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VI. CEQA QUESTIONS
The California Environmental Quality Act (CEQA) requires that an EIR address certain general questions that bridge the discussion of individual technical topics. This Chapter addresses those statutory issues.
A. GROWTH INDUCING ASPECTS OF THE PROPOSED PROJECT
CEQA guidelines state that growth-inducing impacts are defined as ways in which the proposed project could foster economic or population growth, or the construction of additional housing, either directly or indirectly, in the surrounding environment. The concept of growth inducement also includes the characteristic that some projects may encourage and facilitate other activities which could significantly affect the environment, either individually or cumulatively.
The proposed program is the continuation of existing routine maintenance activities performed by the District. The purpose of the maintenance project is to maintain the District channels to be able to carry the 100-year (1%) flood, or existing design, and to maintain the channel conditions upon which the Federal Emergency Management Agency (FEM.) flood insurance mapping is based. Maintenance activities do not increase the amount of land that has flood protection and therefore do not alter the land use or economic constraints to the surrounding flood plain. Likewise, the purpose of the District's ten canals is water conveyance, which does not increase growth potential. Since the District's activities only maintain the infrastructure supporting existing and planned land uses, the District's maintenance activities are not growth-inducing.
Minor routine maintenance activities as listed in the Project Description do not increase the population-serving capacity of the District's facilities, and are therefore not growth-inducing.
B. SIGNIFICANT, IRREVERSIBLE ENVIRONMENTAL CHANGES
The proposed program is the continuation of ongoing sediment removal, vegetation management and bank protection activities that have been carried out by the District for many years. The need for ongoing routine maintenance activities has resulted from land use change around and from past modifications to once natural channels first done to support agriculture, and later to provide flood protection and to accommodate transportation corridors for urban developments on the valley floor and low foothill areas of Santa Clara County. Agricultural modifications included clearing of vegetation, stream straightening, and diverting water from channels. Flood control modifications included straightening streams and installing concrete lined-sections, culverts, and construction of levees.
In most work reaches, sediment removal, vegetation management and even bank protection are ongoing maintenance processes, and the facilities will not function as intended without the maintenance.
Over-steepened banks are prone to failure and need frequent armoring and other stabilization. Ongoing regular maintenance compensates for the unstable conditions in the channels that compromise their flood capacity or result in property damage (bank failure) from floods. The maintenance program did not create the conditions that led to the need for maintenance, but once created, modified channels in the District require routine maintenance to protect surrounding properties from flood damage. The proposed multi-year project helps the District provide long-term protection from flooding.
The ongoing nature of maintenance means that impacts identified in the EIR will tend to persist as long as the maintenance program continues. Some of the effects are judged to be reversible if maintenance were discontinued.
The structures created by bank protection can be considered essentially permanent. Chapter IV.B., Biology identifies hardscape installation for bank protection; as having the potential to have cumulative, significant, irreversible environmental changes: Although implementation of the BMPs would reduce the adverse impacts, habitat would be lost or reduced in value resulting in residual impacts . The actual amount of hardscape versus softscape to be installed by future bank protection cannot be projected because the conditions of each site and resulting design vary greatly and cannot be predicted. The cumulative impacts from bank protection would thus remain significant and unavoidable.
Other biological impacts remain significant even after application of mitigation measures: resuming herbicide use in the Pajaro River Basin, thus holding vegetation to a lower successional stage, and fragmentation of habitat caused by breaking the linear stream corridors into smaller pieces. Since at this time it is unknown the extent of impacts caused both of these practices, these impacts are considered significant even after mitigation. However, both of these practices do not result in irreversible changes, as the impacts would disappear if the practices were discontinued.
C. EFFECTS FOUND NOT TO BE SIGNIFICANT
Effects found not to be significant in the Initial Study in conjunction with the Notice of Preparation were effects on agricultural resources, mineral resources, population and housing, transportation and traffic, public services, and utilities/service systems.
Air quality was found not to be significant in the Initial Study but is addressed in the Program EIR to incorporate the standard construction dust abatement mitigation measures required by the Bay Area Air Quality Management District as Best Management Practices.
D. CUMULATIVE IMPACTS
CEQA Guidelines state that "an EIR shall discuss cumulative impacts of a project when the project's incremental effect is cumulatively considerable" (§15130). A cumulative impact consists of an impact which is created as a result of the combination of the project evaluated in the EIR together with other projects causing related impacts. The discussion of impacts contains a list of past, present, and probable future projects producing related or cumulative impacts, including those projects outside the control of the agency. The discussion of cumulative impacts should focus on the cumulative impact to which the identified other projects contribute rather than the attributes of other projects which do not contribute to the cumulative impact.
There are two types of cumulative discussion that are addressed in this section: 1) activities within the purview of the proposed SMP; and 2) activities which either are proposed by the District (such as Capital Improvement Projects) or activities attempted by others that may affect streams in the District (see Table II-10, Other Future District Projects in Creeks).
The Program EIR is explicitly directed to assess the cumulative impacts of separate maintenance activities spread over space and time. Thus, the cumulative impacts of the planned Program are discussed under the individual environmental factors (Chapter IV) where cumulative impacts are significant or potentially significant, or otherwise relevant: geomorphology; biology; land use; hazards and hazardous materials; and cultural resources. The environmental setting for evaluating the impacts of maintenance reflects the cumulative, historic impact of land use encroachment, land use change, and modification of creeks in the District.
1. Cumulative Impacts of the SMP
As stated in the Project Description, most of the individual sediment removal and vegetation management activities repeatedly take place on the same reaches of District channels. These reaches are the portion of the District most affected by past urbanization and by the geomorphological factors that cause sediment deposition or erosion. Vegetation management is usually an adjunct to sediment removal, particularly in the intervening years between treatment. Bank protection and other minor activities can occur anywhere within District jurisdiction; however, it historically has occurred in cities and semi-rural foothills of the Santa Clara Valley.
As stated in IV-B Biology, under the approach adopted by the District for the proposed SMP, any removal of wetland or riparian vegetation associated with the SMP is considered cumulatively significant. Implementation of the BMPs would reduce the adverse impacts of the SMP caused by removing wetland and in-stream riparian vegetation; however, residual impacts would primarily be associated with fragmentation of wildlife habitat. Although residual impacts may be considered insignificant when reviewed on an individual project basis, when evaluated on a program basis, there is the potential for significant, cumulative impacts.
The placement of additional hardscape within stretches of vegetated bank may also contribute to significant cumulative impacts. 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 the stream corridors. Increasing the amount of hardscape along a channel reduces the amount of cover available to wildlife traversing these reaches and may make them vulnerable to predation.
There are potential cumulative environmental impacts associated with the mitigation projects, such as Los Capitancillos freshwater wetland creation and Pond A-4 tidal wetland restoration, which are being done to support the SMP. Project specific environmental impacts of the mitigation projects will be addressed as part of the specific CEQA documents that will be prepared for all mitigation projects.
2. Impacts From Proposed Mitigation Projects
The SMP includes a compensatory mitigation package to compensate for significant residual impacts. This mitigation is described in detail in Chapter 5 of the SMP. There are potential cumulative environmental impacts of the mitigation program which will be addressed as part of the Mitigation and Monitoring Program to be prepared prior to completion of the Final EIR or under specific CEQA documents to be prepared for certain mitigation projects (e.g. Pond A-4 and Los Capitancillos). This section summarizes what is currently known about potential environmental effects of these mitigation projects and how these will be resolved. All environmental effects are expected to be resolved, therefore, no cumulative effects along with the SMP work activities will occur.
Coyote Lakes Park Site 10A
The project will potentially require fill in Waters of the U.S. in the existing percolation pond, (an impoundment of Coyote Creek) gravel pond or creek for water control structures. Construction of water control structures or other site features may also result in removal of riparian forest, scrub or wetland vegetation. These impacts can likely be mitigated by post-construction restoration at the site of the impact or by providing new habitat within the wetland mitigation project.
Steelhead trout and fall-run chinook salmon may be present in the adjacent reaches of Coyote Creek. Fish could become stranded within the wetland if they were to enter the wetland via the water inlet connection with the percolation pond. Therefore, measures will be taken to limit transmission of fishes between the existing percolation pond and the mitigation wetland (such as installation of a fish screen on the water inlet structure).
Potential construction-related impacts to water quality (i.e. increased sediment) in the gravel pond or creek would be avoided by taking measures to limit turbidity during construction. Once constructed, water flowing out of the wetland could potentially increase stream or gravel pond temperature or turbidity. If this is found to pose a potentially significant impact, measures to avoid this effect will be taken. Potential measures include but are not limited to placement of the outflow structure away from the stream or gravel pond or management of outflow timing and amount.
No take of Red-legged frog habitat is expected, but surveys will be conducted prior to construction to avoid any potential construction related impacts to individuals.
Western pond turtle breeding habitat could be affected. Impacts to turtle breeding would be avoided by conducting surveys in the immediately adjacent section of creek to determine if turtles use habitat in the vicinity of the project area. If turtles are present, measures to avoid impacts to turtle nesting would be taken such as avoiding construction during the nesting season or installing exclusion fences to prevent turtles from nesting on-site during construction.
Suitable Burrowing Owl nesting habitat may be present, however the likelihood of this is small due to the large trees that border the site and provide habitat for Burrowing Owl predators. Pre-construction surveys will be conducted to determine if Burrowing Owls are present. Occupied areas will be avoided or off-site compensation may be required.
Several special-status songbirds and raptors could potentially breed on or adjacent to the project site. Their presence would be determined by pre-construction surveys within the breeding season. A construction-free buffer around any active nest would be established with width determined by a qualified biologist consistent with the District's most recent nesting migratory bird procedures.
A potential increase in flood hazard to existing infrastructure, including Highway 101 is unlikely but will be further investigated during the project design phase to determine with more certainty.
Cultural resources are known from nearby locations on Coyote Creek. If present on the mitigation site, excavation could result in a potentially significant impact. Prior to final design and construction, a qualified archaeologist will assess the site to determine the likelihood of project impacts to cultural resources. Measures will be taken to avoid, minimize or compensate for any identified significant impacts.
Church Pond Number 2 Wetland Mitigation Site:
This reach of Llagas Creek has limited potential to be a migratory corridor for steelhead trout. This potential will be further evaluated during the project's individual CEQA review. If necessary, the water diversion structure will be designed to allow for fish passage throughout the year, by installation of a fish ladder or other means, thus avoiding impacts to migrating steelhead.
Fish could be transported via the water intake structure between and Llagas Creek and the off-stream percolation ponds. A fish screen or other design feature will be installed to avoid this impact.
Construction of a diversion structure within Llagas Creek will constitute fill in Waters of the U.S., and may result in removal or alteration of riparian woodland or wetland habitat. This potential impact will be determined during the design phase CEQA evaluation. Avoidance, minimization and mitigation measures will be implemented as needed to reduce this potential impact to a less-than-significant level.
Los Capitancillos Freshwater Wetland Project
The proximity of the Los Capitancillos Freshwater Wetland Mitigation Project to Guadalupe Creek introduces certain biological constraints to the project including minimizing impacts to existing riparian habitat and avoiding thermal impacts to salmonids. Mercury-containing sediments are also known to be present in the Guadalupe Creek drainage as a result of historic mining. Soil testing results indicate that total mercury concentrations exceed sediment screening criteria for wetland cover in some areas. The project team plans to resolve issues related to the proximity of the project site to Guadalupe Creek and the presence of mercury-containing sediments as follows:
· The overflow structure will be designed to minimize impacts to the riparian habitat;
· Discharges to Guadalupe Creek will be limited to the minimum necessary to prevent flooding of upland areas, and timed to minimize thermal impacts to salmonids;
· Soils excavated from the project site will be handled according to guidance provided by Regional Water Quality Control Board staff with respect to mercury contamination; and
· The wetland area will be over-excavated and lined with a layer of clean topsoil to minimize mercury methylation.
Pond A-4 Tidal Wetland Restoration Project
The Pond A-4 Tidal Wetland Restoration Project (Pond A-4 Project) will provide 30-acres of mitigation for impacts of the Stream Maintenance Program to tidal wetlands. Potential significant impacts to biotic resources and regulated habitats associated with the Pond A-4 Project will be identified during the CEQA evaluation for the project. Alternatives for avoiding, minimizing or mitigating the potential significant impacts will also be determined during the planning study for the Pond A-4 Project. Preliminary analyses, however, have identified a number of potential impacts that may result from the restoration of the salt pond to tidal wetland.
Potential impacts to water quality may occur during construction from the release of inorganic and organic hazardous substances occurring at the site and in imported sediment. Phase I and II Hazardous Substance Liability Assessments (HSLA) have been completed at the site. A Phase III investigation will be done in the planning study phase. Levee soils, pond perimeter sediments and groundwater were sampled and analyzed. In both levee soils and pond perimeter sediments, levels of arsenic (and one sample of copper) were detected in excess of Sediment Screening Criteria for Cover Material. Sediment Screening Criteria for Noncover Material was not exceeded in any of the samples. In the groundwater, diesel fuel, antimony, lead, nick and copper were detected in one or more of the samples; no volatile or semivolatile organic compounds were detected in any samples. Mercury was tested only for its elemental form. The findings of the Phase III HSLA will determine what remedial measures are appropriate. Depending on the results of the Phase III HSAL, it may be possible to reduce the impacts of construction on water quality to less than significant through the implementation a project-specific soil and water quality best management plan during construction. In the event that dredged sediments are imported to raise the pond bottom elevation, they will be tested and selected in coordination with the U.S. EPA and the San Francisco Bay Regional Water Quality Control Board to ensure that they are suitable for re-use in aquatic system based on chemical and biological testing.
The project has the potential to temporarily and permanently impact wildlife species. During wildlife surveys of the pond between 1999 and 2001, 82 species of birds, two species of mammal (Ground Squirrel and Black-tailed Jackrabbit) and two species of fish (Yellowfin Gobie and Longjaw Mudsucker) were recorded. Three Federal special-status bird species and 21 California Species of Special Concern were among those found at the pond. Temporary impacts to wildlife may occur during construction. Best management practices will be used to avoid or minimize construction impacts and may include measures such as avoiding work during the breeding season. The project will have permanent impacts to some wildlife species due to the habitat conversion from open water to wetland, but these impacts may not be significant. The conversion will ultimately favor wetland-dependent species over those species, such as diving ducks, that use deeper open water habitats. Finally, the project may result in erosion of brackish or salt marsh habitat located down slough of the project site. Wetland erosion may occur because of the increased tidal prism after the site is opened to tidal flows. The nature of the impacts and mitigation measures will be addressed in subsequent documents.
It will be necessary to consider regional flood protection issues in the hydraulic modeling for the project to insure that the restoration design does not impact the flood conveyance of nearby streams. The analysis will include an evaluation of an alternative to raise the bayfront levee and other measures to protect the adjacent upland areas from flooding.
An existing spine trail of the Bay Trail is located on the southern levee of Pond A-4. Because of concerns regarding the impacts of adjacent recreational use on wildlife, it will be necessary to evaluate these impacts. Future analyses will consider a variety of measures that would attempt to balance public access and wildlife protection, such as limiting public access during nesting season or other appropriate times of year; limiting access to those activities, such as wildlife observation or environmental education, that are compatible with wildlife; and providing buffers between trails and high quality wildlife areas.
The restored site will provide habitat for invasive or nuisance species that occur in brackish tidal marshes and adjacent transitional areas and uplands. The invasive plant species, perennial peppergrass, has the potential to substantially impact wetlands by altering habitat structure or substantially reducing populations of native species. A major commitment will be needed to control the spread of peppergrass and others invasive species. In addition, it will be important to address the potential for providing habitat for mosquito species that cause human health concerns. Input from the local vector control district will be sought to ensure the design takes vector concerns into consideration.
Stream and Watershed Protection
Stream and Watershed Protection comprises two elements: 1) land acquisition; and 2) projects to restore or manage stream resources on acquired land. No significant impacts are expected to be associated with the land acquisition element. Restoration or management projects could result in potentially significant impacts due to the sensitive nature of stream habitat. Restoration or management projects will be identified on a site by site basis as land is acquired, and will vary based on site characteristics. The types of projects to be done is not known at this time, and therefore, the nature of the potential impacts is not known. Each project will be evaluated for potential impacts, and will be subject to CEQA compliance. Measures will be taken to avoid, minimize or compensate for potentially significant impacts.
Giant Reed Control Component
The Giant Reed Control component consists of the strategic removal of approximately 125 acres of Giant Reed (Arundo donax) on target streams throughout Santa Clara County. The removal of the non-native species would be followed up by revegetation with appropriate native species in areas where natural revegetation is not likely to occur.
The potential impacts associated with the removal Arundo donax are as follows:
•Potential loss of nesting habitat in areas where large monocultures of Arundo are removed.
•Potential loss of Shaded Riverine Aquatic habitat in areas where large monocultures of Arundo are removed adjacent to a stream.
•Potential increase in water temperature due to loss of overhanging growth in areas where large monocultures of Arundo are removed adjacent to a stream.
•Overall increased use of specific herbicides as a control mechanism within the program.
The use of Arundo as habitat has been studied to some degree but extensive published literature does not exist at this time. All evidence indicates that Arundo donax provides neither food nor habitat for native species of wildlife (Bell, G. 1997 Ecology and Management of Arundo donax, and approaches to riparian habitat restoration in Southern California). The same study cites earlier studies that show that Arundo donax lacks the canopy structure necessary to provide significant shading of bank-edge river habitats, resulting in warmer water than would be found with a native gallery forest of cottonwood or willows. Anecdotally, the findings have been similar. No appreciative habitat use of Arundo by native species has been found. The exception has been the use of Arundo for nesting by two species of herons in Santa Clara County. District biologists reported nesting in stands of Arundo by Black-Crowned Night Heron and Green Heron (Ryan comment, 2000).
The potential loss of nesting habitat is a temporal loss that can be reduced through a series of Best Management Practices in areas where this could be a concern. By timing activities to avoid the nesting season and through surveys, impacts from actual work can be reduced to less than significant. In areas where the predominant species is Arundo and no other habitat is available, removal can be phased over a number of years with revegetation occurring in the interim to replace the any temporary habitat losses.
Both the literature and anecdotal information point to little or no impacts to water temperature or Shaded Riverine Aquatic values from the removal of Arundo donax. In areas where the predominant stream-side vegetation is Arundo, BMPs such as phased removal and revegetation can again be implemented to reduce any potential impacts to less than significant.
The increased use of the herbicide, glyphosate, in both terrestrial and aquatic formulations is a necessary component of this program. This herbicide is currently used in routine vegetation management and is discussed extensively within this environmental document. As the use proposed is consistent with current practices and represents no changes other than the amount of material used at a program level, the impact is not considered significant. Further, the fact that the Arundo removal program is being implemented over a period of more than ten years implies that any increase in herbicide use would have impacts lessened by the extended period of time.
3. Cumulative Impacts of Other Activities Affecting District Channels
Additional actions by the District and many others are taken into account for the cumulative analysis where relevant. The District is currently planning and designing several flood protection projects (Table II-10). In each case, these capital improvement projects are subject to an environmental review and will as necessary mitigate incremental impacts on the channels to levels of environmental insignificance. Therefore, any potential cumulative effects will be avoided or mitigated by the future CIP projects during their CEQA review.
The Project Description describes how CIPs are not part of the proposed SMP and will analyze long-term maintenance impacts under separate future environmental review. Any environmental effects of new CVP will be compared to the conditions currently evaluated for that reach of stream under the SMP. New mitigation for CVP will only be required if there are impacts for the same reach of creek that require new mitigation in addition to the package contained in this document and the SMP.
The Total Maximum Daily Load (TMDL) program is a District cumulative activity, but future TMDL will not increase environmental impact of routine maintenance. This program will reduce impact by imposing additional water quality protection measures as necessary.
Other minor activities by others in District facilities are taken intoaccount by the District in its permit review process. Refer to Chapter II.E.4. Definition of Potential for Cumulative Impact for a list of current major stream projects by others and a summary of the general amount of such projects reviewed by the District each year. The District comments on new projects proposed by other agencies or property owners within 50 feet of a creek to determine if they will affect the flow of water, collect debris, or will adversely affect the ability of channel banks to carry flood waters or resist erosion (District Ordinance 83-2). The District encourages projects to be designed so as to avoid unstable bank conditions, large increases in discharge, or conditions that might cause pollution. Additionally, the District and the various cities participate in a Non-Point Source Control Program as defined in Section III of this document. One of the main purposes of District review of channel encroachment and construction by others in and near channels is to prevent incorrectly designed or poorly installed work from causing channel sedimentation or bank failure. These stream projects by others are not expected to cumulatively result in additional impacts along with the SMP for two reasons. First, by reviewing these other projects under its permit program, the District is usually able to avoid any significant effects to the streams. Second, SMP activities are proportionally much greater in size (265 miles of streams) than stream projects implemented by others, yet the SMP avoids or mitigates for most of its own impacts, thus there is no cumulative effect when combined with these much smaller projects.