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CAI
Contra
Costa
TO: BOARD OF SUPERVISORS
County
FROM: CARLOS BALTODANO, DIRECTOR
BUILDING INSPECTION DEPARTMENT
DATE: July 20, 1999
SUBJECT: Contract for Geotechnical Investigation and Topographical Dapping
SPECIFIC REQUEST(S)OR RECOMMENDATION(S)&BACKGROUND AND JUSTIFICATION
RECOMMENDATIONS
APPROVE and AUTHORIZE the Director of the Building Inspection Department to enter into a
contract with Alan Kropp and Associates for $24,900 to perform a geotechnical investigation of
La Colina Road landslide area in EI Sobrante, and APPROVE and AUTHORIZE the Director of
the Building Inspection Department to anter into a contract with Kellog Aerial Survey for$5,700
to perform topographical mapping for this purpose.
FISCAL IMPACT
$10,000.00 from the General Fund.
ACKGROUNDIREASONS FOR RECOMMENDATIONS
A landslide occurred on East Bay Regional Dark District (EBRPD) property on February 19, 1998.
The landslide was located just upslope from the south terminus of La Colina Load. According
to consultants hired by EBRPD, Earth Max Consultants (EIEC), the slide was about 0008 wide,
500` long, and 150' high. EMC stated that the landslide was a smaller, More active part of a
Massive ancient landslide complex that existed well beyond EBRPD property, and beneath ten
to thirteen houses along La Colina Road. _
CONTINUED ON ATTACHMENT: x- YES SIGNATURE
RECOMMENDATION of COUNTY ADMINISTRATOR RECOMMENDATION OF BOARD COMMITTEE
APPROVE OTHER
SIGNATURE(S): 3 = u
ACTION of BOARD Old -_+s f4 20: i 72`/ APPROVED AS RECOMMENDED OTHER
VOTE of SUPERVISORS
I HEREBY CERTIFY{THAT THIS IS A TRUE
UNANIMOUS(ABSENT AND CORRECT COPY OF AN ACTON TAKEN
AYES: NOES: AND ENTERED ON THE MINUTES OF THE
ABSENT: ABSTAIN: BOARD OF SUPERVISORS ON THE DATE
SHOWN.
Contact: Carlos Saltodano(925/335-1108)
C c: County Administrator Phil Batchelor,Clerk of the Board of Supervisors
County Counsel and County Administrator
Community Development
Public works
a
DEPUTY
CB:r.r
Lacolina.slide.bdord7-20-99
Board of Supervisors
Contract for Geotechnical Investigation and Mapping
July 20, 1999
Page Two
As a result of this landslide one of the houses on La Colina was "red-tagged" and residents
could not occupy the structure because the slide had impacted the foundation of the
property. Meetings have been held with residents of the La Colina area and discussions
have been held with a variety of agencies with the view to perform a coordinated
investigation of the extent of the slide. Supervisor John Gioia has met with representatives
of the EBRPD and they have committed $15,000.00 towards the study of the landslide
area. Negotiations have been underway with East Bay Municipal Utility District (EBMUD),
and it is anticipated that EBMUD will contribute approximately $5,000.00 towards the study.
It is recommended that Contra Costa County provide $10,000.00 as its share toward the
study. The study will entail the following:
1. Review of the existing materials and reports;
. Providing an analysis of the extent of the slide, and,
3. Providing proposals for stabilization of the slide area and possible community actions
(e.g., funding, etc.)
In order to provide these recommendations in a meaningful away, it is proposed that orthoa
photo-der€ved topographic mapping at 5' contour intervals, as well as 2' contour intervals,
be developed for certain affected areas.
While there are many landslide areas throughout Contra Costa County, the La Colina i
one of the most unstable in the County, and a more extensive investigation and mapping
of this area will supply consultants and staff with a better array of€ nderstanding other slide
areas. Since the affected area has public roads with underground utilities, the County and
other public utilities will be well served in looking at the infrastructure of this area before
the potential damage of future slides.
CB.nr
Lacollna.slide.bdord7-20-33