HomeMy WebLinkAbout7-30-08 Drainage Coordination Meeting Minutes PSOMAS
2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380
DRAFT MEETING MINUTES
06-Ker-178
PM R6.7 /T9.2
06-0C9400
6BAK040100
File No. 390
MEETING TYPE: Drainage Coordination Meeting
SUBJECT: Thomas Road Improvement Program
Morning Drive/SR 178 Interchange Project
Drainage Analysis and Design
DATE OF MEETING: Wednesday, July 30, 2008
TIME: 11:00 a.m.
LOCATION: City of Bakersfield
Public Works Department Conference Room Conference Room
1501 Truxtun Avenue
Bakersfield, CA 93301
ATTENDEES:
Name Organization Telephone E-mail Address
Manny Behl City of Bakersfield 661-326-3576 mbehl@bakersfieldcity.us
Jim Holladay City of Bakersfield 661-326-3590 jhollanda@bakersfieldcity.us
Dick Meyer Meyer Civil Engineering 661-836-9834 rmeyer@meyerce.net
Sean Hamblet Psomas 916-929-7100 shamblet@psomas.com
Matt Lampa Psomas 916-929-7100 mlampa@psomas.com
ITEM
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PERSON
TOPIC DISCUSSED OPEN CLOSED STATUS
1.0 PROJECT OVERVIEW
1.1 Sean Psomas began with an overview of the project:
The Project is currently in the Project Report
and Environmental Document phase.
Existing facility: SR 178 is a two-lane highway
with an at grade tee intersection at Morning
Drive. The Fairfax interchange is currently
under construction to the west.
1.2 Sean Proposed Project:
Morning Drive/SR 178 Interchange Project
July 30, 2008, 11:00 AM
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PSOMAS
2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380
ITEM
NO.
RESP
PERSON
TOPIC DISCUSSED OPEN CLOSED STATUS
An exhibit showing the proposed layout and
improvements was presented to the group
Under the proposed project, the SR 178 will be
upgraded to a 4-lane divided highway. The at-
grade intersection at Morning Drive will be
changed to a Caltrans L-9 or L-2 interchange
configuration or variations of these. The
existing travel lanes on SR 178 will be located
in the approximate location of the future
westbound lanes. Two new lanes will be
constructed to the south for the eastbound
direction.
Morning Drive will be widened to 6 lanes to the
north of SR 178 and will be extended to the
south to support future development
2.0 Drainage Analysis and Design
2.1 Sean Assumptions and Existing Drainage Patterns
were described.
Northeast quadrant: Runoff from the area to the
northeast of the SR 178/Morning Drive
intersection flows generally east to the eastern
project limit, where it crosses SR 178 and flows
to the south.
Southeast quadrant: Portions of the adjacent
land to the south of SR 178 and east of Morning
Drive flow towards SR 178. This runoff flows
easterly along SR 178 and eventually to the
south into the Breckenridge Planned Drainage
Area.
West of Morning Drive: The offsite areas west
of Morning Drive generally flow to the south
into the Shalimar Planned drainage area.
Roadway drainage: Along SR 178 there is an
existing high point just west of Morning Drive.
East of the high point, the roadway runoff
generally flows to the east and eventually to the
south into the Breckenridge Planned Drainage
Area. West of the high point the runoff
generally flows to the west and eventually to the
Morning Drive/SR 178 Interchange Project
July 30, 2008, 11:00 AM
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PSOMAS
2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380
ITEM
NO.
RESP
PERSON
TOPIC DISCUSSED OPEN CLOSED STATUS
south into the Shalimar Planned Drainage Area.
Assumptions: Infrastructure noted in the
Breckenridge Plan will be in place so that runoff
from morning drive can be routed to the system.
2.2 Sean Approach:
Psomas will determine existing peak discharges
(Rational Method) to the Breckenridge and
Shalimar Drainage areas. The goal under post-
development conditions will be to attenuate
discharges to match existing peak flows.
2.3 Dick Meyer CE described the existing City drainage
systems and highlighted that there are generally
no outfalls. Instead, runoff is routed to basins
where it diminishes via infiltration and
evaporation. In addition to peak flow
attenuation, total volume must be examined.
The total volume of additional runoff generated
by additional impervious surfaces must either be
retained on site, or one of the existing basins
within the Breckenridge or Shalimar Areas must
be expanded to retain the additional volume.
Because of R/W constraints, on-site detention
will likely be the most viable solution.
Psomas is currently planning to use SCS Unit
Hydrograph methodology for
detention/retention analysis.
07/30/08 Psomas to
examine total
runoff volumes
in addition to
peak discharges
when
conducting the
analysis.
Psomas is
currently
planning to use
SCS Unit
Hydrograph
methodology to
for this.
2.4 Sean Proposed Drainage:
Existing drainage patterns will be maintained to
the maximum extent possible under the
proposed project. SR 178 runoff will generally
be routed via a system of drainage inlets, pipes,
and roadside swales to drainage channels within
the Breckenridge and Shalimar Drainage Areas.
3.0 Questions and Comments
3.1 Sean Psomas asked about the City’s water quality
requirements. The City indicated that the
07/08/08 Psomas to
coordinate
Morning Drive/SR 178 Interchange Project
July 30, 2008, 11:00 AM
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PSOMAS
2295 Gateway Oaks Drive, Suite 250 • Sacramento, CA 95833 • Tele: (916) 929-7100 • Fax: (916) 929-6380
ITEM
NO.
RESP
PERSON
TOPIC DISCUSSED OPEN CLOSED STATUS
California BMP Handbook should be referenced
when considering water quality issues. The
City also noted that they have a list of approved
treatment products that can be provided.
obtain list of
approved
treatment
BMPs from the
City.
3.2 Dick The City’s drainage consultant indicated that the
100 year event should be utilized when
determining retention requirements.
3.3 Sean Psomas asked about existing flooding or
maintenance related problems on the existing
facility. The City stated that they were not
aware of any problems.
Note: These minutes are preparer's understanding of items discussed at the meeting. If discrepancies are noted, please
contact the preparer within three days of receipt.
Prepared by: Sean J. Hamblet
Distribution: File 390
Nick Izadpanah, TRIP
Masis Kayaian, Caltrans
Attendee List