HomeMy WebLinkAbout01-17-2012 c4 mid-higuera bypass preliminary fundingcounci lj ac en Oa RepoRt
C I T Y O F S A N L U I S O B I S P O
FROM :
Jay D . Walter, Director of Public Work s
Prepared By :Matt Horn, Supervising Civil Engineer
9'DW
SUBJECT :MID-HIGUERA BYPASS, SPECIFICATION NUMBER 9064 9
PRELIMINARY DESIGN FUNDIN G
RECOMMENDATIO N
Appropriate $100,000 from the Flood Control and Water Conservation District Zone 9 Count y
Advisory Board program to fund Preliminary Design Services for Mid-Higuera Bypass project ,
Specification No . 90649 .
DISCUSSIO N
Backgroun d
In 1995 flooding caused damage throughout the San Luis Obispo watershed, including creek s
breaching their banks and creek bank failures . In response to the damage, the City requeste d
• permits from regulatory agencies to repair the damage to public facilities . In response to thi s
request, the Army Corps of Engineers and other regulators requested the City prepare a
comprehensive watershed based management plan that could be used as the basis for future project s
planning, decision making, and permitting .
The Waterway Management Plan (WMP) preparation was approved by Council in the fall of 1999 .
In January 2002, the WMP was presented to Council and direction was received for various aspect s
of the program which included flood protection levels, major projects and design policies . O n
October 21, 2003 Council adopted the WMP, a three volume document which includes a strea m
management and maintenance component, a drainage design component and a flood managemen t
plan which identifies six preferred projects .
Of the six preferred projects identified by the WMP, two projects presented the highest cost benefi t
ratio and were reviewed further by the Flood Control and Water Conservation District Zone 9
County Advisory Board (Zone 9). Those two projects were the Cuesta Park Detention project an d
the Mid-Higuera Bypass project . The Cuesta Park Detention project had the highest cost benefi t
ratio, but also presents significant project risks that could ultimately delay the project indefinitely .
The project required that the 101 highway at Cuesta Park basically becomes a dam, thereb y
allowing the water to be retained behind the freeway and gradually released at a rate tha t
downstream facilities could accept without flooding . The project would require review an d
approval from Caltrans as well as the California Division of Safety of Dams . In addition to thos e
approvals, the cost of the Cuesta Park Detention project was estimated to be roughly twice the cos t
•
of the Mid-Higuera Bypass project . The Mid-Higuera Bypass project presented the second highes t
cost benefit ratio of the six projects . The project could be constructed predominantly on City -
Meeting Dat e
1/17/1 2
Item Numbe r
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Mid-Higuera Bypass, Spec . No . 90649 - Preliminary Design Funding Page 2
•owned facilities, had a lower construction cost, and decreases the existing flooding through this are a
of the creek.
Current Statu s
Since the Zone 9 Advisory Committee determined to move forward with the Mid-Higuera Bypas s
project, a feasibility study and environmental technical studies have been completed . The next ste p
for the project is to complete preliminary design work to determine :
1.Project footprint, limits of excavation, detailed cross sections :
2.Staging areas, temporary access routes ;
3.Excavation volumes and surface areas ;
4.Disposal sites for excavated materials ;
5.Details of phasing, including project timing ;
6.Location, type and size of trees, and any needed tree removals ;
7.Construction traffic volumes and haul routes ;
8.The methods, materials, volumes, and locations proposed for additional bank stabilizatio n
(outflows of terraces and by-passes);
9.and, re-vegetation details .
This information will then be used with the project's technical studies to complete th e
environmental document . The project's anticipated timeframe is as follows :
Task Anticipated Completion Dat e
Preliminary Design July 201 2
Complete Environmental Document July 201 3
Design and Project Permitting July 201 5
Construction October 2015
CONCURRENCE S
The Flood Control and Water Conservation District Zone 9 concurs with this recommendation an d
has made this funding available to support this project in the current budget .
FISCAL IMPAC T
This project was approved in the 2007-09 Financial Plan, Appendix B, page 3-287 . At that time it
was acknowledged that progress was dependent upon receipt of funding from Zone 9 . The project i s
also included in the current 2011-13 Financial Plan, Appendix B, page 3-201 as a placeholder for a
future construction funding element . This project to date has been completely funded by Zone 9 ,
and the Board of Supervisors has authorized $100,000 to support the Preliminary Design phase o f
the project . Current action proposed will not require any City funding .
Zone 9's annual revenue is approximately $400,000 with an approximate reserve balance of $2 .1
million . Zone 9's funding is intended to be used within the San Luis Obispo watershed, but thes e
funds can be used at County Board of Supervisor's discretion in other areas of the County for floo d
protection and improvement work . It is unclear at this time whether Zone 9 funding will be diverte d
into other areas of the County . Staff recommends the appropriation of $100,000 in Zone 9 funding
•
•
C4-2
Mid-Higuera Bypass, Spec . No . 90649 – Preliminary Design Funding Page 3
for the Mid-Higuera Bypass preliminary design . This will allow the Mid-Higuera Bypass project t o
move forward and compete for future construction funding .
ATTACHMENT S
1.Cuesta Park project schemati c
2.Mid-Higuera project schemati c
1 .,u anal agenda repulazu12120 iz-u i-1 i c5-spec 90649 mid-higie r bypase twakrr-I ayta Ja rr i ~.~~c
SECTION A-A '
OPTION 1 : ELEVATE HIGHWAY 10 1
MODIFY ENTRANC EOPEXISTING '
-
?--EF~LViiRTi 'i---i
------------------------------------
N CO CO 0)O
CC)• Co o O0
O O
0 r r
HORIZONTAL DISTANCE (M )
SECTION A-A '
OPTION 2 : CONSTRUCT UPSTREAM EMBANKMEN T
FILL
LiMODIFY ENTRAN C
OF -EXISTING -T----
;-GUL-VER-T--i
HIGHWAY 110 1
------------------------ ----- ------ -----------
----------------- ------------------ -----------
--------------- ------------------ -----------
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------ - ---------------------------
----------------- ------ ----- -----
O O O O O O O O o 0 O O O O O O O 0 O 0 O ON CO a t0 CO N- CO 0) 0 r N M Cp CO n CO 0)N N N
HORIZONTAL DISTANCE (M )
109
107
105
Z 1032101
99
w 97
95
93
109
107S105
z 10 3
Q 10 1
w 99
w 97
95
93
C)C0 N-COO0)O O 0CoO0)r r r r r r r N N N
Cuesta Park Detention Storag e
SLO Creek Phase I I
Waterway Management Plan
QUESTA ENGINEERING CORPORATION C4
Figure
-4 6-5
a r
CROSS SECTION A-A '
(LOOKING DOWNSTREAM )
5 5
47 N CEO CO O 0
0
r .—r
HORIZONTAL DISTANCE (M )
CROSS SECTION C-C '
(LOOKING DOWNSTREAM )
50
HORIZONTAL DISTANCE (M)
*Area below OHW to be protected and remain undisturbed .
44
•5 3
48
•
CROSS SECTION B-B '
(LOOKING DOWNSTREAM)
N CAD ccO O N 0
HORIZONTAL DISTANCE (M )
HORIZONTAL DISTANCE (M )
CROSS SECTION D-D '
(LOOKING DOWNSTREAM )
54
50 -
z
q 48
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w oHw'CWT—'
42 0 0 0NttCO
Mid-Higuera Design Alternativ e
SLO Phase I I
Waterway Management Plan
QUESTA ENGINEERING CORPORATION
Figure
C4-5 6 -4