0) Selected Frequency S. •I...I..Ii1 . 'I'i ;'i;-I ii, 3.0 4A * 'I I ii IIF I .1 Ij L 5 1) P6 27h' p24= 4.1, 6 24 / %* - I•i......1 Ii L..- I.,. iHIH!,r S f i1 I ri JJ2.0: 2) Adjusted *P I!Jj .. I1[.fl:15 3) t 54 mm.. . I - . 1t 1Ji1 4) I i'O in/hr. S .. .. S *Not Applicable to Desert Region -. . 111111 This chart replaces the Intensity- Th .. - S. .. S. I11llJ ' Duration-Frequency curves used since 1965. 10 20 30 40 50 1 .. 2 .. - - - -.-..- - , —.—.— _•;_ - - -1. INTENSITY!DURATION DESIGN CHART 1984. ' 1,J}f 1iITI1TF LLa;L3T i.7.44PD' Directions for Application: • Equation: 6 From precipitation maps determine 6 h. and Z . . I • Intensity (In./Hr.) . 24 hr. amounts for the selected frequency. These maps are printed in the County Hydro10 Il I P 6 •. 6 H P i r. reciptation (In.) Manual (10, 50 and 100 yr.. maps included in Design and Procedure Manual). • jj D - Duration (Mm.) . .• -. 4. I ' un r Adjust 6 hr. precipitation (if necessary) so that It Is within the range of 45% to 65% Of 3. - . . J..!. I . the 24 hr. precipitation. (Not applicable •• . . to Desert) 0 !II • II: Iji ,! • . . I! 0 - 0 - • 3) Plot 6 hr. precipitation on the rig)t side 2. • ... t!I . ,,iI li i i - I of the chart. I I J. liI I I Ii . !': ' Draw a line t..ough the point parallel to th j plotted lines. 1 j II• Is.... iIIi flh & I L • This line is the intensity-duration curve fo .IIh11. ; '..-.6.O the location being analyzed. 'NL ft j lN'Th.4.5 : 'kJI FL!Ifhk!iifli'4.0 5 !!!j • cJi 1MT1t2.0 -k -r1 f'f HTHL . 1j15 wp -crNJfl II ±FF:FfW IUll1.0 Application Form: 0) Selected Frequency J_yr. 1) p6 1.7 In., p24= * = P24 Adjusted *6 t mm. I in/hr. *Not Applicable to Desert Region I I. . I I III II 1111111 111111 II Jill JJ If JJ 1n1 tllarL repiai.e i' in eris 1 L- ii- 1 ilII 11 -1-1I1[.JJ 111.1!.! . -• 1111 Duration-Frequency curves used since 1965• 10.1 • 20 30 40 50 1 • .. 2' .. 3 4 , 6 . • . . .. In •c I,Equation: 7S44ihIIkU I 2 — — . -- — — — IHTEUSITY-DURATION DESIGN CHART . ,.. . .. . . 1984. I -. 744 P D'645 Directions for Application: 6 1) From precipitation maps determine 6 hr. and I • Intensity (In. /Hr.) . 24 hr.. amounts for the selected frequency. . . These maps are printed in the County Hydrolo P6 •• 6 Hr. Precipitation (In.) Manual (10, 50 and 100 yr. maps included in Design and Procedure Manual). D • Duration (Min.') I11r11flV11 T:' -r 2) Adjust 6 hr. precipitation (if-nece'sary) so JJJ 111111 -. J • I that It Is within the range of 45% to 65% Of fl3JJflJ .j•. I.....J the 24 hr. precipitation. (Not applicable I [ to Desert) 'IiIIT •'•i !I:t, 1 IIJ : Ort H LQ4.0. i 1 '1 1' frit3 0 IN 2.0 1.0 Plot .6 hr. precipitation on the rig)t side of the chart. Draw a line t...ough the point parallel to th plotted lines. This line is the intensity-duration curve fo the location being analyzed. Application Form: 0) Selected Frequency 5.0 yr. 1) p6 in. If P24= 40 P 24 Adjusted *6 225 in. t -61 mm. I • /2o in/hr. *Not Applicable to Desert Region 'ulluuluu" 1111111 This chart replaces the Intensity- lull lJJ]JJJJJflJll1j JIIIIJIJ 1,111111.11111 01114 ' Duration-Frequency curves used since 30 40 50 1 .. '2 . 3' 4. 6 • 1965. -. Tn. - - -. - .- - - -... --- - •.- ._. INTENSITY-DUMT1ON DESIGN CHART 1984. : Directions for Application: Equation: 1 6 "F . 1) From precipitation maps determine 6 hr. and - .. r I a Intensity (In./Hr.) 24 hr. amounts for the selected frequency. f P6 6 Hr. Precipitation (In.) These maps are printed in the County Hydraloc Manual (10, 50 and 100 yr . maps included in 1i . . • . Design and Procedure Manual). Duration (Mm.) 4. D - . t'..! • - • H • . :' • 2) Adjust 6 hr. precipitation (if necessary) so 1 . -. I • • I • that It is within the range of 45% to 65% Of 3. - if - I I • . - - J•.. J • the 24 hr. precipitation. (Not applicable • l • f 11,• 1 .i. • to Desert) kj I • . i... - I. _ .uluuuuIuuugIIIIuuIIIIiIIIIIIi Is4050 !!U ?j ki t! ii; Jill iii i. Ii .,'.. 416.0 5.5 _a '•t 4.0 ' Iffij Ll.iNk. 143.o 2.0 ! 0.5 'b_ I 1TtT1.T1Ti.1itL;111i1t1iHAA1.0 Plot 6hr. precipitation on the right side of the chart. . Draw a line t..ough the point parallel to th. plotted lines. This line is the Intensity-duration curve Ic the location being analyzed. plicat1on Form: ) Selected Frequency /PC yr. ) P6 - 2.7 in.. P24= 4,1., p24 ) Adjusted *P 7 in. t 'f mm. i 50 in/hr. *Not Applicable to Desert Region This chart replaces the Intensity- .rn Duration-Frequency curves used since ZS 1965. • H S -I.. I ! t• I ;1 i ffirrii 6 •. ...I-. .i i 4 i•i...........r•h I Tftr: III L4 ..! 0 C -I. Jil l 16-0 IL! H i.thfliiN3.5 . Il•; rriif.° . I. I — — - —.— - - —. _• ,_ —..— - - - .• 0 . 0 INTENSITY-DURATION DESIGN CHART . . 1984. 9. - 11 1 [Ii 11 Equon:I -a7.44PD 45 Directions for Application: & - - - 6 . 1) From precipitation maps determine 6 h. and I • Intensity (In./Hr.) 24 hr. amounts for the selected frequency. Ii -. 6 Hr. Precipitation (In.) These maps are printed in the County Hydrolo Manual (10, 50 and 100 yr. maps included in Design and Procedure Manual). I I D • Duration (Min.) 4. 2) Adjust 6 hr. precipitation (if-necessary) so • ! I 0 -. J . F ii that it Is within the range of 45% to 65% Of 3.- -1- '- -- .J: . II . the 24 hr. precipitation. (Not applicable I • • l i ii ,'. ' I { j to Desert) Plot 6 hr. precipitation on the rig)t side of the chart. Draw a line t..ough the point parallel to • plotted lines. This line is the intensity-duration curve fo the location being analyzed. ppllcatlon Form: 0 ') Selected Frequency /t yr. 6 a /.7'1n., P24= 30 = P24 . ) Adjusted *P6= 17 in. ) t SQ mm. ) I Jn/hr. *Not Applicable to Desert Region 'UHuInhu" IiiIIIIiIiI ffI 30 40 50 1 .. 2 3 - This chart replaces the Intensity- Duration-Frequency curves used since 1965. • - - - -. - - :Eli - . - - - - - . . . . IUTEUSiTYDUMT1or1 DESIGN.CHART 1984. f4i:[LI1. Equation: I 7 44 p D Directions for Application: N'kJ LI 11111111 - 645 L 0 6 : 1) From precipitation maps determine 6 hr. and • -.r - Intensity (In./Hr.) 24 hr amounts for the selected frequency. I 1i These maps are printed In the County Hydrolo I I P6 6 Hr. Precipitation (In.) . Manual (10, 50 and 100 yr. maps included in - . . ii • . . Design and Procedure Manual).. 4.I 1 j I D Duration (Min.,) p 1 •• . •1 2) Adjust 6 hr. precipitation (if nece.sary) so -F .. that It is within the range of 45% to 65% Of 3. — .f I.. . . . . .. :. .1 I J . . the 24 hr. precipitation. (Not applicable I j to Desert) .' :! 1f ! !I 1 Ii !:. ! 3) Plot 6 hr. precipitation on the right side 2 , p I •' ' I I '. . ' of the chart. 4) Draw a line ti...ough the point parallel to th 1 • It •. I I ' I . ;', !Ii plotted lines. Ii . . I ' ••• :'I L Too . 5) This. line Is the intensity-duration curve fo L .................. . . . '. •-)6.0 the location being analyzed. I I III !II f •. . '. . I'i'S 5 ..'. .... j . .1. .. 'I' !I 1.1 •' •..!,' L15.0 0 . .. .. i.I •_J 114 . I jjii • I j• 'h' 4.0 . Application Form: 6 • .J • ' I 'k11f3'5 0) Selected Frequency O yr. S . • lj ii -I. j .j''i4;. jj)fl3.0 . * I . Ij I I l . 1) p6 4 P24= .0 . P6 = .LL f 'lI1Hi' . •0 0 24 2) Adjusted * in. I I I . IHçj -HIH LI •. _.j•. 3) t.5O mm. 'I 11111 III I -. . fitli ff1 - Ffftti1fl1T1 J 4) 1 in/hr. 1.0 . *t Applicable toDesert Region ------- ---- - loll I EX 10: 20 30 OP 11A 11121 This chart replaces the Intensity- Duration-Frequency curves used since 1965. . rn .0 r.. INTENSITY?DUMT1ON DESIGN CHART . 1984. f.j]IiLJI 11 Ii ifi [J [rthnuuuli IçL.LL.LJ LLzjñ1;; Directions for Application: ..rrw 1.1 11111111 Equation: I - 7.44 P D & . . 6 1) From precipitation maps determine 6 hr. and ..I I Intensity (In./Hr.) . 24 hr. amounts for the selected frequency. I l These maps are printed In the County Hydrolo P6 6 Hr. Precipitation (In.) Manual (10, 50 and 100 yr. maps included in . Design and Procedure Manual). . D Duration (Mm.) . 4 flq . . . .1.1 2) Adjust 6 hr. precipitation (ifnecesry) so I. . -. . . .1 I that It Is within the ranqe of 45% to 65% Of - .f I. . . .... .1.. i the 24 hr. precipitation. Ulot applicable to Desert) 3) Plot 6 hr. precipitation on the *righ t side of the chart. iI ! I . ! III I!1' . •, III -' J 4) Draw a line tt..ough the point parallel to th liII,ii I .• I I I ,tbll% plotted lines. Ild Iii i & . . 5) This line Is the intensity-duration curve 10 : L• • • ••.• • S .ir;. •0 .. the location being analyzed. 1 s I i iii 'i: .1 ft hIt II j II 4.5 • • I I j; 4.0 Application Form. 6 .: ........11. I . ....... I . : . . I ' ' !! • • I, I I '11i 0) Selected Frequency /00 yr. j •I...•I •I • •' 1 • • I 3.0 5$ — .........4.. II •I I i . -I •i). • . 1) •P6 aZ,?'_ 24 = I f I I!:: J •! .rf 24 2.0 2) Adjusted * 2.7 in. .•1. 1I ri 1.5 3) t 50 mm. 4) in/hr. . . . •• .. 1.0 *Not Applicable to Desert Region S S This chart replaces the Intensity rn - - S S Duration-Frequency curves used since Zs 20 30 40 50 1 •. 2 •. 3 4 ,,. 6 . • 1965. • S.-.. Cfse,,tt,E3 Vif FZ6w Ar EJrRA#,'CE A ( #11,4 !! O.YE b' hL +42,8 237/. c 1'100'YEAIZ 41.3#42. 2O.6 +104..46+.1.9 +49,927,/ A 'r 90 5;eA VoOY 4 Pi e'# f £7. - 13 , ft7,f *,9 if 0 33.O+VLOtI ,*B3 ,T t.H. • ••. ' + 3 917, + 32, 2 S 3 I •c /00 O.1,8*/02,7 •• • I 4 C 2 II. S C FS ;C,RLsp cBP S'rervVt4 j OJB B/z/19 I LATEPYrRAMOF. C -( h7.roo Al lea + tfj- I !Li ±9 t .29.+Z43 +2E.7 21 ~51 5 CF I 3O4 43),cf +,+7Zô + i i t c I 00 6,C) f 3 9,2 1-) 1 CF T I I I S 1 : S I I S I .1 . ., •5, . • S • APPENDIX B STORM DRAIN HYDRAULICS FRASER & ASSOCIATES, Consulting Engineers o, _____ - • •c 1 • -. 0 /.''O /7 • 7 C •t/-.Y. . • • A !./J • I I I . I I I. I I I I I I I I I I I . I. FRASER & ASSOCIATES, Consulting Engineers 3.93 f/ra<' 6i : J3, jLp • 4t_• .• -- _,---_ -.-• . &_• - - 44. / -4 - - -- .• .r4- 2 -- :-• '= - - - -- - • - -4 - - - Jo e NO. BY SUBJECV' DATE SHEET NO. FRASER & ASSOCIATES, Consulting Engineers 6 .i• J7 117 le 7/• 1' .:i/ t . -. • -r4- I .-.L4-.4--. .it ---4 --. • - .j--i- - 7,4 I • •• H -- - DATE SHEflNO. F I I I I I I I I I I I I I I I