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SEWER CAPACITY ANALYSIS
THE ELMS & THE IVY
DEVELOPMENT
SUBMITTAL DATE: AUGUST 7, 2013
2013
LATITUDE 33 PLANNING & ENGINEERING
5355 MIRA SORRENTO PLACE, SUITE 650
SAN DIEGO, CA 92121
JOB NUMBER :1114.00
SEWER CAPACITY ANALYSIS
BONITA GLEN
DEVELOPMENT
ORIGINAL DATE: 04/05/2018
2018
LATITUDE 33 PLANNING & ENGINEERING
9968 HIBERT STREET, SECOND FLOOR
SAN DIEGO, CA 92131
JOB NUMBER :1522.00
PRELIMINARY SEWER STUDY
FOR
BONITA GLEN
ORIGINAL DATE:
Prepared Under the Responsible Charge of:
Giovanni Posillico RCE 66332 EXP: 06-2018
Latitude 33 Planning and Engineering
9968 Hibert Street, Second Floor
San Diego, CA 92131
TABLE OF CONTENTS
INDEX PAGE
Introduction 1
Project Description 1
Vicinity Map 2
Design Criteria 2
Calculations and Results 3
Conclusion 3
APPENDICES
Appendix A Sewer Study Calcualations
Appendix B Sewer Study Exhibit
INTRODUCTION
This preliminary sewer study addresses the proposed development of Bonita Glen. The purpose of this
preliminary sewer study is to determine the impact on the existing 8” sewer main downstream from the
proposed development to its point of connection to the existing 8” sewer in Bonita Road.
PROJECT DESCRIPTION
The proposed project is located northeast of the Pont Bonita Apartments and Townhomes and
north of Bonita Glen Dr.
EXISTING CONDITIONS
The existing site is vacant land with a jurisdictional waters in the center flowing to the west on the site.
PROPOSED CONDITIONS
Silvergate Development, LC, is seeking approval to construct 130 townhome/stacked flat units
with associated structure/surface parking. The proposed development will be served by
connecting to existing public infrastructure (storm drain, water and sewer) within the adjacent
street (Bonita Glen Drive). Refer to the proposed site plan below.
The public sewer system will be analyzed per City of Chula Vista Sewer Guidelines.
DESIGN CRITERIA
The public sewer main systems have been analyzed per the City of Chula Vista Sewer Design Guide,
2012. The following assumptions were used in the calculations:
1) Average flows are based on 80 gallons per day per equivalent population per the Sewer Design
Guide Subsection 3‐301.1.
2) Population calculated based on residential (R1) zoning and land use with a density of 4 dwelling
units per acre and 3.3 persons per dwelling unit per Sewer Design Guide subsection 3‐301.
3) Existing flows were calculated using the listed peaking factors in CVD‐SW01.
4) For existing sewer systems reference drawings:
5) The Manning’s roughness coefficient (n) of 0.012 was used for open channel flow calculations for
PVC and (n) of 0.013 for exiting V.C. pipe per Sewer Design Guide subsection 3‐301.2.
CALCULATIONS AND RESULTS
Flow calculations were based off of the following equation:
K=Qn / d^(8/3) s^(1/2)
Where,
K=Kings Handbook Table 7-14
Q= Flow (cfs)
n=Manning’s coefficient of roughness
d=Depth of Flow
s=% Slope
CALCULATED SEWER FLOW RATE RESULTS
The existing conditions contribute a sewer flow rate of 29,180 gallons per day (0.045cfs), see Table 3.
The proposed development contributes a sewer flow rate of 43,180 gallons per day (0.067cfs) see Table
4.
CONCLUSION
In accordance with current zoning and field observations and based off the calculations found in Tables
3 and 4, Bonita Glen is contributing an additional 0.02 CFS to the existing system for an increase of 0.9%
of the total flow for the study area.
The existing sewer system is flowing less than half full, therefore the additional flows generated by the
proposed development will be serviced by an existing sewer system with adequate capacity per City
standards. The proposed development will not increase the existing service above the anticipated flows
per the City of Chula Vista Wastewater Master Plan.
APPENDIX A
Sewer Study Calculations
TABLE 3
JOB NO. 1522.00 PREPARED BY: J.L.DATE: 2015.08.19
PEAK DESIGN FLOW LINE DESIGN dn(FT)
FROM TO POP. SERVED PEAK/AVG SIZE SLOPE n= **dn/D Rh VELOCITY Comments
LINE MH MH INLINE TOTAL RATIO M.G.D. (calculated) M.G.D. (metered) CFS (calculated) CFS (metered) (INCHES) (%) 0.013 (ft) (fps)
(EXISTING)
145.9 145.9 2.50 0.029 n/a 0.045 n/a 8 3.00 0.07 0.10 0.04 2.4
A-3
TABLE 4
JOB NO. 1522.00 PREPARED BY: M.M. DATE: 2017.11.28
PEAK DESIGN FLOW LINE DESIGN dn(FT)
FROM TO POP. SERVED PEAK/AVG SIZE SLOPE n= **dn/D Rh VELOCITY Comments
LINE MH MH INLINE TOTAL RATIO M.G.D. M.G.D. (metered) CFS CFS (metered) (INCHES) (%) 0.013 (ft) (fps)
(PROPOSED)
215.9 215.9 2.50 0.043 n/a 0.067 n/a 8 3.00 0.08 0.12 0.05 2.7
A-4
APPENDIX B
Sewer Study Exhibit