Stream Maintenance Program
DRAFT STREAM MAINTENANCE
PROGRAM
Chapter 1
INTRODUCTION
This chapter describes the
objectives and applicability of the Santa Clara Valley Water District's
(District) Stream Maintenance Program (Program). As a foundation for understanding
the resource protection and maintenance issues discussed in this report,
this chapter also defines routine stream maintenance and briefly describes
the District's facilities where stream maintenance is required. In conclusion,
this chapter provides a summary of related programmatic documentation
that is required for implementation of the Stream Maintenance Program
and the organization of subsequent chapters.
A. PROGRAM PURPOSE AND OBJECTIVES
The Stream Maintenance Program is designed to provide long-term guidance
to the District 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.
This authority is provided by the District Act, as amended. The main
goals of preparing the Stream Maintenance Program are to maintain streams
and canals to meet their original design to provide flood protection
and water supply, coordinate the various aspects of routine stream maintenance
to better achieve this goal, and assist in obtaining multiyear permits.
The Stream Maintenance Program only applies to District facilities.
The objectives of the Stream Maintenance Program are as follows:
1. Standardize practices and protocols for routine sediment removal,
vegetation management, and bank protection in and around the streams
and related facilities within the District's jurisdiction.
2. Identify cost-effective routine stream maintenance practices and
protocols.
3. Ensure routine stream maintenance activities reflect the District's
policies of environmental protection and stewardship.
4. To the extent practical, avoid or minimize adverse environmental
effects and encourage preservation and restoration.
5. Establish effective and economically-practical compensatory mitigation
for environmental impacts from routine stream maintenance activities.
6. Establish practices and protocols that optimize operational flexibility
and allow the integration of lessons learned and improvements in Best
Management Practices.
The Stream Maintenance Program will be used by District staff to ensure
that routine stream maintenance practices are conducted in an efficient,
consistent, and environmentally-sensitive manner.
B. APPLICABILITY AND USE OF THE STREAM MAINTENANCE PROGRAM
The Stream Maintenance Program applies to all of the District's routine
stream maintenance activities, including three major types of activities:
sediment removal, vegetation management, and bank protection. Many of
these activities are undertaken to ensure flood conveyance capacity
is maintained in existing streams. In addition, routine maintenance
includes vegetation removal in and around the streams and canals within
the District's jurisdiction to ensure appropriate access and fire control.
More minor maintenance activities are also included in the definition
of routine stream maintenance.
The stream maintenance work area addressed by this Stream Maintenance
Program 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 of the streams.
The Stream Maintenance Program is designed to be a process and policy
document that can be adopted by the District. Once adopted, the Stream
Maintenance Program will be used by the District to guide the implementation
of routine stream maintenance activities and projects. The Stream Maintenance
Program outlines specific measures, protocols, policies, and reporting
requirements to ensure that routine stream maintenance projects are
implemented in an efficient and environmentally-sensitive manner. This
Stream Maintenance Program is subject to future revisions as improvements
and modifications are made to reflect the best available knowledge,
technology, and practices.
The Stream Maintenance Program is intended to establish an ongoing
District program of indefinite length. The Stream Maintenance Program
uses a 20-year planning time frame to project the level of future work,
and this same time frame is used by the Environmental Impact Report
(EIR) to evaluate cumulative impact. Permits for stream maintenance
from regulatory agencies are expected to last for a period of 10 years,
after which the District would apply for a renewal. The Stream Maintenance
Program will be reviewed annually as described in Chapter
3 to determine if adjustments to the BMPs need to be made. The overall
program will be reviewed in 10 years as part of the permit renewal process.
The 20-year time frame was used because this is the period of time
over which future work areas and impacts can be reliably projected.
Projections for future work under the Stream Maintenance Program are
based on an 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 Stream Maintenance Program cannot
represent the exact extent of work that will occur. Actual stream maintenance
activities vary from year to year. There may be some future routine
maintenance activities that are within the District's jurisdiction and
are consistent with the descriptions of work and impacts evaluated for
the program overall but which were not specifically included in 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.
If routine stream maintenance practices are substantially changed at
any time, the program will be updated. If these changes would result
in significant impacts not evaluated in the EIR, then the EIR will also
be updated. New mitigation measures would not be required unless new
significant impacts are identified.
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).
Routine stream maintenance does not alter the flood conveyance or water
supply capacity of a stream or canal. Large construction projects and
Capital Improvement Projects (CIP) are not considered routine stream
maintenance and are not addressed through the Stream Maintenance Program.
For new CIPs, long-term maintenance impacts and any new mitigation will
be analyzed under the CIP's separate future environmental review and
compared to those impacts and mitigation previously evaluated for that
reach of stream under the Stream Maintenance Program. New mitigation
will only be required if the impacts of the maintenance under the CIP
are in excess of impacts included in the Stream Maintenance Program
for the same reach of creek. After the environmental review is completed
for the CIP, the Stream Maintenance Program 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 Chapter 3.
The installation of new or major modification of fish ladders is not
included in the Stream Maintenance Program. See also the "Overview of
the Streams and Canals within the District's Jurisdiction" below for
clarification on what areas are included or excluded from the Stream
Maintenance Program.
C. STREAM MAINTENANCE ACTIVITIES
The following provides a brief discussion of the major activities addressed
by the Stream Maintenance Program. For more information on these activities
and why they are implemented, please refer to Chapter
2. In addition, the Stream Maintenance Program applies to more minor
activities such as fence repair, trash removal, and removal of downed
trees or other blockages.
1. Sediment Removal
Sediment removal is the act of mechanically removing sediment that
has been deposited within a stream. Typically, sediment is removed when
it: (1) reduces stream capacity, (2) prevents facilities or appurtenant
structures1 from functioning as intended, or (3) impedes
fish passage and access to fish ladders. Sediment removal can occur
in the same physical area as vegetation removal.
2. Vegetation Management
The District removes vegetation in and adjacent to creeks and canals
to maintain the ability of channels to function as flood protection
facilities and canals to transport water. Vegetation removal can occur
in the same physical area as sediment removal. In addition, vegetation
is removed to meet local fire code requirements and to reduce combustible
weeds and grasses on property adjacent to the streams within the District's
jurisdiction. The control of invasive nonnative vegetation is another
purpose for which the District undertakes vegetation control. Vegetation
management can be accomplished through mowing, discing, hand clearing,
or herbicide applications (depending on the environmental conditions
of the site).
3. Bank Protection
Bank protection involves any action by the District to repair streambanks
that are eroding as well as preventative erosion protection. The District
implements 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, (4)
negatively affects beneficial uses of surface water, or (5) negatively
affects riparian habitat. Repairs may take several forms ranging from
the installation of "hard" structures (i.e., rock, concrete, sack concrete,
gabions) to the use of "soft" structures (i.e., 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.
Routine stream maintenance includes three major activities,
as follows: (1) sediment removal activities that are designed to
restore the flood conveyance capacity of existing District channels
or associated features (e.g., tide gates), (2) vegetation management
in and around streams and canals in the District's jurisdiction, including
removal of vegetation for flood capacity, access and fire control, and
(3) bank protection activities necessary to protect District or
other facilities. Routine stream maintenance also includes more minor
maintenance activities, such as maintenance of revegetation sites, fence
repair, trash removal, and removal of downed trees or other blockages
from streams.
D. OVERVIEW OF THE STREAMS AND CANALS WITHIN THE DISTRICT'S
JURISDICTION
For the purpose of this Stream Maintenance Program, "streams" are defined
as natural watercourses and modified channels and canals that are within
the District's jurisdiction. In this Stream Maintenance 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, as shown in Figure 1-1.
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 protection
zone and are not in the Stream Maintenance Program.
Only those streams within the District's jurisdiction are included
in this Stream Maintenance Program. The District's jurisdiction on a
stream begins at ths 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 Stream Maintenance
Program area consists of 191 streams for approximately 828 miles
and 10 canals for 41 miles (see Figure 1-1, Streams and Canals in District
Jurisdiction). The ability of the District to perform maintenance activities
may be affected by District ownership, easements, or right to access.
Streams are defined as the natural watercourses and modified
channels and canals within the District's jurisdiction. In this Program,
streams include both the waterway and its immediate geographical corridor,
including riparian corridors.
In addition to maintaining streams and canals for flood protection
and water supply, the District also owns and operates ten major dams
and reservoirs in Santa Clara County and other water supply facilities,
such as pipelines outside of stream corridors, groundwater percolation
ponds, and in-stream summer dams. Maintenance of these facilities is
not addressed by the Stream Maintenance Program. In addition, the Stream
Maintenance Program only addresses maintenance work that is completed
by the District, or through District contracts.
E. RELATED PROGRAMMATIC DOCUMENTATION
Because this Stream Maintenance Program has been designed to guide
the implementation of routine stream maintenance projects and activities
over the long-term, it addresses stream maintenance at a general or
"programmatic" level. As such, this document provides the guidelines
and implementation measures that characterize how stream maintenance
will be conducted by the District.
In addition to this document, several other programmatic requirements
must be met before the Stream Maintenance Program can be implemented,
as follows:
- Program Environmental Impact Report. Consistent
with the California Environmental Quality Act (CEQA), an EIR will
be prepared and certified by the District for this Stream Maintenance
Program. The EIR will evaluate the potential environmental impacts
of the Stream Maintenance Program and determine measures to mitigate
impacts.
- Long-Term Permits. The District is seeking the
approval of a long-term permit for routine stream maintenance activities
in streams under the jurisdiction of the United States Army Corps
of Engineers (USACE), including Waters of the United States and special
aquatic sites (wetlands) pursuant to Section 404 of the Clean Water
Act as well as Section 10 of the Rivers and Harbors Act. This Individual
Permit would grant general authorization and set conditions for all
routine stream maintenance activities subject to jurisdiction of the
USACE. In addition, the District will be required to comply with requirements
under Section 7 of the Federal Endangered Species Act (ESA). The California
Regional Water Quality Control Boards (RWQCB) will also require compliance
with Waste Discharge Requirements (WDR) permits and Section 401
of the Clean Water Act. The Santa Clara Valley is divided into two
RWQCBs, based on major drainage areas. These are the San Francisco
Bay RWQCB and the Central Coast RWQCB.
The District will also revise Memorandums of Understanding with the
California Department of Fish and Game (CDFG) for stream maintenance
activities. The CDFG will review routine stream maintenance activities
for consistency with California's endangered species protection regulations.
The San Francisco Bay Conservation and Development Commission (BCDC)
regulates activities occurring in tidally-influenced areas. The BCDC
renewed Permit No. M77-113 on July 28, 2000, to cover the District's
routine stream maintenance activities that occur in or near tidal waters
of San Francisco Bay. The expiration date is June 1, 2005.
The permits and approvals from these agencies for routine stream maintenance
are expected to last for a period of 5 to 10 years, after which
time applications will be made for renewal of these permits and approvals.
In addition to these programmatic requirements for adoption and implementation
of the Stream Maintenance Program, the District uses a variety of supporting
documentation to guide stream maintenance activities. These will be
referenced and described in the following chapters of the Stream Maintenance
Program. Examples include BMPs, the Maintenance Guidelines, and Fish
Relocation Operation Guidelines. Several of these guidelines, or portions
thereof, are provided as appendices to this Stream Maintenance Program.
F. THE ROLE OF STAKEHOLDERS IN THE PLANNING PROCESS
Stakeholder involvement was a primary element of the Stream Maintenance
Program development process. In this planning process, a stakeholder
is an individual or organization who will be affected by or has an interest
in the final Stream Maintenance Program. 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 Stream Maintenance
Program that reflects community interests and achieves maximum acceptance.
The stakeholder process included four organized meetings with over
20 organizations and representatives. These External Stakeholder
Committee meetings were held on May 7, 1999, June 30, 1999, April 20, 2000,
and August 31, 2000. The External Stakeholder Committee was a collaboration
of key stakeholders convened to advise the District as it drafted and
revised the Stream Maintenance Program.
In addition, the District held a series of informal meetings with representatives
of regulatory agencies who were also part of the External Stakeholder
Committee. These meetings were held at the suggestion of the agency
representatives in order to facilitate the planning and permitting process.
G. ORGANIZATION OF THIS DOCUMENT
This document is organized into the following sections:
- Chapter 1 : Introduction.
This introduction provides a brief overview of the Stream Maintenance
Program.
- Chapter 2 : An Overview
of Stream Maintenance Activities. This Chapter provides an
overview of the extent of routine stream maintenance activities.
- Chapter 3 : Stream Maintenance
Process Overview. This chapter provides an overview of the
stream maintenance planning, implementation, and reporting process.
- Chapter 4 : Resource
Protection. This chapter details the resource protection
policies that are included in the Stream Maintenance Program.
- Chapter 5 : Compensatory
Mitigation. This chapter describes the compensatory mitigation
that is proposed as part of the Stream Maintenance Program.
- Chapter 6 : Linkages
to Other Programs and Projects. This chapter will explore
the relationship of the Stream Maintenance Program with other District
planning efforts.
- Chapter 7 : References.
Provides the full references of documents and correspondence used
in the preparation of this Stream Maintenance Program.
Participating in this process were representatives from
federal and state agencies (i.e., USACE Environmental Protection Agency,
U.S. Fish and Wildlife Service (USFWS), CDFG, and RWQCBs), cities (i.e
Palo Alto, Sunnyvale Milpitas, San Jose, and Gilroy), and community
groups (i.e., Coordinated Resources Management and Planning, Natural
Resource Conservation District, Clean South Bay Streams for Tomorrow).
Chapter 2
AN OVERVIEW OF STREAM MAINTENANCE ACTIVITIES
The Stream Maintenance Program
provides long-term guidance for the implementation of routine stream
maintenance work. Three major types of stream maintenance activities
are sediment removal, vegetation management, and bank protection. This
chapter provides an overview of these stream maintenance activities
and their average frequency and extent on an annual basis. Also included
in this Stream Maintenance Program are minor maintenance activities
described in this chapte .
The projections for work area amount under the Stream Maintenance Program
are based on approximately 20 years of historical data. The numbers
provided are program-level projections of future stream maintenance
activities and are not intended to represent the exact extent of work
which will occur in the future. As described further below, stream maintenance
activities can vary from year to year. There may be some future routine
maintenance activities in streams and canals within the District's jurisdiction
that are consistent with the descriptions of work and impacts overall
but which were not specifically included in 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 Stream Maintenance Program as
a whole.
Routine maintenance occurs on a year-round basis. However, it is scheduled
to avoid or minimize impacts to environmental resources. Typically,
routine maintenance that requires the operation of heavy equipment in
the channel is limited to the dry season.
A. SEDIMENT REMOVAL
1. Overview
Sediment removal is the act of mechanically removing sediment deposited
within a stream. Typically, sediment removal is indicated when it (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, for example. Occasionally, sediment is removed from
canals to maintain their function as water conveyance facilities. Sediment
is removed from canals on an irregular basis, with similar equipment
used for sediment removal from streams. Based on seven sediment removal
projects undertaken in canals from 1992 to 2000, the average annual
amount of sediment removed from canals is estimated to be less than
1,000 cubic yards. Sediment removal in canals takes place primarily
in Almaden-Calero Canal, Coyote-Alamitos Canal, Coyote Canal, and Coyote
Canal Extension.
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. In developed areas,
this deposition affects flood flow capacities.
Typical equipment used for sediment removal includes excavators, draglines,
loaders, and 10- or 20-cubic-yard dump trucks. 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. Saturated sediments may be temporarily
placed adjacent to the work site to dry out before being removed to
a landfill or to other suitable disposal or reuse sites. Most often,
sediment removal projects are implemented in the dry season (summer).
The District also implements BMPs to ensure that sediment removal projects
have the least impact possible. The District's equipment and work methods
are updated as new equipment or better methods become available. Sediment
removal projects are also revised as new CIP are completed.
2. Sediment Removal Methods
The method of sediment removal is dependent on channel configuration
and geometry, equipment reach and rate of production, channel type (tidal
or nontidal, concrete or earth bottom), moisture content of the silt,
ramp location, and access road width. For example, wide tidal reaches
with a channel bottom of wet bay muds which will not support equipment
require silt removal by a dragline or an excavator positioned on the
top of the creek bank. This method requires wide roads for the equipment
and for truck access.
Concrete-lined channels may be cleaned by pushing sediment into a
pile with a bulldozer and using a loader to place the material in trucks
for removal to an approved disposal site. The trucks are located at
strategic points either in the channel bottom or at the top of bank
depending on the method of routing the trucks. Another example is cleaning
or creating a low-flow channel with excavation equipment working in
the channel bottom, loading trucks either in the channel bottom or moving
the sediment to trucks at the top of bank.
3. Annual Sediment Removal Activity
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. This average includes both concrete-lined and earth-lined channels.
This is an average annual quantity and will vary from year to year depending,
in part, on rainfall conditions of the past season. Table 2-1 summarizes
recent annual sediment activities.
The number of sediment removal sites each year also varies widely.
Historical records show that the District removes sediment from an average
of 19 sites annually but may work at as few as two sites or as many
as 39 in a given year.
TABLE 2-1
Recent Sediment Removal Activity
District Fiscal
Yeara |
Cubic Yards |
Stream Miles |
Number of
Sediment
Removal Sites |
| 1996 |
11,500 |
1.5 |
2 |
| 1997 |
2,900 |
5.5 |
6 |
| 1998 |
132,300 |
12.9 |
27 |
| 1999 |
115,100 |
7.5 |
12 |
aDistrict convention: fiscal year
1998 = July 1, 1997, through June 30, 1998
B. VEGETATION MANAGEMENT
1. Overview
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 function for water conveyance. 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.
The District also plants and maintains revegetation or mitigation
projects, often along creeks. In the first few years after initial planting,
it is important 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 control of invasive, nonnative plants is another purpose for which
the District undertakes vegetation control. Plant species are targeted
that are not native to this area of California and are known to aggressively
spread. These plants can migrate into other areas where they can affect
channel capacity as well as reduce native plant populations. This can
lead to reduced channel capacity and overall habitat degradation. Current
practice is to assign this a lower priority and do it on an ad hoc basis
as it fits in with higher-priority work.
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.
2. Vegetation Management Methods
Over the past 30 years, the District has continually revised vegetation
management approaches to control vegetation on District facilities.
This approach consists of utilizing three basic methods: 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.
As an example, herbicides can often be a more effective vegetation
control method when compared to mechanical or hand removal. This is
because of their ability 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; however, the treatment area is greatly reduced,
as only a small percentage of regrowth will occur. As a result, this
program includes herbicides as the primary method by which vegetation
is controlled in channels and on streambanks.
Herbicides are not broadcast sprayed across the channel, but are selectively
sprayed at the plants targeted for removal by the design parameters
of each particular stream reach. In some streams, only woody saplings
(no greater than 2 inches in diameter at breast height) are removed
in the target area, while other streams require removal of both herbaceous
and woody vegetation. 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 only uses herbicides according to the label directions
and for uses approved by the United States Environmental Protection
Agency (USEPA) and the California Department of Pesticide Regulation
(DPR). Currently, the primary postemergent herbicides which the District
uses are Roundup® Pro and Aqua Master®
(formerly known as Rodeo®). These herbicides are formulations
of the chemical glyphosate, which is a nonselective broad spectrum herbicide.
Aqua Master® is approved for use in aquatic areas, whereas
Roundup® Pro is not approved for application directly
in water or to areas where surface water is present.
Other herbicides which will be used by the District are shown in the
following table.
TABLE 2-2
Herbicide Use for the Multiyear Stream Maintenance Program
Product
Name |
Chemical Type |
Use |
Average
Annual
Amount |
| 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 |
In total, the District currently uses approximately 2,000 gallons
of herbicides, 50 percent of which is Roundup® Pro and
35 percent is Aqua Master®. In addition, the District
uses approximately 3,580 pounds of Pendulum and 450 pounds of Gallery
per year. Appendix H contains a literature review of pesticides used
by the District.
The Stream Maintenance Program 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 of Directors 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 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:
- In 1980, the District discontinued the use of the herbicide 2,4-D.
- In 1986, the District switched to using herbicides in the sulfonylurea
family which are applied at rates of ounces per acre, rather than
previous herbicides which were applied at rates of pounds per acre.
This step not only reduced the overall amount of herbicides being
applied throughout the county, but also relied on using herbicides
with a lower toxicity.
- In 1988, the District went beyond state requirements and required
all District employees who handle pesticides to be certified as Qualified
Applicators by the DPR. As Qualified Applicators, these employees
are trained on pesticide laws and regulations, safety, and application
methods and are required to receive annual training to keep updated
in this field.
- Likewise, even before state requirements, the District required
that a District Pest Control Advisor (PCA) prepare a pesticide use
recommendation for any use of herbicide on District facilities. For
the District's purposes, PCAs are required to have a relevant bachelor's
degree, be trained in integrated pest management and groundwater protection,
and continue to receive 40 hours of relevant training every 2
years.
- At the District, the PCA is required to conduct a field survey
to assess the site conditions, types of weeds and nontarget plants,
surrounding land uses, and potential wildlife use prior to writing
a pesticide use recommendation. This information is used to make a
recommendation with detailed instructions to the applicator regarding
the type of herbicide, rate, equipment, treatment area identified
on a map, target vegetation, vegetation to protect, and any special
instructions relevant to the site and treatment.
- Certain types of herbicides were found as contaminants in groundwater
in California's Central Valley. Although no restrictions were placed
by the state on their use in Santa Clara County or on soil types found
in Santa Clara County, the District voluntarily discontinued the use
of certain preemergent herbicides on our facilities in 1993 to avoid
any potential problems with groundwater. This practice continues today.
PCAs receive groundwater training every 2 years from the DPR and receive
routine updates in changes to the regulations. Though none of the
regulations currently apply to this county, the District discontinues
use of products that are known groundwater contaminants in other areas
of the state.
- In 1994, the District voluntarily eliminated the use of residual
preemergent herbicides on our groundwater recharge facilities. Today,
only herbicides that are registered for use in aquatic areas are used
at these locations.
- In 1996, the District retrofitted its spray trucks to include the
Patchen WeedSeeker. This device utilizes a light sensor attached to
the front of the spray equipment that detects the presence of chlorophyll
(and, therefore, living plants) and controls individual spray heads.
Instead of spraying the entire width of a facility as the spray truck
passes over it, individual spray heads are turned on only as they
pass over vegetated areas. This eliminates the treatment of bare ground
and reduces the amount of herbicide applied by 20 to 90 percent.
This equipment is primarily limited to use on flat areas where all
vegetation needs to be controlled, such as maintenance roads.
- The District currently uses primarily Category III and IV herbicides.
Under a ranking system developed by the USEPA, pesticide products
are given an acute toxicity rating which is reflected in the warning
label of the pesticide container. Category III is considered slightly
toxic ("caution" warning on label) and Category IV is considered practically
nontoxic (no warning language included on label).
As a result of these improvements, the District is now proposing that
herbicide use be reinstated in the Pajaro River Basin. This change would
require the following actions:
- The District's Board will need to adopt implementation of the Stream
Maintenance Program, changing the maintenance practices in the Pajaro
River Basin to include herbicides as a routine maintenance tool.
- The maintenance documents for the federally-sponsored Llagas Flood
Protection Projects (PL-566 projects) will require amendment by the
federal sponsoring agency, Natural Resources Conservation Service
(NRCS), to include this activity.
Staff has been working with the Board and NRCS toward the implementation
of this change. Both the Board and the NRCS agree this is a beneficial
change.
Hand removal of vegetation is undertaken in a few locations where
it is not possible to access the area with spray equipment. In some
cases, the vegetation is sprayed with herbicides, and then approximately
6 months later, the dead material is removed by hand removal methods,
if necessary. This latter category of work is referred to as follow-up
hand removal. Follow-up hand removal of vegetation is only necessary
when herbicide spraying is new to an area and there is a larger volume
of dead 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.
The five types of vegetation management in upland areas are: discing,
mowing, herbicide application, hand removal, and removal of overhanging
growth to provide maintenance access.
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 streambanks and outboard levees slopes to create
a firebreak.
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 assist in establishing a firebreak. Pre and postemergent
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.
3. Annual Vegetation Management Activity
The frequency of vegetation management activities varies from semiannually
to once every several years, depending on the method used. Herbicide
spraying in stream channels is conducted July 1 through October 15.
Removal of woody vegetation by hand is conducted July 1 through March
1. Hand removal in stream channels is conducted November through December.
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:
- 923 acres of vegetation management work is conducted in 222 miles
of stream channels with 132 acres of the total actually receiving
treatment (585 work acres or 75 acres of treated area on 166 miles
in the Santa Clara Basin, and 338 work acres or 57 acres of treated
area and 56 miles in the Pajaro River Basin);
- 23 acres on which vegetation management work is conducted on 27
miles of canals with 6 acres of the total actually receiving treatment;
and
- 3,021 acres of uplands on which vegetation management work is performed,
with 1,885 acres actually receiving treatment. Upland vegetation management
is outside of the area of inundation, and generally has a buffer of
grass or vegetation on the slopes between the right of way and the
stream.
Vegetation management activities are relatively the same from year
to year. Slight variations in flood protection activities occur due
to weather patterns. For example, historically, increases in some work
activities occur during flood years, with decreases in other activities
occurring during extended periods of drought. Right of way activities
remain constant regardless of these weather patterns.
C. BANK PROTECTION
1. Overview
Bank protection involves an action by the District to repair streambanks
that are eroding or are in need of preventative erosion protection.
The District implements 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.
Streambank 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. The new work is considered routine maintenance because it
is either restoring the flood protection function of a modified channel
or it is repairing a natural bank to its approximate condition prior
to becoming an erosion problem.
Repair of existing bank protection structures occurs when these structures
fail and are replaced with in-kind, in-place materials. New bank protection
projects are those that repair or protect the watercourse from further
degradation or erosion using the most appropriate method. This type
of protection is considered maintenance if the work does not significantly
alter the flood conveyance capacity of the streams.
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.
2. Bank Protection Methods
The general design criteria and plan for each of the bank protection
methods used by the District are included in Appendix E. In addition
to these 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.
In natural stream conditions where there are no flow capacity requirements,
vegetation components for streambank repair are selected. In modified
creek channels where the flow requirements must be retained (such as
for the 100-year flood), this will often necessitate a roughness maximum
which, depending on the channel design, may limit the vegetation component
of the design.
A range of methods is used for bank protection, as can be exemplified
by several District bank protection projects. Many of the following
examples demonstrate how soft methods can be combined with harder methods
when site conditions cannot maintain a purely natural solution.
- Log crib walls were used on Guadalupe River, downstream of Coleman
and downstream of Woz Way and on Bodfish Creek upstream of Santa Teresa.
- Earth repairs with vegetated slopes were included in the Princevalle
storm drain downstream of Chestnut, Sunnyvale East Channel downstream
of Evelyn and Lower Penitencia Creek, downstream of Redwood Drive.
- Rock hybrids include Permanente Creek at Lundy Lane, Stevens Creek
downstream of Fremont, and Los Gatos Creek downstream of Bascom Avenue.
- Cottonwood seedlings growing on articulated concrete mats are located
on Guadalupe River upstream of Highway 880.
For all bank protection projects, the District makes an inspection
of the stream upstream and downstream of a project site to determine
if there is an identifiable cause of the erosion. In some cases, the
cause of erosion is obvious, such as a blockage (e.g., downed tree)
or weak streambanks of silt or gravel stratas. In other cases, a further
inspection is conducted to determine if flows are being directed toward
the bank from a source upstream, whether the channel invert is down
cutting, or if illegal drainage is causing the problem. These factors
can affect the bank protection approach implemented by the District.
3. Annual Bank Protection Activity
The District estimates that an average of 5,000 linear feet of banks
may be repaired annually based on historical records, District experience,
and current levels of funding. This is an average annual quantity and
will vary from year to year. Facilities are inspected after the winter
storms for damage and maintenance needs and a work plan is prepared.
Under the Stream Maintenance Program, the District is committing to
installing no more than 50 percent of future bank protection work
using hardscape designs.
In the past 14 years, the total length of bank protection activities
in an individual year ranged from approximately 1,500 to 13,000 feet.
The District has completed an average of 38 bank protection jobs per
year, based on historical records, but there is considerable deviation.
For example, there were nine jobs in 1994 and 73 in 1987. A more detailed
summary of historical bank protection activities is provided in Table
2-3.
TABLE 2-3
Bank Protection Activities
1987-1999
|
|
Length (feet)
|
|
|
Year
|
Total
|
Livea
|
Mixedb
|
Hardc
|
Othera
|
| 1987 |
1,249 |
130 |
6,414 |
3,564 |
11,357 |
| 1988 |
3,525 |
0 |
7,815 |
980 |
12,320 |
| 1989 |
210 |
0 |
3,680 |
2,305 |
6,195 |
| 1990 |
410 |
0 |
4,156 |
8,012 |
12,578 |
| 1991 |
316 |
0 |
5,298 |
500 |
6,114 |
| 1992 |
3,210 |
0 |
2,153 |
214 |
5,577 |
| 1993 |
145 |
0 |
3,412 |
2,288 |
5,845 |
| 1994 |
738 |
620 |
4,408 |
225 |
5,991 |
| 1995 |
7,659 |
0 |
155 |
535 |
8,349 |
| 1996 |
25 |
0 |
2,105 |
250 |
2,290 |
| 1997 |
205 |
50 |
2,359 |
1,218 |
3,832 |
| 1998 |
138 |
535 |
485 |
341 |
1,499 |
| 1999 |
6,442 |
905 |
195 |
4,027 |
11,569 |
|
|
|
|
|
|
| Minimum |
25 |
0 |
155 |
214 |
1,499 |
| Maximum |
7,659 |
905 |
7,815 |
8,012 |
12,578 |
| Average/year |
1,734 |
160 |
3,039 |
1,747 |
6,680 |
| |
|
|
|
|
|
Source: SCVWD 1999e.
aLive: seeded or vegetated
bMixed: crib walls, geoweb, hybrid rock, wooden retaining
walls, all with vegetation
cHardscape: concrete, shotcrete, sacked concrete, rock, without
vegetation (impervious)
dOther: fence with brush, concrete, or rock removal, replacement
of existing rock, concrete or gabions. In 1999, the "other" category
consisted of installing a chain link fence and brush on a bank as temporary
fix, replacing a failed wall, replacing earth fill behind a wall, placing
a kickboard on a fence at top of bank, replacing failed concrete panels,
and installing a drain inlet.
Unlike sediment removal and vegetation management, the historical
location of bank protection activities is not a good predictor of where
future bank protection will be required. The quantity and location of
bank protection activities varies greatly from year to year, based upon
watershed conditions, degree of safety hazard, work load, budget, and
of other work to be done in a given year.
D. MINOR MAINTENANCE ACTIVITIES
Minor maintenance activities included in this Stream Maintenance Program
are: 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 streambanks 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, and 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.
Chapter 3
STREAM MAINTENANCE PROCESS OVERVIEW
This chapter provides an overview of the stream maintenance planning,
implementation, and reporting process that is committed to as part of
the Stream Maintenance Program.
The District's stream maintenance planning, implementation, and reporting
process can be broken down into three distinct phases: program development
and documentation, implementation of annual routine stream maintenance
work, and annual reporting.
Specific guidelines and implementation measures which are to be followed
with the implementation of stream maintenance activities are provided
in Chapter 4.
A. PROGRAM DEVELOPMENT AND DOCUMENTATION
This Stream Maintenance Program has been developed to guide the long-term
implementation of the District's annual routine stream maintenance work.
This annual routine work consists of significant work identified in
the spring as well as other work needed throughout the year that has
been evaluated under the Stream Maintenance Program. This Stream Maintenance
Program (along with the Program EIR and long-term permits) provides
the guidance and regulatory compliance for the District to provide routine
maintenance of its streams and canals without having to perform separate
CEQA review or obtain permits for each individual routine stream maintenance
project. The Stream Maintenance Program will also enable the District
to employ a watershed-wide approach to environmental protection. Through
these programmatic documents, the District is committed to implementing
individual maintenance projects in an environmentally-sensitive manner.
In addition, the District has committed to a compensatory mitigation
program for those impacts that cannot be avoided.
B. IMPLEMENTATION OF ANNUAL ROUTINE STREAM MAINTENANCE WORK
Maintenance work can be proposed either as part of the Annual Work
Plan or as other work identified later in the year through individual
work orders. All stream maintenance activities would follow the Resource
Protection Protocol, which is further described in this section and
illustrated in Figure 3-1.
The District has historically used work orders to describe and implement
stream maintenance projects. Work orders provide a description of the
project, schedule of implementation, estimated costs, and permit requirements
or other special conditions. This tool will continue to be the primary
vehicle for the implementation of maintenance projects. In addition,
an Annual Work Plan that identifies the major (sediment removal, vegetation
management, and bank protection) projects planned for the year will
be developed. This plan will identify the stream maintenance work that
forms the basis of the annual budget. Specific information, such as
location and size of the major stream maintenance projects, will be
provided in the Annual Work Plan.
As maintenance work is proposed, it will be evaluated to determine
if the work is addressed under the Stream Maintenance Program. If not,
the work will follow the appropriate project development process which
may include individual CEQA review and individual regulatory permits
or clearances. An example of this type of work may be removal of a drop
structure in a stream.
The proposed work is also evaluated under the requirements of the Maintenance
Guidelines to ensure that the maintenance meets preestablished engineering
requirements. For example, if a sediment removal project is proposed,
the Maintenance Guidelines provide the information on the allowable
depth of sediment for a reach that will still provide design flood protection
for a community. Maintenance Guidelines are updated as new CIP are completed,
as better maintenance methods are developed or as refinements are made
as to the level of maintenance required in a reach of creek.
FIGURE 3-1
Resource Protection Protocol
If a proposed project or activity is of low impact and is typically
exempt from detailed environmental review, the appropriate resource
protection measures and BMPs will be identified and work could proceed.
Minor work activities are described in Chapter 2.
The activities considered low impact will change over time with changes
to CEQA, regulatory direction, and court decisions. As a separate planning
effort, these types of activities are currently being evaluated for
a regional general permit being prepared by the RWQCB. Should this regional
general permit be approved, it will be used to help define whether or
not a proposed activity is low impact.
If the project is not low impact work as described above, a more detailed
review process will occur. The project will be reviewed to verify that
it is covered under the long-term regulatory clearances provided in
conjunction with the Stream Maintenance Program. If needed, the District
will apply for individual permits or clearances. The work will be evaluated
for compliance with the Migratory Bird Treaty Act. Appropriate resource
protection measures and BMPs will be identified and added to the work
order.
Prework conferences will be held with staff which may include the appropriate
staff from Watershed or Countywide Watershed Management Units to discuss
site-specific requirements, environmental constraints, and BMPs.
Annually, in November, District staff will hold a "Lessons Learned"
meeting to evaluate the effectiveness of both resource protection and
maintenance methods used in the preceding construction season. The information
and assessments will be used to update BMPs, Stream Maintenance Program
processes, and the Maintenance Guidelines and to create a greater understanding
of how to accomplish environmentally-sensitive, fiscally sound maintenance
work.
C. ANNUAL REPORTING
The District's Annual Stream Maintenance Work Plan, which includes
the description of the proposed work, location, and extent of work area
will be submitted to USACE, United States Fish and Wildlife Service
(USFWS), CDFG, BCDC, and RWQCB prior to the commencement of the work
(likely in May).
The sediment sampling and characterization plan will be revised in
June, prior to the work season. Over the years of this program, it is
expected that the requirements for sediment sampling and characterization
are to be reduced as the usefulness and repetitiveness of the data of
previous years is evaluated.
A final annual report detailing what work was accomplished will be
submitted to USACE, USFWS, CDFG, BCDC, and RWQCB at the end of the maintenance
season (prior to January 1) which will specify which projects were completed
for the year including type of work, location, and size of the project.
In addition to reporting on the maintenance activity completed for
the year, the District will also provide reporting on the implementation
of the mitigation program. For the first 5 years of the program, the
District will provide the agencies with a tour of representative work
areas (especially those along target streams and watersheds) for that
year and all mitigation sites. This tour will take place after completion
of the work season. Preconstruction photographs will also be provided.
The District's Geographic Information System (GIS) may be utilized
as a tool for reporting annual work activities and implementation of
mitigation projects.
Chapter 4
RESOURCE PROTECTION POLICIES
This chapter details the policies that are included in the Stream Maintenance
Program. These policies have been developed by the District through
the routine stream maintenance planning process to ensure that resources
are protected to the furthest extent feasible during routine stream
maintenance projects. BMPs have been developed to implement these policies.
These are listed in a table in Appendix G.
The policies in the Stream Maintenance Program have been developed
to guide decision-making for stream maintenance projects. Policies are
based on the Stream Maintenance Program objectives identified in Chapter
1 and are means to the District's Ends Guidelines (Board of Directors
Policy No. E-1; October 19, 1999). Specifically, the Stream
Maintenance Program resource protection policies have been developed
to meet the following Ends Policies:
1.0. There is a healthy and safe environment for residents and visitors.
1.2. There is a reduced potential for flood damages.
1.2.1. The cost of reducing the potential for flood damages is balanced
with benefits (including possible environmental restoration and enhancement).
1.2.2. There is a balance between the contributions of watersheds
and streams in providing for public health and safety and in providing
protection of natural resource benefits.
2.0. There is enhanced quality of life in Santa Clara County.
2.1. Watersheds, streams, and the natural resources therein are protected
and when appropriate enhanced or restored.
2.1.1. Healthy creek and bay ecosystems are protected, enhanced, or
restored as determined appropriate by the Board of Directors.
2.1.1.1. Mitigation for adverse impacts of District activities are
identified.
2.1.1.2. Opportunities to enhance or restore natural resource benefits
of streams and watersheds are identified.
2.1.1.3. Mitigation, enhancements, or restoration are implemented
when determined appropriate by the Board of Directors.
For many of the Stream Maintenance Program policies, BMPs have been
identified. A BMP is an action, procedure, program, or technique that
carries out a policy. These BMPs provide specific guidance to District
managers and staff in the environmental review, processing, and implementation
of individual stream maintenance projects.
The policies included in this chapter are categorized by the following
groups:
- Process and Protocols
- Watershed Restoration and Management
- Protection of Listed Species and Species of Concern
- Fisheries Protection and Enhancement
- Maintenance Site Dewatering
- Minimization of Erosion
- Preservation and Replacement of Riparian and Shaded Riverine Habitat
- Wetlands Protection
- Use and Management of Herbicides
- Hazardous Material Management and Control
- Additional Work Site Management Practices
These categories are both by resource type (e.g., sensitive species,
fisheries, wetland) and by individual maintenance practices that require
special consideration (e.g., dewatering, herbicide use). Though some
activities and measures clearly fit into one category or another, they
are sometimes overlapping. For example, some measures related to fisheries
protection apply specifically when a site is dewatered.
All routine stream maintenance projects must adhere to the policies
contained in this chapter.
A. PROCESS AND PROTOCOLS
Policy 1: The District will process all
routine stream maintenance activities according to the process and protocols
established in Chapter 3 of the Stream Maintenance
Program.
Policy 2: Decisions regarding the necessity
of routine sediment removal and vegetation management activities (to
restore channel flow capacities) will be made following the thresholds
established in the Maintenance Guidelines. This information will be
used to formulate in part an annual routine maintenance work plan.
Policy 3: The District will continue
to develop, implement, and update BMPs for implementation of stream
maintenance projects to ensure that maintenance activities are conducted
in the most effective and environmentally-sensitive way possible and
are technically feasible and economically reasonable.
Discussion of Policy 1
Through the development of the Stream Maintenance Program, the District
defined a protocol for processing maintenance work orders, as summarized
in Chapter 3. In addition, several other documents
will provide the District with guidance when implementing stream maintenance
projects.
This process described in Chapter 3 will ensure that
each routine maintenance project is reviewed for its potential for negative
environmental effect and that sensitive species and habitats are protected
consistent with the federal and state ESA. The District is committed
to performing routine maintenance activities in a manner that demonstrates
an appropriate effort to avoid or minimize impacts to the environment.
Discussion of Policy 2
The District has developed detailed Maintenance Guidelines to address
the ongoing need for maintenance of vegetation or sediment in modified
streams and canals. The guidelines are engineering based and outline
the thresholds for maintenance that are required to ensure adequate
flood capacity is maintained in the streams within the District's jurisdiction.
These guidelines support field evaluations of need and are consistent
with the District's flood management objectives and applicable District
Ends Policies.
Maintenance Guidelines are based on two concepts: (1) the maintenance
standard and (2) the acceptable maintenance condition. The maintenance
standard is defined as the design facility condition, where the modified
stream has full design capacity and freeboard. The acceptable maintenance
condition is the condition to which a channel can be allowed to deteriorate
before capacity is determined to be compromised and maintenance work
becomes essential. The focus of the hydraulic analysis is related to
sediment accumulation and vegetation management since these two factors
typically affect capacity. The Maintenance Guidelines may also apply
to other activities such as trash pick-up, blockage removal, fence repairs,
and access road maintenance. By conducting these routine maintenance
activities, the District ensures that facilities continue to provide
the level of flood protection for which they were constructed. These
efforts protect the public's investment and help to comply with regulations
of the federal flood insurance program (Flood Damage Reduction Objective
6, District Guidelines and Procedures 0-105).
The Maintenance Guidelines detail information for each creek to the
extent it is available. This information includes whether or not the
guidelines are existing (based upon construction documentation) or new
(based upon new engineering calculations), background information (e.g.,
available studies, facility engineering reports, and applicable permits),
average frequency of maintenance activities (history), and any additional
supporting data and calculations.
Discussion of Policy 3
BMPs are activities, maintenance and operations procedures, or other
standard management and work practices that are designed to prevent
or reduce pollution or other negative environmental consequences. The
District currently implements BMPs when completing stream maintenance
projects.
The District will use the most current BMPs and will continually evaluate
the performance of BMPs and update or otherwise modify BMPs as appropriate.
The District will conduct annual BMP training for District staff who
support the implementation of the Stream Maintenance Program.
The District will maintain a BMP manual which details design, installation,
and work practices for stream maintenance activities. The manual includes
documentation and implementation information for the District's BMPs
and is updated as new and better information, approaches, and technologies
are developed. Annual training for watershed personnel is also conducted
by the District to familiarize all employees with the current BMPs.
B. WATERSHED RESTORATION AND MANAGEMENT
Policy 4: The District will use the Stream
Maintenance Program to manage its routine stream maintenance activities
in a programmatic way, including BMPs and a mitigation program. The
District will evaluate the environmental impact of the program in an
EIR.
Discussion of Policy 4
For the purpose of the Stream Maintenance Program, the District can
be divided into two major basins: the Santa Clara Basin (which drains
to the San Francisco Bay) and the Pajaro River Basin (which drains to
Monterey Bay), as previously shown in Figure 1-1. Each basin is made
up of numerous watersheds. A watershed is a geographic area from which
water is drained by a river and its tributaries to a common outlet.
Traditional stream alteration work was done for flood hazard reduction
and relied heavily on engineered channels based on straight, clean (i.e.,
low hydraulic resistance) channel models. Today's water and flood protection
districts are faced with the high maintenance costs of these previously-developed
systems, particularly in areas subject to freshwater or tidal sediment
deposition. In the development of older flood protection systems, vegetated
riparian corridors, wetlands, and system stability were not considered
to the extent they are today.
Current District Board of Directors Ends Policies call for a balance
between public health and safety and protection of natural resource
benefits (Board of Directors Policy No. E-1.1.2.2). This balancing has
changed the way the District now views the issue of watershed management
and its role as a steward of aquatic environmental resources.
Under Board of Directors Ends Policies, the District will manage activities
to be reflective of stewardship of watersheds and riparian corridors,
while proactively complying with regulatory mandates. The District is
committed to understanding the stream corridor, watershed, and landscape
as a complex of working ecosystems that influence and are influenced
by neighboring ecosystems. Future projects, programs, and initiatives
are, and will continue to be, focused on a watershed and ecosystem approach,
rather than a facility-by-facility approach.
Examples of such projects and programs that the District is currently
involved in include the Watershed Management Initiative (WMI). This
collaborative effort is being undertaken by the USEPA, California State
Water Resources Control Board (SWRCB), and the RWQCB and is aimed at
implementing an integrated watershed management approach to administering
water pollution control programs.
The Natural Resources Management Program (NRMP) is an ongoing project
that will consolidate acquisition of natural resource data and provide
for the development and implementation of natural resource management
plans in support of integrated water resource management. This project
will develop a Districtwide strategy to identify and resolve sensitive
resource issues.
The District has developed a mitigation approach for the Stream Maintenance
Program that incorporates the restoration and protection of stream environments,
as detailed in Chapter 5. The District will continue
to look for opportunities to implement a watershed approach and to support
and implement restoration efforts.
The District explores opportunities to reduce sediment loads through
watershed management and restoration. The District is committed to improving
the flood management system so that flood protection is provided in
an efficient manner and in ways no more costly than necessary. One way
to achieve this is by reducing the frequency that sediment removal activities
must occur. Alternative approaches in the development of flood protection
facilities can result in the reduction, if not the complete elimination,
of maintenance requirements. The Stream Maintenance Program addresses
routine maintenance activities only and does not involve redesign of
such facilities. However, the Stream Maintenance Program provides a
means by which new CIPs can be compared to the Stream Maintenance Program,
adjustments made, and then new maintenance incorporated into the program,
as described in in Chapter 2.
In addition, sediment loads could potentially be reduced through a
larger watershed approach and the restoration of natural systems in
the area. It is important to consider the relative value of sediment
reduction projects within the District's watersheds.
Sediment transport characteristics of streams and rivers are affected
by many natural and human-induced agents and physical processes. The
most significant agents include the local geology, regional seismicity,
tidal processes, past subsidence in the region, a rising sea level,
changes in land use in the watersheds and floodplains, urbanization,
channel improvement projects, sediment accumulation from tidal and terrestrial
sources, and bridge constrictions. All of these agents contribute to
decreasing channel capacity with time and increasing annual maintenance
requirements to meet present and future levels of flood protection (Northwest
Hydraulic Consultants 2000).
In addition to the effect on channel capacity, increased sediment over
natural conditions or sediment deposition at different life stages can
negatively affect aquatic communities by clogging fish gills and suffocating
eggs and aquatic insect larvae. In addition, if fine sediment settles
within bottom gravels or cobbles where fish lay eggs, spawning can be
negatively affected. Sediment intrusion can reduce permeability and
intragravel water velocities, thereby restricting the supply of oxygenated
water to developing embryos. Excessive fine sediment deposition can
effectively smother incubating eggs.
In-stream sediments are used as nesting and spawning grounds for fish
and habitat for bottom dwelling aquatic invertebrates, vertebrates,
and plants. However, larger particle size and a low embeddedness and
compaction are essential to provide appropriate habitat. These characteristics
ensure adequate water flow through the sediment/gravel spaces to fully
oxygenate incubating eggs and hatched larvae.
It is commonly implied that oversizing of the channel is the cause
of sedimentation. However, the dominant cause of sedimentation is of
a regional natural basis. Sediment deposition is primarily controlled
by channel slope. Sedimentation occurs where the stream gradient flattens
out in the valley floor, or where the gradient is flat over long reaches.
Channel excavation provides temporary improvement of flood conveyance.
However, maintaining flood capacity will require continuing excavation
in perpetuity. Recognizing that sediment will continue to accumulate,
future project designs should be developed to be compatible with aggrading
channel dynamics. This includes programs to manage sediment production
and delivery to streams and channels.
Restoration efforts may be useful for controlling loads of sediment
and sediment-associated pollutants from the watershed to streams. Restoration
is defined as the reestablishment of the structure and function of ecosystems
(National Research Council 1992). Ecological restoration is the process
of returning an ecosystem as closely as possible to predisturbance conditions
and functions (Federal Interagency Stream Restoration Working Group
1998). Implicit in this definition is that ecosystems are naturally
dynamic; therefore, it is not possible to restore a system exactly.
The restoration process reestablishes the general structure, function,
and dynamic self-sustaining behavior of the ecosystem. Successful restoration
of degraded streams requires an understanding of watershed history,
including both natural events and land use practices, and the adjustment
process active in channel evolution (Federal Interagency Stream Restoration
Working Group 1998).
Restoration efforts may range from efforts to reduce upland erosion
to treatments that reduce sediment delivery through the riparian zone.
To achieve success, restoration design and implementation must treat
the stream corridor, watershed, and landscape as a complex of working
ecosystems that influence and are influenced by neighboring ecosystems.
Future restoration efforts will require capital improvements or the
approval of a specific restoration project. While the District is dedicated
toward these efforts, the Stream Maintenance Program does not identify
or commit to specific restoration projects. The planning and implementation
process for restoration projects will be ongoing.
Regardless of the extent of future restoration efforts, the District
remains committed to maintaining flood capacity within its system in
the present and must have the ability to conduct stream maintenance
within the existing system for the foreseeable future. For this reason,
the Stream Maintenance Program and the ongoing implementation of maintenance
projects is required regardless of future restoration guidelines. However,
it is acknowledged that future stream maintenance requirements may be
reduced (specifically sediment removal requirements) with the successful
implementation of restoration efforts. These efforts will include working
with local governments to ensure planned land uses and land use guidelines
do not conflict with flood protection mandates.
C. PROTECTION OF LISTED SPECIES AND SPECIES OF CONCERN
Policy 5: The District will implement
measures to avoid and minimize impacts to native species, especially
special-status and riparian-dependent species.
Discussion of Policy 5
Removal of sediment and vegetation management in streams using mechanical
equipment (e.g., excavators, drag lines, bulldozers, loaders) and installation
of bank protection measures using mechanical equipment (e.g., excavators,
dozers, concrete pump trucks) can result in a direct take of listed
species, including habitat degradation and habitat loss. Species of
concern are affected in a similar manner as listed species; however,
"take" has a specific legal definition and applicability to listed species.
This policy is directed at avoiding and minimizing impacts to listed
species and species of concern. Issues related to maintenance site dewatering
are specifically addressed in "Maintenance Site Dewatering" below.
Project-specific resource protection measures, including alterations
of stream maintenance project timing, project implementation practices,
special design considerations, or other BMPs will be selected as appropriate
for each site. These measures will be attached to the Work Order for
individual stream maintenance projects through the environmental review
protocol described in Chapter 3 of the Stream Maintenance
Program.
If stream maintenance activities are within an area of known or likely
listed species or special-status species occurrence, the District will
avoid stream maintenance activities during breeding or nesting seasons,
migration periods, or other sensitive seasons. Work may occur during
these seasons (exclusive of fisheries), if preconstruction surveys conducted
according to species protocols do not find sensitive resources or if
an adequate buffer can be established between maintenance activities
and the resources. All work in an area where sensitive species are present
must comply with adopted HCPs. Absent such plans, work must be approved
by all applicable regulatory agencies with species and permit oversight.
For stream maintenance activities that may affect the breeding or nesting
period of migratory birds (generally February 1 to August 31), the District
will conduct its work in a manner consistent with the protocols established
by the most current version of the Nesting Migratory Bird Procedure
(Appendix C).
In addition, the District is currently developing informational pamphlets
entitled "Sensitive Plants, Wildlife, and Fish at your Worksite," which
are designed to inform staff about sensitive species and environmental
protocols and procedures.
D. FISHERIES PROTECTION AND ENHANCEMENT
Policy 6: The District is committed to
protecting fishery resources when technically feasible and economically
reasonable when individual stream maintenance projects are implemented.
Discussion of Policy 6
The streams of Santa Clara County harbor a number of migratory fish
species. The regular anadromous fish species include steelhead (Oncorhynchus
mykiss) and Pacific lamprey (Lampetra tridentata). Recent
records of chinook salmon (O. tshawtscha) also exist. Of these
species, the steelhead are considered sensitive due to their known occurrence
and recognition by regulatory agencies.
Steelhead occur in many of the streams of the South San Francisco Bay
including, but not necessarily limited to, the Guadalupe River, Coyote
Creek, Stevens Creek, and San Francisquito Creek. Steelhead also occur
in the tributaries of the Pajaro River System, including Uvas/Carnadero
Creek, Llagas Creek, and Pacheco Creek. Regular upstream migration occurs
typically in winter through early-mid spring (from mid/late December
through early April), although estaurine areas may have upstream migrants
earlier. Although no recent data exists, there may be some holdover
out-migration as observed in other systems which may occur in the fall
with the earliest storms.
Other, more localized movements may occur among resident species of
fish. These species may make short-range movements within a system.
This typically occurs during spring, fall, and winter. Breeding for
a broad component of resident fish typically occurs from late winter
through spring (February to May).
Installation of cofferdams and water bypass structures to isolate the
work can create barriers to sensitive anadromous fish species. Cofferdams
and water bypass structures are often required to create a work environment
outside of stream flow to ensure that excessive erosion and sedimentation
does not affect water quality and habitat value.
In addition, installation of bank protection measures using mechanical
equipment (e.g., excavators, dozers, concrete pump trucks) can result
in the loss of undercut banks, which provide important habitat for fish,
including sensitive anadromous species.
Policy 6 is directed at ensuring that these potential impacts to fisheries
do not occur and that opportunities for fisheries enhancement are realized.
The District will look for cost-effective opportunities to enhance fishery
resources.
Potential impacts to steelhead will be avoided by timing stream maintenance
projects in streams where there are or could be steelhead so that work
is conducted outside of the migration and spawning season. Steelhead
migration and spawning season is generally between December 15 to June
30.
If fisheries or native aquatic vertebrates are present, a fish and
native aquatic vertebrate relocation plan will be implemented when cofferdams,
water bypass structures, and silt barriers are installed to ensure that
fish and native aquatic vertebrates are not stranded. The District's
most current version of the fish relocation guidelines at the time of
this publication are provided in Appendix D.
The District will allow undercut banks to remain in place for fish
habitat, as long as they remain stable and do not endanger the public.
E. MAINTENANCE SITE DEWATERING
Policy 7: The District will take measures
to reduce increases in short-term stream turbidity that can result from
stream maintenance activities.
Discussion of Policy 7
Sediment removal and bank protection activities can require the installation
of cofferdams and water bypass structures (such as berms) to isolate
the work area from flowing water. If improperly managed, the installation
and removal of water bypass structures, channels, and silt barriers
can create or increase turbidity (water cloudiness) in the stream in
the short term, which can negatively affect aquatic resources, including
sensitive species. Once dewatering structures are installed and removed,
the turbidity levels return to normal background levels.
Short-term increased turbidity can increase water temperature and decrease
dissolved oxygen (DO). Water temperature is a crucial factor in the
stream environment because temperature governs many biochemical and
physiological processes in cold-blooded aquatic organisms. In addition,
increases in temperature can reduce DO. DO is a basic requirement for
a healthy aquatic ecosystem as most fish and aquatic insects 'breath'
oxygen dissolved in the water column. DO is essential not only to keep
aquatic organisms alive but also to sustain their reproduction, vigor,
and development. Potential species' impacts that could result from increases
in turbidity include both direct take and habitat degradation.
This policy is directed at minimizing and avoiding increases in-stream
turbidity attributable to stream maintenance projects. Increases in
turbidity can result from actual maintenance activities directly, from
the installation of cofferdams and water bypass structures to isolate
the work area, and from the reintroduction of bypassed flows to dewatered
areas.
To the extent feasible, stream maintenance activities will not occur
in live stream flow. If flowing water is present at the proposed maintenance
area, the District will isolate the work area through the best use of
cofferdams, berms, or bypass systems. For example, cofferdams would
not be the appropriate dewatering method at sites where the removal
of sediment is small, such as at the inlet or outlet of culverts. In
such an instance, the dewatering system would create more turbidity
than the actual sediment removal.
In tidal areas, cofferdams and water bypass structures will be installed
at low tide when possible. This measure may not be possible when the
cofferdam or other structure is large and requires an extended installation
period.
Bypassed water will be discharged in a nonerosive manner. Specific
project implementation measures may include the use of geotextile fabrics
as a splash apron, silt fences, straw bale barriers, sand bag barriers,
brush or rock filters, sediment basins, or sediment traps. When bypassed
flows are reintroduced to dewatered areas, they will be reintroduced
in a nonerosive manner. For example, bypassed flows could be slowly
reintroduced into the dewatered area by leaving a silt barrier in place
to allow water to slow and drop sediment to the extent possible.
To prevent increases in temperature and decreases in DO, if bypass
pipes are used, they shall be properly sized (i.e., larger diameter
pipes to better pass the flows). Bypass pipes may also be avoided by
creating a low-flow channel or using other methods to isolate work area.
If fisheries or native aquatic vertebrates are present, a fish and
native aquatic vertebrate relocation plan will be implemented when cofferdams,
water bypasss structures, and silt barriers are installed to ensure
that fish and native aquatic vertebrates are not stranded.
F. MINIMIZATION OF EROSION
Policy 8: Vegetation control and removal
will be minimized to the extent practicable. Where appropriate, measures
will be taken to leave the work site in a vegetated condition after
individual projects are implemented.
Discussion of Policy 8
Vegetation control and removal on slopes of levees and maintenance
roads, via herbicides or mowing, can exacerbate erosion and sediment
accumulation. This policy is directed at minimizing vegetation removal
and ensuring that appropriate revegetation and erosion protection measures
are implemented.
Vegetation control and removal along levees and maintenance roads will
be limited to removal necessary for facility inspection purposes, removal
that is necessary to meet regulatory requirements, removal that is required
to comply with fire codes, and removal that is required to meet capacity
requirements.
If maintenance work leaves slopes in a bare soil condition, the District
will plant slopes with native vegetation through hydroseeding or other
vegetation methods as identified as appropriate in the Maintenance Guidelines.
G. PRESERVATION AND REPLACEMENT OF RIPARIAN AND SHADED RIVERINE
HABITAT
Policy 9: The District will avoid and
minimize impacts to the quality and extent of riparian and Shaded Riverine
Aquatic (SRA) habitat.
Discussion of Policy 9
Mechanical removal of vegetation and sediment within stream corridors
and along levees and depressed access roads can result in the removal
of riparian and SRA habitat and the stripping of vegetation from channel
banks. SRA habitat is the aquatic area occurring along the edge of a
channel or stream where the adjacent bank is composed of natural materials
and supports riparian vegetation that overhangs or protrudes into the
water. SRA habitat provides important habitat for fish, including sensitive
anadromous species. Removal of SRA habitat can cause the increase in
a stream's temperature and an associated decrease in DO. The installation
of bank protection measures using excavators, dozers, and other equipment
can also result in the removal of riparian habitat.
This policy is aimed at preserving and replacing riparian and SRA habitat
when implementing routine stream maintenance activities.
Project-specific measures will be identified through the resource protection
protocol detailed in Chapter 3 to avoid and minimize
impacts of individual stream maintenance projects on the value and extent
of riparian and SRA habitat.
The District will utilize biotechnical bank protection methods where
appropriate that allow restoration of riparian streambank vegetation
and SRA habitat. Projects where bank protection is to be performed will
be evaluated for the most appropriate repair method possible given the
characteristics of the site. Bank protection methods used by the District
are provided in Appendix F.
Areas that must be temporarily cleared for access to routine stream
maintenance project sites will be seeded as appropriate for the site.
Woody material will be retained unless it is threatening a structure,
results in flood capacity deficiencies, or impedes reasonable access.
When retention will not compromise flood management system reliability,
woody vegetation will be left in the channel to maintain SRA habitat.
When woody material is removed, priority will be given to reuse of the
materials in bank protection projects. Woody materials may also be used
as mulch.
H. WETLANDS PROTECTION
Policy 10: When wetlands must be removed
or have the potential to be negatively affected in order to restore
flood capacity, work will be limited to that defined by the Maintenance
Guidelines.
Discussion of Policy 10
Mechanical removal of sediment and vegetation from streams using in-stream
equipment (e.g., excavators, drag lines, bulldozers, loaders) can result
in a loss of tidal and nontidal wetland habitat. In addition, vegetation
control activities can negatively affect these wetland habitats. This
policy is provided to minimize impacts to wetland habitats related to
routine maintenance activities.
No wetlands will be affected over and above what is required to restore
the design capacity of the stream or the proper function of structures
and facilities within the stream corridor. The District will try to
avoid or minimize impacts to the quality and extent of wetland habitat
in all stream maintenance activities.
Project-specific measures will be identified and implemented for each
individual stream maintenance project that requires removal of wetland
vegetation (and other direct or indirect impacts) to minimize the extent
and negative effects of the maintenance activities.
The District will use biotechnical bank protection methods where appropriate
and consistent wit |
