Loading...
HomeMy WebLinkAboutCT 13-02; COASTAL 10; SWMP ADDENDUM 1; DWG 480-5, DWG 480-5A; 2014-07-14:J i_ J :J i.J .. J . _i ' ! l ,-~) r 1 i j ADDENDUM NO. 1 STORM WATER MANAGEMENT PLAN SWMP 13-20 For COASTALlO CT 13-02 July 14, 2014 JN 13-1003 Prepared For: Coastal 1-, LLC 7668 El Camino Real Carlsbad, CA 92009 Ste. 104-280 Prepared By: O'DA Y CONSULTANTS 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92010 Nichole Fine C 70035 Exp. 9/30/14 PLAN CHECK NO,. I /A G:\131003\SWMP\swmp-addl .docx 1 TABLE OF CONTENTS 1. Project Description 3 Attachments: 1. BMP Calculator Output and Bioretention Calculations ,--, 2. BMP exhibit -__ J i I --, L J G:\131003\SWMP\swmp-addl .docx 2 L._J , __ J i ... l C. J c·, 1. PROJECT DESCRIPTION Addendum No. 1 for the Storm Water Management Plan for Coastal IO was prepared to support the application for Construction Change No. 1 for the Grading Plans for Coastal IO of Carlsbad DWG 480-5A. The original Storm Water Management Plan for Coastal 10 was prepared on November 21, 2013. The Construction Change includes the revision ofbioretention areas #1 and #2 , and the revision to the retaining wall along the easterly and westerly property lines. See Attachment #1 for the revised bioretention calculations and Attachment #2 for the updated hydromodification calcs. G:\131003\SWMP\swrnp-addl .docx 3 i .J :_1 Attachment 1 Calculations for the Bioretention Areas _J , .i ,_.i G:\131003\SWMP\swmp-addl .docx 4 __J !_ i ··, L . .J ~.J Hydromodification and Water Quality Calculations In order to meet Hydromodification requirements outlined in the Final Hydromodification Plan prepared for the County of San Diego on January 13, 2011 by Brown and Caldwell, an IMP sizing factor was determined. Table 7-4 Sizing Factor for Flow-Through Planter Lower Flow Threshold: 0.1 Q2 Rain Gauge= Oceanside Soil Type: D Existing Slope: Flat Results: IMP sizing factor of 0.16 Lower Flow Threshold: 0.1 Q2 Rain Gauge= Oceanside Soil Type: D Existing Slope: steep Results: IMP sizing factor of 0.105 There are 2 flow-through planter areas on the site along the east and west perimeter. See Attachment 3 for a typical section. Attached are excerpts from the BMP Calculator The treatment volumes required from the BMP Calculator are summarized in the table below. The depth of the gravel layer was adjusted to accommodate the smaller treatment areas. Flow-Through Planter Treatment Facilities at Coastal 10 Volume Reguired Per BMP IMP Facilitv Provided Calculator* Vl (cf} V2 (cf} Vtotal SF Vl (cf} V2 (cf} De(!th of Gravel Basin 1 609 439 1048 498 413 635 ** Basin 2 811 584 1395 464 385 1010 ** *See attached results from BMP Calculator, LID Summary ** Depth of Gravel= V2/SF/0.40 assumes 40% porosity. In order to get the perforated underdrain to drain towards the street, there are depth restrictions near Navarra Drive. See next page for additional calculations. G:\131003\SWMP\swmp-addl .docx 5 il ,_j LJ i _ _J For Basin 1 Sub Basin at the back of Unit No 1 SF =138 sf*2.4*0.40porosity= 132 CF ofV2 Remaining Bioretention Area (498-138)=360 SF Remaining V2 = (1048 CF-132CF)= 503 CF Depth ofremaining sub-basins (within Basin 2): 503CF /360SF/0.4= 3.5' deep For Basin 2 Sub Basin at the back of Unit No 10. SF =113 sf*4.7'*.40porosity= 212 CF ofV2 Remaining Bioretention Area (464-113)=351 SF Remaining V2= (1-010 CF-212CF)= 798 CF Depth ofremaining sub-basins (within Basin 2): 798CF /351SF/0.4= 5.7' deep G:\131003\SWMP\swmp-addl .docx 6 l .. J u I~ u ·, I'---j u ---j In addition, the orifice size delineated by the BMP Calculator is based on a depth of 4.0 feet (1.5' gravel+ l.5'soil/cornpost). Since we are adjusting the depth of the gravel, the size of the orifice based on the lower flow threshold is summarized in the table below. The Orifice Equation per San Diego Drainage Design Manual= Q=C* A(2gd)"0.5 C= 0.67 g= 32.2 d=head of water over orifice A= area of orifice Summarv of Orifice Sizinl! Calculations for Coastal 10 Lower Flow Depth of Head C*(2*g*d}"0.5 Diameter of Threshold* d** orifice (in) Basin 1 4.53 feet 11.45 0.2" 0.002 cfs Basin 2 5.83 feet 12.98 0.2" 0.003 cfs *See attached BMP Calculator Output * *Depth of head equals depth of gravel layer + 18" for soil/ compost layer + 1 O" ponded water G: \131003\SWMP\swrnp-add l .docx 7 ------ ' ' • I o· I I I 1/350 -~--~------~--- 10' 1;·;;;.,q• \ \ 20' "' ' i I i , .1.' 1 'l i ' ' \ \ \ \ J ..-·· ,J ,, !/ ' TREATMENT CONTROL I HYDROMODIFICATION ' BMPID# BMP TYPE SYMBOL CASQA NO. QUANTITY CD-0 FLOW THROUGH f.~ I 960SF0 PLANTER TC-32 t2a9 SF LOW IMPACT DESIGN (L.I.D.) BMPTYPE SYMBOL CASQA NO. QUANTITY ROOF DRAIN TO BMP SD-11 SOURCE CONTROL BMP ID# BMPTYPE SYMBOL CASQA NO. QUANTITY 0 EFFICIENT SD-11 IRRIGATION CD PERVIOUS f)o''J SD-20 5180 SF PAVEMENT , __ ;<_>/,:~ ©2012 O'Day Consultants, Inc. BMP TABLE DRAWING NO. SHEET NO. 4a0-5A 3-5 . DRAWING NO. SHEET NO. BLDG PLANS - DRAWING NO. SHEET NO. 480-5L -· 480~5A 3.5 . \ _,,. l INSPECTION FREQUENCY BI-MONTHLY & AFTER MAJOR STORM EVENTS ACTION X ! I ' I I I if i I I L ,/ MAINTENANCE CONSTRUCTION . FREQUENCY SIGN OFF SEMI-ANNUALLY OR IF REQUIRE AFTER INSPECTION ROOF DOWNSOUTS & OTHER IMPERVIOUS AREA TO BE DIRECTED TO BIORETENTION AREAS INSPECTION MAINTENANCE CONSTRUCTION FREQUENCY FREQUENCY SIGN OFF SEM~ANNUALL Y & AFTER MONTHLY MAJOR STORM EVENTS ANNUALLY 2-3 TIMES PER YEAR _,,/ i I I ' \ I ' I / ,/ D SCALE· I' ~ 10' i I I \ <C w "' <C \ "' \ ~ :J \ u VJ CQ D i \ ) I . } /\ I ' ) ,\ \ I ·-~--I ·,·~--1·· I ,, C~hT s 2710 Loke",: ·Av~nu~··_Vi'.est Civil Enginee~irig Suite 100 Planning Carlsbad, Colifornio·-92010 Processing 760-931"..:.."77()0 Surveying Fax: 760-~31·;-.. ~680 \ \ \ 0'·E:_OOL \ I \ \ ., DESIGNED BY: A.M. DRAWN BY: J.S. PROJECT MGR.· K.W.H. ENGINEER OF WORK KEITH w. HANSEN DATE: MARCH 2013 SCALE: , .. = 10' JOB NO.: 131003 DATE: RCE: 60223 DAlE ,_. ,. .... / J ,/ /···· ( ' '" \ ~ X \ '(:_\ INITIAL /1\ ENGINEER OF WORK \/ I ! I 'NIT 7 I I I I L _ _J I I I I I // ' / I 1/ I I /\ '/' /,,;'\, I (/ I I le I I I i , /i I I,,.,.!" I .V ' 1' • I J • ·-, I I l 'r-1 i I ·Y. f ' ! \ j j<[ 1,--· 1 /W1 I Cl'.:'.\ / <C , j I . /'/ / I I I I II I 11 '; I ' f ·v·· .. J I ' ./ '// I I j ,, I I I I I I I /J // i f/ I i 1 .,,., . I ! ,-,' f I , j .,.,' ! i ~-r-·· i i i j i , ' I I I I I I I I I I I I / I I j I I I I I I . I/ I y ;/ G)I , I !; I I I I/·· I t I : I I I 1 I I ' \ /, J ; J/ /, ,/// ' !, I I ,-------- 1 II I I : ,. DATE / / / ( ' i /\ (/ ' \ \ ... -, ... \ ,\, INITIAL DATE SWMP NO. 13-20 MAINTENANCE AGREEMENT DOCUMENT: RECORDA TION 'NO. __ _ PARTY RESPONSIBLE FOR MAINTENANCE: NAME· COASTAL 10, LLC ADDRESS: 7668 EL CAMNO REAL, STE 104-108 CARLSBAD, CA 92009 PHONE N0.:(619) 995-6044 PLAN PREPARED BY: COMPANY.· O'DAY CONSULTANTS, INC. AODRESS· 2710 LOKER A VENUE IIB"T SUITE 100 CARLSBAD, CA 92010 PHONE NO.: 760-931-7700 BMP NOTES: YES_X_ NO __ _ 1. THESE BMPS ARE MANDA TORY TO BE INSTALLED PER MANUFACTURER'S RECOMMENDA llONS OR THESE PLANS . 2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET "1THOUT PRIOR APPROVAL FROM LAND DEVELOPMENT ENGINEERING. J. NO SUBSllTUTIONS TO THE MATERIAL OR T'iPES OR PLANllNG T'iPES "1THOUT . PRIOR APPROVAL FROM LAND DEVELOPMENT ENGINEERING. 4. NO OCCUPANCY "1LL BE GRANTED UNTIL /HE CITY INSPECTION STAFF HAS INSPECTED /HIS PROJECT FOR APPROPRIATE BMP CONSfflUCTION AND INSTALLATION. VERIFIED BY: INSPECTOR DATE . I SH1ET I CITY OF CARLSBAD I SH1ETS I ENGINEERING DEPARTMENT SS 81,/P SIT£ PLAN FOR: COASTAL 10 APPROVED BY: JASON S. GELDERT CITY ENGINEER RCE 63912 EXP. 9/30/14 DATE INlllAL DWN BY: PROJECT NO. DRA'M NG NO. REVISION DESCRIPTION CHKD BY: CT JJ-02 480-5SW 01HER APPROVAL CITY APPROVAL RVWD BY: G: \13100.3\SWMP\BMP-Exhibit-cc, .dwg Jul 14, 2014 1: 15pm Xrefs: 1J03ASITE; 1303TOPO; 1303AMAP; 1303ogrd; 1303autl; 13037utl