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HomeMy WebLinkAboutXR2022-1900 - Alternative Material & Methods (3)X1zZ�Z2 -I R vrJ ��EWPURr CITY OF NEWPORT BEACH COMMUNITY DEVELOPMENT DEPARTMENT BUILDING DIVISION 100 Civic Center Drive I P.O. Box 1768 1 Newport Beach, CA 92658-8915 u www.newocrtbeachoa.gov 1(949)644-3200 CASE NO.: is 2. 5 RECEIVED BY COMMUNITY DEVELOPMENT JUN 16 20B CITY OF NEWPORT BEACH OR STAFF USE ONLY ❑ REQUEST FOR MODIFICATION TO PROVISIONS heck # PCZb22-1'I 51# of Stories OF TITLE 9 (FIRE CODE) OR TITLE 15 (BUILDING CODE) ncy Classification OF THE NEWPORT BEACH MUNICIPAL CODE (See Reverse for Basis for Approval) (Fee $297) Building C'IP ���_Q_ Ou # of Units �_ Status G ® REQUEST FOR ALTERNATE MATERIAL Construction n Type l3 FP4�" OR METHOD OF CONSTRUCTION M �1era Items (See Reverse for Basis for Approval) (Fee $2971 �n e —n'�'r�RFor above requests, complete Sections 1, 2 & 3 RIB TON:below Owner Plan Checkelitioner by printing in ink or typing. ❑ Inspector ire ❑ Other JOB ADDRESS: PETITIONER: SITE ADDRESS, 2516 Ocean Blvd petitioner CJ Light Assoc. Owner 2516 Ocean Partners. LLC lf+eWonarro be.mnrceerore.g creed Address 14n1 rail St Suite 120 Address 1401 Quail $t. Suite 120 Newport Beach. Zip 92660 Newport Beach CA Zip 92660 Daytime Phone (949 ) 851-8345 Daytime Phone (94y) R51-8445, Email: brianCa,ciliaht.net $ REQUEST: Submit tans if necessary to illustrate request. Additional sheets a ma beatached. e�opcques to deviate rom core section .7:: he garage an floor a eve ons are lower than the rear allev. :jJUSTIFICATIONIFINDINGS OF EQUIVALENCY: CODE SECTIONS: CBC 1808.7.4 int that is 6" above the alley flow line The design proposes a 6" ridge at the rear alley. This ridge sets a high p elevations. Per our calculations, the fronting alley has "der 7,00 sq. ".of n u ary area ere y e ns o -ding inaevis . The main floor a0o in due to ogarage elevations are set 4 - 5 a ova the Position Project Architect Petitioners Signature WCA Professional Lie. # 22334 Dale: 05-01-23 FOR STAFF USE ONLY DEPARTMENT ACTION: In accordancewith: ❑ CBC 104.11fCFC 104.9 ❑ CBC 104.101CFC 104.8 (Alternate materials s methods) (CBC Modification) ❑ Concurrence from Fire Code Official is required. ❑ Approved ❑ Disapproved ❑ written Comments Attached By: Date ❑ Request (DOES) (DOES NOT) lessen any fire protection requirements. ❑ Request (DOES) (DOES NOT) lessen the structural integrity The Request is: ❑ Granted ❑ Denied (See reverse for appeal information) ❑ Granted (RefMeation required) Conditions of Approval: ' -_—.Position CHIEF BUILDING OFCIA6 t90 r'— I Print Name APPEAL OF DIVISION ACTION TO THE BUILDING BOARD OF APPEALS (See Reverse) (Signature, statement of owner or applicant, statement of reasons for appeal and filing fees are required.) NV- G000'Ilaq$ CASHIER RECEIPT NUMBER: 4 Fomisvnodlf 07ro8/22 HYDROLOGY STUDY 2516 OCEAN BOULEVARD Lot 4, Block 131, Resubdivision of Corona Del Mar Corona Del Mar Newport Beach, California Prepared for: C/O CJ Light and Associates 1401 Quail Street, Suite 120 Newport Beach, CA 92660 Prepared by: Toal Engineering, Inc. 139 Avenida Navarro San Clemente, CA 92672 Tel: (949) 492-8586 Fax: (949) 498-8625 June 7, 2023 0, 7-03 ESSIp�,� Rips No. 57587 ML \9TF DF ICAL\/ ..... f ......... ................................... Caleb Rios R.C.E. 57587 JN 22055 1.0 PURPOSE This report has been prepared to demonstrate that for the proposed residence at 2516 Ocean Boulevard, Newport Beach, runoff from the adjacent alley will not enter the property during the calculated 100 year storm flow. 2.0 DESCRIPTION OF SITE The existing developed rectangular shaped 0.075-acre (3,300 sq. ft.) lot consists of a developed building and detached garage with sideyards and frontage that sheet flow toward the curb onto Ocean Boulevard. The property is bounded on the westerly side by Ocean Boulevard, similar residential properties on the northerly and southerly side, and on the easterly side by an alley. The site slopes from the easterly alley side of the property at an elevation of about 80 to the westerly Ocean Boulevard side at an elevation of about 71.5. The alley adjacent to the property is a concrete swale that runs southeast to northwest from Dahlia Avenue to Carnation Avenue. The area of alley upstream from the property is approximately 1,900 square feet. This portion is bounded on the easterly and westerly sides by residential properties and on the southerly side by Dahlia Avenue. A second alley intersects the previously described alley at a location just northwest of the property. Based on topographic data, the flow from this alley is downstream of the property and does not contribute to this project's tributary area. See Figure 1 for a depiction of the project location, Figure 2 for an aerial photograph of the site and Figure 3 for a portion of the Tributary Drainage Map (Appendix A). 3.0 EXISTING DRAINAGE The existing tributary drainage area of the alley upstream of the property is estimated to be approximately 20,000 s.f. This drainage area consists of the adjacent easterly lot (209 Dahlia Avenue) and portions of the adjacent westerly lots (2528, 2524, and 2520 Ocean Boulevard). This drainage area is bounded by Dahlia Avenue and the property frontage of 2516 Ocean Boulevard. Runoff flows within the alley swale from Dahlia Avenue, to Carnation Avenue, and then to the catch basin at the end of Carnation Avenue. The existing garage is located about 3' horizontally and about 2" above the adjacent alley right of way, so runoff at the garage face drains to the alley. The existing drainage on the property sheet flows along the sideyards from the rear of the property to the front of the property along ocean boulevard. It enters the gutter of Ocean Boulevard which conveys water to the city storm drain system that outlets to Newport Bay. 4.0 PROPOSED DEVELOPMENT At 2516 Ocean Boulevard, the developer proposes to construct a new building, a front patio with planter walls, a basement, a 2 story residence with an attached garage, and a driveway above the basement connecting to the alley. 5.0 PROPOSED DRAINAGE The drainage within the alleyway will remain the same. The proposed development will construct a driveway ridge 4.5' from the alley right of way and a minimum of 6" above the alleyway flow line, so runoff from the alley will not flow past the ridge to the rest of the property. Additionally, two 5" trench drains have been proposed along the driveway to pick up driveway runoff. 6.0 FLOW ANALYSIS METHODOLOGY 6.1 Rational Method For 100 Year Storm For post -project conditions, the study performed a rational method hydrologic analysis based on Orange County Hydrology Manual (OCHM) Section D to estimate the peak runoff quantities discharged from the site. The site time of concentration was conservatively estimated to be 5 minutes, which is the minimum allowed by the OCHM. The peak runoff quantity was calculated based on the tributary drainage area to the alleyway flowline located at the rear of the property. 6.2 Hydraulic Toolbox Model for Swale Capacity The full flow depth of the existing alleyway swale was modeled using the channel analysis tool of Hydraulic Toolbox 5.0 Build August 21, 2020 developed by the Federal Highway Administration. This channel was analyzed at the section of the alley swale as shown on the hydrology map. Calculations are shown in Appendix B. The Hydrology Map in Appendix C graphically depicts the project watershed and data relevant to the runoff calculations. 7.0 FLOW RESULTS AND ANALYSIS Our hydrologic and hydraulic analysis of the site based on the methods described in section 6.0 yielded the following results: Table 1. 100-Yr Peak Runoff. Drainage Area ac C I (in/hr) Qtoo (cfs) 0.459 0.90 6.19 2.56 Table 2. Swale Capacity Verification. Section Ridge Height Flow line Flow Depth at Qioo Flow elevation of Q100 Sufficient Capacity @Alley 79.81' 79.31' 0.234' 79.54' 79.81'>79.54'...OK Table 1 shows the 100 year storm flow is 2.56 cfs. Table 2 shows the Q100 storm flow elevation at the building stem cross section is calculated to be 79.54' which is lower than the driveway ridge height elevation of 79.81'. Calculations for the required Q and the Swale Capacity can be found in Appendix D. 8.0 CONCLUSIONS The proposed driveway ridge is sufficiently elevated to prevent 100 year runoff from the alleyway from flowing onto the property past the ridge. APPENDIX A Vicinity Map, Aerial Image and Tributary Drainage Area Map Figure 1. Vicinity Map maps.google.com Figure 2. Aerial Image maps.google.com h Sll lkk V h�� e ry^ ryM1 b l02\ SITE Hoye la> P M1yti M10 � q � M1^M1 \\ h yti M1 0 °i M1h e 1 [ vw NBG6 © 0� Feet D9C1 ck PIl01 MU2P ...34PN 3¢ 9ItIB 3CCC dC/CI N2 NL�OrWWea. Mu'eYe TM CNCI Ne'x0a'IB N ak IifioC�o� e NY rib91 4�en150 N: MarM al�r PT y wNmee eo mouse - Figure 3. Tributary Drainage Area Web site: https://www.arcgis.com/apps/webappviewer F,9 .1 t Calculations Orange County H,dology Manual iAean Precipitation Intensities for Nanmountainous Areas T')min) 1 5 Also 20.000 A laa) 0.459 6 Ft loi 0.25 pry=old Wo/hp 0.000 A Return Frequency a b I)in/hr) Q cfs )years) 2 5.702 d57 2.26 0.94 5 7.870 -0.56 3.19 132 10 30209 -057 C06 168 25 11.995 0.57 4.82 1.99 50 13.521 L.52 5." 2.25 100 15.560 0.57 6.19 2.56 Sari Melysls Rexules from Hydraulic Table. Allei Section Results Longitudinal Slope 2.56 ft/ft Flaw 0.234 c6 Depth 1.117 ft Area of Flow 9.524 f-2 Wetted Perimeter 0.117 ft Hydraulic Radlus 2.291 ft Average Vclotlty 9.56E R/s Top Width 1,191 ft Froude Number 025 Critical Depth 2005 ft Critical Velocity 000421 ft/s Crlasl Slope 10.2E ft/ft Critical Top Width pop. ft A, Shear Stress 0.044 Ibi Max Shear Stress 0029 Ib/kA2 Composite Manning'sn Lotter method Mannin 's d 0.12 F�