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Home My WebLink AboutSDP 2018-0014; 635 PINE AVENUE CONDOS; PRELIMINARY HYDROLOGY & HYDRAULICS STUDY; 2021-02-23- - - Preliminary Hydrology & Hydraulics Study SOP 2018-0014 / MS2018-0011 635 Pine Avenue Condominiums at 635 Pine Avenue Carlsbad, California 92008 Dwg. No. APN: 204-082-01-00 Prepared For Tony Cassolato 576 Camino Eldorado Encinitas, CA 92024 Phone: 619-823-3602 Prepared By Landmark Engineering Corporation Lawrence E. Cole, RCE 36292 3443 Camino Del Rio South #204 San Diego, California 92108 Phone 619-260-0420 ~ RCE36292 Exp. 6/30/22 Project #2462 February 23, 2021 - ~ ~ TABLE OF CONTENTS C INTRODUCTION ,,,,... PROJECT DESCRIPTION METHODOLOGY Existing Condition Hydrology Post-Development Hydrology HYDROLOGY CALCULATIONS INTENSITY-DURATION DESIGN CHART (100-yr Tc= 5 min.) INTENSITY-DURATION DESIGN CHART (2-yr Tc= 5 min.) RAINFALL ISO PLUVIALS 100-YEAR 6-HOUR PRECIPITATION 100-YEAR 24-HOUR PRECIPITATION 2-YEAR 6-HOURPRECIPITATION 2-YEAR 24-HOUR PRECIPITATION RUNOFF COEFFICIENTS FOR URBAN AREAS (Table 3-1) -CONCLUSION CERTIFICATION REFERENCES ATTACHMENTS C DRAINAGE MAPS C DRAINAGE MAP (EXISTING) DRAINAGE MAP (PROPOSED) ,,,,.. ,,... C - -- - INTRODUCTION The proposed project site is located in the City of Carlsbad, County of San Diego. The project is located at on the southeast side of Pine A venue between Roosevelt Street and Madison Street. It is bordered to the northwest by Pine Avenue, to the northeast by an unnamed alley, to the southeast by existing developed property and southwest by Roosevelt Street. The Assessor's Parcel number for the project lot is 204-082-01-00. The project proposes grading and improvements for four residential condominium units. This drainage study calculates the peak stormwater discharge entering and leaving the project site (onsite and offsite drainage) in the existing condition and after development. PROJECT SITE DESCRIPTION The project proposes 4 residential attached condominium units. Each unit will have a two-car garage with access from a driveway which is entered from Roosevelt Street. The project proposes four on-street guest parking spaces on the southeast side of Pine A venue. There is no on-street parking in Roosevelt Street. - - - - METHODOLOGY Storm water runoff was calculated using the Rational Method as outlined in the San Diego County Hydrology Manual, dated June 2003. Stonnwater runoff was calculated for an existing and post- development condition resulting from the 100-year, 6-hour storm event for the project and its drainage area. Standard intensity-duration curve data was used for the San Diego region supplied in the Manual. The soil group used for the site and in the drainage area is soil hydrologic Group B from Map Soil Hydrology Groups in County Hydrology Manual. EXISTING CONDITION HYDROLOGY The existing project site drainage area is approximately 0.420 acres. The site varies in elevation from a high of 39.90 at a point on the southeast property line to a low elevation of 39.02 at the northeast corner of the project site and to the lowest elevation of 37.48 at the POC in the cross- gutter of Roosevelt Street. The calculation, the 0.420 acre drainage area in the existing condition is divided into 2 separate basins (see Drainage Map (See Drainage Map (Existing)) each described as follows: Area E 1 is a portion of the northeast half of Roosevelt Street and a southwesterly portion of the property on the southeast side of Pine A venue Street that flows to the northeasterly gutter in Roosevelt Street and then northwesterly in the gutter away from the site. The stonnwater flows to POC#l at a point in the northeasterly gutter of Roosevelt Street and confluences with stonnwater from Area E2 described below. The runoff flows northwesterly to the southwesterly gutter of Oak A venue the surface flow southwesterly along Oak A venue through a series of cross gutters toward the Pacific Ocean. Area E2 is a portion of the southeast half of Pine A venue Street, a northeasterly portion of the property on the southeast side of Pine A venue Street and the full width of the unnamed alley that flows to the southeasterly gutter in Pine A venue and then southwesterly in the gutter away from the site. The stonnwater flows to POC#l at a point in the northeasterly gutter of Roosevelt Street and confluences with stormwater from Area El described above. The runoff flows northwesterly to the southwesterly gutter of Oak A venue the surface flow southwesterly along Oak Avenue through a series of cross gutters toward the Pacific Ocean. -- - - - C - METHODOLOGY (continued) POST-DEVELOPMENT HYDROLOGY The project site drainage area is approximately 0.420 acres. The calculations for, the 0.420 acre drainage area that is graded or disturbed is divided into 2 separate basins (see Drainage Map (See Drainage Map (Proposed)) each described as follows: Area Pl is portions Area El and Area E2 that flows to the northeasterly gutter in Roosevelt Street and then northwesterly in the gutter away from the site. The stormwater flows to POC# 1 at a point in the northeasterly gutter of Roosevelt Street and confluences with stormwater from Area E2 described below. The runoff flows northwesterly to the southwesterly gutter of Oak A venue the surface flow southwesterly along Oak A venue through a series of cross gutters toward the Pacific Ocean. Area P2 is portions Area El and Area E2 that flows to the southeasterly gutter in Pine Avenue and then southwesterly in the gutter away from the site. The stormwater flows to POC#l at a point in the northeasterly gutter of Roosevelt Street and confluences with stormwater from Area El described above. The runoff flows northwesterly to the southwesterly gutter of Oak A venue the surface flow southwesterly along Oak A venue through a series of cross gutters toward the Pacific Ocean. - -- - - - -- HYDROLOGY CALCULATIONS Area< 0.5 square miles. Use Rational Formula Q100 = CIA ~ = N33 ° O 9' 2 8 . 9 4" A= Wll 7 ° 2 O' 4 3 . 5 6" From Hydrology Manual Soils Map -Soils Group B Developed Site (Existing) 33.2% impervious Commercial & Residential (Proposed) 76.7% impervious C = 0.47 C = 0.56 From INTENSITY-DURATION DESIGN CHART Loo= 6.59 in/hr. Tc= 5min Iz= 2.90 in/hr. Tc= 5min From Existing Drainage Map POC#l Area El: Area E2: Area El: Area E2: From Proposed Drainage Map POC#l Area Pl: Area P2: POC#l Area Pl: Area P2: Area E 1 = 0 .15 5 acre Area E2 = 0.265 acres 0.420 acres Qwo =CIA= (0.47)(6.59)(0.155) = 0.48 cfs Qwo =CIA= (0.47)(6.59)(0.265) = 0.82 cfs 1.30 cfs Qz =CIA= (0.47)(2.90)(0.155) = 0.21 cfs Qz =CIA= (0.47)(2.90)(0.265) = 0.36 cfs 0.57 cfs Area Pl = 0.155 acres Area P2 = 0.265 acres 0.420 acres Q100 = CIA= (0.56)(6.59)(0.155) = 0.57 cfs Q100 =CIA= (0.56)(6.59)(0.265) = 0.98 cfs 1.55 cfs Qz =CIA= (0.56)(2.90)(0.155) = 0.25 cfs Qz =CIA= (0.56)(2.90)(0.265) = 0.43 cfs 0.68 cfs ••• •••••••••••••••••••••••••• •••••••••••• 10.0 ,.....,,...........,.....,.....,......,.......,.,.--,.....,.-,-1-,-,--rr+,-rn'MTntT'1",'.rniTIITT!'TT'lfrnl'l"TlTT:TITT+-.-t1TT,r"IT!"TTT!T7tTITit 601 "-l ; "kl: F'k.F'i-'1:7",-N-L'"i•P"K.i l 11 llliili!lll l 11111 : 1:; I Ill: I 2.0 I i i l'iJ : I i I f II~ 11 : fTtiml I I mtH{I I ~; Hfl~~; 11 . 1 I I II l I; 1111111 Ol ::i: :5 : i , . ,, ..... j.J I I . ~rk.l 1 '1'! t li-'I ! N I I 1'JI' Plr:s ,-..,~1'11 r-1 ·t "'' f".,•,1 11· !· g 0 ' ' I l'r-, I; i1' I I ' II I J JI 'I ' I • r,. I .. ' -, f: I I ' : I ' ' ' '' I I"' I 1' ·, ... ' I ' -;.. ,,..., ' :\l :ll ' · 1 ', , 'Iii , I r-, ~ ' 1 ,~J' ro g10 , 1 1 : 1 ! ,~ .. ~ ;11 , n~ : l1tt 1,1:1.~~:; 1-~ ,,~~i. 1+1 • 6.0~ """o.9 I 1 ; ! i 1 , ~K.li I I : N-:, , l l.':'!,.l.lld ld~ 1 N 7' :1-J N-i lf'! 11:ii 5.5 ~ ~ ; I I I , ; ;; N :I i 'ti .: !II '!!NI-., i !"'N. I "r-J . : !l's11 5.0 g ffi0,8 'I. I i I,' 1-1. ! I! ,,, 1.:J ll,ilq,.,'i---l 17 I ~-i \i-i..l]: .!1 1 4.5'§' +-Q.7 , , , , · · , ,,, tr,ir. :·!i ! 1"'-.. 1 , ,lfi,1 E I ' i 1. ! I ' ,, :· I 1 .. i ••;• 1111• "1 ·•~q ' ! N.; ' I '~I ''I'• 40 g. I , I I' II N, , ' !I I , . I , ! . ~ , ' NJ , · ro 0.6 1 1 ~ t ; ~ 1 , 1 : ; : ; I:: ~ i 1 '. i : I : t : ; 1 : : 3.5 ~ I '. ' I ! I ·I 1',,.l! 11 'I I '; 11 , ,,.. : I ,... ...,,, I "' ; ' .. '' ,, I : I 'f'I' l!i I I l ' ' ,... f' l i I, 0.5 . I , : I I ,,!, 1 ii; ·:ii: , .... , , , ~ , I : ~ , :·~ 30 1 1 . :. , Ii ?s muih: N ' , 1 , ~! I rn ! I,; I I .,, :/1· ! , ! , ! "'j,.' ~ 04 I ' L I ":ih '' ! ! ' "' ". l ,, 1,,1, 2.5 ' I I ' I '"l[ipi ~·• 'I ·~· ,,·,11'1' , , 1 I I 1 : 1!,q. r;..., i : 1 ~ i i ,l . · 1 1 1 j 1!1 ! I I i ii,,; ! I ~I l I, '1-NJ J. i 2.0 03 -,.t 0,11 ! ! , I ~ ' "I I 1 " I I I ill l l •jl•ti •ll,,I ;' "l""i"""' "'' 'i I I ' j • ""' I""'' 5 6 7 8 9 10 15 2.0 30 40 50 1 2 3 4 5 6 Minutes Hours Duration 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 applicapte 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 _.!.QQ_ year (b) p = 2.5 in. p = 4.1 ~ = 60.9 %<2) 6 --• 24 --•p - (c) Adjusted P6<2> = ~ in. (d) lx = _5_ min. 24 (e) I= ~ in./hr. Calculated by formula Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. I P6 l 1.5 2 2.5 3 3,5 4 4.5 5 5.5 6 Ouro11on l I I I I I I I I ' l 5 2.63 3 95 5.27 6 59 7.90 9.22 10.5-1 1 i,86 '13.17' 14 49 15 81 7 2.12 3.18,424, 5.30 6.36,7.42 8.48 9.54 10.60 11.66'12.72 10 1.58 253 3.37 4.21 5.05 5.90 6.74 7.~8 8.42 9.27 10.11 1s 130 u,s· 2.59 324 -3.89 4.54 s . rn 5.84 6.49 7.13 , 7.78 20 1 08 1 62 2.15 2.69 3 23 3.7i' 4.3i 4.85 5.39 5.93 6.45 25 0.93 HO 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 4.55 4 98 40 0.69 1 03, 1.38 I 72 2.07 2.41 2.76 3.10 3 -15 3.71] 4.13 50 0.60 0 90 'I 19 I 49 1 79 2 09 2 39 2.69 298 3.28 3.58 60 0.53 0 80 1,06 1.33 t.59. 1 86, 2 12 2.39 2.6S 2.92 3.18 90 0.41 061 0.82 1.02 1.23 1.43 1.63 1.84 2.04 2.25 2.45 120 0.3•1 0.51 0.68 0.85 102 I 19 1.36 1.53 1.70 1,87 2.04 150 0.29 0.44 0.59 0 73 , 0.88 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 O.i'G. 0.87 0.98 1.08 1.19 1.30 300 o. 19 o 2s o.:38 · 0.47 o 56 o 66 o.75 0.85 0 94 1.03 1.13 360 0.17 025 0,33 0 .. 12 0.50 0 58 0 67 0.75 0.84 0,92 1.00 FI GU R E ~ ••• •••••••••••••••• ••••••••• •••••••••••• 100 ' · • I! , 'I· ', '· ",,, ,,,1 ! i Iii, ';Ii · ---..........1 • i j j · 1 1 ! : 1 1 ! i ; ;q. _ 1 I , \ ~ 1 \ ! j _N.1"-~~ ~ . , . ·, ,,., i',l:':' . 1, : lj, :j , 9.o ......_. 1'. i~r i ·, J, .iJ !!J ::" : µ14;, : . ' !'!' JI: 80~j i--· . ..., ~fill i,r';~ II !1 J il ,I, i ! 1d!:11i 'i ! ' "" :Ii: 7.0 ,.. , • ,,_ , • ,... , 1 ., 1 Iii ' t t EQUATION I :I I'-' '1'!:: I'-' '1 · '-4-N~?1f~:' 11 'll"l'"l ·II I' I I I: 1; 111111;1 6.0 ~ j I 17'[ -x_T ~ , t t !! 11 ! I I · ~, , = ?.44 P6 o·0.645 = Intensity (in/hr) i I 'd' Tm • It i1 2.o r,-+'~:-t-t-t-t-r~t-H+tfl'i~m lffi!:H+H-FH.i-H~~~~~J-kl~4-I-Wl++.,µ.;.1.W+i+jWLJJl. O') ~ I ::\: ~ 0 0 C C ~ -~ ~ ro C n g 10 t--t-+-t-+-H-++-H +-t-+-t-rl-F,,,H+t++lffiH-H-i++H-++H#++t!'j~~~iri-+--'1~-l-l-"!,,,!-P~~~~~~ 6.0 'E. ~0.9 t--t-+-+-+-H-++-H+i-+-t+t++t+fN.l-lffiH-H-i++H-+'l'k:H+tl+l-l+H~-M,++cii-+~.+-i-+!'h--.~µ:.,1+-1=>.i.:,;J. 5.5 ~- -~ o.Bt----t-+++H i-++H+t+f++++-H+H+~~+4-!+++H+l+-1.!-H.ll+!+l++~kl-+-l~.J-l-P~i-l-l~~~~.!J. 5 .. o g El o 7 t--t-,--t-+-Hl-++-H +-t-+-t+t++t++H+itWH-m~H-++tt#+tl+l~+tr++l#+~l-+-l-l~i--1-i~J-H~~~.ll-4 .5 S-c · n 4,0 ffi 0.6 t--t-+++-H-++-t-++-t-+-t+t+t-H+t++-M4tt!+H-H-+~+l+tl+l+l+!+!-i+~i,,;-+-ii-+~..Wi--l-iH4,4,l~.W-W::iSI-3.5 ~ 051 l : l 11 l : ! l :11:1:1111P!ll !IPillllllllllH:ql fltl~!L:.l:I I ;1 '1 11;TtNJ :l:i:l itl iffll 30 0-41 · 1 -, 1 1 , · 1 1 111T 111 w·1111r11111 ,11 11111;,•11111w·•n rrn,t. 1 · : 1 Ti'-1-J -11 : r~r 111 25 ' f ~l ii { ,.J . I,!~;l ; l ~ I ! '1 1~ ~1! ~ 11l'i 2,0 03L L J t1 I 0.21 ! l , I i ; .. 1.0 + iy 01 1 '' 1 1 I ' 'I 1'"I""''11'1'"1""1"''1 ·"'I , 5 6 7 ~ 9 1'0 15 20 30 40 50 2 Minutes Hours Duration 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 (1 0, 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 _2 __ year p (b) P6 :c _1.2_ in., P24 = _l_.8_ .~ ::= _§_]_ %(2) 24 (c) Adjusted p6(2l ::= _l_. l_ in . (d) tx = _5_ min. (e) I = -1.2Q_ inJhr. Calculated by formula Note: This chart replaces the Intensity-Duration-Frequency curves used since 1965. PG 1 1.5 2 2,5 3 J,5 4 4.5 5 5.5 6 Duration I I I I I I I I I I l 5 263 395 5.27 659 7,90 922 10.54 11,86 1317 14491581 7 2. i2 3.18 4.24 5,30 6.36 7.42. 8.48 9,54 10,60, 11.66 12.72 10 I 68 2 :i3 3.37 4.21 5.05 5.90· 6.74 7.58 8A2 . 9 27 10.11 15 l.30 l 95 2.59 3.2.) 3.89 4.54 5.19 5.84 6,.19 ' 7.13 . 7.78 20 l.08 I 62 2, 15 2,69 3 23 3.77 4.31 4.85 • 6.39 , 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 l.24 1.66. 2.07 2.49 2.90 3.3:.! 3.7'.1 4.15 4.55 4,98 40 0 69 1 03 1 38 1.72 2.07 2.41 2 76 3.10 3 ,15 3,79 4.13 50 0,60 0.90 1.19 1.49 1 7~ 2.09 2.39 2.69 2.98 3,28 . 3.58 so o.53 oso· 1.00 1,33 1.59 1 86 2 12 2 39 2.65 2.92 ' 31a 90 0.4 l . 0 6 I 0.82 1.02 1.23 1 .43 1 6:l 1.84 2.04 2.25 2.J5 120 0.3'1 0.51 0,68 0.85 l.02 I 19 1 36 1.53 1.70 1 87 2,04 150 0.29 0 44 0.59 0.73 0.88 l 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. HI 1.30 300 0.19 0 2s' O.:iS 0.47 0.56 0.66 0 75 0.85 0,94 1.03 1.13 360 0.17 0.25 0.3<3 0.-12 0 50 0 58 0 67 0.75 0.84 0,92 1.00 F IGUR E r ... . .. l 3-1 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • r 1 . I . ,, i ·, I j I ·=;,.,,,,,..,.__, + J .. l. \ L C • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • :: . ---, -· L __ --J~t-,! -. .. ,. ~ -~-~ ~ ; -~--~-~ ;··. -L ~ j -' 1 ~ i ri,Y--JI .,# k r ---·r-~~~~~-;-·--------;~ -~ ., \ ;_,,-7':S I~-; -~ ~ _, i ~~~~= ~ I ~~~ .i ; --~--t"'""""'--.-.. i . -6, '-· ~ ~ -" ' L . ""-;:_·#··1· -. '~ ,'~ \ l == ~-\~ , ' - I I -.. ------1--' 1 I ~-----+,•-· ' 0 .,..._. ,_,...,,.k \)/ ""I >-----•-1= + ~~ , _, , -+- .C:.. ! : • ;---t,{.\;J Jc~ -~ 'W ' :-.. ,, 0 ) .... -.....; / 'I -_! ,n. r -· ■._)~. v+ --• t 1 , 1..,0.::~v I Z ; • ---r--· t -t -~<(--: 'I : ' I I :W ··'i ···· ··· ·•· 1 ---i ---ttl·-+ <' • 10 ' ' ··-·; -'' --+-·-·-·· _, --t ,( ·-· _,_; --··-·--•. ~ I ( l -~--"1 i I -+-! ' --+-··- I i r---r-- i . .. -r w I-' (f) ,._ .c ,q-N I ,._ >, 0 0 ~ • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • I ., # ,, , # ~ j<~ ··,;:!, ' ""'·,k l /1-. , # # , , "',t"' , ' .. T r:Z ;(.) z w l '~--~ -c r I ! ~ ; V .. i '\ . .. ,. ' ,~· :~?' .' = i-.c \0 I i-;;.-, M • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • I ~-'!"'·•--_,,._-----;- .. ! t ,t ~1 • I I LO ~ 0 en C') ,,,,,._ · .. ·El en z ;< w C.) 0 />/ \ _f r L L l_ ,, n n ' ' • ·1\ , n ~ 8 n z, n ;1 ,. I ~ l -l n I\ 'ti ~ , .1 f'. .~ 1 1 :, J!Rt1"t 1·1-"t ; , ·: ~ I 4. J t J San Diego County Hydrology Manual Date: June 2003 Table 3-1 Section: Page: RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use I Runoff Coefficient "C" Soil T~ee NRCS Elements Count Elements % IMPER. A B Undisturbed Natural Terrain (Natural) Permanent Open Space 0* 0.20 0.25 Low Density Residential (LOR) Residential, 1.0 DU/A or less 10 0.27 0.32 Low Density Residential (LOR) Residential, 2.0 DU/A or less 20 0.34 0.38 Low Density Residential (LOR) Residential, 2.9 DU/A or less 25 0.38 0.41 Medium Density Residential (MOR) Residential, 4.3 DU/A or less 30® 0.41 0.45~ 0.47 Medium Density Residential (MOR) Residential, 7.3 DU/A or less 40 0.48 0.51 Medium Density Residential (MOR) Residential, 10.9 DU/A or less 45 0.52 0.54 Medium Density Residential (MOR) Residential, 14.5 DU/A or less 50 0.55 0.58 High Density Residential (HOR) Residential, 24.0 DU/A or less 65 0.66 0.67® High Density Residential (HOR) Residential, 43.0 DU/A or less ([f.j) 0.76 0.77 .75 80 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 I.) Limited Industrial 90 0.83 0.84 Commercial/Industrial {Gerieral I.} 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 0.78 0.78 0.81 0.84 0.84 0.87 3 6 of 26 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 Cp=0. 90x(%imper)+0im!)er( 1-¾imper) Exist Cp=0.90xt-)32)+.25(.668)=0.47 Proposed Cp=0.90x(.767)+.25(.233)=0.7S 3-6 l 1 rt -- - tt.:: -' - C -- CONCLUSION 1. The proposed project does not substantially alter the existing drainage pattern of the site or area. No flooding will occur due to development. 2. With no reduction in Time of Concentration, the peak Q at POC#l is increased from 1.30 cfs to 1.055 cfs, or by 0.25 cfs. Routing the flow of stormwater to and through the driveway pavers further reduce the post-construction Q to less than or equal to pre- construction which is satisfactory. The flow through landscape areas will treat the runoff adequately. Added Time of Concentration will reduce Intensity sufficiently to also be satisfactory. 3. The proposed project does not create or contribute any runoff water which would exceed the current capacity of existing storm water drainage systems. 4. Hydrology Report Summary: EXPECTED RUNOFF DISCHARGES (ii), 5 minutes Outlet Tributary Area Ql00 Peak Q2 Peak Discharge (Acres) Discharge ( cfs) (cfs) Pre Post Pre Post Pre Post POC# 1 Roosevelt 0.420 0.420 1.30 1.55 0.57 0.68 Total 0.420 0.420 1.30 1.55 0.57 068 Outlets shown are based on changes per development of the project site. Storm water runoff was calculated using the Rational Method as outlined in the San Diego County Hydrology Manual, dated June 2003. Stormwater runoff was calculated for an existing and post-development condition resulting from the 100-year, 6-hour storm event for the project and its drainage area. Standard intensity-duration curve data was used for the San Diego region supplied in the Manual. *POC#2 is the only one which requires mitigation to reduce Post to below Pre. See conclusion no. 2 above. - - CERTIFICTION Report Preparation I certify that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to ensure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system or those persons directly responsible for gathering the information, to the best of my knowledge and belief, the information submitted is true, accurate, and complete. 'fl": CIVIL ENGINEER C .,.. Lawrence E. Cole, RCE 36292 February 23, 2021 Date C -' tr; REFERENCES 1. County of San Diego Department of Public Works Flood Control Section, San Diego County Hydrology Manual dated June 2003. 2. County of San Diego Stormwater Standards Manual. cc, v5 x L,.J ------<t-, EX. SIDE:WALK C0 w--- x Cw ! I 2 !:2.- EX. n FH 9 EX. CON.C 270'± I ' I ' / I 3 I ) Ul w ----- z < ;:,; IL w $ w w o_ - §; x ~ I <d I \ ' I +I c:, ~ 1-- ...J w > w V) 0 0 a:: P1 2-3"PVC -t- RSD f 27 ,:-:,. FL37. 9 , i i w "' 65 x w I p c; z 8 ' ,r , I: :-r", i \_, w > ~ 0 fr; L'J ! ,-, 'L-L.... 1,...... __ ! '----" i: I :: i! ii !! c:, N ----i,;:g Vi---+ '/ ai,1. i.,·--"'rt=='===i ,. V r . (Q....._ i ! i l : I .. ,-;::, ~ PROPOSED i WATER ESM'T LANDSCAPE AREA UNIT FF 40.20 GF 39.85 2-CAR S GE 1 4 4. ". i'l ?"". ,,---; 8 i! J.------E:X. PLAN i t:.R z r_, n w 6"X24" CUT- OFF WALL EX. BUiD:NG (Fr 4-C.60) LOT 1 BcGCK 40 ;\/A? NO. 775 ----- FS40. O LANDSCAPE AREA LOT 16 UNIT 2 FF 40.20 GF 40.10 ,..--.") 2-¾R s AGE 4 w PINE AVENUE I PROPOSED CURB & GUTTER ",. EX. CONC tSMl• Cl . LANDSCAPE AREA w--- ' UNTT 3 P2 EX. PORC!-3 i FF tQ.20 W GF . 1 i0.10 11543.35 SF 0.265 AC S 2-CAR AGE 'NIT 4 FF 40.20 GF 39.85 No. 5097 Exp. 06/30/21 'N--- No. X a..!..C >-w ...J ...J <( u 8 X w I C: r..r; < x c;..J w--- t IA ~ ' 15 '± ' ,"'-[ -·:, !._\) ! I ,-, -,-~ ,-.. LJ: lj REVISIONS Description Approved Date SITE DEVELOPMENT PLAN TENTATIVE PARCEL MAP SOP 2018-0014 ,MS 2018-0011 ~ VICINITY MAP NO SCALE LEGAL DESCRIPTION: LOT AREA 6994.7419 SF IMPERVIOUS AREA 3370 SF 48.2% IMPERVIOUS LOT 15 AND 16 IN BLOCK 41 OF TOWN OF CARLSBAD, CITY OF CARLSBAD, IN THE COUNTY OF SAN DIEGO, STATE OF CALIFORNIA, ACCORDING TO MAP THEREOF NO. 775, FILED IN THE OFFICE OF THE COUNTY RECORDER OF SAN DIEGO COUNTY, FEBRUARY 15, 1894. THAT PORTION OF PINE AVENUE AS SHOWN ON AMENDED MAP OF THE TOWN OF CARLSBAD, MAP NO. 775, SAID MAP RECORDED IN THE OFFICE OF THE THE COUNTY RECORDER OF SAIN_ SAN DIEGO CQUNTY_.__MORE_P...ARilCUl.AfilY. -DEScR"itJE!J AS FOLLOWS: ~ ~. THE SOUTHERLY 10.00 FEET OF PINE AVENUE ADJOINING LOT 16, BLOCK 41 OF SAID MAP NO. 775. ASSESSOR'S PARCEL NUMBER: 204-082-01 -00 DRAINAGE MAP (PROPOSED) FOR: 635 PINE A VENUE Carlsbad, CA PREPARED FOR: TONY CASSOLATO 576 CAMINO ELDORADO ENCINITAS, CA 92024 PH. (619 823-3602 L E C LANDMARK ENGINEERING CORPORATION 3443 Camino Del Rio South Suite 204 San Diego, CA 92108 (619) 260-0420 Sht 1 of 1 Date: 21/-Z."?>fZ.i. Dwn. MC Apr. LEC Dwg. No. 2462-SD-1 EX STCP P SIGN (Sa) ] i r ---Y ~-,I C/) ------I c::) ~ =5 < "' L._j C, u'j x u ' ,-, ( 0 \ \___ 'J '-\..--.. \~ ' '? \~ \' . ' \--.:'!, ·~. .<" i I I I i i ,. 'I " ~ • ' :::r:::8:'.: ::c::;::! :=: ,-Ucc, "' i'.:J<>c -:,1 :~1 -~, \' <].'='' !_J\. ) I ~ 2:. !..,J z :s ·:...w "' m x w 40' I ! I ) I \ t--.....J LL.I > w V) 0 0 a:::: \ ,____,_j "' 65 x I ! I ' \ ! ~ cc :::::... i \40' \ s-.'.2- :z 8 x L: • .' u z 8 x LJ I _;..;· ' . ' EX. W~i C I I r1 / ! r I ! l ' ¾ EX. Cct<C ---(38)- 1 -1-"" ;,, ·-.~ ) :~ r 1·_;_.I I'-!--- ! x ~= 1: --~--- - E1 6741.52 SF 0.155 AC I'· X~' \ \ ,-_ jr-7---py Pl Pf1TC:-~ 0:.,...; _,,. ,_,,,1..,\ :2; Ld l'----- LOT 16 LOT 15 I DiRT BLOCK 4 MAP NO. 775 fv':AP 1\0. LOT ! 3L0Cl{ 40 :V:AP NO. 775 PINE I D~. :::.o[,;C CLOSED II~ PAT;O EX. BLDG AVENUE i i -------- I EX. H8USE FF 4:.93 X y r--: --,.,,.., u· z 8 2 i ' 0.-$'1 1-----------------------'·_i -i(:ic;; . .- '· --Ji ! /l's BENCH MARK CLSB-130 (SEE ROS 17271) SET 2.5" DISK IN SOUTHEAST CORNER OF DRAINAGE BOX INLET AT THE END OF CURB RETURN IN THE NORTHEAST CORNER OF GRAND AVENUE AND WASHINGTON ST. NGVD29 ELEV,: 40.91 0 No. I EX. CGl<C X LJ x k.: >-yJ .J ....J :,,<C ,--~37 -,Y u z Q u ' x - / ~ .,_..-\ ,~-~;,-,--, 1/ LCT 4 7 REVISIONS Description Approved Date / SiTE DEVELOPMENT PLAN TENTATIVE PARCEL MAP SDP 2018-0014 MS 2018-0011 LEGAL DESCRIPTION: LOT AREA 8396.56 SF IMPERVIOUS AREA 2822 SF 33.6% IMPERVIOUS LOT 15 AND 16 IN BLOCK 41 OF TOWN OF CARLSBAD, CITY OF CARLSBAD, IN THE COUNTY OF SAN DIEGO, STATE OF CALIFORNIA, ACCORDING TO MAP THEREOF NO. 775, FILED IN THE OFFICE OF THE COUNTY RECORDER OF SAN DIEGO COUNTY, FEBRUARY 15, 1894. THAT PORTION OF PINE AVENUE PS SHOWN ON AMENDED MAP OF THE TOWN OF CARLSBAD, MAP NO. 775, SAID MAP RECORDED IN THE OFFICE OF THE THE COUNTY RECORDER OF SAIN SAN DIEGO COUNTY, MORE PARTICULARLY ---DE:SCRfBl:[) AS ~FOI..L.OWS: ~~ -------~ - THE SOUTHERLY 10,00 FEET OF PINE AVENUE ADJOINING LOT 16, BLOCK 41 OF SAID MAP NO. 775. ASSESSOR"S PARCEL NUMBER: 204-082-01 -00 DRAINAGE MAP (EXISTING} FOR: 635 PINE A VENUE Carlsbad, CA PREPARED FOR: TONY CPSSOLATO 576 CAMINO ELDORADO ENCINITAS, CA 92024 PH, (619) 823-3602 L E C LANDMARK ENGINEERING CORPORATION 3443 Cami.no Del Rio South Suite 204 San Diego, CA 92108 (619) 260-0420 Sht 1 of 1 Date:8/07/18 Dwn. MC Apr. LEC Dwg. No. 2462-SD-1