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3.4.7 Environmental Consequences: Non-salmonid fish species The adult life-stages of non-salmonid species are, given their evolutionary history in the Sacramento-San Joaquin River system, relatively tolerant of a wide range of flow, temperature, and turbidity conditions. Their spawning migrations generally occur in spring and summer, when turbidities from runoff would have been high and they are adapted to conditions in freshwater and estuaries. Sacramento splittail spawn in the winter when vegetated habitat on the flat grassy benches along the river bank is flooded during periods of high flow and turbidity. The juveniles of the non-salmonid species all spend considerable time in the freshwater system, and have also thus adapted to variable conditions. With the exception of the Pacific lamprey, these species are unlikely to spawn in or adjacent to the Action Area's levees. Larvae and juveniles of all non-salmonid species are likely to be in the substrate or water column for a most of the year, and eggs of Sacramento splittail may adhere to submerged vegetation associated with riprap. 3.4.7.1 Effects of Combined Pumping Plant/Fish Screen Construction Again, only construction and operation of facilities associated with the Combined Pumping Plant and Fish Screen have potential to affect non-salmonid fish species. Other aspects of the project are isolated from the riverine environment. During cofferdam construction, it is likely that eggs, larvae, and adults of non-salmonid fish species (except Sacramento splittail which generally do not initiate spawning runs until high flows occur) may be adversely affected. These effects will occur as a result of an initial stranding behind cofferdams and subsequent injury or death during fish rescue operations. Stranding may also occur following cofferdam construction, if flows are high and the cofferdams are overtopped. The frequency of such effects is unpredictable. There will also be turbidity and visual disturbance associated with cofferdam removal. Pacific lamprey may spawn and rear in the Action Area, although the spawning substrate in this reach may tend more towards silt and mud than the sand-gravel preferred by this species. Ammocoetes of both Pacific lamprey and river lamprey are likely in the Action Area, and this larval form is likely to be entrained during construction of the cofferdam and any subsequent overtopping during high flows. Eggs, larvae, juveniles, and adults will be subject to increased levels of suspended sediments during construction. Given the generally higher tolerance for turbidity exhibited by non-salmonids, the low levels of turbidity generated by the project are not likely to lead to adverse effects on any life history stage. 3.4.7.2 Effects of Decommissioning Existing Diversions Pilings at the three decommissioned pumping plants will be removed by cutting the off below grade and then lifting the remaining pilings from the water with a crane. This operation will involve divers using conventional cutting tools to cut off pilings at about 2 feet (0.6 meters) below the channel bottom and lifting of pilings out of the river. This operation, which may take as many as 5 days per site, would result in disturbance of the sandy/silty bottom and in a small plume of suspended sediments and turbidity every time a piling is removed. This will create a localized and short-term increase in suspended sediment and turbidity levels, but (as noted above) these levels will decline rapidly and will be limited to a small portion of the river channel. 3.4.7.3 Effects of Operating Screens and Diversions Operation of the project will not change effects on eggs and larvae compared to be baseline condition. Eggs and larvae in the water column will continue to be entrained, although approach velocities to the screen may be somewhat reduced from the approach velocities of the current facility. Based on general industry experience, reductions in entrainment of juvenile life history stages at the project site may be up to 99% when compared to those associated with operation of the unscreened diversion (Mathew et al. 2004). Although it is likely that there will be eggs and larvae of some species in the vicinity of the Combined Pumping Plant and Fish Screen, screen operation will reduce the entrainment (and subsequent death) of larval stages, juveniles (all non-salmonid species), and adults (except for green sturgeon, which is unlikely to be entrained by the existing facilities). Specifically:
Because it is not possible to determine the numbers of eggs, larvae, and juveniles in the vicinity of the Combined Pumping Plant and Fish Screen, it is not possible to quantify the number of each species juveniles that will be entrained or indirectly affected by screen operation. Based on Nobriga et al. (2004), it is likely that such entrainment will be reduced by up to 99% when compared to baseline conditions. The potential for juveniles to come in contact with the screen face and be injured somewhat offsets this otherwise beneficial effect. 3.4.8 Environmental Consequences: Swainson’s Hawk Swainson's hawks are sensitive to noise and visual disturbance during nesting and they are known to forage in agricultural fields. The potential for the project to affect nesting and foraging is a function of construction of the Combined Pumping Plant and Fish Screen, construction of inland facilities (canals and associated facilities such as the afterbay), and construction traffic on levee roads. 3.4.8.1 Effects of Combined Pumping Plant/ Fish Screen Construction One Swainson's hawk nesting site was found about 900 meters north of the Combined Pumping Plant/Fish Screen in May of 2001. It was abandoned by the June of 2001 surveys. There is potentially suitable riparian habitat for nesting about 300 meters north of the site on the river side of the west levee. Construction noise and visible construction activity could disturb Swainson's hawks if construction occurred during the nesting season, which is typically late March/early April through early August. If there is an active Swainson's hawk nest within the riparian corridor, human activities, especially early in the nesting cycle, could result in disturbance to the breeding pair and/or nest abandonment. Based on general distribution criteria established by CDFG, such construction activities could potentially disrupt or disturb Swainson's hawk nesting activity if the nest was within a distance of approximately 0.5 miles of the Action Area. There is ample evidence of raptor nesting on the west side of the river. If the riparian habitat north of the site supports an active Swainson's hawks nest during the proposed construction period, then there is potential for nests to be disturbed and to fail as a result of noise and other activity. In consultation with CDFG, a conservation measure has been identified and incorporated as part of the Proposed Project. Implementation of this measure described in Section 4.1.2 will avoid and minimize potential project effects on Swainson's hawks. 3.4.8.2 Effects of Construction Canal Construction and Construction Traffic Potential Swainson's hawk nesting habitat, and confirmed nests, have been identified along the levee from Millers Landing to Poker Bend. Two of these sites are well within 0.5 miles of Highway 45. Nesting at the Millers Landing site was confirmed in both May and June 2001 surveys. There are patches of potentially suitable nesting habitat along the levees at Millers Landing/Boyers Bend, north of the Combined Pumping Plant/Fish Screen site, near Poffenberger's Landing, near Howells Landing, and at Poker Bend. Traffic volume on Highway 45, which will be the main artery for movement of construction materials, is extremely light. In 2003, peak use at Subaco Road, just north of the project area, was 70 vehicles/hour (Caltrans 2003). Truck traffic makes up a significant proportion of this traffic. North of the project area, at the nearest truck traffic site for which data are available (Highway 45 at Grimes-Arbuckle Road), truck traffic constitutes from about 13 to 25 percent of total traffic. Construction traffic west of and along Highway 45 is unlikely to increase ambient noise or visual disturbance at nesting sites, and raptors often nest and successfully fledge young adjacent to major roadways; it is only when occupants leave their vehicles that there is likely to be disturbance to nesting raptors. As a worst case, peak construction traffic would generate about 60-70 truck trips per day, thus adding about 8 vehicles per hour to the local traffic flow, increasing peak traffic from 70 vehicles per hour to 78 vehicles per hour. This traffic alone is unlikely to cause a significant change in ambient noise and visual disturbance levels for nesting birds, given (a) that Highway 45 is from about 660 feet (200 meters) to about 2 miles from the levees in the project reach and (b) that construction personnel will not leave their vehicles during use of Highway 45. With the exception of the Millers Landing site, nesting sites are also on the river side of the levees and thus protected from distant road noise. The Millers Landing nest, which is about 200 feet (60 meters) from Highway 45, was not in use for nesting during 2001 surveys, but two adult hawks were observed perching and flying in its vicinity. Construction traffic has potential to disturb nesting sites when traffic leaves Highway 45 and enters the construction zone at the base of the levees. Here, construction traffic will come within about 300 feet (91 meters) of the nesting site at Millers Landing, and within 150 feet (45 meters) of nesting sites on the Sacramento River. Construction equipment would also be on site along the entire canal alignment. Except at the Millers Landing site, all known nests and suitable habitat are screened from construction disturbance by the levee. The canal and the construction equipment would be at the base of the levee and not in line of sight of nests. It should be noted that agricultural activities, including grading and plowing fields, occur up to the base of the levees during nesting season, and these activities can generate noise and dust and other visual disturbance. Adverse effects to nests on the river side of the levee from canal construction and construction traffic are not anticipated. Nevertheless, there is some potential for nest disturbance during canal construction. This would be limited to reaches of the canal within 0.5 miles of an active nest. In consultation with CDFG, a conservation measure has been identified and incorporated as part of the Proposed Project. Implementation of this measure described in Section 2 will avoid and minimize potential project effects on Swainson's hawks as a result of construction traffic. 3.4.8.3 Effects of Demobilization of Existing Diversions Demobilization of pumping facilities at Boyers Bend, Howells Landing, and Tyndall Mound can be scheduled for the post-nesting season, and no adverse effects on Swainson's hawk are anticipated. 3.4.8.4 Effects of Operating Screens, Diversions, and Canals There is no mechanism for direct effects from screen operation, inspection, or maintenance to affect nesting hawks. No individuals or habitat would be affected by operations. Operation and maintenance of the Combined Pumping Plant/Fish Screen would not result noise or vibration that would be expected to affect nesting Swainson’s hawks. Vehicle traffic and access to the fish screen would be comparable to the existing baseline operating and maintenance conditions occurring at the three existing diversions. It is anticipated that operation of the Proposed Project as a whole would not affect cropping patterns or land use within the service area when compared to baseline conditions because the new facilities would not result in an increase in water diversions or water availability within the service area. Agricultural practices and cropping patterns within the area affecting habitat and foraging opportunities are expected to be similar with and without the Proposed Project. Maintenance and repair of canal facilities may, at times, occur in the vicinity of Swainson's hawk nests. In general, maintenance activities will not involve re-construction or use of heavy construction equipment. Rather, routine maintenance will involve levels of activity less disturbing than routine agricultural operations that will continue throughout the project area. It is not likely that intermittent routine maintenance will create a level of noise or visual disturbance at any nesting site that would affect nesting success. In the event that a section of canal must be replaced or repaired using heavy equipment, and this action occurs within 0.5 miles of an active nest, RD108 would implement the Swainson's hawk conservation measures to ensure that no effects on nesting hawks occur. Also, small segments of canal would in general be repaired during the pre-nesting or post-nesting season, when irrigation demand is low. 3.4.9 Environmental Consequences: Giant Garter Snake Project elements that may affect giant garter snakes are borrow site operations and construction traffic. Giant garter snakes are highly unlikely to utilize the mainstem Sacramento River or to be found in or adjacent to existing canals or along new canal alignments along the dry base of the river levee. Operation of the fish screen and other facilities will not affect the species. 3.4.9.1 Effects of Combined Pumping Plant/Fish Screen Construction No suitable habitat exists for giant garter snakes west of Highway 45. Only two small rice fields occur between the levee and Highway 45, and these are isolated within a matrix of row crops such as wheat and alfalfa. There is no permanent aquatic habitat in the well-drained irrigation canals. Construction at the Combined Pumping Plant/Fish Screen site itself is not anticipated to affect giant garter snakes. 3.4.9.2 Effects of Borrow Site Use and Construction Traffic Since 1976, there are only three records of giant garter snakes between the Main Drain and the Sacramento River Levee (single-snake sightings) (CNDDB 2004). There is no permanent habitat in the irrigation canal system, and there is no record of connectivity between the areas which will be affected by construction and known populations of giant garter snakes. Construction traffic is thus unlikely to adversely affect giant garter snakes, but individual snakes incidentally using irrigation canals could be injured or killed on area roadways located adjacent to vegetated ditches by construction personnel traveling to and from the project site. Borrow Site 2 along the Main Drain may provide a corridor for incidental giant garter snake movement, but this is not likely because (a) routine maintenance disturbs the aquatic habitat, (b) daily pumping regimes cause fluctuating water levels and have virtually eliminated emergent vegetation types such as tules from the banks, and (c) there is no adjacent estivation habitat because crops are planted to the edge of the levee, which is itself annually maintained as an unpaved access road. In addition, in the vicinity of the Main Drain Borrow Site, crops are dominantly row crops, not rice. There remains, however, some possibility that giant garter snakes may utilize the Main Drain in the vicinity of the Main Drain Borrow Site. The buried power line to the new Combined Pumping Plant/Fish Screen will cross an active agricultural field. During plowing and seeding, this field would not provide adequate cover for giant garter snakes and during the growing season, dense cover would preclude basking. The site thus would not provide habitat for giant garter snakes. The Proposed Project incorporates rigorous conservation measures for avoidance and minimization of adverse effects to giant garter snakes. The implementation of these conservation measures listed in Section 4.1.2 will further reduce the already minimal potential for construction traffic and canal construction to have adverse effects on this species. 3.4.9.3 Effects of Decommissioning Existing Diversions There is no giant garter snake habitat in the vicinity of the three diversion structures/pumping plants at Boyers Bend, Howells Landing, and Tyndall Mound. Decommissioning of these facilities is not anticipated to affect this species. 3.4.9.4 Effects of Operating Screens, Diversions, and Canals Proposed Project operations would have no effects on giant garter snakes, because there is no suitable habitat for the species associated with the facilities and no mechanism by which take could occur. 3.4.10 Environmental Consequences: Valley Elderberry Longhorn Beetle 3.4.10.1 Effects of Combined Pumping Plant/Fish Screen Construction There are no elderberry shrubs within 300 yards of the Combined Pumping Plant/Fish Screen site; therefore, construction activity at the site will not affect valley elderberry longhorn beetle. 3.4.10.2 Effects of Canal Construction and Construction Traffic At least 10 elderberry shrubs suitable for the valley elderberry longhorn beetle are located within the riparian corridor along the Sacramento River from north of Boyers Bend Pumping Plant to south of Tyndall Mound Pumping Plant. Elderberries are located within 100 feet of construction traffic and canal construction activity at only one site, Howells Landing, where they occur within 100 feet (30 meters) of the road leading to the existing pumping plant and in and around buildings to the west of the pumping plant and east/south of the existing canal. Canal construction (removal of the old canal sections and re-construction of canal) would occur on the opposite side of the levee from these bushes. No elderberries or adjacent riparian vegetation would be affected by the project. Although a dust control program will be implemented throughout construction, some temporary increase in dust may occur in the vicinity of canal construction areas, and elderberry shrubs may accumulate some dust on their leaves. Dust accumulation is a common occurrence in this area where farm machinery routines operates without dust controls. The low levels of dust generates during 7-14 days of construction near elderberry shrubs are not anticipated to cause damage to the shrubs. 3.4.10.3 Effects of Decommissioning Decommissioning of facilities at Howells Landing would involve use of the existing unpaved road leading to the existing in-channel diversion structure. There is a valley elderberry shrub that at dripline is within 20 feet (6 meters) of this road. This existing shrub, on the river side of the levee, is not presently affected by maintenance traffic use of the facility. Decommissioning of the existing intake and pumping facility will involve activities within the existing road alignment, including driving trucks to and from the site to collect materials from the decommissioned facility and use of a crane to remove pilings. None of the adjacent riparian vegetation, including elderberries, lie within the zone of potential construction effects. Decommissioning of the existing facilities will not affect elderberries or valley elderberry longhorn beetle. 3.4.10.4 Effects of Operating Screens, Diversions, and Canals Operation and maintenance of the proposed fish screen and diversions from the Sacramento River would not affect valley elderberry longhorn beetles, as there is no habitat at the Combined Pumping Plant/Fish Screen facility or along the concrete-lined canal system. 3.4.11 Northwestern Pond Turtle 3.4.11.1 Effects of Combined Pumping Plant/Fish Screen Construction There is no suitable habitat for northwestern pond turtle at or adjacent to the Combined Pumping Plant site. There is no permanent habitat in the concrete-lined canal system or in the well-drained local irrigation canals. Construction at the Combined Pumping Plant/Fish Screen site itself is not anticipated to affect northwestern pond turtle. 3.4.11.2 Effects of Construction Traffic and Canal Construction Within the construction area, traffic is unlikely to affect northwestern pond turtles because there is no suitable habitat in the highly disturbed Action Area, except along the Main Drain where northwestern pond turtles have been found. The conservation measures on Table 2-2 are intended to reduce potential for adverse impacts to this species. 3.4.11.3 Effects of Decommissioning Existing Diversions There is no suitable habitat for northwestern pond turtle in the vicinity of the three existing pumping plants; therefore, their decommissioning and the removal of materials from these sites will not adversely affect northwestern pond turtle. 3.4.11.4 Operating Screens, Diversions, and Canals There is no suitable habitat for northwestern pond turtle in the vicinity of project screens, diversions, and canals, and routine operation and maintenance is not expected to affect this species. 3.4.12 Environmental Consequences: Loss of Non-Native Grassland/Shrub Habitats 3.4.12.1 Affected Environment The majority of 4.4 acres of upland habitat at the site of the Combined Pumping Plant/Fish Screen is covered with disturbed non-native grasslands. The suite of animals which may utilize this habitat consists of common small mammals and herpetofauna which are adapted to disturbed conditions. No evidence of occupation of special-status species was observed during 2001 or 2005 surveys. Most of the permanent right-of-way for canal construction at the base of the western-facing slope of the Sacramento River levee, along Highway 45, and connecting the Highway 45 segments to the levee segments, consists of agricultural lands and the existing disturbed canal alignment/levee maintenance road. The permanent canal right-of-way of 40 to 60 feet extends from the levee maintenance road west into adjacent agricultural fields. The expanded construction right-of-way will also extend into agricultural fields. There are patches of non-native grass and weedy species such as mustard in this right-of-way, but where there is no canal or levee maintenance road, farming extends to the base of the levee. 3.4.12.2 Environmental Consequences The proposed project at the site of the Combined Pumping Plant and Fish Screen would result in temporary loss of 4.4 acres of non-native grasslands habitat that probably serves as a movement corridor and foraging habitat between the various patches of riparian vegetation along the west levee of the Sacramento River. Of this temporary loss, only about an acre will be permanent, as following construction the levee will be replanted and cover will be restored. The extent of non-native grassland habitat in the canal alignments is variable, depending on farming activity in any given year, but probably does not exceed 2-3 acres and is generally along the margin of fields or in thin strips between the existing canal and maintenance/access roads. Some of this ruderal weedy habitat will be permanently converted to canal and maintenance road. Following construction, the 40-60 foot expanded canal right-of-way will be characterized by an 8-10 foot maintenance road along the levee, the 20-25 foot canal and its embankments, and an 8-10 foot maintenance/access road facing adjacent agriculture. This area will be routinely maintained and re-establishment of non-native grasslands will not be likely. As a result of canal construction, then, there will be a permanent loss of up to 3 acres of non-native grassland along the 5-mile canal right-of way. Where new canal structures are to be constructed, the proposed project will involve leveed canal sections placed about 10-20 feet from the base of the west side of the Sacramento River levees and this will allow development of ruderal vegetation away from the levee base. As a result, the net loss of movement corridor will be substantially less than 3 acres. The proposed borrow sites are spoil disposal sites and are routinely disturbed areas in a matrix of agricultural fields. Growers routinely plant non-irrigated crops such as oats and winter wheat on the spoil sites and the main borrow along the Main Drain is alternatively planted, maintained free of vegetation, and/or used for disposal of new spoil from canal dredging. When borrow operations are completed, the two borrow sites will be actively farmed. No temporary or permanent habitat loss is anticipated as a result of borrow operations. Decommissioning of the three diversions at Boyers Bend, Howells Landing, and Tyndall Mound will not affect terrestrial habitats. All work will be done within the existing facility boundaries. All operations will take place within the permanent rights-of-way for the project. If major repairs are needed for the canal facilities, temporary construction rights of way will be on adjacent agricultural fields. No habitat loss is anticipated as a result of on-going operations. |