Stream Maintenance Program

Program
Environmental Impact Report

Summary

A. THE SANTA CLARA VALLEY WATER DISTRICT

The Santa Clara Valley Water District ("District") is a special purpose governmental agency responsible for providing water supply and flood protection for Santa Clara County, California in an environmentally responsible manner. For flood protection, all creeks in Santa Clara County with a watershed greater than 320 acres are in the District's jurisdiction.

B. PROPOSED PROJECT: THE STREAM MAINTENANCE PROGRAM

1. The Scope of the Stream Maintenance Program

The Stream Maintenance Program (SMP) describes a proposed program for conducting routine stream and canal maintenance. The program is intended to be ongoing and can be modified as conditions change. The program is intended to apply to three major activities, sediment removal, vegetation management, and bank protection, and a group of minor activities. The program is intended to cover these activities wherever they may occur in the District's jurisdiction, subject to several specific limitations.

The SMP incorporates several explicit steps for evaluating and reporting the effectiveness of the mitigation in the Program ( see SMP Figure 3-1, SMP Resource Protection Protocol). This cycle of annual evaluation and improvement makes the SMP capable of adapting to new information and changing conditions to improve Best Management Practices (BMPs) effectiveness. It is expected that the full suite of resource protection incorporated in the SMP will allow the District to minimize environmental effects under a wide range of actual work needs.

2. Sediment Removal

Sediment removal occurs when an accumulation of sediment (1) reduces flood water conveyance capacity, (2) prevents facilities or appurtenant structures from functioning as intended, or (3) impedes fish passage and access to fish ladders. Thus the overall purpose is to ensure the proper function of District facilities.

The District estimates that it removes an average of 80,000 cubic yards of sediment on about 16 miles of channel per year in Santa Clara County. The actual quantity and location varies from year-to-year depending, in part, on rainfall of the past season. Cumulatively, sediment removal is projected for approximately 60 miles of streams. Sediment removal from canals is estimated to be less than 1000 cubic yards per year.

Sediment removal generally occurs between July 1 and October 15. A variety of heavy equipment is used. The average duration of a sediment removal project is 10 days. Appropriate temporary dams and pipes are used if water must be bypassed around the site during work. Excavated sediment is disposed at a landfill or other suitable site.

3. Vegetation Management

Vegetation management removes plant growth which blocks channels or which reduces flood flow. Vegetation management helps maintain the ability of channels to function as flood protection channels and also provides control of invasive, non-native plants and control of weeds at revegetation sites. The District also manages vegetation to protect levees, and concrete linings from plant roots; to meet local fire codes, to provide visual clearance of a facility; and to provide access along maintenance roads. Depending on the original design and the characteristics of the channel, the frequency of vegetation management varies from annually to every few years.

In many creek sections, both sediment removal and aquatic herbicide application are done in different years within the maintenance cycle. For example, in the year following sediment removal, herbaceous wetland vegetation may become established, and in the third year, may pose a potential flood hazard. Herbicide is applied to kill the vegetation, and herbicide application may continue in subsequent years before sediment accumulates until it eventually reaches a point where flood capacity is significantly reduced and sediment removal is again required.

Herbicides are used extensively and are preferred by reason of lower cost over mechanical and hand control methods. Currently, the District does not use herbicides in the Pajaro River Basin ("South County"), but would do so under the proposed SMP. The herbicide use in the Pajaro River Basin would be on approximately 56 miles of channel, 11 miles of which would be done in conjunction with sediment removal. Vegetation in these areas of the Pajaro River Basin is currently controlled by hand or mechanical methods.

Currently, the District uses glyphosate (Monsanto's Roundup® Pro and Aquamaster®, an aquatic formulation formerly marketed as Rodeo®) to control in-channel vegetation . Upland herbicide spraying applies to levees, unpaved maintenance roads, District right-of-way, and along some property lines. 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. This particular application may change to reflect new restrictions under consideration by the California Department of Pesticide Regulation.

4. Bank Protection

Bank protection involves an action by the District to repair stream banks that are eroding or are in need of preventative erosion protection. The District may implement bank protection when the problem (1) causes or could cause significant damage to a property or adjacent property, (2) is a public safety concern, (3)  adversely affects transportation or recreational use, (4)  adversely affects water quality or beneficial uses, or (5) adversely affects riparian habitat. Based on past experience, the District estimates that an average of one linear mile of stream banks may be repaired each year spread over some 30 to 50 individual work sites. Work is usually done between July 1 and October 15.

Bank 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. 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% of future bank protection projects under the SMP as hardscape.

5. Minor Activities

Minor maintenance activities include trash removal, installation of fences and gates; repairs to restore access roads and levees; grading small areas to improve drainage and reduce erosion; repair to existing structures (e.g. replacement of concrete linings and culverts); sediment removal at stream gages, outfalls, culverts, flap gates, tide gates, inlets, grade control structures, fish ladders, fish screens; graffiti removal; tree pruning along maintenance roads; irrigation, weeding, replanting and other maintenance at mitigation sites; removal of obstructions to flow at bridges, streamflow measuring stations, box culverts, storm drain outfalls and drop structures; removal of trees in 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.

6. Mitigation Incorporated in the Project

Chapter 4 of the SMP presents policies to protect resources during the implementation of routine stream maintenance activities. These policies provide guidance to District managers and staff in the environmental review, design, and implementation of individual stream maintenance projects. BMPs have been developed to implement each of these policies and to mitigate environmental impacts identified in the EIR.

a. Best Management Practices (BMPs)

The SMP has specifically developed BMPs applicable to routine stream maintenance, and these are incorporated into the SMP (SMP Appendix G). The BMPs provide mitigation for potential Water Quality, Vegetation, Wildlife and Fisheries, Land Use and Cultural Resources impacts.

b. Wetland and Riparian Compensation

Over the long-term, the SMP has the potential to significantly affect the ecological and biological environment of Santa Clara County by cumulatively affecting wetland habitats, including tidal and freshwater wetlands and riparian habitats. Though measures in this EIR will avoid or reduce these impact, the District acknowledges that it would not be to a less-than-significant level if compensatory mitigation were not provided.

The SMP includes a compensatory mitigation package to compensate for the significant residual impacts of sediment removal and vegetation management on in-stream wetlands and riparian vegetation. The compensatory mitigation package includes the following components: (1) tidal wetland restoration; (2) freshwater wetland creation; (3) stream and watershed protection; and (4) control of giant reed. This mitigation is described in detail in Chapter 5 of the SMP.

Bank protection is addressed by the Programmatic Impact and Mitigation for Bank Protection protocol (SMP Appendix E) which compares the intensity of the work method and amount of hardscape against the environmental sensitivity of the work location. Impact and mitigation are balanced between individual projects.

c. Special Status Species

The avoidance and minimization measures incorporated in the project, described in SMP Chapter 4, are considered sufficient to reduce most, but not necessarily all, potential impacts of the SMP on special-status species to a less-than-significant level. Residual impacts are reduced to less than significant by specific provisions in the compensatory mitigation program described above.

7. SMP Exclusions

a. Activities Outside of Routine Maintenance are Excluded

In the course of CEQA review, the District determined that there were possible channel maintenance activities that may not be accommodated by the BMPs and other programmatic mitigation proposed as part of the SMP. The following maintenance activities are excluded from the SMP: sediment removal and vegetation management on stream reaches above the 1,000-foot elevation contour which is above the reservoirs; hardscape bank protection projects which occur in high quality fisheries habitat or existing high quality riparian habitat, and initial removal of in-channel trees in Llagas Creek downstream of Luchessa Avenue to the confluence with the Pajaro River.

b. Other Activities are Excluded

Routine maintenance restores flood conveyance capacity to design levels, but does not increase design capacity. The District also plans and carries out flood protection projects as Capital Improvement Projects (CIP). The CIP are subject to separate engineering and environmental review which will take into account project specific impact and mitigation. Once the CIP is completed, maintenance at the project site will be incorporated into the SMP.

The SMP does not include certain other District maintenance activities such as percolation ponds, in-stream water infiltration barriers (summer dams), or dam and reservoir maintenance.

C. REGULATORY SETTING

1. CEQA

The District acts as the lead agency in fulfilling the requirements of the California Environmental Quality Act (CEQA).

The District has conducted routine maintenance of canals and channels used for water supply and stormwater conveyance in the past. Previously, routine activities have been subject to a case-by-case determination of potential for environmental impact followed by appropriate CEQA review.

The District is preparing this Program Environmental Impact Report (EIR) because: 1) The District is seeking new long-term regulatory permits for some routine maintenance activities from other agencies which require the District to prepare a CEQA review; 2) the District is proposing the use of herbicides for stream maintenance in the Pajaro Basin, an area where they are not currently used; and 3) the District can minimize future case-by-case review by considering the cumulative effects of all potential SMP activities in a single Program EIR.

A Program EIR, defined in CEQA Guidelines Section 15168, is used for a series of individual actions that are related "geographically, as logical parts in a chain of contemplated actions in connection with ... a continuing program, or as individual actions carried out under the same statutory or regulatory authority having generally the same environmental effects that can be mitigated in similar ways." Thus the SMP and this EIR emphasize the role that formally established programmatic mitigation will play in the District's future maintenance work.

The maintenance activities described in this program EIR are ongoing and will remain effective for an indefinite period of time as long as the nature of the work or environmental conditions do not substantially change. Because permits from other agencies will need to be renewed in 10 years, the District will reexamine the applicability of the Program EIR at that time and make revisions as needed.

2. Permits from Other Agencies

The District is applying for permits or other forms of regulatory approvals for those activities included in the SMP that are under the jurisdiction of the California Department of Fish and Game, the Regional Water Quality Control Board and the U.S. Army Corps of Engineers. It is the District's intent that the program and mitigation defined by the SMP would serve as the basis for state and federal permits and permit conditions. The program EIR will help state and federal agencies comply with their environmental review requirements.

D. ENVIRONMENTAL EFFECTS

The proposed program is the continuation of routine sediment removal, vegetation management and bank protection activities that have been carried out by the District for many years. Work is done on modified and unmodified channels. The need for ongoing maintenance has resulted from land use change in the watershed 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. The maintenance program did not create the conditions that led to the need for maintenance, but routine maintenance is now needed to protect surrounding properties from flood and bank failure damage.

The environmental setting of the project - the environmental baseline from which project impacts are measured - is the present-day disturbed creek condition. In this context, most of the effects of maintenance are either insignificant or can be mitigated to less than significant by application of the BMPs included in the SMP.

The Draft Program EIR identifies several impacts on biological resources as significant and unavoidable.

A) Sediment removal and vegetation management remove wetland and riparian (streamside) vegetation which provides habitat for fish and wildlife, including some special status species. Mitigation through the BMPs and the compensatory mitigation program appreciably reduce the magnitude of the wetland and riparian impact, but local effects near work sites may not be completely offset by mitigation away from the affected reach or in a different watershed. The local effect is fragmentation of wildlife habitat, with loss of habitat area, quality, and connectivity. The residual, unmitigated effect is considered adverse, significant, and unavoidable (Impact Bio-4).

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).

C) Repeated herbicide vegetation control has the effect of holding channel vegetation to a lower successional stage and changes the vegetation community (the plant and animal species present). Because the District has been using herbicides in North County for many years, the environmental baseline already shows this effect and further work under the SMP will not have a significant incremental impact. Resuming herbicide use in the Pajaro River Basin, however, will produce changes and a concomitant loss of stream vegetation functions and values, which would cause a significant cumulative adverse impact on wildlife habitat. (Impact Bio-6).

The impacts on wetland and riparian vegetation (Bio-4) and impacts of herbicide use on the vegetation community (Bio-6) would gradually abate if the practices were discontinued. The cumulative effects of hardscape bank protection, however, are deemed irreversible.

The potentially significant effects found in the Draft Program EIR are listed in the Summary Table S-1, along with the BMP identification code number and the short title of the BMP. The full list of BMP's is attached as SMP Appendix G.

There are environmental effects that do not exceed the threshold of CEQA significance found in Chapters IV-C Land Use and IV-D Hazards, Public Health and Public Safety. While many of these effects will be further reduced or avoided by the implementation of the BMPs these less than significant effects are not listed in Table S-1 or otherwise discussed in the Summary.

E. CUMULATIVE EFFECTS

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.

The District is currently planning and designing several flood protection projects. These Capital Improvement Projects are not part of the proposed SMP. 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. There are potential cumulative environmental impacts associated with the compensatory mitigation projects for 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.

F. ALTERNATIVES TO THE PROPOSED PROJECT

The alternatives analysis focuses on the ways that the long-term, cumulative impact of routine maintenance could be reduced. The proposed project is adoption of the SMP and implementation of its work performance protocol and programmatic mitigation. The proposed SMP is characterized as the "Multi-Year Program Alternative" and is the District's preferred alternative. The "No Project" Alternative represents the District not adopting the SMP and continuing the current practice of routine maintenance. The "No Work" Alternative projects conditions with no maintenance work conducted. All of the other alternatives evaluated in this Chapter focus on different ways to operate under an SMP. The main differences between the alternatives are 1) the amount of flood protection provided; 2) the amount of herbicide used; and 3) the amount of stream vegetation affected.

1. Alternatives Evaluated in EIR

1. Multi-Year Program Alternative The Multi-Year Program Alternative, which is described in detail in the SMP and is the Preferred Alternative, includes sediment removal, vegetation management, bank protection and minor associated work. Projected levels of work are based on historical levels with minor adjustments made for foreseeable future changes. The program includes BMPs and a compensatory mitigation package. This programmatic EIR would serve as the major vehicle for evaluating future work under CEQA, and projects are expected to be covered by 10-year permits.

2. Existing Program Alternative [No Project] continues current maintenance criteria and practices without establishment of programmatic assessment and mitigation; continuation of case-by-case regulatory review.

3. No Work Alternative discontinues maintenance of streams, canals and other associated District facilities. Allows channels to form by themselves. Over time, these facilities could fill in with more sediment and vegetation and could reduce flood protection.

4. No Herbicides Alternative assumes no use of herbicides in routine stream or canal maintenance. Instead, vegetation will be managed by mechanical and hand methods in those areas in which herbicides are currently used in the Santa Clara Basin, and no herbicides will be used in the Pajaro River Basin.

5. Modified Pajaro River Basin Alternative is similar to the proposed Multi-Year Program Preferred Alternative except that it will not include the use of herbicides in stream channels of the Pajaro River Basin unless they are for the control of non-native, invasive plants. Instead, hand and mechanical methods will be used to control vegetation in the Pajaro River Basin stream channels. Herbicides would be used in adjacent upland areas in the Pajaro River Basin, and in channels associated upland areas in the Santa Clara Basin and in canals.

6. Reduced Work Alternative reduces the overall amount of routine stream maintenance work. Sediment removal and vegetation management would no longer take place in unmodified channels except 100 feet upstream and downstream of bridges or road crossings as needed and at stream gages, outfalls, trash racks and other in-stream structures. Herbicide use will resume in the Pajaro River Basin. Maintenance activities in canals would be the same as under the Multi-Year Program Alternative. Hardscape structures would not be included in the SMP with this alternative.

2. Environmental Comparison of Alternatives

The primary environmental difference among alternatives is in the magnitude of significant biological effects. Most other areas of potential impact are not significant for the proposed project, or can be reduced to insignificance by mitigation incorporated in the project, and do not vary appreciably among alternatives.

The No Work Alternative would eliminate all maintenance and would have significant public safety and economic impacts due to increased risk of flooding. Overall, there would be more vegetation in the stream channels.

The Existing Program Alternative would have less opportunity for regional compensation for cumulative maintenance impact. Although some mitigation could be imposed during individual project review, the SMP represents a significant opportunity to accomplish a regional aquatic, wetland, and riparian enhancement program.

Alternatives with reduced herbicide use (Existing Program, No Herbicides, Modified Pajaro River Basin, and Reduced Work) have the benefit of less long term vegetation change, but would result in a greater annual removal of vegetation. Because mechanical methods are less efficient than herbicides, regrowth between treatment is greater in areas treated only with mechanical methods so there is usually more vegetation present when the work is done.

The "Reduced Work" Alternative would reduce impacts to stream vegetation by one-fifth and would not have cumulative impacts from hardscape structures, however, it may reduce the amount of flood protection.

3. Alternative to Maintenance is Beyond Scope of SMP

Maintenance does not include activities such as raising levees to increase design flood capacity, reconfiguring stream channels, or limiting or modifying upstream land uses. While the need for maintenance and hence the impact of maintenance in some streams could be reduced by changing the channel condition, the necessary design and construction work is beyond the scope of routine maintenance and the proposed SMP.

Table S-1

Summary of Potentially Significant Impacts and Mitigation Incorporated into the Proposed SMP

Key to Table S-1:

Impact:	The impact number and short description from EIR Chapter IV.
BMP Code	The code number cross referencing BMPs in EIR Chapter IV and SMP Appendix G, Best Management Practices listing.
Short Title	Short title of the BMP
Activity	Category of maintenance activity most affected: SR = Sediment Removal; VM = Vegetation Management; BP = Bank protection; MM = Minor Maintenance.

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