HomeMy WebLinkAboutCDP 15-17A; 6125 Paseo Del Norte; HYDROLOGY AND HYDRAULICS STUDY; 2016-07-24J
Brian C. Regan P .E.
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REC}-:IVED
HYDROLOGY AND HYDRAULICS STUDY
COP 15-17{A)
DWG 486-SA
For
6125 PASEO DEL NORTE
PHASE 2
Prepared: June 13th, 2016
Revised: July 24, 2016
Prepared By:
Hofman Planning & Engineering
3156 Lionshead Ave,
Suite 1
Carlsbad, CA 92010
PE C35343 exp. 9-30-17
JUL 2 6 2016
LOPMENT
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Date
6125 PASEO DEL NORTE Ph. IV Final Hydrology and Hydraulics Study
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TABLE OF CONTENTS
Prepared by: BCR
Section 1. Project ................................................................................................ 3
Section 1.1 Objective . . . .. . . . . .. . .. . .. . .. . . . . .. . . .. .. . . .. .. . . . .. .. .. . .. . .. .. . . .. . .. . .. . . .. .. .. .. . . 3
Section 1.2 Project Description ...... .. .... ...... ...... .... ........ ...... ...... .. . .... .. ... .. .. ... .. 3
Section 1.3 Existing Condition ................................................................ 3
Section 1.4 Proposed Improvements 3
Section 2. Methodology ...... .. .... . . . . . . ... . . . .. .... ... . . . ... ... .... . . ... ... ... . .. ...... ... .... . . . . . 4
Section 3.1 Rational Method ................................................................ 4
Section 3. Results ............................................................... .............................. 4
Section 3.1 Proposed Condition ................................................................. 4
Section 4. Conclusit:m .... . . ... ... . . .... .. . . .. ... ... .. . .. .... ... . . . ... ... ... ... ... ... . . . ... ... ...... . . . ... ..... . ... 5
Section 5. Attachmtents
Attachment A Vicinity Map
Attachment B Post-Developed Hydrology Calculations
Attachment C Post-Developed Hydrology Exhibit
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6125 PASEO DEL NORTE Ph. IV Final Hydrology and Hydraulics Study
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SECTION 1. PROJECT
1.1 OBJECTIVE
This Hydrology study has been prepared in support of the construction documents:
grading and surface improvements plans Dwg. 486-5A based on the Coastal
Development permit CDP-15-17(A) for the 6125 PASEO DEL NORTE in their PHASE 2.
The 6125 PASEO DEL NORTE PHASE 2 parking lot as well as incidental utilities,
landscaping, and hardscape improvements are proposed within the existing site on two
parcels. It will contain one main building and covered outdoor parking spaces. In
addition, there will be hardscape and one relocated trash enclosure.
The site has one study areas since there is only one storm drain facility proposed. The
remainder of the site outside of Phase II only involves the renovation of an existing
structure and no new proposed drainage facilities.
1.2 PROJECT DESCRIPTION
The 6125 Paseo Del Norte Phase 2 parking expansion project is located on the west
side of Paseo Del Norte south of Palomar Airport Rd. in the City of Carlsbad. The
surrounding area is composed of commercial and office professional land uses.
The 6125 Paseo Del Norte Phase 2 parking expansion site currently consists of an
addition of 26 parking spaces. Due to the increase in paved surface a bio-retention
facility is proposed
1.3 EXISTING CONDITION
The area to be disturbed by the proposed development is currently undeveloped, but
previously graded and covered with spoils.
1.4 PROPOSED IMPROVEMENTS
A parking lot expansion will be constructed across the site and will be improved with the
incidental utilities, landscaping and hardscaping.
We are incorporating pervious pavers combined with a bio-retention facility.
Total disturbed area is .642 Acres .
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6125 PASEO DEL NORTE Ph. IV Final Hydrology and Hydraulics Study
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SECTION 2: METHODOLOGY
2.1 RATIONAL METHOD
This study followed the rational method as outlined in the 2003 San Diego County
Hydrology Manual. Basin areas as well as areas of impervious surfaces (pavement,
concrete,) were calculated. Given the amount b of the previous/ impervious for
proposed conditions, the runoff coefficients C was calculated at 0.9.
We then used the Advanced Engineering Software using Rational Method Hydrology
program version 7.7 to calculate the flows and time of concentration for the100 year
storm events using different "c" coefficients according to the corresponding DMA
(Drainage Management Areas) surface conditions. We have used a constant C value of
0.9 for the study area.
The actual runoff for the one basin is based on the initial time of concentration of a
minimum of 5 minutes.
SECTION 3: RESUL Tl~
3.1 RATIONAL METHOD
Proposed ConditiC>ns 100 year storm event: See exhibit H
BMP-1
BIORETENTION
POST PROJECT SURFACE AREA
Nodes TYPE (A c) "C" Q100 (cfs)
10-11 POROUS CONCRETE 0.3 .9
TOTAL 0.3 0.9 2.28
For the sake of conservatism we have rounded up the flow to be 3 cfs. These results
do not reflect the detention and infiltration capacity of the system; no flow reductions
have been calculated due to the retention, infiltration and treatment in bio-retention
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6125 PASEO DEL NORTE Ph. IV Final Hydrology and Hydraulics Study
Page 5 of 5
SECTION 4: CONCLUSION
This Hydrology study has been prepared in support of Coastal Development permit
CDP-15-17(A) for the Ei125 PASEO DEL NORTE in their phase 2
The main focus is to quantity the maximum flow into an out of the bio-retention basin.
The storm water quality issues from the 6125 PASEO DEL NORTE, PHASE 2 have
been addressed in the Storm Water Management Plan (SWMP) for 6125 PASEO DEL
NORTE PHASE 2 submitted in the package under a separate cover. Please refer to the
SWMP for information on all the proposed LID BMP's.
This Hydrologic and Hydraulic Analysis has been prepared by me or under my direction
and supervision. I attest to the technical information contained herein and the
engineering data upon which recommendations and conclusions are based.
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PROJECT
SfTE
CITY OF OCEANSIDE
~ITY. OF VISTA
CITY OF ENCINITAS
VIC IN AP
NTS
ATTACHMENT "A"
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ATTACHMENT "B" PAGE 1
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RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003, 1985, 1981 HYDROLOGY MANUAL
(c) Copyright 1982-2015 Advanced Engineering Software (aes)
Ver. 22.0 Release Date: 07/01/2015 License ID 1517
Analysis prepared by:
BRIAN REGAN P.E. 35343
************************** DESCRIPTION OF STUDY **************************
* HYDROLOGY ANALYSIS FOR PARKING EXPANSION 6125 PASEO DEL NORTE *
* * * * **************************************************************************
FILE NAME: PASEO.DAT
TIME/DATE OF STUDY: 10:19 06/13/2016
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 3.200
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS (DECIMAL) TO USE FOR FRICTION SLOPE = 1. 00
SPECIFIED CONSTANT Rill/OFF COEFFICIENT = 0. 900
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF-CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN-/ OUT-/PARK-HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0312 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth= 0.00 FEET
as (Maximum Allowable Street Flow Depth) -(Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6. 0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
ATTCHMENT "B" PAGE 2
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
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FLOW PROCESS FROM NODE 10.00 TO NODE 11.00 IS CODE= 22
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
*USER SPECIFIED(GLOBAL):
OFFICE PROFESSIONAL/COMMERCIAL RUNOFF COEFFICIENT= .9000
S.C.S. CURVE NUMBER (AMC II) = 77
USER SPECIFIED Tc(MIN.) = 5. 000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 8.431
SUBAREA RUNOFF(CFS) = 2.28
TOTAL AREA(ACRES) = 0. 30 TOTAL RUNOFF(CFS) = 2.28
END OF STUDY SUMMARY:
TOTAL AREA(ACRES)
PEAK FLOW RATE(CFS)
0. 3 TC(MIN.) =
2.28
END OF RATIONAL METHOD ANALYSIS
FOR CONSERVATISM SAKE USE 3 CFS
5.00
//