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2.2 Alternative 2: No-Action Alternative Given the emphasis in the CALFED Record of Decision (August 28, 2000) on meeting ecosystem restoration goals in a manner consistent with meeting water supply and water quality needs, the No-Action Alternative is based on continued operation of the three existing diversion plants as unscreened diversions. Actions that would involve a significant change in the operation of these existing facilities would be considered a new project, not the No Action Alternative. Therefore, under the No Action Alternative, no new facilities would be constructed and routine maintenance of the existing facilities would continue. Operations of the pumping plants at Boyers Bend, Howells Landing, and Tyndall Mound would continue as they have historically. Fish entrainment would continue.
Several alternative methods for providing fish protection at RD108 diversions were evaluated as part of the feasibility assessment (CH2M HILL 2004). These fish screen alternatives were carried forward in parallel with the proposed project until it became clear that they were either infeasible and/or would not achieve the project purpose and need. These alternatives included the use of a flat panel screen, application of a V panel configuration, and alternative intake locations and designs for the Combined Pumping Plant/Fish Screen site. Alternative sites for the proposed facilities included various sites for the Combined Pumping Plant and Fish Screen Facility, but these were eliminated due to (a) closer proximity to riparian vegetation, (b) proximity to known cultural resource sites, and/or (c) less favorable hydrologic conditions.
3.1 Introduction This section describes the environmental setting of the Proposed Project and describes potential environmental consequences with regard to the following categories:
3.2.1 Affected Environment There are no known active faults or any Alquist-Priolo Special Studies Zones within Colusa County or Yolo County in the area of the proposed project, and there are no known major faults within the proposed Action Area. The best geologic evidence currently indicates that Yolo/Colusa Counties would be expected to experience only low-intensity earthquake shaking from a fault outside the County. Soils in the immediate project vicinity and where construction would occur are identified as recent alluvial fan and flood plain soils, with moderate to highly permeable soils to depths of 20 to 60 feet. This non-expansive soil type is found primarily along a relatively thin strip on each side of the Sacramento River (DWR 2003). No known geologic features, mineral resources or mineral extraction activities occur within the project area. 3.2.2 Environmental Consequences of Proposed Action There are no known mineral resources and no unique geological features in the area that would be affected by construction or operation of the Proposed Project. Mineral resource mining does not occur in the vicinity of the proposed project and therefore construction of the Proposed Project would not adversely impact mineral resources at the site. The proposed project will not cause or contribute to geologic hazards and would not conflict with legal requirements regarding geological hazards and soil conservation. The project is not in a designated geologic hazard area, active fault zone, or landslide zone. The proposed project is not likely to expose people or structures to geological hazards. The preliminary soils map prepared by the USDA NRCS does not indicate that the area is subject to liquefaction; liquefaction is not a likely issue for the project site. Except for minor erosion that may occur during construction, the project will stabilize the levee and surrounding project site and reduce potential for erosion. The project's design, and erosion-control measures incorporated into the project's construction plan, will reduce potential for erosion. As a result of these measures, impacts resulting from soil erosion and construction activity will be substantially avoided. The proposed Combined Pumping Plant/Fish Screen fish screen would be located on soil that is not likely to collapse or subside because its texture is coarse enough not to be affected by groundwater drawdown. In addition, the fish screen will be submerged within the Sacramento River and not subject to groundwater drawdown. Subsidence is not a major design criterion for the fish screen and associated facilities. Therefore, subsidence is not considered an issue. Based on Natural Resource Conservation Service and CH2M HILL analyses, project area soils have low to moderate expansion-contraction potential (i.e., they are not classified as expansive soils). The proposed project foundation and other important structures will be designed to accommodate any shrink-swell potential that may occur at the site. The intake structure has been designed to eliminate deformation of the foundation and damage to other structures based on soil characteristics at the site. No impacts to unique geologic features will occur because the Combined Pumping Plant/Fish Screen site is continually disturbed by maintenance practices and contains no unique geographical features. The canal alignment contains no unique features, as it is part of the relatively continuous area of historic floodplain that extends along the west side of the Sacramento River for well over 100 miles. 3.2.3 Environmental Consequences of No Action Like the proposed alternative, the No-Action Alternative would not affect mineral resources, unique geological features, soils, groundwater levels, or subsidence. The No Action Alternative would also not effect soil erosion and associated turbidity in adjacent waters. The No Action Alternative would involve on-going dredging of the forebay and would periodically increase turbidity of adjacent river during these dredging activities. 3.3 Hydrology and Water Quality 3.3.1 Affected Environment The Sacramento River is the largest river in California, originating in the Cascade and Siskiyou Mountains and terminating in the Sacramento-San Joaquin Delta (Delta). Major tributaries upstream of the project site include the upper Sacramento, McCloud, Pit, Feather and Yuba rivers; and Cottonwood, Battle, Butte, Mill, Deer, and Thomes creeks. Base flow levels in the Sacramento River are primarily controlled by releases from Shasta, Oroville, and Folsom Dams. These releases are adjusted to meet downstream requirements for water supply; Delta water quality, fish and wildlife habitat maintenance; flood control; and other beneficial uses in accordance with numerous legal and regulatory requirements. Water quality data for the Sacramento River are collected by several agencies, including DWR, USGS, and the Central Valley Regional Water Quality Control Board (CVRWQCB), as part of monitoring programs and special studies. In addition, water quality was monitored at the RD 108 Wilkins Slough diversion as part of the evaluation of alternative fish protection technologies and winter-run Chinook salmon incidental take monitoring (Demko et al. 1994, Hanson 1996; Hanson and Bemis 1997). Dissolved oxygen concentrations at the Combined Pumping Plant/Fish Screen site typically range from approximately 6.5 to 7.5 mg/l. Electrical conductivity was approximately 200 mhos. Water temperature recorded in the Sacramento River in the area of the proposed project typically ranges from approximately 13 ° C (55 ° F) during the winter and early spring to over 20 ° C (68 ° F) during the summer. Water temperatures showed a general pattern of diel variations of approximately 1 - 2 ° C (2 - 4 ° F) within a day. Turbidity within the Sacramento River has been highly variable, with secchi depths ranging from approximately 30-60 cm during periods of low storm water run-off and precipitation to less than 10 cm during high flow periods. Turbidity within the river varies substantially in response to storm activity and storm water run-off primarily during the fall, winter, and early spring. 3.3.2 Environmental Consequences of Proposed Action Based on statistical analysis of hydrologic data from the USGS Wilkins Slough gauging station (gauge #11390500 approximately 3.0 miles upstream of the project site) from 1944 to 2000, Sacramento River flows were assessed to determine the probability of both high flow flood events and low flows within the Sacramento River that would influence the design and operation of the fish screen (CH2M HILL 2004). Accordingly, the fish screen has been designed to operate in accordance with NOAA Fisheries criteria at projected low flows; at higher flows, a greater surface area of screen would be exposed and approach velocities to the screen would be reduced correspondingly, improving screen performance. The 100-year flood occurs at a Sacramento River flow of about 30,000 cfs and water surface elevation at the Combined Pumping Plant/Fish Screen site of 51.6 feet. Accordingly, the top deck elevation of the Combined Pumping Plant/Fish Screen was established at 51.6 feet (Table 2-1). This elevation allows for weir flow over the screen blanks to aid in equalizing pressure should sections of the screens become clogged. Above the 25-year flood elevation, the floodwaters would pass over the screens with associated silt and small debris. Large debris would continue to be restrained up to the 100-year flood event by the structure and sheet pile transition walls. With the exception of the active screen area, structures would be constructed above the 100-year flood elevation. Based on hydrologic model calculations and simulations using the one-dimensional HEC-RAS mathematical model, which was reviewed by the State and Federal regulatory agencies on the Technical Team, the proposed screen would not increase flood river stage by more than several inches to a foot. The Combined Pumping Plant and Fish Screen will be sited close to the levee edge and will not reduce net river cross-section significantly. This calculated rise in flood flow stage would not be expected to adversely affect river conditions. The projected rise in river stage is also statistically insignificant; that is, it is within the estimated standard error of the model calculations. Because diversions would continue during construction and no change in long-term diversions for water supply are contemplated by the project, construction and operations of the proposed positive barrier fish screen would not adversely impact water supply or urban or agricultural demand for water. Construction of the fish screen would not contaminate public water supplies. There are no urban water supply intakes within the approximately 1,000-foot long area of projected turbidity increases as a result of construction; no effects to a public drinking water supply are therefore anticipated. The project includes a hazardous materials spill prevention and response plan designed to avoid contamination. Construction and operation of the fish screen would not affect the quality or quantity of groundwater when compared to baseline conditions. No groundwater would be used in fish screen construction or operations above baseline conditions and the proposed project would have no affect on groundwater recharge; concrete lining of canals would eliminate potential for significant leakage from these new facilities. Construction activity, including site preparation, dredging, and installation/removal of the cofferdam would result in temporary but very small localized increases in turbidity and suspended sediments within the Sacramento River downstream of the project. Construction of the screen within the cofferdam would reduce and avoid turbidity and suspended sediment within the river. Installation of the cofferdam is anticipated to require up to 60 days. Analysis of potential for suspended sediment concentrations to exceed Regional Water Quality Control Board standards of 0.1ml/l (260 mg/l) suggests that a majority of the suspended sediment (by weight) generated by pile driving would settle out within an area about 200 feet in length, 20 feet in width, and 3 feet (on average) in depth. Suspended sediments generated by pile driving are therefore unlikely to be measurable at the RWQCB distance of 300 feet downstream from the Action Area. In addition, given that background (baseline) sediment concentrations in this reach of the river during flows when construction would be undertaken would be from 10 mg/l to 100 mg/l, the additional sediment load from construction would not cause the RWQCB standard to be exceeded (or even approached). It should be noted that, for salmonids, most studies indicate behavioral and/or physiological responses to suspended sediment loads occur at concentrations of about 250 mg/l or greater and mortality occurs only at much higher concentrations (Griffin 1938; Phillips 1970; Whitman et al. 1982; Newcombe and Flagg 1983). Baseline suspended sediment loads during high flows in wet years are higher than the range used above, and the aquatic community has thus adapted behaviorally and physiologically to such short-term increases in suspended sediment concentrations. The short-term and narrowly distributed increase in project-related suspended sediment concentrations will be below levels that would cause injury. 3.3.3 Environmental Consequences of No Action Implementation of the No-Action Alternative would avoid the short-term temporary increases in turbidity in the Sacramento River and the risks associated with release of hazardous materials during in-river construction activities and other hydrology and water quality effects associated with the project. Except for periodic localized increases in turbidity due to maintenance dredging, implementation of the No Action Alternative would therefore have no effects on water quality in the Sacramento River or in local groundwater. 3.4 Biological Resources 3.4.1 The Action Area and Species in the Action Area Construction and long-term operation and maintenance activities for the Proposed Project will occur in an area approximately 4 miles long by 1 mile wide. Within this area, baseline environmental conditions vary, but are generally characterized by a high level of disturbance. The Action Area, the area potentially affected by project activities, is functionally defined below. 3.4.1.1 Fish For fish, the action area is the Sacramento River mainstem, from approximately 300 meters upstream and downstream of the four facilities which would be affected by underwater noise, diver activity, and suspended sediment/turbidity during construction/demolition activities. Underwater noise will be primarily associated with the initial installation of the cofferdam, when percussion hammers are used to drive pilings into the riverbed. Although noise travels well underwater, the meandering river and the rip-rapped banks will attenuate noise. Percussion from installation of cofferdams will be attenuated at the severe river bends upstream and downstream of the Combined Pumping Plant and Fish Screen. The Action Area related to potential suspended sediment and turbidity effects is the area from the immediate vicinity of in-river construction activities (cofferdam placement and removal, removal of pilings at three old diversion structures) to not more than 300 meters downstream. Pile driving will resuspend sediments only in the immediate vicinity of the pile being driven and will result in intermittent "puffs" of sediment created by impact. These will rise only several feet from the substrate and will thus be carried downstream for only a short period before settling out of the water column. Some very fine particles may cause a below surface turbidity plume extending 300 meters. The Action Area for all other effects on fish will be the immediate vicinity of the Combined Pumping Plant and Fish Screen. 3.4.1.2 Nesting Raptors For nesting raptors, based on CDFG guidelines, the Action Area is nominally the area within approximately 0.5 mile of the four facilities which could be affected by construction noise and visual disturbance of nesting birds during construction/demolition activities. Practically, the Action Area may be smaller, because levees and vegetation may limit line-of-sight disturbance effects. For purposes of analysis, the 0.5-mile perimeter will be utilized. 3.4.1.3 Nesting Resident and Migratory Songbirds No special-status resident and migratory songbirds were found in the vicinity of the project area, but incidental fly-by may occur and nesting in trees along the levee could occur. For nesting resident and migratory songbirds, the Action Area would be the area within100 feet (30 meters) of suitable trees-shrub nesting habitat. Such habitats only occur near existing diversion facilities 3.4.1.4 Upland, Ground-nesting, and Aquatic Species For upland, ground nesting, and aquatic species the Action Area is the area within the construction right-of-way for construction and demolition of pumping facilities, for construction and modification of irrigation canals, for excavation of borrow and for the construction access roads. The Action Area does not include the Main Drain, which will not be affected by use of the adjacent borrow pit. 3.4.1.5 Valley Elderberry Longhorn Beetle For valley elderberry longhorn beetle the Action Area is the area within 100 feet (30 meters) of elderberry shrubs with a stem diameter of 1 inch or greater at ground level. 3.4.2 Baseline Conditions 3.4.2.1 The Sacramento River Channel In the project reach, the mainstem river is constrained by levees, many sections riprapped to prevent erosion, with managed and regulated flows occurring throughout most of the year. The river channel has a sandy/silty bottom with little submerged aquatic or emergent vegetation. The levee edge of the riprapped channel up to the normal high water level is generally devoid of submerged or emergent aquatic vegetation. Upland vegetation on the 20-foot bench at the base of the levee is a mix of predominantly non-native shrubs such as Himalaya berry with natives such as poison oak. Conditions in the river channel reflect the effects of numerous upstream impoundments, long-term and on-going mining in the upstream watersheds, levee construction, numerous water diversions from the river, and upstream watershed agricultural and urban development. Federal, State, local, and private flood control and water supply reservoirs have altered hydrologic regimes, resulting in reductions in winter and spring flows (runoff from rainfall and runoff from snowmelt, respectively) increasing flows in the summer and fall. Riprapped levees and high flow velocities have reduced instream emergent and submerged aquatic vegetation. Summer boating contributes to loss of emergent and submerged aquatic vegetation by creating waves that erode and resuspend sediment along the shoreline, inhibiting vegetation growth. Runoff from urban and agricultural development has increased sediment and nutrient loads. Water temperature regimes have been altered. Levee construction and maintenance has reduced active river meander and associated habitat complexity. The mainstem channel in the Proposed Project Reach has thus lost habitat diversity as well as hydrologic variability. Constrained within levees, channel substrate is subject to frequent scouring, there has been loss of submerged and emergent stream bank vegetation, and there is thus limited cover and foraging habitat in the Proposed Project reach. These and other changes are documented in detail in the CALFED Ecosystem Restoration Plan. Their combined effect has been to alter the ecological function and value of the project reach of the Sacramento River. The designated Essential Fish Habitat functions for this reach of the river are accordingly limited to adult and juvenile migration pathways. Information on fish entrainment at unscreened diversions located on the Sacramento River, including fishery monitoring conducted at the RD 108 Wilkins Slough diversion approximately 3 miles north of the project area, has documented entrainment losses for juvenile Chinook salmon, steelhead, and a variety of other fish species (Hanson 1996, Hanson and Bemis 1997). Fish entrainment during migration and foraging is being ameliorated by a number of CALFED and other screening projects, including the recently-completed Wilkins Slough Positive Barrier Fish Screen and the proposed Tisdale Bypass Positive Barrier Fish Screen. Other similar projects are in planning. Their effect on the baseline condition is/will be to reduce entrainment of fish during migration and foraging. The environmental baseline, therefore, includes entrainment losses for fish inhabiting the Sacramento River as a result of continued operation of the three unscreened diversions at Boyers Bend, Howells Landing, and Tyndall Mound, and their adverse effects on salmonid and other species, particularly effects associated with entrainment of juvenile life history stages. These diversions are located within an area of the Sacramento River designated as critical habitat for winter-run Chinook salmon. The area is also being reviewed by NOAA Fisheries for potential designation as critical habitat for spring-run Chinook salmon and steelhead. The Sacramento River in the vicinity of the Proposed Project also serves as EFH for Pacific salmon, including fall-run, late fall-run, spring-run, and winter-run Chinook salmon. 3.4.2.2 Mainstem Sacramento River Levees There is an existing 2-lane road on top of the levees. In some reaches, the levees are set back from the channel 10 to 100 feet (3 to 30 meters), and there is a low vegetated bench between the levee slope and the river (see, for example, the aerial photograph of Tyndall Mound Pumping Plant, Figure14, above). In other areas, the levee slope continued to the water's edge. At the site of the Combined Pumping Plant and Fish Screen, there is a bench about 10 to 20 feet (3 to 6 meters) between the levee slope and the river bank. Vegetation along the river side of the levee is patchy. There are portions of the levee that support a mature overstory of valley oak (Quercus lobata), walnut (Juglans hindsii), Box elder (Acer negundo, var. californica), Oregon ash (Fraxinus latifolia), willow (Salix spp.), Freemont's cottonwood (Populus fremontii, spp. fremonti), and California sycamore (Plantanus racemosa), often with dense shrubby underbrush of Himalaya berry (Rubus discolor), wild grape (Vitis californica), poison oak (Toxicodendron diversilobum), California wild grape (Vitis californicus), button willow (Cephalanthus occidentalis), California wild rose (Rosa californica), and occasional clumps of elderberry (Sambucus mexicana) (see for example, the aerial photographs for the Boyers Bend and Howells Landing pumping plants, Figures 12and 13, respectively). As Figure 13illustrates, there is often an abrupt transition between vegetated and unvegetated sections of levee. The project Action Area on the western side of the Sacramento River Levee consists of the area immediately adjacent to the existing Boyers Bend, Howells Landing, and Tyndall Mound intake facilities and the Combined Pumping Plant and Fish Screen site about a mile south of Boyers Bend. In this reach, the levee supports no mature riparian forest. On the river side of the levee, vegetation along the bench at the base of the levee is a dense mix of Himalaya berry, poison oak, willow saplings, and wild grape. Vegetation upslope of the bench and along the land-side of the levees consists of non-native grasses with patches of weedy shrubs. Common plant species in these disturbed habitats include: slender wild oats (Avena Fatua), curly dock (Rumex crispus), perennial rye-grass (Lolium multiflorum), rip-gut brome (Bromus diantrus), and soft chess (Bromus hordeaceus). In addition to existing concrete-lined canals RD 108 canals, there is generally an unpaved levee maintenance road at between the canal and active agriculture (Figure 15). In a few areas near the existing canals, the levee maintenance road may be separated from the canal by a band of weedy non-native grassland, and there may be another maintenance road between the canal and adjacent farmland. In general, shrubs and trees on the landside of the levees are confined to areas around housing and farm facilities. Land at the landside base of the levees is often mowed and there are patches of bare ground. It is probable that the transition zone between the levees and adjacent agricultural fields provides a movement corridor for wildlife, particularly given that there are patches of good quality riparian forest along the riverside of the levees. It is not uncommon for wildlife to utilize such corridors, and species likely to be found moving (and foraging) in the vicinity of the levees include raccoons, coyotes, skunks, opossum, red fox, grey fox, mule deer, black-tailed hares, California ground squirrels, gopher snakes, and other species that are somewhat adapted to living in proximity to human activity. 3.4.2.3 Inland Areas (Canal Construction Zone and Borrow Sites) Land use on the inland side of the levees is agricultural. There are no urban areas within the general project area, the nearest small towns on the west side of the river being Dunnigan (7 miles west of Tyndall Mound), Grimes (8 miles north of Boyers Bend), and Arbuckle (about 10 miles west of Boyers Bend). Most of the farms in the area are relatively large, and there are therefore only a few housing/farm complexes per square mile in the project area. Farms are separated by small unlined irrigation canals and unpaved field access roads (Figure 16). These canals are wetted during irrigation and generally dry following the irrigation season. There are only two isolated rice fields adjacent to the alignment of the canals to be constructed. The project area does not include sites with permanent crops such as nuts, fruits, or vineyards. Field crops in the action area include corn, cotton, hay (alfalfa, oat, and Sudangrass), safflower, wheat, and others including tomatoes and beets. Rice is generally not grown in the area west of Highway 45 because sandy soils drain rapidly and maintaining a crop requires high water use. Some rice has been grown near the levees, in small patches, imbedded in the matrix of other field crops. From year to year, field crops at any given site may vary (Yolo County Agricultural Commissioner 2004). For example, from 2002 to 2003, Yolo County acreage in corn varied by 29%, acreage in wheat varied by 40%. Other crops showed smaller variation, and total acreage farmed within Yolo County varied by 6%. Among other factors, these variations reflect year-to-year changes in crop economics, routine cropping variation to maintain soil quality, and hydrologic conditions. Soils in the area between Highway 45 and the Sacramento River are sandy alluvium, and drain rapidly. RD108 lines its main irrigation canals with concrete to reduce losses during conveyance. Water is then delivered to farmers via turnouts from the lined canals to generally unlined irrigation canals. When not in use for irrigation, any water in these unlined canals percolates rapidly into the ground. Permanent vegetated wetland conditions do not exist in either the main (lined) irrigation canals or the secondary (on-farm) irrigation canals. Agricultural drainage is collected in unlined canals and conveyed to the Main Drain, which runs from northwest to southeast to the west of the project Action Area. 
Figure 15. Photograph showing landside of the Sacramento River Levee at the site of the proposed combined pumping plant/fish screen, illustrating the disturbed nature of the levee, levee maintenance road, and adjacent farm field. 
Figure 16. Aerial photograph of the land adjacent to the Tyndall Mound Pumping Plant. Note the system of local canals and unpaved access roads (Source: USGS 22 August 1998). In the project reach, the Main Drain is a sandy-bottomed steep-sided canal about 75 to 100 feet (23 to 30 meters) wide. In this reach, the Main Drain collects agricultural drainage during the day, and it is then pumped out of the basin (over the levees) to the Sacramento River during the night (off peak hours for energy use). As a result, water levels in the Main Drain fluctuate by 2-to-3 feet (0.6 to 0.9 meters) over a 24-hour period, exposing the side slopes to drying. As a result, stands of emergent vegetation such as tules do not become established. There may at times be patches of submerged aquatic vegetation in this canal, but routine maintenance dredging eliminates the potential for permanent wetlands in this facility. Wildlife use of the inland areas is probably incidental for a number of reasons. First, wildlife movement from the foothills to the west is constrained by Interstate 5 and the Colusa Basin Drainage Canal, and from the east by the Sacramento River. In a 10-mile area west of the project Action Area, there are only four road crossings of the Colusa Basin Drainage Canal: grimes-Tule Road, White Road, Subaco Road, and Road E11. Within the Action Area, farmers optimize land use and farm to the edge of canal banks and unpaved access roads, limiting the availability of suitable habitat for many species. There is suitable wildlife habitat about 15 to 20 miles north of the Action Area at the Colusa National Wildlife Refuge, and some north-south movement of wildlife is possible. Lack of suitable wildlife habitat in the 15 miles between the Refuge and the Action Area would limit wildlife movement into the Action Area. The borrow site to the west of the fish screen site and along Highway 45 is currently in field crops. The borrow site along the main drain is a mound of earth created by annual spoil disposal from maintenance activities along the main drain. It is periodically dry-farmed. When not farmed, it is disked and treated with herbicides to control weedy vegetation. 3.4.2.4 Other Projects Other projects in the immediate vicinity of the Proposed Project that have affected baseline conditions include construction and operation of the positive barrier fish screen at the RD 108 Wilkins Slough and a proposed Positive Barrier Fish Screen on the east side of the Sacramento River just south of the Tisdale Bypass. Both of these projects have been designed to operate in accordance with CDFG and NOAA Fisheries intake screen design criteria. The Wilkins Slough fish screen represented an environmental enhancement of baseline conditions as a direct result of the reduction in entrainment mortality that previously occurred at the unscreened diversion site prior to construction and operation of the positive barrier fish screen. In addition, additional parking and a boat launch ramp is proposed north of the Tisdale Weir to enhance recreational access and opportunities for fishing and boating on the Sacramento River about 3 miles north of Boyers Bend. |