Revisions to the EIR Document are indicated below. These are organized by page numbers as they appeared in the Draft EIR. Revisions to EIR Tables and Figures are attached at the end of this section.
P. S-2, paragraph six
Bank repairs may take several forms from installing "hard" structures (e.g., rock blanket,
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. An important feature of the SMP is a
programmatic approach to impact assessment and mitigation at bank protection sites that takes into
account fisheries and riparian resources values (SMP Appendix E). The District will install no more than
50% ½ mile on an average annual basis of future bank protection projects under the SMP as impervious
hardscape.
P. S-5, paragraph six
B) Hardscape installation for bank protection has the potential to reduce riparian vegetation
functions and values and associated wildlife and fisheries habitat. Placement of hardscape is a permanent
change that can contribute to the increasing fragmentation of the natural bank landscape, which can
affect wildlife that depend on stream corridors. Although implementation of the BMPs and programmatic
mitigation (SMP Appendix E) would reduce the magnitude of impacts, there would likely be residual
unmitigated impacts is some watersheds. The Cumulative impacts from bank protection would thus
remain significant and unavoidable (Impact Bio 5).
P. S-6, paragraph three
Most sediment removal and vegetation management activities repeatedly take place on the same
reaches of channels, in places most affected by past urbanization and channel alteration. As described
above, the removal of wetland or riparian vegetation associated with the SMP is considered cumulatively
significant. The placement of additional hardscape within stretches of vegetated channel may also
contribute to significant cumulative impacts in some watersheds over the years.
P. S-8, Table S-1 revised (see revised table)
P. II-7, description under photo
The decision to remove sediment from a particular reach in a particular year is based on the
sediment history design requirements, flood concern, workload of the District and cost of the
project. The District's Sediment Removal Program is designed to restore the ability of creeks to
carry stormwater while protecting adjacent property from flooding.
P. II-8 through II-18
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. Revised Figure II-3 shows the Projected Channel Vegetation Work Areas. Revised 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
In-channel vegetation management occurs on the channel bottom of the creek or canal where seasonal aquatic conditions can create conditions suitable for wetland or riparian vegetation. Portions of the channel above the bottom, such as benches or channel banks or slopes, which do not support seasonal aquatic conditions are not included as part of in-channel vegetation management (see Upland Vegetation Management below). The 2 types of in-channel vegetation management (also called channel vegetation management) are herbicide application and hand removal of vegetation. 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 where it is not possible to access the area with spray or mowing equipment.
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
Upland vegetation management occurs on upland areas associated with creeks and canals including all land above the channel bottom such as the levee or bank top and slopes, benches and maintenance roads inside the levee, and adjacent land outside the levee. These upland areas are not seasonally inundated by water so as to create conditions for wetlands, and are vegetated with upland plants, primarily annual grasses or shrubs. 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 vegetation management in channels is 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. Seasons of work for vegetation
management are generally undertaken in the following time periods. Some adjustments to these
time periods can occur on some project sites where provisions regarding the protection of nesting
birds and anadromous fish are followed as provided in BMPs 3.2 and 3.10. Herbicide treatment
is undertaken in the channel from July 1 through October 15. Upland herbicide work is
undertaken from October 15 through June 30. Removal of woody saplings by hand is undertaken
July 1 through March 1. Hand removal of herbaceous wetland vegetation is undertaken in
November and 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:
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.
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 continue to use herbicides as the
primary method by which vegetation is controlled in channels and on stream banks managed in the
Santa Clara Basin. Because of concerns regarding the gradual environmental change to wetlands,
herbicide use in the Pajaro River Basin will be limited to the following situations: upland areas
including channel banks, levee slopes, maintenance roads and fire breaks above the channel
bottom; and upland and channel bottom areas for the control of non-native invasive plants.
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, 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. Roundup® Pro contains glyphosate, a surfactant, and water. Surfactants aid the ability of an herbicide to penetrate the surface of the vegetation. Aquamaster® and Rodeo® contain glyphosate and water without a surfactant. The District generally adds the surfactants R-11® or Target Pro-Spreader when using either Aquamaster® or Rodeo®.
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 Revised Table II-5.
e. Herbicide Use in South County Vegetation Management in the Pajaro River Basin
The SMP includes the limited 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 limited on mitigation plantings of the
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:
[Note: See Revised Tables II-4, Extent of Projected Vegetation Management and II-5, Existing Projected
Annual Herbicide Use, in the Revised EIR Tables section.]
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.
Herbicide use in the Pajaro River Basin will be limited to the following situations: upland areas including channel banks, levee slopes, maintenance roads and fire breaks above the channel bottom; and upland and channel bottom areas for the control of non-native invasive plants.
Historically, routine vegetation management has been limited at the following locations in the Pajaro River Basin: Llagas Creek from Chesbro Reservoir to Machado Creek, Llagas Creek from Hayes Creek to Church Avenue, Jones Creek and Uvas-Carnadero Creek. Work in these areas under the SMP will continue to be performed as described in the maintenance guidelines for each facility and as described in the engineering guidelines for improved facilities. Vegetation management in these areas will continue to be limited to the control of nonnative invasive species and the hand removal of woody saplings less than 2 inches in dbh which occur no closer than 20 feet apart.
P. II-20 , first and second paragraph
Bank Protection Techniques That Tend To Limit Biotic Potential:
Gabions
Rock blanket (includes larger rip-rap with small rock fill)
Sacked concrete
Articulated concrete mat
Synthetic cellular confinement
Bank Protection Techniques That Tend To Retain Biotic Potential:
Large boulder revetment
Root wads and boulders
Log crib walls
Concrete crib walls
Organic surface matting
Compacted earth fill
Based on 15 13 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.
P. II-23, second paragraph
2. Hardscape bank protection projects whichlimitreduce or eliminate biotic potential and would occur in high quality fisheries habitat or existing high quality riparian habitat. Referto Table II-8, Bank Protection: In-stream Impact and Mitigation, Table II-9, Bank Protection: Stream-side Impact and Mitigation andto Appendix E of the SMP for further definition of those bank protection projects which are not covered by the SMP.
P. II-23, third paragraph
3.Initial removalAny sediment removal, wetland vegetation control, or removal of in-channel treesof in-channel willow trees and other treesin Llagas Creek downstream ofLuchessa Avenue (which is approximately 600 feet downstream ofHighway 152)to the confluence with the Pajaro River and the Pajaro River within Santa Clara County. This section of Llagas Creek 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. Maintenance work in this section of Llagas and the Pajaro River are not considered routine until the status of the Least Bells vireo at this location is determined and a plan for future maintenance developed. At that time, future routine maintenance will be evaluated under a new or revised CEQA evaluation. Control of giant reed on the pajaro River and Llgas Creek is included in 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.
P. II-26, Table II-8, In-Stream Impact and Mitigation Matrix (See revised table in Appendix E of the SMP)
P. II-27, Table II-9, Bank Protection: Stream-side Impact and Mitigation Matrix (See revised table in Appendix E of the SMP)
P. II-30, second paragraph
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. Work is considered included in the SMP if similar work has been performed historically at that location, the work is consistent with the District's Maintenance Guidelines, or the work is needed to maintain the flood conveyance capacity but does not increase the designed flood conveyance capacity. Based on annual reporting, the cumulative extent of maintenance work for sediment removal, channel hand and channel herbicide forms of vegetation management should not exceed the length amounts shown in revised Tables II-3 and II-4 by basin in order to be consistent with the environmental evaluation and mitigation provided under the SMP.
P. III-3, Table III-2, Upland Vegetation Management column for RWQCB-Section 401:
No.Yes, for mowing, hand removal, and herbicide spraying activities in upland areas that may promote soil erosion, increase sediment loading in runoff, and affect water quality. Total maximum daily load (TMDL) documents will assess impacts to impaired surface waters from these activities. Impaired surface waters include Llagas Creek and the Pajaro River.
P. III-9, third paragraph
The District is currently negotiating a new MOU planning to negotiate revisions to these MOUs
to cover the relevant activities and locations of work in the Stream Maintenance Program. As a basis for
the negotiations, the District has submitted the Joint Aquatic Resource Permit Application for the San
Francisco Bay Area (JARPA) and is requesting the CDFG approval for the SMP be granted for a period
of 10 years. This new MOU will be for a period of five years. At the end of five years, either a new
MOU will be executed by CDFG or the existing MOU will be renewed for another five years, to coincide
with the length of the U.S. Army Corps of Engineers permit for this project.
P. III-14, first and second paragraphs
P. III-29, first paragraph
Relevance to the Proposed Program: Implementation measures are listed in the General Plan to mitigate for impacts caused by new development upstream and upslope of the channels. The General Plan identified participation in the National Flood Insurance Program, and maps released by the Federal Insurance Administration support the contention that the present condition of the stream channels can carry the runoff from the "design flood" without adversely affecting the City. The proposed Program wouldpreserve existingprovide design levels of flood protection for each stream. The General Plan identifies specific goals related to the District, for water quality, bank stability, and habitat conservation/enhancement. The Stream Maintenance Program complements and supports these goals.
P. III-66, add to end of page
4. San Francisquito Creek Joint Powers Authority. District Urban Runoff Program (District Project No. 007902)
The San Francisquito Creek Joint Powers Authority (JPA) consists of 5 member agencies who have adopted a joint powers agreement regarding the protection and maintenance of San Francisquito Creek and its watershed. The purposes of the JPA are to facilitate and perform bank protection and creek maintenance, plan flood control measures, preserve and enhance the environmental values, and coordinate emergency response on San Francisquito Creek. The member agencies are the cities of Palo Alto, Menlo Park and East Palo Alto, the Santa Clara Valley Water District, and the San Mateo County Flood Control District. The JPA is currently coordinating with the District on flood control planning efforts, maintenance efforts, TMDL permitting, and is a participant in the WMI process.
The Corps and San Francisquito Creek Coordinated Resource Management and Planning Group also participate with the JPA on these and other associated projects on San Francisquito Creek. The San Francisquito CRMP prepared a Draft Watershed Management Plan in 1997, and a Reconnaissance Investigation Report of San Francisquito Creek in 1998. In 2000, a San Francisquito Creek Bank Stabilization and Revegetation Master Plan Report was completed by the members of the JPA (prior to formation of the JPA). Business, environmental and other interest groups are also active participants in the JPA efforts
5.Pajaro River Watershed Flood Prevention Authority. District Urban Runoff Program (District Project No. 007902)
The Pajaro River Joint Powers Authority, Corps and other agencies and organizations are coordinating a watershed management plan and feasibility study to remedy water quality, flood damage and other problems in the Pajaro River Basin. A Final Reconnaissance Report and Draft Project Management Plan is due to be completed by the Corps in 2001.
Participants include Santa Cruz, San Benito, Santa Clara and Monterey Counties, San Benito County Water District, Monterey County Water Resources Agency, Santa Cruz Zone 7 Flood Control District, and the Santa Clara Valley Water District. Business, environmental and other interest groups are also active participants in the basin study efforts.
P. IV-A-24, last paragraph and P. IV-A-25, first paragraph
In many locations vegetation management both from herbicide applications and manual methods is
consistent and routine; these areas are less likely to experience this effect. Creek reaches which have
not undergone routine vegetation maintenance, or reaches where the vegetation control system changes
may have greater impact potential, because they may have more trapped sediment within the vegetation.
This effect could occur in the southern portions of the County that will be switching from mechanical to
herbicide vegetation management.
P. IV-A-26, fifth paragraph
Mitigation. Bank stabilization site design will assess hydraulic effects immediately upstream and
downstream of the work area. If the hardscape revetment would cause significant increase in erosion
potential, downstream energy dissipation features such as pools or grade control structures would be
considered in the design. In some instances, proactive protection of downstream areas would include, but
are not limited to, coir logs, riparian enhancement planting, strategic placement of rock, and flow
deflectors.
P. IV-A-28, second paragraph
Other District activities affect channels, as defined in Chapter II, Program Description. Capital
Improvement Projects (CIP), such as construction to provide increased flood capacity on a certain reach
of stream, undergo a separate engineering design and environmental review. As set forth in the SMP, the
CIP must include an assessment of the maintenance implications of the new channel design based on an
analysis of the hydraulics and fluvial geomorphology of the reaches up and downstream using appropriate
methods and tools. This process is intended to minimize adverse cumulative effects on channel stability
and the maintenance obligation of the District.
P. IV-B-1, first paragraph
District activities under the SMP would affect salt and brackish marsh habitat in tidal areas and
freshwater wetland, riparian forest and woodland, ruderal/non-native grassland, and open water habitat in
non-tidal areas. The District's proposed 20 year work program would temporarily remove an estimated
cumulative total of 146 136 acres of jurisdictional wetlands: 30 acres in tidal areas, and 116 106 acres in
non-tidal areas. Implementation of vegetation management under the SMP would also remove an
estimated cumulative total of 78 66 acres of in-stream woody riparian vegetation. An additional,
unquantified amount of riparian vegetation would be removed for bank protection, which will impact
approximately one linear mile of bank per year. The direct and cumulative impacts of sediment removal,
vegetation management, and bank protection would be mitigated by implementing BMPs and providing
compensatory mitigation. Compensatory mitigation would include tidal wetland restoration, freshwater
wetland creation, stream and watershed protection, and control of giant reed.
P. IV-B-28, third paragraph
Pursuant to the ESA, the USFWS and NMFS have regulatory authority over projects that may affect the continued existence of federally-listed species. Because the SMP would require an U.S. Army Corps of Engineers (USACE) Section 404 permit for wetland fill and take of federally-listed species could result, an interagency consultation between USACE and both USFWS and NMFS under Section 7 of the ESA would be required.
P. IV-B-29, third paragraph
For species that are listed under both the ESA and CESA, take authorization under Section 7 of ESA could also suffice for take authorization under CESA, if CDFG finds that the federal permit adequately protects the species. In this case, the District would need to obtain a permit under Section 2080.1(a). This permit would state CDFG concurrence with the measures in the federal Biological Opinion. . . .
P. IV-B-29 (after the third paragraph)
California Fish and Game Code
Species designated as Fully Protected under the Fish and Game Code may not be taken or possessed at any time (Sections 3511, 4700, 5050, 5515). The potential of Fully Protected species to be present within the District's jurisdiction would require an agreement under Section 1802 to prevent take.
P. IV-B-57, third paragraph
The assessment of impacts from the SMP are limited to an evaluation of the changes the SMP
could cause in the physical environment from the current baseline condition. In the impact discussion
below, three two general categories of changes are identified: those which will be caused by continuing
maintenance over an additional period of 20 years, and areas included in the program where routine
maintenance has not occurred on a frequent basis in the past, and the resumption of the use of herbicides
in the Santa Clara Basin. This impact evaluation does not assess the biological impacts of the original
construction of the flood protection projects, nor of prior, longstanding maintenance. Rather, it evaluates
the effect of continuing the existing maintenance practices, with some modification in area and
methodology, in a new program approach for a length of 20 years.
P. IV-B-57, fourth paragraph
The SMP includes an extensive array of BMPs (see SMP AppendixHG)…
P. IV-B-61, last paragraph
Projected vegetation management areas were refined to include the Pajaro River Basin areas
where herbicides are not currently used, but are proposed for herbicide treatment as part of the program.
For those areas, future herbicide use was projected based upon the area of existing hand removal and
mowing operations and known target vegetation.
PP. IV-B-65 through -67
Impact Bio-1: Sediment removal and vegetation management would impact in-stream wetland and riparian vegetation (Criterion Bio-1).
Implementation of the program would cause temporary but repetitive impacts to 116 106 acres of
freshwater wetlands, 30 acres of tidal wetlands, and 78 66 acres of in-stream riparian vegetation due to
sediment removal and vegetation management in stream channels. Concrete-lined channels are included
in these projections as well as earthen channels. Seven of the 116 106 acres of freshwater wetlands
occur in water delivery canals. Refer to Revised Table B-IV-7 for a summary of vegetation impacts and
Table II-4 for a breakdown of vegetation impacts by work activity type. Figure IV-B-13 shows the
location of projected impacts to stream vegetation. As described in the introduction to the significance
criteria for this chapter, any removal of wetland or riparian vegetation from sediment removal or
vegetation management activities is considered cumulatively significant for the purposes of the SMP.
These impact acres are based on the one-time accounting method described above and on the
implementation of the following BMPs, which would reduce the impacts of removing wetland and in-stream riparian vegetation:
| 1.13 | Prevent Scour Downstream of Sediment Removal |
| 2.1 | Minimize vegetation removal |
| 3.6 | Remove Sediment from One Side of Large Channels in Alternate Years |
Implementation of the BMPs referenced above would reduce the adverse impacts of the SMP caused by removing wetland and in-stream riparian vegetation; however, the vegetation would be lost and residual impacts would remain. Implementation of the compensatory mitigation proposed for the SMP would reduce these residual impacts to tidal wetlands, freshwater wetlands, and instream riparian vegetation to a less than significant level. The effect of the compensatory mitigation on these three resources, as well as a summary of other related impacts, is described in the following discussion:
Tidal Wetlands
For tidal wetland impacts, no new tidal work areas are projected, and, in the Pajaro River Basin
where the switch to herbicides is proposed, there are no tidal areas. Thus, the removal of 30 acres of
tidal wetlands over the next 20 years would be a continuation of existing practices and adoption of the
SMP would not result in any new adverse change in ongoing effects. The compensatory mitigation
program includes restoration of 30 acres of tidal wetlands at a location either directly adjacent to or no
farther than 7 miles from the tidal wetland impact areas. The restoration site is expected to support
permanent tidal wetland similar to or of higher quality than the tidal wetland temporarily impacted by
repetitive maintenance activities. Refer to the more extensive description of this mitigation measure in
SMP Chapter 5. This mitigation measure is therefore considered sufficient to reduce the level of impacts
to tidal wetlands to a less than significant level.
Freshwater Wetlands
For freshwater wetlands, sediment removal is projected to occur on approximately 6 miles of
streams (5 miles in the Santa Clara Basin and 1 mile in the Pajaro River Basin) that have not undergone
regular maintenance in the past. Work in this area would affect 3 acres of freshwater wetlands in the
Santa Clara Basin and less than 1acre in the Pajaro River Basin. In the Pajaro River Basin, vegetation
management is projected to occur on an additional 9 miles of streams where vegetation management has
not been undertaken on a regular basis in the past, which would affect 4 acres of freshwater wetlands.
Thus, the SMP would affect 116 106 acres of freshwater wetlands in the future, of which 7 acres would
be a new adverse change.
The compensatory mitigation program includes creation of 14 acres of freshwater wetland (10 in
the Santa Clara Basin and 4 in the Pajaro River Basin) and 920 to 1,210 820 to 1,080 acres of stream and
watershed protection to compensate for impacts to freshwater wetlands. The locations of these
mitigation components will be allocated so that they occur within each basin at approximately the same
level as the impacts. The freshwater wetland creation sites will occur at a few locations on the valley
floor as compared to the impact areas, which are spread throughout each basin. Although the freshwater
wetland creation sites will not be instream as are the impacted freshwater wetlands, they have an
advantage of not being subjected to routine disturbance from flood protection maintenance as the
impacted sites are, and they will provide habitat for common local wildlife and wetland-related plants in a
streamside setting. The types of wetland plant species affected are widespread and regenerate quickly,
thus it should not be difficult to create new wetlands of similar or higher quality.
The specific locations of the stream and watershed preservation efforts have not been chosen yet. They are generally expected to be farther up in the watershed than the impacts, however, since the upper watershed is where land suitable for preservation is most available. The type of stream habitat protected under the stream and watershed component is different than the instream freshwater wetland impacted in modified earthen and concrete channels, but the former consists of more structurally and functionally complex native riparian and riverine habitat that occur on less altered stream reaches.
Refer to the more extensive description of these mitigation measures in SMP Chapter 5. Because of the size and quality of the freshwater creation and stream and watershed compensation components, they are considered sufficient to reduce the level of impacts to freshwater wetlands to a less than significant level.
In-stream Riparian Vegetation
No new work areas are projected that would affect in-stream riparian vegetation. The additional
impact to in-stream riparian vegetation from the conversion to herbicide use in the Pajaro River Basin is
discussed under Impact Bio-6 below. Thus, the removal of 78 66 acres of in-stream riparian vegetation
of a sapling size over the next 20 years would be a continuation of existing practices, and adoption of the
SMP would not result in any new adverse change in ongoing effects.
The compensatory mitigation program includes control of 80 66 acres of giant reed over a 10-year
period to mitigate for the impacts to riparian vegetation. This program includes associated efforts such as
mapping, revegetation, monitoring, and education. Refer to the more extensive description of this
mitigation measure in SMP Chapter 5. Since giant reed displaces open water and native riparian and
wetland plant communities of freshwater streams, its control is appropriate compensation for impacts to
sapling riparian vegetation caused by channel vegetation management activities. The giant reed control
program will be spread throughout the county, as are the impacts, although control areas will be targeted
to those locations where which the most habitat value can be obtained from sustained control efforts.
The giant reed control program will reduce the impacts to riparian vegetation to a less than significant
level.
An additional 45 59 acres of giant reed control is proposed to compensate for any lag time between
maintenance impacts to stream vegetation and implementation of the tidal wetland restoration, freshwater
wetland creation, and stream and watershed protection mitigation components.
Other Impacts
With the exception of a small amount of fill, which may occur from some bank protection projects,
the SMP would not cause a loss of acreage of jurisdictional waters. Incidental fill is expected to be
minimal due to the employment of BMPs. The direct effects to woody riparian vegetation from bank
protection were not quantified. Bank protection rarely directly impacts woody riparian vegetation.
Because bank protection effects on riparian vegetation primarily affect wildlife, this impact is discussed
below in the Impacts to Wildlife Species section (see Impact Bio-5). The cumulative adverse impact of
the loss of wetland and in-stream riparian vegetation on wildlife is also discussed in that section (see
Impact Bio-4). The additional impact to freshwater wetlands from the conversion to herbicide use in the
Pajaro River Basin is discussed below under Impact Bio-6.
P. IV-B-74, third paragraph (regarding BMPs for Impact Bio-5)
| 2.1 | Minimize vegetation removal |
| 2.3 | Minimize Hardscape in Bank Protection Design |
| 2.5 | Planting |
| 3.5 | Minimize Loss of Aquatic Habitat from Bank Protection work |
| 3.14 | Maintain or Provide Escape Cover |
P. IV-B-74, fourth paragraph
Implementation of the BMPs referenced above would reduce the adverse impacts of hardscape
installation for bank protection; however, over the life of the program habitat would be lost or reduced in
value resulting in residual impacts. However, as stated in the Project Description (Chapter II), the
District has committed to installing no more than 50 percent of future bank protection projects under the
SMP using hardscape methods. Although these residual impacts may be considered insignificant when
reviewed on an individual site basis, when evaluated on a program basis the potential for significant,
cumulative impacts remains. Implementation of BMP 3.5, for example, would replace functions and
values lost via the mitigation provided in the Programmatic Impact Assessment and Mitigation for Routine
Bank Protection Activities (SMP Appendix E), but that mitigation would not always occur at the impact
site and therefore could result in a cumulative fragmentation effect. The cumulative impact from bank
protection would thus remain significant and unavoidable. As described in SMP Appendix E,
Programmatic Impact Assessment and Mitigation for Routine Bank Protection Activities, in-stream and
stream-side resources impacts from bank protection will be evaluated and mitigated separately.
Implementation of BMPs and mitigation measures as stated in Appendix E of the SMP Report would
reduce residual impacts to insignificant levels. Additionally, the District will mitigate for all impacts for
impervious hardscape and for unvegetated rock bank protection at a ratio of 3:1 and for all vegetated rock
at a ratio of 1:1 regardless of the determination of the impact assessment matrix. This will account for all
direct, potential and cumulative impacts from the bank protection program. All impacts and credits will be
measured by area and the on-going totals will be reported in the annual report. Mitigation for both in-stream and stream-side impacts will consist of revegetation consistent with the Protocal for Revegetation
Associated with Use of Impervious materials for Bank Stabilization in Appendix E. Over time there will
be a net increase in stream-side habitat from the proposed mitigation.
P. IV-B-75 and -76
The Impact Bio-6 (The cumulative effects of resuming herbicide use in the Pajaro River Basin would substantially reduce the value of the habitat for wildlife) is completely deleted.
P. IV-B-99, fourth paragraph
Several BMPs are designed to minimize impacts from bank protection activities. Biotechnical bank protections, which include soft structures, such as planting native riparian vegetation, will be utilized when feasible (BMPs 1.5, 2.3, 2.5, 2.6, and 2.7). The biotechical stream bank protection methods for fish also apply in part to semi-aquatic reptiles and amphibians see Group B discussion of bank protection impacts). For example, turtles could use submerged instream wood as cover. Frogs and turtles could also use instream wood above the water as basking sites and cover. Rock used in bank stabilization has some value as cover and basking site. Habitat enhancement for semi-aquatic reptiles and amphibians will occur as a result of planting vegetation as part of pro-active bank stabilization (BMPs 2.5 and 2.7) and maintenance of stable undercut banks (BMP 3.14). To avoid injury or destruction of individuals or egg masses during bank protection activities, the work site will be surveyed for special-status species prior to maintenance activities when suitable habitat is present (BMPs 3.1, 3.19, and 3.7). Areas of known occurrences will be listed in the District's GIS database, which will assist in planning activities. Project-specific resource protection measures, such as set-backs or buffer zones, will be used to avoid impacts (BMP 3.2).
P. IV-B-101, third and forth paragraph
The bank protection program avoids impacts by distinguishing three categories of streams based
on the fishery values they support and altering alternative bank protection methods accordingly. First,
reaches of streams supporting or potentially supporting steelhead and resident trout are recognized as
highly sensitive. and bank protection methods that do not incorporate fishery values are not acceptable in
these streams (fish habitat categories are described in Fisheries and the Aquatic Environment, above).
Only bank protection methods incorporating fishery values that, at a minimum, replace those previously
present will be used. If a site requiring bank protection is located in this type of stream but has limited or
no fishery values present, methods incorporating fishery values would be counted as mitigation credit at a
1:1 ratio (by project length) for other bank protection program impacts. If site constraints are such that
methods incorporating fishery values cannot be used, mitigation credits must be used at a 2:1 ratio by
project length. Mitigation will be incorporated in accordance with the SMP, Appendix E, Section 4.3
A second category of stream reaches does not support steelhead or resident trout but occurs
downstream of steelhead/trout habitat and may therefore be used by migrating individuals. In addition,
chinook salmon may spawn in some of these reaches and salmon fry may rear there for brief periods in
the spring. Alternatively these reaches may be dominated by a natural assemblage of native warmwater
fish (primarily Sacramento sucker and California roach) and may also have the potential to support
red-legged frogs and other sensitive species. Although not as critical as the first group of streams, fishery
values including escape cover, velocity refuge, and fine sediment stabilization may still be important. In
this group of stream reaches, bank protection projects will use methods incorporating fishery values at
sites where those values are present. Methods that do not incorporate fishery values may be used but
must be mitigated on a 1:1 basis. If bank protection sites do not support fishery values, using methods that
support such values will gain mitigation credits on a 1:1 basis while use of other methods will result in
neither loss or gain of mitigation credits. Mitigation will be incorporated in accordance with the SMP,
Appendix E, Section 4.3
P. IV-B-102, first paragraph
The third category of stream reaches has no steelhead or trout habitat upstream but may itself support a variety of fish community types, including mixed native and introduced, fish scarce, and no value. In such streams, bank protection projects incorporating fishery values may have little benefit to the aquatic community present. Greater flexibility in selection of bank protection methods is possible in this category and, while other species should be considered, virtually any method may be selected without potential impact to steelhead/rainbow trout, chinook salmon, or fish communities dominated by warmwater native fish (although other biological impacts to non-salmonids may occur; see Impact Bio-5). Mitigation will be incorporated in accordance with the SMP, Appendix E, Section 4.3
P. IV-B-102, second paragraph
Following the guidelines prescribed by the Programmatic Impact Assessment and Mitigation for
Routine Bank Protection Activities, impacts from bank stabilization to special-status anadromous
salmonid fish would be less than significant.
P. IV-B-103, second paragraph
Bank protection may reduce the amount of salt and tidal wetland habitat available for special-status plants, birds, and mammals. Loss of wetlands is not typically associated with an erosion site. Bank protection could occur on streams that are adjacent to salt and tidal wetlands and that have the potential to support these species. However, the only Group D species that could be substantially affected by bank protection are California black rails and California clapper rails. California black rails and California clapper rails are not expected to nest within the stream channel; however, rails may forage in the channels. Bank protection could eliminate foraging habitat. The other Group D species are not expected on stream banks that will receive bank protection because these are typically unvegetated due to soil erosion.
P. IV-D-17, third paragraph
Impact Haz-1: Preventing Exposure of Mercury During Bank Protection Projects
Rosgen, D.l. 1996, Applied River Morphology
P. VII-24, sixth paragraph
US Corps of Engineers, 1997, Bioengineering for Stream-bank Erosion Control