Annual Report For The Period 2017-18 Uvas Creek Levee At Gilroy, Pajaro River Basin, California

2018·12 MB·English

by  Santa Clara Valley Water District., United States. Army. Corps of Engineers. San Francisco District.

SANTA CLARA VALLEY WATER DISTRICT
Uvas Creek Levee and Channel
2017-2018 Annual Pre-Inspection Report

Pursuant to the
U.S. Army Corps of Engineers
Planned Inspection in August 2018 of the
Inspection of Completed Works Project
For Uvas Creek
Santa Clara County, CA

July 2018

TABLE OF CONTENTS
Annual Uvas Report

A. PHYSICAL CONDITION OF THE PROTECTIVE WORKS 1

B. FLOOD BEHAVIOR OF THE PROTECTIVE WORKS 2

C. ENCROACHMENTS AND TRESPASSES 3

D. PERMITS ISSUED FOR WORK WITHIN RIGHT-OF-WAY 3

E. MAINTENANCE MEASURES TAKEN 3

F. FISCAL YEAR 2018 MAINTENANCE COSTS 4

APPENDIX 1
AERIAL PHOTOGRAPHIC MAP OF PROJECT AREA 6

APPENDIX 2
INSPECTION LOCATION SHEETS 8

APPENDIX 3
OPERATIONS & MAINTENANCE COST DETAILS 10

APPENDIX 4
AREAS OF SIGNIFICANT CONCERN 12

Annual Pre-Inspection Report for the period July 1, 2017 to June 30, 2018
Uvas Creek Levee and Channel at Gilroy, Pajaro River Basin, California
The Santa Clara Valley Water District’s (SCVWD) Annual Pre-Inspection Report, for the period
July 1, 2017 to June 30, 2018 for the Uvas Creek Levee at Gilroy, Pajaro River Basin,
California, is as follows:
A. Physical condition of the protective works:
The physical condition of the protective works as indicated by the Inspector’s Report is
summarized as follows:
Introduction:
SCVWD inspects the Uvas Creek Levee project semi-annually each fall and spring. During
these inspections, SCVWD assesses the condition of the levee, main channel, and
appurtenances including culverts, flap gates, and maintenance roads. This period,
inspections were conducted from October, 2017 to June, 2018. Locations referred to in
this report can be identified by station on the aerial photographic map of project area in
Appendix 1. Specific inspection sites are identified in the Uvas Creek inspection location
sheets in Appendix 2. Cost expenditures on maintenance of the protective works for the
period are detailed in Appendix 3. Photos showing areas of significant concern are
included for reference in Appendix 4. The condition ID’s (G numbers) referenced in the
Inspection Summary below are listed in Appendix 4.
SCVWD Inspection Summary:
The levee was observed to be in fair condition and appeared to be functional throughout
the project. Rodent burrowing activity is low overall throughout the project. The highest
rodent activity is located near Gilroy High School and the lower end of the project where
forage appears to support higher rodent populations. Levee reconstruction work performed
in July 2015 improved the levee slope condition near Gilroy High School, but many holes
have returned. Vegetation along the levees that should be addressed includes trees
growing on the slopes throughout the project (G15543, G15545, G19686, and G23826), as
well as tree canopy overhanging or touching the slopes (G15501).
The main channel was observed to be relatively clear and functional. Minor sediment
deposition was noted in several areas, most notably at Miller Avenue crossing. In-stream
vegetation just upstream of the Highway 101 bridge and upstream of Miller Avenue
crossing is being monitored. Presumed presence of the sensitive status species, California
Tiger Salamander, and lack of an Incidental Take Permit (ITP) preclude the SCVWD’s in-
channel work in the area. SCVWD biological staff are working to acquire an ITP. Woody
vegetation and trees are growing in the riprap around the West Luchessa Avenue bridge
crossing (G15548 and G15551).
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Ongoing and Future Work:

SCVWD intends to perform the following repair or corrective maintenance work within the
next year:

Table 1: Summary of proposed maintenance activities, July 1, 2018 through June 30, 2019

Non-Recurring Activities Planned
Item Maintenance Activity General Location Schedule
Trim and remove willows <
Highway 101 to levee end Pending regulatory
1 6-inch DBH in natural
and levee to Miller Ave agencies’ approval
channel
Rodent control - Live
2 Levees Continuously
Trapping
Removal of large downed Inboard levee slope near Fall/Winter
3
oak branch near trail downstream limit of project 2018/2019
Inboard and outboard levee
Repair of rodent damage to slopes from Miller Ave to
4 2018-2019
levee just downstream of West
Luchessa Ave
Recurring Activities Planned
Item Maintenance Item General Location Schedule
1 Creek and levee inspections Entire project area Semi-annually
2 Trash and debris removal Throughout project Quarterly
3 Graffiti removal Throughout project As-needed
4 Fence Repair Throughout project As-needed
5 Sign Install/Repair Throughout project As-needed
Levees, roads, bypass
6 Weed abatement As-needed
channel
7 Revegetation maintenance Revegetation sites As-needed
8 Flap gate maintenance Entire project area Annually
9 Video Inspection Throughout project Every 5 years

The frequencies of maintenance activities shown above are guidelines for scheduling
routine maintenance. SCVWD also performs these and other maintenance activities on an
as-needed basis throughout the year.
B. Flood behavior of the protective works:
No major flooding events occurred during the reporting period.

SCVWD inspects the performance of the project works during significant storm events.
SCVWD inspectors pay particularly close attention to areas with high potential for flow
blockages and flooding, including the Santa Teresa Boulevard, Bolsa Road, West
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Luchessa Avenue (Thomas Road), Miller Avenue, Bloomfield Avenue, and Highway 25
(Hollister Road) bridge crossings.

For inspection and reporting purposes, SCVWD has identified the following stage
thresholds for the project, as measured at the City of Gilroy’s West Luchessa Avenue
(Thomas Road) bridge staff gauge.

Table 2: Stage thresholds for Uvas Creek at West Luchessa Avenue (Thomas Road)
bridge staff gauge
Elevation
Occurrence
Stage (ft)
189.0 Close Miller Avenue low flow crossing, monitor creek stage
196.0 Activate City of Gilroy Emergency Operations Center (EOC)
198.0 Fully open and staffed City and SCVWD EOCs
199.5 Flood warnings provided to residents by Police and Fire Departments
201.7 Creek over banks, sandbag residences

C. Encroachments and trespasses:

There is one existing and previously noted unauthorized farm access ramp into and across
the invert of the Uvas Creek channel. This violation is located approximately 5,320 feet
upstream of Highway 101 between SCVWD stations 322+39 and 325+65. Farmers use
that creek crossing to access their agricultural fields. Although the operation or flood
conveyance of the project is unaffected by this crossing, SCVWD has monitored and will
continue to monitor for signs of erosion.

Three unauthorized staircase access points exist on the project levee. They were installed
by the City of Gilroy as part of their public trail system. These sites have been identified by
USACE as potential erosion sites and now show evidence of minor erosion. During the
previous reporting period, the City of Gilroy placed additional aggregate rock at the stair
locations and other pioneer trails to address the erosion. The rock is holding well and these
sites will continue to be monitored and, if necessary, additional measures will be taken.

A few encampments were noted throughout the project.

D. Permits issued for work within right-of-way:
No new permits were issued between July 1, 2017 and June 30, 2018.

E. Maintenance measures taken:

The status of the deficiencies indicated in the draft 2018 USACE Annual Inspection report
requiring corrective maintenance is shown in Table 3 below. Photo numbers listed in Table
3 reference photos from the draft 2018 USACE Annual Inspection Report.

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Table 3: Status of USACE inspection items for the Uvas Creek LEFT BANK system

Photos Deficiency Action Comment/Status
LEVEE EMBANKMENTS
1. Unwanted Vegetation Growth
SCVWD is addressing vegetation
Trees encroaching within Remove vegetation removal less than 6" in diameter.
6
15' of landside levee toe as permitted. SCVWD in early stages of effort to
address removal of larger vegetation.
3. Encroachments
Unapproved pedestrian Not severe enough to warrant
2,3,9 Monitor
paths and staircase immediate repair
10. Animal Control
Not severe enough to warrant
14,15 Rodent damage Monitor
immediate repair
15. Seepage
SCVWD latest inspection confirmed
Coordinate with
none Sinkhole that the City adequately repaired the
City of Gilroy
sinkhole
FLOOD DAMAGE REDUCTION CHANNELS
1. Vegetation and Obstructions
none Tree in the channel Remove tree Tree has been removed

F. Fiscal Year 2018 maintenance costs
The fiscal statement of the Superintendent’s operations for the current period is as follows:

Table 4: Fiscal statement of operations, July 1, 2017 through June 30, 2018

Category Labor Materials Equipment Totals
Project Inspection $6,827.15 $0.00 $0.00 $6,827.15
Maintenance $78,171.78 $847.68 $4,761.38 $83,780.84
Rodent Control Work done by contract $4,795.50
Flood Fighting Ops. $0.00 $0.00 $0.00 $0.00
TOTAL $84,998.93 $847.68 $4,761.38 $95,402.99

Note: See Appendix 3 for details

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The labor costs shown above include overhead. Costs do not include any planning or
engineering costs associated with operations and maintenance of the project works. Costs
of activities undertaken during storms or to prepare for potential flooding events are
included in the "Maintenance" category.

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