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II. PROJECT DESCRIPTION
The Santa Clara Valley Water District ("District " or "SCVWD ") routinely removes sediment from streams and associated facilities to restore their capacity to carry floodwaters, and from canals to restore their water delivery function. Vegetation is routinely removed from in and around streams and canals to meet flood protection and water supply mandates, and to provide access and fire prevention. The District conducts bank protection activities to restore eroded flood protection facilities and to protect property. Also included in this program are minor maintenance activities.
Stream maintenance is required to meet the District's flood protection and water supply mandates. Cumulatively, stream maintenance is a substantial activity and expense for the District. Recently, the District drafted the Stream Maintenance Program (SMP) to provide specific program policies to effectively implement individual routine stream maintenance projects. The SMP specifies a procedure for maintenance design, field operations and mitigation that would constitute Best Management Practices (BMPs). The SMP includes a regional mitigation program to mitigate cumulative wetland and riparian impacts.
This Chapter summarizes the SMP; the full text of the SMP is published along with this Program EIR.
A. PROJECT LOCATION: THE SANTA CLARA VALLEY WATER DISTRICT
The District is responsible for water supply and flood protection in Santa Clara County, California. The District manages streams, canals, reservoirs, dams, pipelines, groundwater percolation facilities, and water treatment plants throughout the county to meet its objectives. The routine activities covered by the SMP are undertaken in streams and canals and on adjacent District property and easements. Only those streams within the District's jurisdiction are included in this program. The District's jurisdiction on a stream begins at that point where 320 acres (½ square mile) of watershed drain to the stream, and continues downstream to San Francisco Bay or the limits of the Pajaro River in Santa Clara County. The SMP area consists of 191 streams for approximately 828 miles and 10 canals for approximately 41 miles. (See Figure II-1, Streams and Canals in District Jurisdiction; note that figures are bound together at the end of the document.)
For the purpose of this Program, "streams" are defined as natural watercourses and modified channels and canals that are within the District's jurisdiction. In this Program, streams include both the waterway and its immediate geographical corridor, including riparian corridors.
The District is divided into two major hydrologic basins draining either into the San Francisco Bay or the Monterey Bay. In the northern portion of the County, streams of the Santa Clara Basin drain to the San Francisco Bay. To the south, streams in the Pajaro River Basin drain ultimately to Monterey Bay. Streams in the northeast portion of Santa Clara County are not in an established flood control zone and are not in the jurisdiction of the District. (See Figure II-1, Streams and Canals in District Jurisdicition.) Table II-1 lists the two basins, five flood control zones, and 15 incorporated cities of Santa Clara County.
Table II-1
Flood Control Zones
|
Flood Control Zone |
Land Area (square miles) |
Creek Length (miles) |
Cities in Zone |
| Northwest | 97 | 108 | Cupertino, Los Altos, Los Altos Hills, Mountain View, Palo Alto, Sunnyvale |
| North Central | 85 | 87 | Campbell, Cupertino, Los Gatos, Monte Sereno, Saratoga, San Jose, Santa Clara, Sunnyvale |
| Central | 175 | 133 | Campbell, Los Gatos, San Jose, Santa Clara |
| East | 359 | 259 | Milpitas, Morgan Hill, San Jose |
| Santa Clara Basin Subtotal | 716 | 587 | |
| South Zone
Pajaro River Basin Subtotal |
370 | 241 | Gilroy, Morgan Hill, San Jose |
| SMP Work Area Total | 1086 | 828 |
Source: SCVWD, TRA, 3/01
Below the reservoirs, the District has active management over 523 miles of creeks, 44% of which have had some previous bank or flood protection work. This 523 mile portion of the District jurisdiction is the focus of the Program EIR.
Most District streams in urban areas have been modified to increase flood water capacity and to stabilize the banks. Modifications range from a full concrete channel to a variety of earthen channels. Table II-2 shows the major channel types in the Santa Clara and Pajaro River basins. The channels are classified as Natural +/-, mixed, or concrete. Natural (+/-) channels are unmodified or have some modification to the flood plain, but no modification of the stream channel or stream banks. Mixed channels include engineered or otherwise modified streams where the stream bottom is earthen, but banks can be a variety of modified conditions such as excavated earth, earth levees, rock, gabions, sacked concrete, or flood walls. Concrete channels have a concrete bottom and may have either concrete or earthen banks. Unclassified streams are outside of the District's Water Ways Management Model (WWMM) mapping; most of these streams are presumably natural, but that is undocumented.
District facilities require routine maintenance. The principal maintenance activities are: 1) sediment removal from creeks and associated facilities such as sediment basins, fish ladders and stream gage stations, and from water supply canals; 2) vegetation management along and adjacent to creeks and canals, and; 3) bank protection on creeks. Routine stream maintenance also includes more minor maintenance activities, such as maintenance of revegetation sites, fence repair, trash removal, removal of downed trees or other blockages from streams, and rodent control on levees. These activities are the subject of the SMP and this program EIR with the main focus being on the three principal maintenance activities.
Table II-2
Existing Channel Conditions
| Channel Type a | Santa Clara Basin (miles) |
Pajaro River Basin (miles) |
Total (miles) |
| Natural (+/-) | 205 | 103 | 308 |
| Mixed | 115 | 20 | 135 |
| Concrete | 78 | 1 | 79 |
| Unclassified | 190 | 116 | 306 |
|
Totals |
588 | 240 | 828 |
| Canals | 41 |
Source: SCVWD 2001
a Channel classification based on the District's WWMM; Unclassified channels are not in WWMM and are presumably natural.
The work area subject to the SMP includes the streams, canals, and any adjacent property that the District owns or holds an easement for access and maintenance. The District does not provide maintenance on private property when no easement exists. The maintenance work area is the stream channel or canal itself, typically extending to 20 feet past the top-of-bank when access is provided, and less when access is not provided. Creeks with constructed levees may require a wider maintenance easement. The maintenance work area is typically less than the District's permitting jurisdiction, which is within 50 feet of the top-of-bank.
B. PROPOSED PROJECT
The proposed project is District adoption and implementation of the SMP. District activities under the SMP would be a continuation of past routine creek and canal maintenance activities in most of the same areas and using many of the same techniques. The difference is the SMP's comprehensive approach to managing the cost and environmental impact of maintenance which is anticipated to produce an overall benefit. The SMP will be used by District staff to ensure that routine stream maintenance practices are conducted in an efficient, consistent and environmentally sensitive manner.
1. Project Purpose
The SMP is designed to provide specific program policies to implement routine stream and canal maintenance projects in order to meet the District's flood protection and water supply mandates in a feasible, cost-effective and environmentally sensitive manner. The main objectives of preparing the SMP are to maintain flood protection and water supply facilities in the streams and canals within the District's jurisdiction to meet their original design, coordinate the various aspects of routine stream maintenance to better achieve this goal, to reduce the environmental impacts of stream maintenance, and to assist in obtaining multi-year permits for these activities.
2. Contents of the SMP
The SMP is published with this EIR and is incorporated herein by reference. The SMP was developed by District staff with the advice of an external stakeholder committee. Stakeholders are individuals or organizations who will be affected by or have an interest in the SMP. The stakeholder process included four meetings between May 1999 and August 2000 with over 20 organizations and representatives. Stakeholders include regulatory agencies, municipalities, and environmental and business groups. Stakeholders' thoughts, questions and recommendations were solicited through a variety of forums with the goal of developing a SMP that reflects community interests and achieves maximum acceptance.
The Draft SMP attached contains the following Chapters:
1. Introduction. Introduction and summary of the SMP.
Important material also serving the EIR is included in several SMP appendices:
Appendix A Glossary
Appendix B Maintenance Guidelines
Appendix C Nesting Migratory Bird Procedure
Appendix D Dryback/Fish Relocation Operation Guidelines
Appendix E Programmatic Impact Assessment and Mitigation for Bank Protection Activities
Appendix F Bank Protection Locations
Appendix G Best Management Practices List
Appendix H District Use Pesticide Literature Review
3. Relationship of SMP Document to the EIR
The SMP is the proposed project which is the subject of the EIR; the SMP document appended to and incorporated into the EIR serves as the primary project description for the EIR.
A primary
purpose of the SMP is to reduce the environmental impact of maintenance and
to provide compensatory mitigation when needed. Thus, the SMP itself contains
the mitigation for the maintenance activities its prescribes. For the purposes
of the CEQA analysis, it is the District's objective that all mitigation
be incorporated in the proposed program. Some impacts to stream vegetation may
not be at a level of significance to require mitigation; however, the District
has decided to provide mitigation for all impacts to stream vegetation from
sediment removal and vegetation management activities to further its mission
of protecting and enhancing natural resources along streams.
4. Relationship of SMP to the Parallel Permitting
The SMP was developed with assistance from regulatory agencies participating in the permitting process. It is the District's intent that the program and mitigation defined by the SMP would serve as the basis for state and federal permits and permit conditions. As described in EIR Section III, Plans, Ordinances and Policies, this EIR will help state and federal agencies such as the RWQCB and the Corps in complying with state and federal environmental review requirements.
5. SMP Elements
The SMP has three distinct phases: program development and documentation, implementation of annual routine stream maintenance work, and annual reporting. These are described in the SMP in Chapter 3, Stream Maintenance Process Overview.
C. STREAM MAINTENANCE
1. Purpose
To provide its flood protection and water supply functions, the District constructs or manages stream channels and canals. These facilities need routine maintenance to perform as intended. Maintenance is a critical function of the District's role protecting public safety and property. The District also does revegetation and other forms of environmental improvement as mitigation for its projects and as part of its stewardship of the streams in Santa Clara County. These environmental improvement sites also require maintenance.
Most routine maintenance addressed by the SMP is undertaken to ensure that flood capacity is maintained in existing streams. The District uses engineering criteria for modified channels to determine when maintenance is necessary (see SMP Appendix B, Maintenance Guidelines). Vegetation removal in and around the streams is done to provide adequate flood capacity, appropriate access, and fire safety. Sediment removal and vegetation management in canals restore their ability to convey water. Erosion repair and streambank stabilization are undertaken to provide for public safety and protect property, public roads, and utilities. Minor maintenance activities such as fence repair, and trash and debris removal support the functions of the three major routine stream and canal maintenance activities. The SMP contains a description of maintenance in Chapter 2, An Overview of Stream Maintenance Activities.
2. Sediment Removal
Sediment removal is the act of mechanically removing sediment deposited within a stream. Typically, sediment removal is indicated when an accumulation of sediment: (1) reduces capacity; (2) prevents facilities or appurtenant structures from functioning as intended; or (3) impedes fish passage and access to fish ladders.
The District's purposes in performing sediment removal activities are to ensure that a stream will continue to provide flood capacity and to ensure that appurtenant facilities are working as designed. Sediment is usually removed from modified channels. However, sediment is also sometimes removed from natural creeks on an occasional basis to provide proper functioning of outfalls, culverts, bridge crossings and stream gauging stations. Sediment is only occasionally removed from canals.
The District
estimates that it removes an average of 80,000 cubic yards of sediment on about
16 miles of channel per year in Santa Clara County. The actual quantity and
location will vary from year-to-year depending, in part, on rainfall of the
past season. Cumulatively, sediment removal is projected for approximately 60
miles of streams, of which approximately 75 percent are earth-lined channels
and 25 percent are concrete-lined channels. Sediment removal from canals
is estimated to be less than 1,000 cubic yards per year. (See Figure II-2, Projected
Sediment Removal Work Areas.) Table II-3 lists the extent of projected work.
The extent of maintenance work is defined as the total length or area on which
stream maintenance will repeatedly take place. It does not progressively add
the same or different stream maintenance activities for the same reach of creek.
Thus, it indicates how much creek will be affected overall.
In most cases, sediment deposition is a natural process that occurs where the stream gradient flattens out in the valley floor or where the gradient is otherwise flat over long reaches. This deposition affects flood protection capacities.
Sediment removal equipment is dictated largely by site access and the nature of the material to be removed. Typical sediment removal sites are illustrated in the accompanying photographs. The following general description applies to routine sediment removal maintenance activities from flood protection channels. These work methods are updated when new, feasible methods or types of equipment become available.
1. The work generally occurs between July 1 and October 15.
2. Equipment to be used may include excavators, draglines, gradealls, loaders, 10 cubic yard dump trucks or 20 cubic yard haul trucks, pumps, inflatable dams, and personnel transportation. The average duration of a sediment removal project is 10 days.
3. If water must be bypassed around the site during work, water pumps and piping, and cofferdams of earth, gravel, sandbags, hay bales, rubber or other appropriate material may be used. In some cases, a bypass channel or detention basin is appropriate to isolate a site.
4. Sediment is disposed at a landfill or other suitable site.
Currently, the District disposes of sediment at the closer of the BFI landfill at Newby Island or the Kirby Canyon landfill near Morgan Hill. The District has contracts with these landfills through December 2001, and will be soliciting bids for new 5-year landfill contracts this year. The District is undertaking a Solids Material Management Program to develop and implement long-term strategies for managing its solid waste materials.
Stockpiling
of sediment, in order to dry it out prior to hauling it to a landfill, is done
only occasionally. Stockpiling can only be done when there is sufficient space
to allow the temporary piling of material; however, this is not typical. Instead,
dump trucks are lined with heavy plastic sufficient to avoid muddy water dripping
from the sediment, and taken directly off-site. Stockpiling requires double
handling of wet material, but has the advantage of reducing sediment volume
and weight, which reduces hauling and dump fees.
3. Vegetation Management
Management of vegetation in and adjacent to creeks and canals is necessary to maintain the ability of channels to function as flood protection facilities and canals to transport water. Dense vegetation can adversely affect the ability of the channel to contain the flow of flood waters for which it was designed. Therefore, most flood protection facilities require some type of periodic vegetation control. Depending on the original design and the characteristics of the channel, the frequency of vegetation management varies from annually to every few years. Figure II-3 shows the Projected Channel Vegetation Work Areas. Table II-4 lists the extent of projected work.
Vegetation management for environmental purposes includes control of invasive, non-native plants. The District also uses vegetation management to control weeds at revegetation sites to increase the number of native trees and shrubs which survive and to more quickly establish a self-sustaining plant community which provides wildlife habitat.
The District manages vegetation for other purposes including the protection of levees, and concrete linings from plant roots; meeting local fire codes requiring the control of combustible weeds and grasses; providing visual clearance to inspect the condition of a facility; and providing access along maintenance roads.
Over the past 30 years, the District has continually revised vegetation management approaches on District facilities. The three basic methods of vegetation management are: hand removal (chain saws, weed-eaters, etc.); mechanical (mowing and discing); and chemical control through the use of herbicides. A method or combination of methods is chosen for each site depending on the maintenance requirements of the facility. Efficiency, economics and the protection of public health and environmental resources are all considered in the selection of methods.
Some green waste is mulched and stored for later use at a District property near Camden and Meridian Avenue in south San Jose. The balance is delivered to an area landfill that composts green waste. Tree logs are occasionally reused as "root wads", in order to create a woody debris habitat for aquatic species. This is done on a project-specific basis, and there is no location where logs are stored.
a. In-channel Vegetation Management
The 2 types of in-channel vegetation management (also called channel vegetation management) are herbicide application and hand removal. Herbicide use is described in more detail in the "Herbicides Used" section below.
Hand removal of vegetation is undertaken in a few locations where it is not possible to access the area with spray equipment. Weeds, shrubs and trees are removed by the hand removal method. Trees with a trunk diameter up to 6" dbh are removed by the hand removal technique, although the actual number of trees removed by this method is very limited. In some cases, the vegetation is sprayed with herbicides, and then approximately 6 months later, the dead material is removed by hand removal methods. This latter category of work is referred to as follow-up hand removal. Follow-up hand removal of dead vegetation is only necessary when herbicide spraying is new to an area and there is a large volume of vegetation created in the first year or two. In subsequent years, the amount of vegetative regrowth is reduced and follow-up hand removal is necessary much less frequently.
b. Upland Vegetation Management
The five types of vegetation management in upland areas are discing, mowing, herbicide application, hand removal, and removal of overhanging growth.
Upland discing occurs on upland parcels outside of the streambanks and is conducted to create firebreaks. Upland mowing consists of operating a flail mower to eliminate or reduce grasses that would cause a fire hazard during the summer. Mowing can occur from one to three times annually at each location, usually between May and October. Mowing is conducted on the inside slope of some levees or streambanks.
Upland
herbicide spraying is used on levees, unpaved maintenance roads, and along some
property lines. On levees, herbicides are used primarily to keep woody vegetation
and broadleaf weeds from becoming established where they will interfere with
flood flow capacity, damage the levees, or hinder their inspection. Weeds and
grasses are sprayed on maintenance roads to clearly define and keep open the
access route. Herbicide spraying along property lines assists in establishing
a firebreak. Pre- and post-emergent herbicides are sprayed from a truck-mounted
rig or by a controlled drop applicator.
Hand removal of vegetation is conducted in upland areas where mowers cannot access, and herbicides are either not practical due to steep terrain or not allowed. Hand removal of vegetation is generally used in upland areas along property lines to establish fire breaks. Removal of overhanging growth consists of pruning trees branches that impede access roads or hang over fence lines.
c. Extent of Vegetation Management Work
The frequency of vegetation management activities varies from semiannually to once every several years, depending on the method used. Generally, channel herbicide and channel hand removal of vegetation are conducted once every year. Channel herbicide work is conducted throughout the summer dry season whereas channel hand removal is conducted near the end of the growing season.
Vegetation management occurs in creeks, canals, and adjacent uplands. On average, vegetation management work is annually performed on approximately 4,000 acres. Within this larger work area, the targeted treatment area consists of approximately 2,000 acres. These totals include the following approximate levels of activity:
Vegetation management activities are consistent from year-to-year. Slight variations in flood protection activities occur due to weather patterns. For example, historically, increases in some work activities have occurred during drought years, with decreases in some activities occurring during flood years. This is primarily due to the scouring effects of flood flows cleaning out areas of vegetation. Right-of-way activities remain constant regardless of these weather patterns. Revegetation maintenance reduces 3 to 5 years after initial installation of a revegetation site.
Table II-3
Extent of Projected
Sediment Removal
Work Activity |
LENGTH
|
WORK AREA
|
VOLUME REMOVED
|
Stream Vegetation
Impacts
|
|||||||||
Avg Annual |
Extent of Maint. |
20 yrs |
Avg Annual |
Extent of Maint. |
20 yrs |
Avg Annual (cy) |
Extent of Maint. |
20 yrs |
Fresh-water Wetland |
Tidal Wetland |
Riparian Vegetation |
||
| Santa
Clara Basin Streams
Sediment Removal |
14 | 47 | 281 | 59 | 164 | 1,181 | 73,070 | 206,800 | 1,461,400 | 61 | 29 | 0 | |
| Pajaro
River Basin Streams
Sediment Removal |
2 | 14 | 42 | 4 | 31 | 84 | 6,930 | 39,900 | 138,600 | 19 | 0 | 0 | |
| Total,
SCVWD Streams
Sediment Removal |
16 | 61 | 323 | 63 | 195 | 1,265 | 80,000 | 246,700 | 1,600,000 | 80 | 29 | 0 | |
Note: Minor sediment removal of less than 1,000 cubic yards per year would be done in the canals.
Source: Santa Clara Valley Water District, 3/01
d. Herbicides Used
Herbicides often are more effective at controlling vegetation than mechanical
or hand removal methods. This is because of the ability of the herbicide chemicals
to spread into and damage the roots of the target plants, thus preventing resprouting.
When treated with mechanical or hand methods, some woody plants, such as willows,
will resprout with multiple stems. The multiple sprouts result in a greater
flood protection problem and require annual control. With herbicides, annual
retreatment is often necessary, but the treatment area is greatly reduced, as
only a small percentage of regrowth will occur. As a result, the SMP would use
herbicides as the primary method by which vegetation is controlled in channels
and on stream banks.
Herbicides are not broadcast sprayed across the channel, but are selectively
sprayed at the herbacious or woody plants targeted for removal by the design
parameters of each particular stream reach. In streambeds where the removal
of woody plants is required, only saplings no greater than 2" in diameter at
breast height (dbh) are removed in the target area. In upland areas, herbicides
are sprayed on maintenance roads to provide a clear access area and on levee
slopes to eliminate broadleaf weeds.
The District staff routinely reviews new and changed herbicide formulations
and changed label limitations. New products are selected and old products are
discontinued due to the changing availability and suitability of the products
for District use. The District uses criteria for product selection that minimize
worker and public health risk and avoids environmental impact. The District
will not use herbicides that are:
A variety of sources of information are available to instruct the District
in its choice of herbicides. A literature review was conducted for the SMP program
EIR, attached as Appendix H, Santa Clara Valley Water District, District Use
Pesticide Literature Review. The literature review presents use, health and
environmental information about the principal herbicide products that the District
currently uses. In the future, new products will be subjected to a similar review
and that information will be used, along with general product information and
site-specific conditions to determine whether and how a product should be used.
The District uses herbicides according to the label directions and for uses
approved by the EPA and the CDPR. Currently, the primary herbicide which the
District uses to control in-channel vegetation is glyphosate, a nonselective
broad spectrum
herbicide. Glyphosate products include Monsanto's
Roundup® Pro and Monsanto's Aquamaster® (an aquatic formulation formerly
marketed as Rodeo®). Aquamaster® is approved for use on and near open
water, whereas Roundup® Pro is not approved for application directly in water
or to areas where surface water is present.
Pre-emergent herbicides control vegetation on levees
and access roads by preventing the germination of weed seeds. The District uses
a range of pre-emergent herbicides, including pendimethalin and chlorsulfuron.
The CDRP has recently proposed new restrictions
on use of certain pre-emergent herbicides including several which the District
uses (sulfometuron-methly, chlorsulfuron, oryzalin and isoxaben). These proposed
restrictions are intended to minimize potential ground and surface water contamination.
The District is currently reviewing the recent proposal and will determine whether
its Herbicide Program will need to be adjusted. See chapter IV-D Hazards, Public
Health and Safety for more information. Herbicides which are used by the District
for routine maintenance in channel and upland areas are shown in Table II-5.
e. Herbicide Use in South County
The SMP includes the reinstatement of the use of herbicides as part of the
Vegetation Management Program in the Pajaro River Basin. Herbicides are currently
used as part of the Vegetation Management Program in the Santa Clara Basin,
but their use was discontinued in the Pajaro River Basin (South County) at the
direction of the District Board in 1974 because of complaints regarding drifting
of herbicides into agricultural fields. In 1979, the District considered reinstating
a Herbicide Program in the Pajaro River Basin. At that time, there was a general
concern in the community over the use of herbicides, particularly the use of
the herbicide 2,4-D and after public hearings, the District decided not to reinstate
the use of herbicides in the Pajaro River Basin. As a result, the use of herbicides
was also excluded on new federally sponsored flood protection projects on Llagas
Creek in the Pajaro River Basin.
Since that time, the District has revised its Herbicide Program to address
environmental, health risk and public safety concerns, but at the same time
recognize that herbicides are a cost effective means for maintaining flood protection
and water supply facilities. Many of the improvements made to the District's
Herbicide Program are described below:
Table II-5 br>Existing Annual Herbicide Use
Name
Amount
As a result of these improvements, the District is now proposing that herbicide
use be reinstated in the Pajaro River Basin. Herbicides would be used on approximately
56 miles of channel in the Pajaro River Basin, 11 miles of which would be done
in conjunction with sediment removal. Implementing this change would require
the following actions:
Staff has been working with the Board and the NRCS toward the implementation
of this change. Both the Board and the NRCS agree this is a beneficial change.
Initial removal of trees in Llagas Creek from approximately 600 feet downstream
of Highway 152 down to the confluence with the Pajaro River is not considered
routine maintenance and will require separate environmental review. See Section
II.C .7. Activities Not Included in SMP, c Non SMP Maintenance Projects, Item
3.
4. Bank Protection
Bank protection involves an action by the District to repair stream banks
that are eroding or are in need of preventative erosion protection. The District
may implement bank protection when the problem: (1) causes or could cause significant
damage to a property or adjacent property; (2) is a public safety concern; (3) negatively
affects transportation or recreational use; (4) negatively affects water
quality or beneficial uses; or (5) negatively affects riparian habitat. Repairs
may take several forms from installing "hard" structures (e.g., rock, concrete,
sack concrete, gabions) to "soft" structures (e.g., willow brush mattresses,
log crib walls, pole plantings) or a combination of hard and soft structures.
Bank protection also includes preventative maintenance to ensure that banks
do not erode in the future. Such bank protection can reduce sedimentation and
improve water quality.
Stream bank erosion is a natural process, which mostly happens during major
storm events. Erosion can occur because of hydraulic forces and geotechnical
instabilities, and can be accelerated by human intervention and land uses. Accelerated
erosion is typically a result of particular land uses that affect the stream
corridor, including grazing, agriculture, and road and utility construction.
Erosion of banks can result in increased sediment deposition, which can lead
to decreased flood flow capacities and potential flood hazards. Erosion on banks
may also cause vegetation and soil loss, damage to private or public property,
transportation and utility impacts, safety hazards, and turbidity injurious
to fish and aquatic life. Levee erosion may lead to failure of the structure
and flooding.
Bank protection work may either occur as repair of an existing bank protection
project which is failing, or as new work along a bank which is eroding. Repair
of former work provides the opportunity to incorporate new designs with better
engineering and environmental benefits. Bank protection is considered routine
and is included in the SMP because it is a regular and frequent function the
District must perform. The new bank work is also considered routine maintenance
because it often is restoring the flood protection function of a modified channel.
Typically the District conducts some form of erosion and bank repair at 30 to
50 different sites each year. Approximately 70% of bank protection work will
be done on unmodified channels and 30% will be done on modified channels for
the reasons cited above or to restore the modified channel design elements.
The District uses a wide range of bank protection techniques. Repairs can
take several forms, ranging from the use of soft structures (i.e., willow brush
mattresses, log crib walls, pole plantings) to the installation of hard structures
(i.e., rock blankets, concrete, sack concrete, gabions) or a combination of
hard and soft structures.
Bank protection measures that create extensive inflexible, impervious channel
banks with essentially no revegetation are termed "hard," and the product is
called "hardscape." Measures that retain natural earth banks and have higher
capacity to support vegetation are termed "soft," and the product is called
"softscape." Although the intensity of impact varies within a category and depends
upon site conditions, hard methods generally limit biotic potential of a site
and soft methods tend to retain biotic potential. The former have the greatest
potential for adverse impacts, and the latter generally are less likely to have
adverse impacts and even have the potential to improve site quality. Recognizing
the potential impacts due to the exclusive use of hardscape materials, the District
is committed to doing no more than 50% of future bank protection using hardscape
methods. Recent designs of bank protection measures that employ hardscape materials
have evolved with the emphasis of limiting such use to the extent practicable.
Also, revegetating the stabilized slopes with native vegetation has become the
norm wherever site conditions allow. This is especially true in unmodified channels
that still retain riparian value. The methods listed here are defined and illustrated
in Appendix E of the SMP. These measures are updated when new, feasible methods
or types of equipment become available.
Bank Protection Techniques That Tend To Limit Biotic Potential:
Bank Protection Techniques That Tend To Retain Biotic Potential:
Based on 15 years of historical records, the District estimates that an average
of roughly one linear mile of stream banks may be repaired annually. Many erosion
sites are small and are not easily predicted. The quantity and location of bank
protection activities varies greatly from year-to year, based on watershed conditions
(heavy rains often lead to more work in the following year), degree of safety
hazard, work load, budget, and quantity of other priority work to be done in
a given year. The description of historical bank protection in the SMP shows
that a greater concentration of bank protection occurs in cities and semi-rural
foothills of the Santa Clara Valley. Actual future bank protection work could
potentially be done anywhere it is needed within District jurisdiction.
Many areas receiving bank protection are devoid of native riparian vegetation
as a consequence of erosion. The District's design criteria may determine that
soft erosion control methods are not adequate at a particular site. Therefore,
some bank protection would utilize hardscape methods, and riparian vegetation
may be precluded from re-establishing. The general design criteria and cross-section
for each of the bank protection methods used by the District are included in
Appendix E of the SMP. In addition to those criteria, design of a particular
bank protection project includes evaluation of other site specific characteristics
such as bank slope, shear stress, location (such as the inside or outside of
a curve), soil type, flow velocity, characteristics of the channel adjacent
to the site and the available right-of-way. The site is evaluated for the repair
method consistent with the characteristics of the site. Revegetation potential
is also evaluated for each bank protection project. This potential is not only
dependent upon the method of bank protection used, but also the physical properties
of the stream where the repair is taking place.
Equipment used for bank protection may include excavators, dozers, cranes,
loaders and 10- and 20-cubic-yard dump trucks, concrete trucks, and pumps and
water trucks. If water must be bypassed around the site during repair work,
water pumps and piping, and cofferdams of earth, gravel, sandbag, hay bales,
rubber or other suitable material may be used. In some cases, a bypass channel
or detention basin is appropriate to isolate a site. Most often, bank protection
projects are implemented in the dry season. The average duration of bank protection
work is 10 working days.
Bank protection maintenance activities generally occur between July 1 and
October 15, but the work can begin sooner or later than these times depending
upon conditions in the field. Most often, bank protection projects are implemented
in the dry season.
5. Minor Activities
Minor maintenance activities include trash removal at trash racks and more
generalized locations; repair and installation of fences and gates; grading
and other repairs to restore the original contour of access roads and levees;
grading small areas without vegetation above stream banks to improve drainage
and reduce erosion; repair of structures with in-kind materials within the same
footprint (such as replacement of concrete linings, culverts, pipes, valves
or similar structures); cleaning and minor sediment removal at stream gages,
outfalls, culverts, flap gates, tide gates, inlets, grade control structures,
fish ladders, fish screens; graffiti removal; tree pruning along maintenance
roads and fence lines to provide access and to remove hazards; irrigation, weeding,
replanting and other types of ongoing maintenance at mitigation sites; removal
of obstructions to flow in the immediate vicinity (not to exceed 100 feet) of
bridges, streamflow measuring stations, box culverts, storm drain outfalls and
drop structures to maintain functions of such structures; removal of trees or
branches that are in imminent danger of falling, fallen trees, and associated
debris to maintain channel design capacity; and ground squirrel and rodent control
with traps, smoke bombs, and pesticides.
Minor activities also include repair of existing structures with minor deviations
in the configuration or filled area, including changes in materials or construction
techniques providing the environmental impacts from those changes are minimal.
Rodent control is directed primarily at ground squirrels and occasionally
gophers whose burrows threaten the integrity of levees, dams, or canal banks
intended to retain water. The District specifies the area to be treated and
the contractor selects the methods from those permissible by law and the County
Agricultural Commissioner. Currently, the majority of ground squirrel control
is with a grain bait treated with the rodenticide chlorophacinone.
6. Activities Not Included in SMP
a. Emergency
Routine stream maintenance does not include emergency repair. A situation
is considered an "emergency" if it is a sudden, unexpected occurrence involving
a clear and imminent danger that demands immediate action to prevent or mitigate
loss of or damage to life, health, property, or essential public services (Public
Resource Code Section 21060.3).
b. Capital Improvement Projects
Large construction projects and Capital Improvement Projects (CIP) are not
considered routine stream maintenance and are not addressed through the SMP.
A routine stream maintenance activity does not alter the design flood conveyance
capacity of the stream. After adoption of the SMP, all future CIP will analyze
long-term maintenance impacts under separate future environmental review and
any environmental effects of new CIP will be compared to the conditions currently
evaluated for that reach of stream under the SMP. New mitigation for CIP will
only be required if there are impacts for the same reach of creek that require
new mitigation in addition to the impacts projected in the SMP. After the environmental
review is completed for the new project, the SMP will be updated to incorporate
any revisions to the mitigation program, and the implementation of the new maintenance
and its annual reporting will be conducted in the same manner as indicated in
the SMP.
c. Non SMP Maintenance Projects
The SMP and Program EIR do not address certain other District maintenance
activities that are either not routine maintenance, or not located within or
next to streams and canals. Activities that alter the design flood conveyance
or water supply capacity of a stream or canal are not included. Maintenance
of groundwater percolation ponds; instream summer dams; reservoirs and dams;
pipelines outside of stream corridors; and installation/modification of new
fish ladders are not included. Work conducted on private property by owners
or by other agencies is not included.
d. Activities Outside of the Scope of Routine Maintenance
Although the SMP is intended to be comprehensive, there are possible channel
maintenance activities that may not be accommodated by the BMPs and other programmatic
mitigation proposed as part of the SMP.
The following maintenance activities are excluded from the SMP because they
are located where there is insufficient environmental information, there is
high environmental sensitivity, or the magnitude of the activity is greater
than is reasonably considered routine maintenance:
1. Sediment removal and vegetation management on stream reaches above the 1,000-foot
elevation contour which is above the reservoirs.
2. Hardscape bank protection projects which limit biotic potential and would
occur in high quality fisheries habitat or existing high quality riparian habitat.
Refer to Table II-8, Bank Protection: In-stream Impact and Mitigation, Table II-9,
Bank Protection: Stream-side Impact and Mitigation and Appendix E of the SMP
for further definition of those bank protection projects which are not covered
by the SMP.
3. Initial removal of in-channel willow trees and other trees in Llagas Creek
downstream of Luchessa Avenue (which is approximately 600 feet downstream of
Highway 152) to the confluence with the Pajaro River. This section of Llagas
Creek has not been regularly maintained as provided for in the original flood
protection project design (co-sponsored by the NCRS under Public Law 566) over
the past 4 to 5 years because of sighting of a nesting pair of Least Bells vireo
and for other reasons. In the meantime, young trees have developed substantial
growth in this section of the creek and their removal has the potential for
environmental effects not within the scope of vegetation management reviewed
under the SMP. For this section of Llagas Creek, the District will continue
to remove trees less than 2" dbh as routine stream maintenance. Removal of trees
greater than 2" dbh, as necessary to restore this section of Llagas Creek to
its original design, is not considered routine maintenance and will require
separate environmental review. Once this section, is restored, its subsequent
routine maintenance would be covered by the SMP.
D. MITIGATION INCORPORATED INTO THE PROJECT
The SMP is intended to incorporate all actions necessary for the District
to conduct needed maintenance and to reduce impact to an acceptable level. Mitigation
is presented in three areas: 1) overall Policies for Resource Protection, 2)
specific design and worksite practices termed BMPs, and 3) compensatory mitigation,
particularly for wetlands.
1. Policies
Chapter 4 of the SMP includes 15 policies to protect resources during the
implementation of routine stream maintenance activities. These policies provide
guidance to District managers and staff in the environmental review, design,
and implementation of individual stream maintenance projects. BMPs have been
developed to implement each of these policies. (SMP, Chapter 4 and Appendix
G).
2. Best Management Practices
The District has worked for several years to develop BMPs which apply generally
to many different types of District work. The SMP has specifically developed
BMPs applicable to routine stream maintenance, and these are incorporated into
the SMP (SMP Appendix G). The approach taken in formulating the BMPs was to
develop a set of design and work practices that could effectively mitigate maintenance
impacts wherever the work needed to be done throughout the District. Different
BMPs apply to different maintenance activities and apply differently in different
parts of the District. The District will use its Geographic Information System
(GIS) to apply the BMPs effectively.
3. Compensatory Mitigation
Over the long-term, the SMP has the potential to significantly affect the
ecological and biological environment of Santa Clara County by cumulatively
affecting wetland habitats, including tidal and freshwater wetlands and riparian
habitats. Though measures in this EIR will avoid or reduce these impacts, the
District acknowledges that cumulatively it would not be to a less-than-significant
level if compensatory mitigation were not provided.
The SMP includes a compensatory mitigation package to compensate for the significant
residual impacts of sediment removal and vegetation management on in-stream
wetlands and riparian vegetation. The compensatory mitigation package includes
the following components: (1) tidal wetland restoration; (2) freshwater wetland
creation; (3) stream and watershed protection; and (4) control of giant reed
(Arundo donax), This mitigation is described in detail in Chapter 5
of the SMP. The four components of the in-stream compensatory mitigation package
are summarized in Table II-7, and proposed sites are shown in Figure II-7, Compensatory
Mitigation Sites. Additionally, the SMP includes a compensatory mitigation package
to compensate for the significant residual impacts of the bank protection program.
This mitigation is described in detail in Appendix E of the SMP. The two components
of the Programmatic Impact Assessment and Mitigation for Routine Bank Protection
Activities are summarized in Tables II-8 and II-9.
Table II-7
Impacts to:
And for lag time in implementing other mitigation
components
2012
Table II-8
Environmental
Sensitivity
Bank Protection Technique Effect
Fisheries Present on Reach
Environmental Sensitivity is primarily determined
by fisheries values, as follows:
High Quality. Cold water fishery with trout
or steelhead, warm water fishery with trout potential (DEIR fish habitat
categories 5, 6, and 7).
Medium Quality Fisheries. Warm water native
fishery, salmon present (DEIR fish habitat categories 3 and 4) or any reach
used for steelhead migration.
Low Quality Fisheries. Warm water fishery,
mostly introduced species, fish limited or no value (DEIR fish habitat categories
1, 2 and 8, but only where the reach is not used for steelhead migration).
Effects are defined as follows:
Impact = Net adverse impact; must be mitigated
1:1.
Neutral = No effect; no mitigation required.
Benefit = Net improvement; provides mitigation
credit 1:1.
Table II-9
Existing riparian habitat quality is characterized
as follows:
High Quality Riparian Habitat. Sites with
native overstory with continuous understory or occurring in dense thickets;
dense native overstory with sparse, non-native or no understory; and native
willow thickets. Site may provide overhanging escape cover and shading.
Moderate Quality Riparian Habitat. Sites with
sparse native overstory with sparse, non-native or no understory; non-native
overstory with native understory; and dense non-native overstory with sparse,
non-native or no understory. Site may provide some overhanging escape cover
and shading.
Low Quality Riparian Habitat. Sites with no
or only sparse non-native overstory with sparse, non-native, or no understory.
Site may provide some overhanging escape cover for fish.
Restoration Potential is characterized as follows:
High Riparian Restoration Potential. Sites
where dense native overstory and dense native understory, including willow
thickets where appropriate, can be readily established. Overhanging escape
cover and shading can be incorporated.
Moderate Riparian Restoration Potential. Sites
where sparse native overstory with moderate to dense native understory can
be established. Overhanging escape cover and shading may potentially be
incorporated.
Low Riparian Restoration Potential. Sites
where no or only sparse native overstory and no or only sparse native understory
can be established.
Impacts are defined as follows:
Impact = Net adverse impact; must be mitigated
1:1 in area; 3:1 in tree stems over 6 inch DBH.
Neutral = No effect; no mitigation required.
Overhanging escape cover and/or shading must be incorporated if present
in pre-project conditions.
Benefit = Net improvement; provides mitigation
credit 1:1 in area. Overhanging escape cover and/or shading must be incorporated
if present in pre-project conditions.
These actions will be coordinated so that multiple functions of the natural
systems are provided or enhanced. In some cases, this may result in a concentration
of mitigation actions on certain sections of a stream or streams to gain the
maximum benefit to the natural values of the watersheds and streams.
Final designs for each mitigation component will be developed and submitted
to the regulatory agencies for their review and approval. Detailed design is
underway for several of these components, and some have received preliminary
review by the regulatory agencies. Separate environmental review under CEQA
will be prepared for some mitigation projects because of their own potential
for creating significant physical environmental effects. Maintenance work is
spread out over many years, and likewise, mitigation design and implementation
will be spread out over a period of approximately 10 years.
4. Special Status Species
The avoidance and minimization measures incorporated in the project, described
in SMP Chapter 4 and Appendix G, are considered sufficient to reduce most, but
not all, potential impacts of the SMP on special-status species to a less-than-significant
level. Residual impacts are reduced to less than significant by specific provisions
in compensatory mitigation.
5. Program Adaptation and Reporting
The SMP incorporates several explicit steps for evaluating and reporting the
effectiveness of the mitigation in the Program. Reference to SMP Figure 3-1,
SMP Resource Protection Protocol, shows steps for monitoring work, a "lessons
learned" evaluation, report to agencies, and an annual update of BMPs to improve
their effectiveness. This cycle of annual evaluation and improvement makes the
SMP capable of adapting to new information and changing conditions. It is expected
that the full suite of resource protection policies incorporated in the SMP
will allow the District to minimize environmental effects under a wide range
of actual work needs.
E. PROGRAM EIR METHODOLOGY
1. Environmental Baseline
Impacts to streams in Santa Clara County began long ago with the expansion
of agriculture and human settlement in the region. Modifications to stream channels
pre-date the formation of the District (1952) and the environmental protection
laws and regulations of the last several decades. These impacts and modifications
have intensified over the years as human population and development has increased.
Though the District has conducted stream maintenance activities for many years,
environmental review of these activities has only occurred within the last decade,
and when it has occurred, it has been on an annual basis. The SMP would allow
these activities to be implemented more effectively and with more environmental
sensitivity over the long term.
The environmental "baseline" is the condition described as the Environmental
Setting in the EIR from which future changes and, therefore, impacts of the
SMP are projected. The baseline is normally the physical environmental conditions
in the vicinity of the project as they exist at the time when the Notice of
Preparation of environmental review is published. However, lead agencies have
the flexibility to establish other points in time as the baseline when necessary
to provide a reasonable analysis.
The District has chosen the 1997 to 2000 time period as the baseline since
that is the period over which the streams were surveyed and best represents
current conditions. The baseline physical conditions are the conditions by which
the District will determine whether an impact is significant (CEQA Guidelines
Section 15125(a)). As further described in Chapter IV.B, Biology, the baseline
conditions for wetlands and riparian vegetation were either surveyed or estimated
in 1997 and 2000.
2. Work Projections and Planning Horizon
The SMP is intended to establish an indefinite, ongoing District program.
The SMP and the Program EIR use a 20-year planning time frame to evaluate cumulative
impacts. Permits from the Corps and other agencies are expected to last for
a period of 10 years, after which time the District would apply for renewal.
The program will be reviewed in 10 years and the EIR amended if necessary.
The projections for future work under the SMP is based on analysis of historical
data going back to 1977. All forms of maintenance show a consistent pattern,
however projections of future stream maintenance activities for the SMP and
Program EIR cannot represent the exact extent of work which will occur. Actual
stream maintenance activities can vary from year-to-year. There may be some
future routine maintenance activities which are consistent with the descriptions
of work and impacts overall but which vary in location from the District's projection
of work areas. Maintenance at such sites is still included in the program as
long as it does not result in significant environmental effects substantially
different than those evaluated for the Program as a whole.
Under CEQA, the lead agency normally limits its examination to changes in
the existing physical conditions in the affected area as they exist at the time
the Notice of Preparation is published unless another specific baseline is established
(Sec 15126.2(a)). As a result, this EIR does not review the environmental effect
or provide mitigation for the original construction of the flood protection
facilities or for the maintenance which has occurred up until the time of this
review. This EIR evaluates the proposed program including changes which will
occur as a result of adoption of the SMP. These changes are limited to new work
areas where maintenance work has not been undertaken on a frequent basis; the
use of herbicides for vegetation management in the Pajaro River Basin; the incorporation
of BMPs and a compensatory mitigation program to avoid and reduce environmental
impacts; and the overall coordination of routine maintenance in a program, including
annual review and reporting.
3. Definition of Alternatives
The proposed project is District adoption of the SMP. This EIR examines two
groups of alternatives to the proposed project: 1) alternative courses of action
in which the District does not adopt a SMP, and 2) alternative ways to develop
a SMP. The alternatives are evaluated and described in detail in Chapter V,
Alternatives.
The first group, alternatives to an SMP, include the Existing Alternative.
This is considered the No Project Alternative, as defined by Section 15126(e)
of CEQA. Under Existing Alternative, the District would still conduct maintenance
of channels and other facilities, but would do so on a case-by-case basis with
individual environmental review, as in the past. The Existing Alternative does
not mean "no maintenance."
In principle, there are ways that District channels can be changed to accommodate
flood flow without the present need for sediment removal or vegetation management.
There are ways that erosion pressures on stream banks could be reduced. The
physical factors which give rise to the need for routine maintenance are discussed
extensively in supporting studies and in this EIR in Section IV. A. Geomorphology.
Present channel conditions are the result of numerous external constraints;
a redesign of the channel in order to reduce maintenance requirements would
be a major engineering undertaking, usually requiring substantial increase in
channel right-of-way and substantial channel construction. Changes of the necessary
magnitude cannot be accomplished within the scope of routine maintenance as
described in the SMP. The general class of geomorphic or engineered alternatives
is addressed in this EIR at a screening level of detail and eliminated from
further consideration.
Alternatives in the second group, different ways to implement a SMP, are evaluated
in the EIR to show the tradeoffs between amount of work, level of public benefit,
extent of environmental protection and mitigation. The March 2001 version of
the SMP is the proposed project subject to the Draft Program EIR (also called
the Multi-Year Program Alternative). After public review, the SMP may be revised
to incorporate features of the various alternative programs or in response to
comments on the Draft EIR.
4. Definition of Potential for Cumulative Impact
Cumulative effects of maintenance can occur as a result of the same activities
repeated at the same location, different types of routine maintenance occurring
at the same location, District capital improvement projects, projects by other
agencies and property owners in and adjacent to creeks, and the implementation
of mitigation programs.
The SMP addresses all forms of stream maintenance over a long term, thus the
Program EIR for the SMP considers the cumulative effect of stream maintenance
throughout the District. Indeed, one of the main motivations for the SMP was
the opportunity to deal comprehensively with maintenance impacts and mitigation
on an effective regional scale.
Most of the individual maintenance activities take place repeatedly on a limited
number of District channels (239 miles out of 828 miles within the District's
jurisdiction). In many creek sections, both sediment removal and aquatic herbicide
application are undertaken, but in different years within the facility's particular
maintenance cycle. For example, sediment removal may be conducted in year one.
The following year, herbaceous wetland vegetation may begin to establish where
the sediment was removed. In year three, vegetation may be sufficiently established
to pose a potential flood hazard, so herbicide is applied to kill the targeted
vegetation. Herbicide application may continue in subsequent years. In the meantime,
sediment accumulates until it eventually reaches a point where flood capacity
is significantly reduced and sediment removal is again required.
There are potential cumulative environmental impacts associated with the mitigation
projects, such as Los Capitancillos freshwater creation, and Pond A-4 tidal
restoration, which are being done to support the SMP. Project specific environmental
impacts of the mitigation projects will be addressed as part of the specific
CEQA documents that will be prepared for all mitigation projects.
Table II-10 lists future District CIP projects. As discussed earlier, the
SMP has a procedure for comparing CIP projects to SMP projections and for CIPs
to be incorporated into the SMP.
The effects of District maintenance are also cumulative with other activities
that may affect the same channels in Santa Clara County. The SMP lists several
parallel programs that the District has undertaken. (See SMP Chapter 6. Linkages
to Other Programs and Projects). Many of these will work cumulatively with the
SMP to reduce impact on the stream system, others, such as capital improvement
projects, will change the stream environment, possibly altering the type of
maintenance needed. Where the nature of the cumulative interaction can be reasonably
defined, this EIR addresses those parallel activities.
The District reviews and comments on new projects proposed by other agencies
or property owners within 50 feet of a creek to determine if they will affect
the flow of water, collect debris, or will adversely affect the ability of channel
banks to carry flood waters or resist erosion (District Ordinance 83-2). The
District encourages projects to be designed so as to avoid unstable bank conditions,
large increases in discharge, or conditions that might cause pollution. Additionally,
the District and the various cities participate in a Non-Point Source Control
Program as defined in Section III-12 of this document. One of the main purposes
of District review of channel encroachment and construction by others in and
near channels is to prevent incorrectly designed or poorly installed work from
causing channel sedimentation or bank failure. Thus, one function of the District
review is to minimize the potential for cumulative impact on the creeks resulting
from work by others increasing the need for routine maintenance.
In 1999 and 2000, over 400 stream related permits were issued each year by
the District's Community Projects Review Unit to other agencies and property
owners for culverts, outfalls, bridges, riprap, stabilization, sediment activities,
utility crossings, grading and other types of construction work in or near creeks.
The District is currently reviewing applications for over 75 outlet/culvert
projects, bridge/road projects, bank protection projects and pipelines. Major
projects which have recently been built or are under construction in streams
or are under review are:
The amount of permits reviewed by the District varies from year to year, but
these numbers indicate that many small project are undertaken in creeks by others.
Beyond the named activities, the streams of Santa Clara County are affected
by numerous activities outside of the District's control. Some of the regional
effects are being explored through programs such as the Watershed Management
Initiative (WMI , discussed in SMP 6. B. 10. RWQCB Watershed Management Initiative
). Other regional effects are considered in this EIR in an extensive discussion
of the General Plans of the cities and the County that affect Santa Clara County
streams. Given the complexity of streamside land use, however, it is impossible
to isolate individual projects or activities that may cumulatively impact the
streams. The Program EIR defines the existing stream condition as the environmental
baseline because the existing setting includes the numerous effects on streams
other than maintenance.
Other Future District Projects in Creeks
(Location)
(Reaches 1-5, 7-9, 11-13) (flood protection,
bank protection)
(Palo Alto Flood Basin - Foothill Expressway)
(flood protection)
(San Francisco Bay - Foothill Expressway)
(flood protection)
(San Francisco Bay to Searsville Dam)
(flood protection)
(downstream of Hwy 101) (restore existing
levee)
(upstream of Highway 85)
(fish passage)
(Guadalupe Slough to Hwy 101)
(flood protection)
(Guadalupe Slough to Interstate 280)
(flood protection)
(Miller Avenue to Wardell Road) (flood protection)
(Lawrence Expressway to Miller Avenue)
(revegetation)
(Bollinger Bridge) (enlargement of existing
bridge)
(Monroe Street to Williams Road)
(repair of reinforced box culvert)
(Comber Debris Basin) (removal of debris
basin)
(Union Pacific Railroad to Interstate 880)
(flood protection)
(Highway 880 - Highway 280)
(flood protection)
(Almaden Expressway to Masson Dam)
(creek restoration)
(flood protection)
2012-2016
(Central Pipeline)
(bank protection)
(Guadalupe River to Camden Avenue)
(bank protection)
(Lincoln Avenue to Meridian Avenue)
(bank protection)
(Lower Penitencia to Piedmont Avenue)
(flood protection)
(Berryessa Creek to Hwy 680) (flood protection)
(at Union Pacific Railroad) (flood protection)
(Montague Expressway to Hwy 208)
(flood protection)
(South Bay Mobile Home Park) (flood wall)
(Rock Spring neighborhood) (flood protection)
(Reaches 1-6) (flood protection)
(Cunningham to Quimby Road, Lake Cunningham)
(flood protection)
(Coyote Creek to King Road)
(flood protection)
2007-2010
(Pajaro River to Buena Vista Avenue)
(flood protection, environmental cleanup)
(Buena Vista Road and Wright Avenue)
(flood protection)
Product
Chemical Type
Use
Average Annual
Gallery
Isoxaben
Preemergent, selective to broadleaf weeds.
Used on levee slopes and maintenance roads.
447 pounds
Garlon 3A
Triclopyr, triethylamine salt
Postemergent, selective to broadleaf weeds.
Used on levee slopes.
5 gallons
Garlon 4
Triclopyr, triethylamine salt
Postemergent, selective to broadleaf weeds.
Used on levee slopes.
62 gallons
Oust
Sulfometuron
Preemergent, nonselective. Used on access
roads/firebreaks.
206 ounces
Pendulum
Pendimethalin
Preemergent, selective to grasses. Used on
access roads/firebreaks.
3,576 pounds
Aqua Master (formerly known as Rodeo)
Glyphosate
Postemergent, nonselective. Approved for
aquatic use. Used in channels.
750 gallons
Roundup Pro
Glyphosate
Postemergent, nonselective. Roundup used
in upland areas on maintenance roads/firebreaks.
1,021 gallons
Surflan (AS)
Oryzalin
Preemergent, selective to grasses. Used on
access roads, firebreaks, and landscape/ revegetation areas.
1,269 ounces
Telar
Chlorsulfuron
Preemergent, selective to broadleaf weeds.
Used on levee slopes and maintenance roads.
2,140 ounces
Transline
Clopyralid
Postemergent, selective to specific broadleaf
families. Some minor preemergent activity. Used for control of yellow star
thistle on levee slopes/upland parcels.
16 gallons
Target Pro-spreader/ activator or Wilbur-Elias
R-11 spreader activator
Surfactant used with Aqua Master®, Garlon,
and Transline products.
310 gallons
Compensatory Stream Vegetation and Special Status Species Mitigation
Mitigation
Component
Location
Size of Mitigation
Compensates for
Description
Date
Tidal Wetland Restoration
Pond A-4
30 acres
30 acres of tidal wetlands:
Restore diked salt evaporator
pond to historical tidal marsh conditions
2006
Freshwater Wetland
Creation
Three sites currently identified:
14 acres of freshwater wetland
in stream channels:
3
acres, Santa Clara Basin
Convert annual grasslands
to seasonal or perennial wetlands adjacent to Guadalupe River
2002
7
acres, Santa Clara Basin
Convert ruderal grasslands
to near-perennial wetlands adjacent to Coyote Creek
No date yet
4
acres, Pajaro River Basin
Convert open water in inactive
percolation pond to wetland bench
2003
Stream and Watershed Protection
Undeveloped parcels with streams
Approx. 920 to 1,210 acres
102 acres of freshwater wetlands:
Preserve, protect, and improve
streams and associated wetlands
As lands become available
in first 10 years
Giant Reed Control
Throughout county
125 acres
78 acres of riparian vegetation from vegetation
management:
Control giant reed outbreaks
and provide associated mapping, revegetation, education, and coordination
throughout county
2002-
Bank Protection: In-stream Impact and Mitigation Matrix
In-stream Functions
Methods that Tend to Retain
Biotic Potential (e.g., Large boulder revetment, crib walls)
Methods that Tend to Limit
Biotic Potential (e.g., small rock rip-rap, gabions, sacked concrete)
High Quality
Present
Neutral
Not Covered by
SMP
Absent
Benefit
Not Covered by SMP
Medium Quality
Present
Neutral
Impact
Absent
Benefit
Neutral
Low Quality
Present
Neutral
Neutral
Absent
Neutral
Neutral
Work Measure is lineal extent
of stream channel.
Bank Protection: Stream-side Impact and Mitigation Matrix
Existing
Riparian Habitat Quality
Bank Protection
Project Restoration Potential
High Potential
Medium Potential
Low Potential
High Quality
Neutral
Impact
Not covered by SMP
Medium Quality
Benefit
Neutral
Impact
Low Quality
Benefit
Benefit
Neutral
Work Measure is lineal extent
of stream channel, also taking into account total area affected and number
of tree stems removed.
Table
II-10
Project Name
Construction Dates
Adobe
2003 - 2007
Matadero/Barron Creek Remediation
2003-2008
Permanente Creek
2009-2016
San Francisquito Creek
2006-2009
San Francisquito Creek
2002-2003
Stevens Creek Drop Structure
Modifications
2002-2003
Sunnyvale West Channel
2011-2012
Sunnyvale East Channel
2014-2016
Calabazas Creek
2012-2014
Calabazas Creek
2002-2004
Calabazas Creek
2002-2003
San Tomas Creek Repairs
unknown
Calabazas Creek
unknown
Lower Guadalupe River
2003-2005
Downtown Guadalupe River
2002-2006
Guadalupe Creek Restoration
2002
Upper Guadalupe River
2002-2007,
Los Gatos Creek Erosion Repairs
2002
Los Gatos Creek Bank Stabilization
2004-2005
Randol Creek Flood Risk Study
(study)
unknown
Los Gatos Creek at Gilgan
2004
Berryessa Creek
2003-2007
Calera Creek
unknown
Calera Creek
2002
Coyote Creek
2014-2016
Coyote Creek Outdoor Classroom
(bank protection, revegetation)
2002
Coyote Creek
2002
Coyote Creek
2005
Lower Silver Creek
2002-2009
Silver/Thompson Creek
2002
Upper Penitencia Creek
2002-2004,
Lower Llagas Creek, Church
Ponds
2002-2007
South Zone Buffer Strips (revegetation)
2003-2005
Upper Llagas Creek
2002-2007