HomeMy WebLinkAboutMINUTES - 04141992 - 1.2 (3) Zo
TO: BOARD OF SUPERVISORS
FROM: J. MICHAEL WALFORD, PUBLIC WORKS DIRECTOR
DATE: April 14, 1992
SUBJECT: Limited Herbicide Use on Wildcat and San Pablo Creeks
SPECIFIC REQUEST(S) OR RECOMMENDATION(S) &BACKGROUND AND JUSTIFICATION
I. Recommended Action:
APPROVE the recommendation of the Chief Engineer allowing the use of chemical herbicides
to control weeds within one meter of mitigation landscaping plants being established as part of
the Corps of Engineers Wildcat and San Pablo Creeks Project, and DIRECT staff to prepare a
plan of integrated pest management for long term maintenance of the project for review by the
Board.
ll. Financial Impact:
Hand weeding is currently practiced using sheriff's inmate crew labor at an annual cost of
approximately $70,000. Use of chemical herbicides will save an estimated $50,000 in annual
plant establishment costs.
III. Reasons for Recommendations and Background:
On March 15, 1989 the Board accepted and approved the final report of the Wildcat and San
Pablo Creeks Design Team. The report included the "Maintenance Master Plan" for the Wildcat
and San Pablo Creeks Project which prohibited the use of chemical herbicides for a five year
period. On September 19, 1989, the Board Executed an agreement with the Corps of Engineers
which provided for reimbursement of the Flood Control District's costs to plant landscaping and
to maintain it for three years. Funding for maintenance of the landscaping was limited to a
maximum of $31,000 per year.
Continued on Attachment: X SIGNATURE:
_ RECOMMENDATION OF COUNTY ADMINISTRATOR
_ RECOMMENDATION OF BOARD COMMITTEE
APPROVE OTHER
SIGNATURE(S):
ACTION OF BOARD ON APR 14 1992 APPROVED AS RECOMMENDED OTHER _
VOTE OF SUPERVISORS
V' UNANIMOUS (ABSENT
AYES: NOES:
ABSENT: ABSTAIN:
I hereby certify that this Is a true and correct copy of
an action taken and entered on the minutes of the
GC:pc :Board of Supery on the date shown.
c:607A4 ATTESTED: X14 1992
PHIL BATCHELOR,Clerk of the Board
Orig. Div: Public Works (Maintenance) of Supervisors and County Administrator
cc: County Administrator
Community Development By
PW Design
PW Accounting
go
Limited Herbicide Use on
Wildcat/San Pablo Creeks
Page 2
April 14, 1992
The Flood Control District has maintained the landscaping over the last year using Sheriff's
Inmate Crew labor. Weeding around the mitigation plantings has been performed with small
tools. Weeding the entire project takes approximately three weeks and the weeding cycle must
be repeated every eight to ten weeks. The cost of this effort is $70,000 to $90,000 per year.
In spite of the hand weeding effort, conditions in the channel are ideal for sustained weed
growth. The opportunistic weeds are outcompeting the desirable mitigation plants for soil
moisture and nutrients and for sunlight. As a result, our mitigation landscaping is not growing
vigorously. In addition, the weed stock is supporting an increased pocket gopher population
which feeds on the mitigation plants as well as the weeds.
On March 26, 1992 District staff met with the former Design Team to discuss the above
concerns. It was the consensus of the Design Team that the limited use of chemical herbicides
to clear weeds in a one meter radius around the mitigation plants was desirable. The Design
Team also requested that the District prepare an integrated pest management plan for the long
term maintenance of the project.
IV. Consequences of Negative Action:
Without authorization for the limited use of herbicides on Wildcat and San Pablo Creeks, the
District's. cost to maintain the mitigation landscaping will continue to exceed the Corps of
Engineer's reimbursement amount by $50,000 to $70,000 per year and the growth of the
mitigation plants will continue to be impaired.