APPENDIX J WATER SUPPLY AND SEWER CAPACITY STUDY

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1 I NITIAL S TUDY/MITIGATED NEGATIVE D ECLARATION NO M ARCH 2018 K ILLEFER SQUARE A PARTMENTS C ITY OF ORANGE, COUNTY OF ORANGE, CALIFORNIA APPENDIX J WATER SUPPLY AND SEWER CAPACITY STUDY P:\WSH1601\March 2018\Killefer ISMND _City Comments_ docx «03/08/18»

2 Raymond K. Phua, P.E., Principal Maurice E Yee, P.E., Senior Associate Lan V Nguyen, P.E., Senior Associate RPM ENGINEERS, INC. February 26, 2018 Project: Re: Water and Sewer studies We prepared this sewer and water capacity study for the proposed 135 beds student housing project. The sewer flow in the existing 8 Ø sewer pipe at Lemon Street manhole 4030 to 4138 is CFS. (Cubic Feet per Second) d/d= where d = depth of the liquid inside the pipe, D= Diameter of pipe. See page 2 & 3. The design maximum flow is CFS. The proposed project sewer flow is based on 135 beds at 109 gallon per person per day per City of Orange design standard is equal to 135x109= 14,715 gallon per day or CFS. Total sewer flow including this project = =0.0811CFS. See attached P-1. This is less than the maximum flow capacity of CFS. d/d = /8 = See page 4. Percentage of maximum flow on 8 Ø sewer pipe = /0.3854= or 21.04%. Percentage of sewer flow from the project = /0.3854= or 5.92 % of the design maximum flow in the 8 Ø sewer pipe. No improvement is needed. Based on the fire flow water calculation data: The available water flow on Olive Street is 3,210 GPM. The available water flow on Lemon Street is 6,216 GPM. The domestic water requirement for the proposed 24 units with 135 beds is 198 fixture units or 66 GPM. See attached sheet P-2. This is only 2% of the Olive Street water flow or 1% of the Lemon Street water flow. The existing water supply is sufficient for the project. No improvement is needed. Submitted by, Raymond K. Phua, P.E D i s c o v e r y, I r v i n e, C A, T el: F ax: P a g e 1 o f 5

3 Raymond K. Phua, P.E., Principal Maurice E Yee, P.E., Senior Associate Lan V Nguyen, P.E., Senior Associate RPM ENGINEERS, INC D i s c o v e r y, I r v i n e, C A, T el: F ax: P a g e 2 o f 5

4 Raymond K. Phua, P.E., Principal Maurice E Yee, P.E., Senior Associate Lan V Nguyen, P.E., Senior Associate RPM ENGINEERS, INC D i s c o v e r y, I r v i n e, C A, T el: F ax: P a g e 3 o f 5

5 Raymond K. Phua, P.E., Principal Maurice E Yee, P.E., Senior Associate Lan V Nguyen, P.E., Senior Associate RPM ENGINEERS, INC D i s c o v e r y, I r v i n e, C A, T el: F ax: P a g e 4 o f 5

6 Raymond K. Phua, P.E., Principal Maurice E Yee, P.E., Senior Associate Lan V Nguyen, P.E., Senior Associate RPM ENGINEERS, INC D i s c o v e r y, I r v i n e, C A, T el: F ax: P a g e 5 o f 5

7 Sewer Capacity Analysis For: City of Orange Prepared by: GILBERT ENGINEERING & ASSOCIATES, INC. 2 Merriweather Place Ladera Ranch, California (949) Project Number: Supervising Engineer: R. William Gilbert, P.E. RCE No Latest Revision March 2018

8 Table of Contents Table of Contents... 1 I. Vicinity Map... 1 II. Project Description... 2 III. Sewer Atlas... 3 IV. Existing Sewer Flow Map... 4 V. Existing Flows... 5 VI. Flow Generation Analysis... 5 VII. Summary... 6 VIII. Appendices... 7 Appendix 1 - Proposed Normal Depth Calculations

9 I. Vicinity Map Google Earth, 2016

10 II. Project Description Geographic Setting The Analysis area consists of a proposed 26 unit apartment project among two buildings on a 1.70 acre parcel located west of N. Olive Street, east of N. Lemon Street and north of W. Walnut Avenue in the City of Orange. For the purposes of this Analysis, a maximum of 135 beds were assumed. Existing Topography The existing project site is the Historic Killefer School site and parking lot. The existing site consists of three existing buildings, a shed, sidewalks, landscaping and a parking lot. The site has 1 foot of fall from north to south. Analysis Basis The basis of this Sewer Capacity Analysis is based on the City completed a sewer master plan study in The 2012 Sewer Master Plan recommended a per capita flow rate of 109 gallons per person per day for ultimate built out condition. The project site will have a new 6" sewer lateral connection into Lemon Street, downstream of manhole #4030, into the existing 8" sewer main. The proposed connection will service the new proposed building and the existing building that is to be improved. There will be no sewer connections into Olive Street.

11 III. Sewer Atlas

12 IV. Existing Sewer Flow Map

13 V. Existing Flows The sewer flow in the existing 8 diameter sewer pipe at Lemon Street manhole 4030 to 4138 is CFS (Cubic Feet per Second) d/d= where d = depth of the liquid inside the pipe, D = Diameter of pipe. See Existing Sewer Flow Map (Section IV) and Calculations in Appendix 1. VI. Flow Generation Analysis In order to evaluate the impact of the proposed development, a determination of the additional flow from the site is calculated. For the purposes of this analysis, a maximum of 135 beds were assumed. Using typical flow generation values, the City of Orange design standard of 109 gallons per person per day, the probable additional flow from the site can be calculated: 135 beds x 109 gallons/pp/day = 14,715 gallons per day or CFS.

14 VII. Summary A Sewer Capacity Study was conducted for this project using information available from City s 2012 Sewer Master Plan study. The design maximum flow is CFS. From the analysis the proposed development (135 beds) will increase the maximum existing flow by approximately CFS. The total sewer flow, including this project = =0.0811CFS (see Appendix 1). This is less than the maximum flow capacity of CFS. d/d = /8 = Percentage of maximum flow on 8 diameter sewer pipe = /0.3854= or 21.04%. Percentage of sewer flow from the project = /0.3854= or 5.92% of the design maximum flow in the 8 diameter sewer pipe. No improvement is needed. MH Reach Pipe Exist Design Existing Existing Size Slope Q Q d/d (cfs) (cfs) Add l Prop d Prop d Q Q d/d (cfs) (cfs) In all affected reaches, the additional flow will bring the total flow to approximately 21.04% (maximum) of total capacity for the existing sewer system. The proposed development should have no negative impact on the existing sewer facilities.

15 VIII. Appendices Appendix 1 Proposed Normal Depth Flow Calculations

16 Appendix 1

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