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HomeMy WebLinkAboutCD 2017-0003; Kaiser Carlsbad Parking Lot Expansion; HYDROLOGY STUDY; 2017-06-01Prepared By: HYDROLOGY STUDY For: RECORD COPY \)FD /Jil, lnitial ·---·--- Kaiser Permanente Medical Office Building Parking Lot Expansion DWG504-2A PRE 2016-0003; CD2017-0003; DEV 2016-0024 Lots 11-13 of Map 10899 6860 A venida Encinas Carlsbad, CA 92011 RCE 68075 6/14/2017 EXP: 06-30-19 Pasco Laret Suiter & Associates, Inc. 535 N. Highway 101, Suite A Solana Beach, CA 92075 PASCO LARET SUITER ___ & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING+ LAND SURVEYING Prepared for: Kaiser Foundation Health Plan 8010 Parkway Drive La Mesa, CA 91942 June 2017 RECEIVED JUN 14 2017 LAND DEVELOPMENT ENGINEERING )£ 0 PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING June14,2017 CITY OF CARLSBAD LAND DEVELOPMENT ENGINEERING 1635 Faraday Avenue Carlsbad, CA 92008 (760)-602-2781 Re: Kaiser Carlsbad Parking Lot Expansion -Drainage Study To Whom It May Concern: Pasco, Laret, Suiter and Associates has prepared the following Hydrology Study Letter as part of the review of the subject project for an expansion of the parking lot at the site as described below. PROJECT DESCRIPTION The 0.48 acre Kaiser Carlsbad Parking Lot Expansion project site is located within the existing Kaiser Carlsbad Medical Office Building site located at 6860 Avenida Encinas in the City of Carlsbad, County of San Diego, California (APN: 214-450-19). The project s ite is located at Latitude 33°06'27"N and Longitude I 17°18'52"W and has a total area of3.16 acres. The surrounding area has been developed and is comprised of existing commercial uses to the north and south. Interstate 5 is directly east of the project with Avenida Encinas directly west of the site and existing residential just west of Avenida Encinas. The existing site is comprised of two (2) medical office buildings and an elevator/stair building, with an interior courtyard between the buildings. To the north and south of the existing buildings are patient and staff parking lots, respectively. The Avenida Encinas frontage of the site is parkway landscaping with an open landscape area in front of building 'B.' For the proposed condition, portions of the existing landscape area will be removed and replaced with asphalt parking area and a sidewalk connection added for pedestrian access to the Avenida Encinas right-of-way sidewalk. Storm water from the newly created impervious area will be treated via biofiltration BMPs along the project street frontage and be connected to the existing site storm drain. Associated utilities for the site parking area will also be installed, as necessary. The proposed project is designated as a Priority Development Project (PDP) regarding storm water, as outlined in the City of Carlsbad BMP Des ign Manual, dated February 16, 2016. Please see the submitted Form E-34 and the project SWQMP, under separate cover, for detailed information on the project's PDP designation. The project is exempt from hydromodification management requirements per the criteria detailed in Section 1.6 of the City of Carlsbad BMP Design Manual. Specifically, the drainage from this project site is conveyed via underground storm drain pipe from the point of discharge until it outlets at Batiquitos Lagoon, an enclosed embayment, which is included in the Carlsbad Watershed Management Area Water Quality Improvement Plan (WQIP), dated June 2016, as an exempt water body. Within the Carlsbad WQ1P, reference Appendix F entitled, "Hydromodification Exemption Analyses for Select 535 N. Highway IO I Ste A Solana Beach, California 92075 I ph 858.259.82 12 I fx 858.259.4812 plsaengineering.com KAISER CARLSBAD PARKING LOT EXPANSION HYDROLOGY STUDY LETTER JUNE2017 PG. 2 Carlsbad Watersheds" by Chang Consultants dated September 17, 20 I 5. The HMP Exemption Exhibit from this report is included in the project SWQMP, highlighting the project site within the HMP exemption area. EXISTING DRAINAGE The existing s ite drainage conveyance for the project site is urban, with area drains located throughout the site in landscape planter areas and in strategic parking lot locations to drain hardscape areas. The northerly parking lot area on the site drains to the NW corner of the parking lot and outlets via surface drainage to the Avenida Encinas right-of-way. Offsite drainage from the Caltrans right-of-way to the directly east of the site is conveyed through the project site via an underground 18" RCP storm drain. Just before reaching Avenida Encinas the 18" RCP confluences at a Type A-4 Cleanout with a 12" PVC storm drain from the southerly parking area and then continues to the west across A venida Encinas. Flow then continues north along Avenida Encinas for a short distance where the storm drain then turns west into Poinsettia Properties, Planning Area 5 (Ref. C.O.C. DWG 378-9), and then to Poinsettia Pro perties, Planning Areas 2, 3, &4 (Ref. C.O.C. DWG 396-7), via increasingly larger storm drain piping until a 60" RCP outlets to an existing 72" RCP storm drain within the San Diego Northern Railway right-of-way. This large main trunk line storm drain continues southerly in the railroad right- of-way and then along N. Coast Hwy l O l for a total of approximately I mile until its ultimate outlet via an 84" RCP storm drain to a rip-rap energy dissipater at Batiquitos Lagoon. (Ref. C.O.C. DWGs 399-7 and 337-9). (See the above Project Description for discussion on the project's qualification for HMP exempt status). PROPOSED DRAINAGE For the proposed condition, portions of the existing landscape area will be removed and replaced with asphalt parking area and a sidewalk connection added for pedestrian access to the Avenida Encinas right-of-way sidewalk. Storm water from the newly created impervious area will be treated via biofiltration BMPs along the project street frontage and be connected to the existing 12" storm drain or an existing storm drain clean-out structure on site. Runoff from the new impervious areas will drain via sheet flow to one of two (2) BMPs located along the project frontage. The new parking area and s idewalk areas (DMA 1) will drain via overland flow (gutters, and concrete swale) to the larger BMP. At the southerly end of the parking lot, where the new parking area entrance and 2 parking stalls are proposed (DMA 2), a trench drain has been added to capture flow from these areas and direct it to the smaller BMP at the project frontage. The outlet of the larger BMP will be an 8" PVC, connecting to a proposed re-built cleanout, while the smaller BMP will outlet to an 8" PVC pipe and connect to the existing 12" PVC storm drain from the southerly parking lot. DRAINAGE CALCULATION SUMMARY The storm water runoff calculations for the Kaiser Carlsbad Parking Lot Expansion have been performed in accordance with the San Diego County Hydrology Manual, dated June 2013. The Rational Method has been used to determine the I 00-year frequency storm runoff for the disturbed area of the site which was broken down into two (3) Drainage Management Areas (DMAs), maintaining the runoff pattern from the existing conditions of the site. In the post-developed condition described, runoff will be routed through biofiltration BMPs for storm water quality treatment before outlet to the existing storm drain. As described above, the s ite is exempt from hydromodification requirements and Hydromodification Management Plan (HMP) BMP sizing was not implemented, though the outfall of the BMPs will limit the runoff outflow below the actual post-deve loped runoff condition for each 535 N Highway 10 I Ste A Solana Beach, Californ ia 92075 1 ph 858.259.8212 I fx 858.259.4812 plsaengineering.com KAISER CARLSBAD PARKJNG LOT EXPANSION HYDROLOGY STUDY LETTER JUNE 201 7 PG. 3 OMA. The proposed overflow outlet (grated catch basin) at each BMP will serve as an emergency outlet for runoff above and beyond the outflow from the BMP storage and underdrain outlet provided. Below is a summary of the storm water runoff calculations for the site using the Rational Method from the San Diego County Hydrology Manual for the I 00-year frequency storm. Reference Enclosure (I) & (2) for the Pre and Post project condition exhibits and Enclosure (3) for runoff calculations. I \I\! I IO l)'\1 \ I (\:<lR III Sllll) Rl :\01 I Sl li\1\1 \RY CONDITION DRAINAGE Q1oo (CFS) AREA (ACRES) Existing 0.34 1.03 Proposed 0.34 1.75* Existing vs. Proposed Comparison More than Existing* *Proposed project flows are mitigated by the use of a biofiltration BMP onsite which mitigates the outflow from DMA I to 0.65 CFS from the 1.75 CFS shown calculated by the rational method in enclosure (3). Reference the Hydraflow Hydrograph Report output found in Enclosure (6) for annotated detention routing calculations. Due to the routing of the Q100 through the biofiltration BMP, the ultimate outflow from OMA I is well under the existing condition flow. Note that even if the full Q100 were outlet to the overflow outlet (grated catch basin) this increase (0. 72 CFS) is negligible (though not expected) at the ultimate outflow to Batiquitos Lagoon (Ref. C.O.C. Dwg 337-9) within an 84" RCP pipe currently carrying 323.2 CFS (0. 72 CFS = 0.22% of total flow) and having an ultimate capacity of approximately 812.2 CFS for which the project flow contributes only 0.09% of the full pipe flow capacity. Reference enclosure (7) for Hydraflow Express pipe capacity calculations and enclosure (8) for Dwg 337-9 as-built plans. I \Ill I 20lli\1\2(SOl 'IIISllll \II\\ DRl\"I \\ \Y) Rl \:< ll I Sl i\li\l.\RY CONDITION DRAINAGE Q1oo (CFS) AREA (ACRES) Existing 0.05 0.24 Proposed 0.05 0.22 Existing vs. Proposed Comparison Less than Existing I \ HI I , o D \ 1 \ , ( I Ro'\ I \ < i I I \ \I llSC \ I' I \RI \) Rl ,\I< >I I Sl 1 ,\1\I \RY CONDITION DRAINAGE Q1oo(CFS) AREA (ACRES) Existing 0.09 0.16 Proposed 0.09 0.15 Existing vs. Proposed Comparison Less than Existing 535 N Highway 10 1 Ste A Solana Beach, California 92075 I ph 858.259.8212 I fx 858.259.4812 plsaengineering.com KAISER CARLSBAD PARKING LOT EXPANSION HYDROLOGY STUDY LETTER PROPOSED PIPE FLOW SUMMARY JUNE2017 PG. 4 Proposed pipe capacities for the newly proposed storm drain onsite are adequate for the proposed runoff calculations above, with OMA-I outlet via a 12" PVC storm drain to the existing 18" RCP which the continues west across Avenida Encinas from the site. DMA-2 is outlet via an 8" PVC which connects to an existing 12" PVC onsite from the south parking lot and then continues offsite as described above. DMA-3 will continue to drain in the manner in which it drains in the existing condition along the right-of-way, having slightly lower total runoff than in the existing condition. Reference enclosure (5) for proposed pipe flow calculations. CONCLUSION The proposed project provides the required storm drain infrastructure to safely and efficiently carry the storm water runoff from the l 00-year design frequency storm per the City of Carlsbad requirements by way of the San Diego County Hydrology Manual. The project, therefore, meets the storm water drainage requirements of the City of Carlsbad. If you have any questions or comments, please feel free to contact me at (858) 259-8212. Sincerely, PASCO LARET SUITER & ASSOCIATES, INC. ll#fo0-~ Gregory W. Lang, P.E. Principal Enclosures: (I) Pre-Development OMA Exhibit (2) Post-Development OMA Exhibit (3) OMA Rational Method Runoff Calculations (4) 100-year, 6-Hour Rainfall Isopluvial (5) Hydraflow Express 12" and 8" PVC Pipe Flow Calculations (6) Hydraflow Hydrograph Routing Summary for OMA l Biofiltration BMP (7) Hydraflow Express Pipe Capacity Calculation (84" RCP Outfall at Batiquitos Lagoon) (8) C.O.C. As-Built Reference Plans (DWG 337-9) 535 N Highway IO I Ste A Solana Beach, California 92075 I ph 858.259.821 2 j fx 858.259.4812 plsaengineering.com Enclosure 1 .....____~ ___ Pre-Development DMA Exhibit I I I w I I 1 10 .... ~_._-1: / / / I EU..DNJS '1 / I I I w ll-,~---1 (EXJBTNO 2-STORY ib / I , / I GJ~~ // I I I AEDCAL.OFRCE) '/ \ I I 8 I \_ \ \\ ... nt.n .4 / =f!c=efI..lL--'-J..L-tt-~ L-------------\ \ : : (: I I I I I , \I I I I I ~ I I I I /\ ,' J DOSnNc PARKING \ / LOT TO R£MAIN £XJSTING PARKING_~ I" I i\ \ I / LOT TO R£MAJN I / I I I I I ,~. I I (rr ·-, ~ \ --............ , .................. " ~~~I; 1 \ .I 1 AW'._,! ( ~ o ( =~~~ I \ \ " .: \ " ~ 8 \ I I ' I~ . __,,,(.,~--~ J -~~~tt~~~~l~x:t~~l'ii:~~~~ ~1~~~, : 11 '1 ~-LOT TO R(UAJN ....._,...,,_,, ,_..,,1=<-=S<C I : \ \ AVENIDA ---s ----s . 11 ~1 Tf II ENCINAS I I ---mi_ s ---s -rt"----0 -ti--C/L -----11 ---- 111 11 s -- PLAN VIEW -DMA AREAS SCALE, I• • 20' ~ 20· 10' 0 20' 40' I t, I SCALE, I• • 20' ~ Know what's below. Call before you dig. LEGEND EXISTNQ STORM ORAN EXISTNQ HAIDSCAPE/ M'SIYIOUS - EXlS1NG l..NCISC»fiG/ PE!IYIOUS - CIIANACE MANACSAENT -(OMA) BOUC>ARY A.OW Dft:CT10N Aff'/.JW SOIL INFORMA TJON 90l.,Trf'EB SITE INFORMA TJON: M'EfMOU9 AIEk /'BMOUSA/EA, TOTAL. CISTIRlED A/EA, «lO-lEAR II-HOl.fl RAIFAL.L' 0.15AC 0.33AC 0411AC 2.5;, DMA SUMMARY DRAINAGE IMPERVIOUS PERVIOUS ==-==== ~ [%~~ ---._ TOTAL AREA MANAGEMENT AREA (AC) AREA (AC) (ACRES) AREA (OMA) 1 0.11 0.23 2 0.04 0.01 3 0.004 0.085 I PASCO LARET SUITER & ASSOC IATES CIVIL f.N3:N££RING • LA.NO PLANNIN~ • LA.hD SURYE11NG. 535 North Highway 101, Suite A Solana Beach. CA 92075 ph 858.259.8212 j fx 858.259.48121 plsaengineering.com 0.34 0.05 0.09 KAISER PERMANENTE -CARLSBAD PARKING LOT EXPANSION PRE-DEVELOPMENT EXHIBIT CARLSBAD, CALIFORNIA PROJl!:CT~Pl!2St2 SCALE·1·•2t:1 MT!:A.INl!:2017 SHEET 1 OF 1 Enclosure 2 ._ ____ Post-Development DMA Exhibit .. LOTl3 I MAP«-t I I ,( "-~ '-\ _J.°'-i-: . s -- ~ 20· 1 o· o 20· 40· I ~y I I SCALE: 1 • • 20· I I I I I 81.1..DNGA <EXBTNG:HJrORY ~ OFRCE) DOSTING PARKING _ I LOT TO REMAIN ~ 1r ·. ~\ ~ : ..._·,,_~ ~: \ \ ~ j~~--~ J ~ LOT TO R(J,,MJN '--'-......._/ --s AVENIDA s -- 81.1..DNGB <EXBTNG 2-STORr ~OFRCE) rp '1 ib I I / r- / -~-Y-CXJsn~c I HARDSC~ & ____.)-4" -------=:;;-.....,: ~ U.NOSCAl'f TO REMAIN-*~-:I j7 - LOTfl ,,,,--<XIS TING LAl'IDSCAl'tNG / -~ 11 ii 111 ENCINAS 11 11 s -n-~-------" I I I I I I I I I I I I I I I I I I I , ___ _ \: ,'~ \ / / I \/ / \ ) £X1SnNJ PARKING-( LOT TO R£MAJN i \ i \ I I I \ I \ I I ,' /\ \ I I \ \ I I I I \ \ I • : \ \ I I (IC/STING STORM '\ DRAIN INLET ' \ i: I I I -----:;=-=-) V: lL_ I -:t-'1~-- ~ C/~ -=----,I, -11----- 11 PLAN VIEW -DMA AREAS SCALE: 1• • 20' ~ Know what's below, Call before you dig. LEGEND PAOPOBED STOIM ~ PAOPOBED HAID8CAPE/ U'ERYIOUs />JEA PAOPOBED LNOl1C/>PH:J/ PBIVIOtJS />JEA DR»IAGE MANAOBENT />JEA (OMA) IIOIH)ARY R..OW Dll:C'l10N Aff'IC1#I SOIL INFORMATION 9;JL,TYPEs SITE INFORMA TJON: M'BMO!.ISAFEk l'EIMOUS A/EA• TOTAL 0071.fllB? A/EA• IOO-~ &-HOC.II 5TOIV Q31AC OJ7 AC Q43AC 25ln OMA SUMMARY ORA/NAG[ IMPERVIOUS PERVIOUS =-==-==-==-= ~ ~ ---... TOTAL AR[A MANAG[M[NT AR[A (AC) AR[A (AC) (ACRES) AR[A (OMA) , 0.278 0.066 2 O.OJO 0.017 J 0."./00 0.089 PASCO LARET SUITER & ASSOCIATES c,~n [fJGINHRING • LANO PLAN,..H(G • L"-NO SURVE/ING 535 North Highway 101, Suire A Solana Beach, CA 92075 ph 858.259.8212 I fx 858.259.4812 I plsaengineering.com O.J 4 0.05 0.09 KAISER PERMANENTE -CARLSBAD PARKING LOT EXPANSION POST-DEVELOPMENT OMA EXHIBIT CARLSBAD, CALIFORNIA P9'0.ll!:CT.....:Jt:Pl'251Z SCAL.f• 1·. 20' 0,.~ANE2011 SHEET 1 OF 1 Enclosure3 Rational Method Calculations PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING RUNOFF CALCULATIONS Methodology Runoff calculations for Kaiser Carlsbad Parking Lot Expansion project have been performed in accordance with the 1985 County of San Diego Hydrology Manual. The 1985 County of San Diego hydrology manual was used for the proposed hydrology on the project as the existing storm drain infrastructure design was based on this methodology per the construction timeline circa 1995. Rational Method Runoff from the project site was calculated by hand for the 100-year storm event. Runoff was calculated using the Rational Method which is given by the following equation: Q =CxixA Where: Q = Flow rate in cubic feet per second (cfs) C = Runoff coefficient I = Rainfall Intensity in inches per hour (in/hr) A = Drainage basin area in acres, ( ac) Rational Method calculations were performed by hand as found on the following pages. To perform the hydrology routing, the total watershed area is divided into sub-areas which discharge to two main outfall locations with a third self-mitigating runoff area maintaining the existing drainage pattern. Runoff Coefficient The runoff coefficients for the project were calculated using Table 3-1 from the County of San Diego Hydrology Manual. The proposed site is designated to be Office Professional/Commercial and has a Soil Type of "B" which provides a Runoff Coefficient of 0.90 for impervious areas and 0.25 for pervious areas. Rainfall Intensity Rainfall intensity was determined by using the 1985 County of San Diego Hydrology Manual as discussed above using the following equation: I = 7.44*P6(1oo)*D"0645 Where: 535 N Coast Highway 10 I Ste A Solana Beach, California 92075 I ph 858.259.8212 I fx 858.259.48121 plsaengineering.com I = Rainfall Intensity (in) P6(100) = I 00-year, 6-hour Rainfall (2.5 in) D = Time of Concentration (5 min., Assumed for all) Rainfall intensity (I) was calculated to be 6.59 inches for the site. Tributary Areas Drainage basins of the proposed project site are delineated in the Post Development Drainage Exhibit located in the Enclosure 2 of this report and graphically portray the tributary area for each drainage basin. Pipe Flow Calculations {Hydrajlow Express) Hydraulic calculations for the proposed storm drain were analyzed using normal depth based on Manning's Equation. The Manning's roughness coefficient "n" used for the calculations for PVC is 0.013. The proposed storm drain is designed to convey the 100-year peak discharge. The Hydraflow Express computer program was used to calculate the depth of flow for each outflow pipe for the max runoff calculated for each drainage area. The output of these calculations is found in Enclosure (5) for the following discharge pipes: I) 12-inch PVC outlet at OMA 1, and 2) 8-inch PVC outlet at OMA 2 535 N Coast Highway 10 I Ste A Solana Beach, California 92075 I ph 858.259 .8212 I fx 858.259.48121 plsaengineering.com PASCO LARET SUITER & ASSOCIATES Date i_;,j,_,,(! I Job# -z.s12- L>MA I -Y1l r;. -De v1= 1,.,orcv corvD1 no tJ *( ~ -;-C / A Aw;-/t/, qq I ~r:) .,.. A ,l'Vff' -;: '11 80</ ~ F { 0,/ /Ar} CAL-C 'C,..' (Tl'le,lc ~-1) ((JJ,3_1-f A-~ 111 :;: /O,l'o1 e;r (o.?5M-) ": o/ L iY l' C '8, ' %,MP -'.,J.-Jo %,, -lo8t 0 -= 0 . 'Io (@, $ t) +-0. 2.. '5 ( (!). {,, B) r✓ =-(/), 'I' ·-. I, -;. 7 , 'f <f ( J <; ) ( '?) O· ft,<()" T -6.5'! IN. -- 0 = ((J),l/bj(p,5"1)((/J,3t/] \~01>== /, (1)3 u-s ] . f'l>(t~ 2.? tN j) '== ~ 7 6 I'll I N . (If 5«; lflV•C'J DfVIA I -pos, /JcVE.t.,,,oP ctJ uoND1no/\J ll -t'-1 , 9'fl ~r (@. 3if ,1z) -? A,,.,,, -=-12, 12-1 sF ( (]). tB,tJ-Z.,) -= ~r -- ( ) ( ) AP -= 1-, f}b<f sr ((J). 07 ,1--c) -= l, = o.c,o . Boer + {J.zr . 1r, C -= (}), 1 B -~- () ~ (]), 1. B ((o. <ict) { (f}, '3'-/) [ q;,;-/.7 !i V'S! "" -t' /1\/Cfl CJtsr;; (f).72 e,,.rs 12.ovtrrl) T,rF'ov16fl Bto ~It-t/l /rJ/(}N B/11 ~, $ C. r r( ·1 Dlf" ;rr l ,.,i.,,J D C rr N n O /IJ I' /h. C vr c. /rT7 O N S e(VC <-c.?'S C-0 , 535 North Highway 101 Ste A Solana Beach, CA 92075 I plsaengineering.com PASCO LARET SUITER & ASSOCIATES Date .z/8/!r Job# 2§"/-:Z -> /.1 ,NJ(> == I, 52 ti. I r; r ( o.o-:::,s!fc) fJ ,., = -5 2 1. 3 .C-r { f) . o I z II r)-=- /1 ,,. .. ,.. : 1 L/, 3% . r ~ &,?q J N 11 ,-, ~ 2. '5. 1 fo --Q ~ (/}. 7 ~ ( (, , -5q) ( 0 . O s-) I Q,11; {/), 'J. I{ C-Fs I p/V/11 2 -po5r~ /)e"VGL-CJPr:1:, lo1vD1no/\l II '11~ '2, {1)'53 . '-/ e;F ( rP. O~ 1t-t:-) -;!> //,111r = I, 1-l s . S 5r( ([). IP3o lk') -= ~ tf % IJ p -== i Lf O . I 'Sr ( 0 . (!) I 7 '1 c_) -= '3 {, % C = (/). 9 f) ( 0 , h'/) -I (/), 2 '5' ( (/), 3 (p) C -= rJ), tp 1· a:; (!).61 r,. 61)(0. (JJ~J ( Q :: (b. z_ z. C-r$ [1/ ic l--~ s TI+-ltN E:'>-! I~ -n rJ ~ , Tttc:-2-C::-n.:tZ -e:-'Ote ~ l IOI 535 North Highway 101 Ste A Solana Beach, CA 92075 I plsaengineering.com PASCO LARET SUITER & ASSOCIATES Date :5/o/r; • Job# 25/2- DfrlfJ 3 -P/2 E -/.JCVE..LOPEl-> roNP r no/\J h :-C I A /1 ~ 3 B I t/ Is F -/1 = I 5 3 C .,._, r 10 o o 3 r-~) : 1.1 b}. <--r 1-17"_,. , ~ • ,-1J/111P , ( 1 • ..., r· (o. 08911-c) /J _ 3 1/0 1 r (c OB'-11-e)-::: OJ o/ C-=-(J).'/O(o,01.l)J. (P.75(0,Cfb) P -1 ·w ,r :J, > t(Jlrtl l---= {/), 2 l:> Q 7:: { (l) , 2 8 ) ( (o, '51) ( @, IJ) BC/ /re,) { 010; (/). I 6 ~rs f D/YJA 3 -Posr:_-Q...E:.V ez oPco C:..tJt,101 notJ A -=-36bL/,J sF -> 11 -:-{j) ":.r A ... -~ 38&-/-1./-sF(O,OtJ°!ttr) /~); ~1 I ~~ V ~ ~ (f). '10 ( O, o) +-(!) 7 S-( /. o) {., -::; (/), 1,,,5 {p -= ( D, Z S) (" , ~1) ( 0 , 0 f:;!f) [ Q,.,"= m. 15 ~ Jr/ 535 North Highway 101 Ste A Solana Beach, CA 92075 I plsaengineering.com ~ n r-~ Enclosure4 ~-~-100-Year, 6-Hour Rainfall Isopluvial arr 0 (\') ~ .... Oranger 33°30' County io ..... ~ ... ..... I t...•' - •• •• -:~:, • :,•· ,<.. •... . : : ~ ... / ... ,:· .1•· t I I j ,., •• t : .. · .: .. ·•O '•••••• ••.' .: •• , IJ•~ •• • • £,• •v• ....... ___ ,.. ,. ,-n ,•J 1 .. ~ ...... .•·· ~· ··' a<):.•· ... ·: ..• ··· :.•·~·-..... . . . • .,, I . . .. ' ... ·· · •. 8 ~ .... ... I ~ ft> ..... ..... I Riverside Oounty "''•-...... ......... "'. -.... .., l ~\ ~ ....... . .. ".. ... ..." "" .. ··•. ·•.. ........ ·... .. .. "• .... •... .. "• "• .... ·. ·. . ·..... ·... ... .. \ 0. ~ 0 co ..... ... I ............ "•, io ... «> ..... ..... .. .. . . ... ·,~ \ \ • ur • • .. . •, . . . ·.. "• .. ··... ... '., . .. . . ~. ·~ c··· .. ll"; • -. : "·· ·. ·o . . . . . . . . . . . . .. . . 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Jt'i~·.1 .. •··· . I 3 "'O CD -, m· 0 0 C :::, :~'< .. 32•••· I ~1\1(1 '1 !..~ ~ ...... --""' !_...-·.. l i \ ~d!J\ ··----</. ) ._ I . ·• .... -...... 82°45' 32•~0' ~ ..-... io ~ ..... ..... f ..... .... ... ·· ... . .. .. ··· .·· ~ co ..... ..... M e . X \ C ~ «> -- . .... ·• .. ~ J..,'• ... . \ ·. in ..... «> ..... ..... 32•30• County of San Diego Hydrology Manual ::: . ,, '1 . ·'--. ,, ' ' ~. ''Ii, ~ ; ;,i \:~}-: Rainfall Isopluvials 100 Year Rainfall Event-6 Houn s N lsopluvial (inches) ~ PfZ. ~ (P. -,., it::. ") L-0~~ (,(io•}-~•:J DPW GIS _,,,..,._ -... ·--- 4 E THI WPIS PACMOEOwm<OUTWAAAIWTYO#' N('( IOI«>, l!JTHfA ElCPAESS OR N'UED, INCWDING. a/T NC1TLMTB> TO, nt@M'UED WAMNmES 0#' MEACIWfTAIIIUTY /WllRTNBll l'OllA PART1Cl.l.NI l'\JAl'08E. ~-,., ... -_..,... _________ ~ -----......----__ .,,_ -~---------.-..,--.... s 3 0 3 MIies ;s...=s Enclosure 5 Pipe-Flow Calculations ~ ____ for Proposed Onsite Storm Drain PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING Hydraulic Pipe Flow Calculations Pipe Flow Calculations (Hydraflow Express) Hydraulic calculations for the proposed storm drain were analyzed using normal depth based on Manning's Equation. The Manning's roughness coefficient "n" used for the calculations for PVC is 0.013. The proposed storm drain is designed to convey the 100-year peak discharge. The Hydraflow Express computer program was used to calculate the depth of flow for each outflow pipe for the max runoff calculated for each drainage area. The output of these calculations is found herein as Enclosure (5) for the following discharge pipes: I) 12-inch PVC outlet at DMA I, and 2) 8-inch PVC outlet at DMA 2 535 N Coast Highway IOI Ste A Solana Beach, California 92075 I ph 858.259.82 121 fx 858.259.48121 plsaengineering.com Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. 12 inch PVC Outlet at OMA 1 Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 0 = 1.00 = 60.75 = 0.50 = 0.013 Known Q = 1.75 Wednesday, Jun 14 2017 Highlighted Depth (ft) = 0.62 Q (cfs) = 1.750 Area (sqft) = 0.51 Velocity (ft/s) = 3.42 Wetted Perim (ft) = 1.81 Crit Depth, Ye (ft) = 0.57 Top Width (ft) = 0.97 EGL (ft) = 0.80 Section 2 Reach (ft) Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. 8 inch PVC Outlet at DMA 2 Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: Known Q ( cfs) Elev (ft) 63.00 62.50 62.00 61 .50 61 .00 60.50 0 = 0.67 = 61.48 = 0.50 = 0.013 Known Q = 0.22 Section - / "" I ' V '--~ / ~ Reach (ft) Highlighted Depth (ft) = Q (cfs) = Area (sqft) = Velocity (ft/s) = Wetted Perim (ft) = Crit Depth, Ye (ft) = Top Width (ft) = EGL (ft) = 2 Monday, May 8 2017 0.23 0.220 0.11 2.04 0.84 0.22 0.64 0.29 3 Depth (ft) 1.52 1.02 0.52 0.02 -0.48 -0.98 Enclosure6 DMA 1-Biofiltration BMP Hydrograplt Outflow PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING+ LAND PLANNING+ LAND SURVEYING CALCULATIONS for DMA 1 Post-Project Runoff Mitigation Mitigation of Post-Project Runoff to Pre-Project Rates (Hydraflow Hydrographs) Post-project runoff from the site in OMA 1 has increased from 1.03 cfs to 1.75 cfs and is being routed through Biofiltration BMP 1 which mitigates the increased flow below pre-project rates. The Hydraflow Hyrdrographs computer program was used to route the peak flow rate through BMP 1, to show the outflow from DMA 1 is mitigated below pre-project runoff rates to 0.65 cfs. The annotated output from the Hyrdraflow Hydrographs program is found in herein as Enclosure (6). With the storage provided within BMP 1, and the 4" perforated underdrain providing the "orifice" outflow, the BMP uses approximately 60% of its storage capacity and will exhibit ±5.3" of surface ponding at the 100-year peak storm outflow (5 hours). 535 N Coast Highway 101 Ste A Solana Beach, California 92075 1 ph 858.259.82 12 I fx 858.259.481 21 plsaengineering.com Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Hyd. No. 1 POST Hydrograph type Storm frequency Time interval Q (cfs) 2.00 1.00 0.00 0.0 1.0 -HydNo.1 = = = I Unmitigated Peak Runoff to BMP 1 Manual Peak discharge 100 yrs Time to peak 6 min Hyd. volume POST Hyd. No. 1 --100 Year 2.0 3.0 4.0 5.0 = = = 6.0 1 Tuesday, 06 / 13 / 2017 1.750 cfs 4.90 hrs 2,862 cuft \ Q (cfs) 2.00 1.00 0.00 7.0 Time (hrs) Hydrograph Report Hydraflow Hydrographs Extension for AutoCAD® Civil 3D® 2015 by Autodesk, Inc. v10.4 Hyd. No. 2 BMP 1 Hydrograph type Storm frequency Time interval Inflow hyd. No. Reservoir name Storage Indication method used. Q (cfs) 2.00 1.00 0.00 0.0 1.0 --Hyd No. 2 = Reservoir = 100 yrs = 6 min = 1 -POST = DMA-1 Biofiltration BMP BMP1 Discharge from 4" PVC Underdrain Outlet at BMP 1 Peak discharge Time to peak Hyd. volume Max. Elevation Max. Storage = = = = = Max Storage required in BMP 1 at 0.651 cfs peak discharge rate (846 cuft total storage available) Hyd. No. 2 --100 Year L, ' ~' N 2.0 3.0 4.0 5.0 6.0 --Hyd No.1 lITTIJTI Total storage used= 502 cuft 2 Tuesday, 06 / 13 / 2017 0.651 cfs 5.00 hrs 2,861 cuft 102.94 ft "- Q (cfs) 2.00 1.00 0.00 7.0 Time (hrs) Pond Report Hydraflow Hydrographs Extension for AutoCAD® Civil 30® 2015 by Autodesk, Inc. v10.4 Pond No. 1 -DMA-1 Biofiltration BMP Pond Data 3 Tuesday, 06 / 13 / 2017 Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation= 100.00 ft Stage / Storage Table Stage (ft) Elevation (ft) Contour area (sqft) 0.00 100.00 144 1.00 101.00 144 2.00 102.00 144 ? ;IQ 1 ll? ;IQ 1.d.d 2.50 102.50 360 3.33 103.33 573 3.50 103.50 620 Iner. Storage (cuft) 0 144 144 71 2 384 101 Total storage (cuft) 0 144 288 'lCn 361 745 846 Sub-surface storage at BMP-1: (40% pore space x 360 SF) Above-ground storage at BMP-1: (360 SF bottom contour area, 620 SF top contour area) Culvert/ Orifice Structures Weir Structures 12" PVC Outlet for 4" perforated PVC underdrain outlet all flow (0.651 cfs peak discharge) [A] [B] [C] [D] Rise (in) = 12.00 4.00 0.00 0.00 Crest Len (ft) = 8.00 0.00 0.00 0.00 Span (in) = 12.00 4.00 0.00 0.00 Crest El. (ft) = 103.33 0.00 0.00 0.00 No. Barrels 1 0 0 Weir Coeff. = 3.33 3.33 3.33 3.33 Invert El. (ft) = 100.00 100.00 0.00 0.00 Weir Type = Rect Length (ft) = 61 .00 0.00 0.00 0.00 Multi-Stage = Yes No No No Slope(%) = 0.50 0.00 0.00 n/a 2'x2' Brooks box N-Value = .013 .013 .013 n/a emergency overflow Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Contour) outlet (No flow at 100-yr Multi-Stage = nla Yes No No TW Elev. (ft) = 0.00 peak discharge) Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage/ Storage/ Discharge Table Stage ft 0.00 1.00 2.00 Storage Elevation ClvA ClvB cuft ft cfs cfs 0 100.00 0.00 0.00 144 101.00 0.35 ic 0.35 ic 288 102.00 0.54 ic 0.54 ic Approx. 0.44' (Elev.= 102.94) ponding depth at peak flow into BMP-1 (Weir is 0.83' above BMP bottom elevation) ClvC PrfRsr WrA WrB WrC WrD Exfil User Total cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0.000 0.00 0.354 0.00 0.538 0.00 0.00 1.87 Enclosure 7 Pipe Flow Calculations For Existing Downstream Outfall Storm Drain Channel Report Hydraflow Express Extension for Autodesk® AutoCAD® Civil 30® by Autodesk, Inc. 84 inch RCP Outlet to Batiquitos Lagonn (Dwg 337-9) Circular Diameter (ft) Invert Elev (ft) Slope(%) N-Value Calculations Compute by: No. Increments Elev (ft) 14.00 13.00 12.00 11 .00 10.00 9.00 8.00 7.00 6.00 5.00 0 = 7.00 = 6.73 = 1.40 = 0.013 Q vs Depth = 20 / I / I ' \ \ ' ' Section ----V ----- ........ ------- 1 2 3 4 5 Reach (ft) Highlighted Depth (ft) Q (cfs) Area (sqft) Velocity (ft/s) Wetted Perim (ft) Crit Depth' y C (ft) Top Width (ft) EGL (ft) ' ' '\ \ ) / V , 6 7 8 Monday, May 8 2017 = 6.65 = 812.23 = 37.79 = 21 .50 = 18.87 = 6.73 = 3.02 = 13.83 Depth (ft) 7.27 6.27 5.27 4.27 3.27 2.27 1.27 0.27 -0.73 -1 .73 9 Enclosure 8 As-Built Reference Plans • .i::"f-4--.: 1-d.-t-l -i;::,,_ '° -1-+·++ l- -;_l' ~ :t_ .. , -• "1'c Ill 11ft1 111 f ,I I ltrn 1rnett I lltttttltl ttffl1l r@. ..__ jc .L =-~ I? le ~ "'i-- l_Lt±,...L LL 1 l--.-1---~ r ~. -~.c..l--~-1- -.P. ~=--F¼-c I t, ~J .fflttllfflt.iitUJ 11 t tflfi ffiffffflit]J l rt f"FfffjJfill4~ l I l~l+++*tftllflJJff Ft-r; if ·+-i= -~. ~ r,? f ~ -:r ~!11• ~' !l!li U! ,,l-d= I'-V:=.--cc .v=.-, I-I-I,: ,7:r-T t a E i-: ~ ~ I ~ ~ , .. kc- --- H-+-FF. ./-4 l=- +·· JI -;..,.. ~ ~ ~r ~ ~ Tf1'fiiir!Wl l~ : !I~ !2.L.,_., t"" r, t, t:: "'"'I=,' -+- .,Eiifbi .Ji, =,=::-._Ji;:.._. 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