HomeMy WebLinkAboutCT 83-04; Windsong Shores; Drainage Study; 1989-08-241 i
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WINDSONG SHORES
(C.T. 83-4)
c?.Y s3h3-0q DRAINAGE STUDY
i
August, 1989
J.N. 300-2
Revised: August 24, 1989
ENGINEERING DEPI LIBRARY city of Carlsbad
2075 Las Palmas Drive
CarlsbaQ CA 92009-4859
D520. B
.28
Crosby Mead Benton & Associates
Planners - Engineers - Surveyors
WINDSONG SHORES
(C.T. 83-4)
DRAINAGE STUDY
August, 1989
J.N. 300-2
Revised: August 24, 1989
CNGINEERING DEPT. LIBRARY City of Carlsbad 2075 Las Palmas Drive
Carlsbad, CA 92009-4859
PREPARED FOR:
CROSBY MEAD BENTON & ASSOCIATES
SUITE 170
5966 LAPLACE COURT
CARLSBAD, CALIFORNIA 92008
(619) 438-1210
BY:
Kim L. Post R.C.E. 23166
Exp. 12/31/89
INTRODUCTION
METHODOLOGY
CALCULATIONS
- Sit2 Hydrology - Offsite Hydrology - Syscem Hydraulics
SITE TRIBUTARY AREA MAPS
SITE FINISH GRADIIJG NAPS (REFERENCE
OFFSITE T3.IBUTARY AREA IdAP
LOCATION MAP
APPENDIX
11
5
20
21
30
33
34
Job Ifo. 300-2
August 1989
Page 1 of 34
WINDSONG SHORES (CT 83-41
DRAINAGE STUDY
This report analyzes the runoff and the proposed drainage system
to be constructed with the development of Lots 1 and 2 of Map No.
11484. Jindsong Shores, in Carlsbad, California.
Windsong Shores is comprised of approximately five (5) acres
adjacent to the north bluff of Agua Hedionda Lagoon lying between
Interstate 5 and the AT&SF Railroad. The site will be developed
with 130 condominium units built over an underground garage. The
land presently slopes to the south and down the bluff to the
lagoon: when developed, the area north of the bluff face will be
drained by a system of pipes which will connect to an existing
drainage system located on the property immediately to the north.
Enclosed location and rough grading plans show this site and its
proposed drainage system, plus the area northerly that is
tributary to the same outfall drainage pipe.
The intent of this report is to provide runoff and pipe flow
calculations to support the proposed private storm drain
facilities which include pipes, inlets and cleanouts.
Windsong Shores
Drainacre Study
Job No. 300-2
August 1989
Page 2 of 34
Drainage maps (reduced site grading plans and offsite topographic
maps) are included with this study: these maps also show the
existing and proposed storm drains on and adjacent to this
development.
Windsong Shores
Erainage Study
Job NO. 300-2
August 1989
Page 3 of 34
METHODOLOGY
This study utilizes the design criteria outlined in the San Diego
County Flood Control District's Desi.gn and ~P~ocedure-.Manugl_ in
its calculations and analyses. The 100-year storm runoff
discharges are analyzed throughout the storm drainage facilities.
Onsite
An inlet on the main storm drain line under the qarage has been
selected as the representative "collection point" for each
tributary area or group of Ireas. Actual inflows into the main
line will occur at various points along its length from roof and
deck drain laterals to be constructed with the building, as well
as fron the area drain laterals shown on the rough plan.
The average runoff coefficient (C) for each tributary area is
based on che approved site plan and final landscape plans:
a. Building & on deck planter areas c = 0.85
(Areas 1, 2, 3, 5, 9 & 12)
b. Landscaping and pool areas
(Areas 4, 6, 7, 10 & 11)
c = 0.55
c. Landscaping & access drive (Area 8) c = 0.1
Windsonq Shores
Drainage Study
Job NO. 300-2
August 1989
Page 4 of 34
Off site
Existing inlets and junctions have been selected as "collection
points" for the tributary areas. The average runoff coefficient
for each tributary area was established by visiting the site and
using the aerial top0 map of the area (see "Offsite Tributary
Area Map", Paqe 33). Existing drainage systems were taken from
Asbuilt plans on file with the City, supplemented by field survey
information in rhe vicinity of the downstream connection point
near the western project boundary.
The Appendix contains the Intensity-Duration Design Chart and
calculations, including the Intensity equation, which was used
directly since the chart only goes down to ten (10) 3inutes. it
also contains the Pipe Flow Charts used to determine the averaas
normal depth and velocity in each reach of pipe and orher
reference materials.
Windsong Shores Drainage Study
Crosby Mead Benton & Associates Sheet 5 of
August 1989
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WINDSONG SHORES (C.T. 83-41
DRAINAGE STUDY
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