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Given these designated characteristics, the primary components of EFH present at the project site are migration pathways. The existing condition of the habitat in the area is disturbed in terms of flow modifications, channel modification (channelization, high scour, and riprap), lack of vegetative cover, and the likely increased predation resulting from habitat modifications. Flow modifications are primarily the result of upstream impoundments, which have reduced flows in winter and spring, when natural precipitation and snow melt would otherwise result in higher flow, and increased flows in summer and fall, which are generally dry periods in California's Central Valley. Smolt migration pathways are affected by the existing water diversion, as well as by diversions upstream and downstream from the project site. 3.4.4.6 Steelhead (Oncorhynchus mykiss) (FT) Central Valley steelhead, like Chinook salmon, are anadromous. Adult steelhead spawn in freshwater and the juveniles migrate to the Pacific Ocean and where they reside for a period of years before returning to the river system to spawn. Steelhead that do not migrate to the ocean, but spend their entire life in freshwater, are known as resident rainbow trout. Adult steelhead migrate upstream during the fall and winter (September through approximately February) with steelhead migration into the upper Sacramento River typically occurring during the fall and adults migrating into lower tributaries typically during the late fall and winter. Steelhead spawn in areas characterized by clean spawning gravels, cold-water temperatures, and moderately high velocity. Spawning typically occurs during the winter and spring (December -- April) with the majority of spawning activity occurring between January and March. Unlike Chinook salmon that die after spawning, adult steelhead may migrate downstream after spawning and return to spawn in subsequent years. Steelhead spawn by creating a depression in the spawning gravels where eggs are deposited and fertilized (redd). The eggs incubate within the redd for a variable period of time, which is dependent upon the water temperature. After hatching, the young steelhead emerge from the gravel redd as fry. Young steelhead rear within the stream system, foraging on insects, for 1-2 or more years before migrating to the ocean. After rearing within the stream the juvenile steelhead undergo a physiological transformation (smolting) that allows the juvenile steelhead to migrate from the freshwater rearing areas downstream to coastal marine waters. Downstream migration of steelhead smolts typically occurs during the late winter and early spring (January - May). The seasonal timing of downstream migration of steelhead smolts may vary in response to a variety of environmental and physiological factors including changes in water temperature, and changes in stream flow and increased turbidity, resulting from stormwater runoff. Juvenile steelhead rear within the coastal marine waters for approximately 2-3 years before returning to their natal stream as spawning adults. The steelhead life cycle is characterized by a high degree of flexibility (plasticity) in the duration of both their freshwater and marine rearing phases. The steelhead life cycle is adapted to respond to environmental variability in stream hydrology and other environmental conditions. Central Valley steelhead historically migrated upstream into the high gradient upper reaches of Central Valley streams and rivers for spawning and juvenile rearing. Construction of dams and impoundments on the majority of Central Valley rivers has created impassable barriers to upstream migration and substantially reduced the geographic distribution of steelhead. Changes in habitat quality for juvenile rearing, exposure to contaminants, predation mortality, passage barriers and impediments to migration, changes in land use practices, and competition and interactions with hatchery-produced steelhead have all been identified as factors affecting steelhead abundance. Factors affecting steelhead abundance are similar to those described for winter-run and spring-run Chinook salmon. One of the primary factors that have affected population abundance of steelhead has been the loss of access to historic spawning and juvenile rearing habitat within the upper reaches of the Sacramento River and its tributaries and San Joaquin River as a result of the migration barriers caused by construction of major dams and reservoirs. Water temperatures within the rivers and creeks, particularly during summer and early fall months, have also been identified as a factor affecting growth and survival of juvenile steelhead. In recent years a number of changes have been made in the local area to improve the survival and habitat conditions for steelhead. Several nearby large previously unscreened water diversions have been equipped with positive barrier fish screens. Improvements to fish passage facilities have also been made to improve migration and access to spawning and juvenile rearing habitat. Although quantitative estimates of the number of adult steelhead returning to Central Valley streams to spawn and are not available, anecdotal information and observations indicate that population abundance is low. Steelhead distribution is currently restricted to the mainstem Sacramento River downstream of Keswick Dam, the Feather River downstream of Oroville Dam, the American River downstream of Nimbus Dam, the Mokelumne River downstream of Comanche Dam, and a number of smaller tributaries to the Sacramento River system, Delta, and San Francisco Bay. The Central Valley steelhead population is composed of both naturally spawning steelhead and steelhead produced in hatcheries. NOAA Fisheries is continuing to evaluate the status of steelhead and to develop a recovery plan for the species. Central Valley steelhead have been listed as a threatened species under the Federal ESA and the Sacramento River has been proposed as critical habitat. Steelhead are not listed for protection under the California ESA but are identified as a species of concern. The MSCS Central Valley steelhead ESU "R" goal is to "Achieve recovery objectives under development for the Central Valley steelhead ESU”. Adult and juvenile steelhead primarily migrate upstream and downstream within the mainstem Sacramento River in the vicinity of the Proposed Project. Juvenile steelhead migrate from the Sacramento River through the Delta and San Francisco Bay during their downstream migration during the winter and early spring migration period (e.g., January-March). Adult steelhead upstream migration in the Action Area primarily occurs during winter and early spring (e.g., December - March). The area of the Sacramento River adjacent to the three existing diversions and the proposed Combined Pumping Plant/Fish Screen serves as a migration corridor for upstream and downstream migration by steelhead. Steelhead do not spawn within the Sacramento River in the proposed Action Area. 3.4.4.7 Non-salmonid Sacramento River Fish Species The non-salmonid fish species addressed in this EA/Initial Study are green sturgeon, river lamprey, Pacific lamprey, hardhead, California roach, and Sacramento splittail. These fish migrate through and rear in the mainstem river system. They may spend a portion of their life history in the mainstem river reach from the Delta to Redding, as well as in major tributaries. Although these fish may have different life-history strategies, adults, juveniles, and larvae utilize the mainstem river in the Action Area for rearing and foraging, as outlined below. The green sturgeon is a large bottom dwelling anadromous fish, widely distributed along the Pacific coast of North America. They are slow growing and late maturing, spawning every 4 to 11 years during the spring and summer months. Adult fish spawn in fresh water and then return to estuarine or marine environments. Preferred spawning habitat is the lower reaches of large rivers with swift currents and large cobble. Adults broadcast spawn into the water column and eggs sink and attach to the rock substrate. Larval and juvenile stage green sturgeon may rear for up to 2 years in freshwater and then migrate to an estuarine environment. In the reach of the Action Area, green sturgeon may spawn both upstream and downstream. Larvae may attach to rip rap, but are not likely to attach to the sandy-silty river bottom adjacent to the Action Area itself. It is probable that green sturgeon larvae or juveniles will be in the water column throughout the year. Sacramento splittail is a large cyprinid (length more than 12 inches) unique to the Sacramento/San Joaquin basin. The species is relatively long-lived (5-7 years), highly fertile (100,000 eggs), and matures at the end of the first year (males) or third year (females). As is typical of a fish evolved in a highly variable riverine system, populations fluctuate annually, depending on spawning success. They are found mostly in slow moving sections of mainstem rivers and sloughs, and have been abundant in Suisun Bay and Marsh. Adults migrate upstream to spawn in conjunction with high flows that inundate their side-channel and off-channel spawning habitat – vegetation temporarily submerged by flooding of riparian and upland habitats. Eggs attach to vegetation. Larvae remain in shallow weedy areas nearshore and move to deeper water habitats as they mature. In the reach of the river near the Action Area, there is virtually no suitable spawning or rearing habitat, although spawning is likely to occur upstream along the Tisdale Bypass and downstream in the Yolo Bypass. It is likely that juvenile splittail will be in the water column of the mainstem river adjacent to the Action Area. River lamprey are an anadromous species widely distributed along the Pacific coast from Northern California to Alaska. They have been captured throughout the mainstem Sacramento River and the downstream Delta. They migrate through the mainstem rivers to spawn in small streams in April and May. Larvae (ammocoetes) burrow into sandy and silty substrates, near the river bank, where they spend several years maturing. They may spend additional time in fresh and brackish water prior to migrating to the ocean. It is likely that river lamprey utilize the project area primarily as a migratory corridor, as there is no spawning habitat and very little potential rearing habitat along the unvegetated substrate and riverbank. They are probably in the water column during their later rearing and emigration stages. Hardhead are freshwater residents of the Central Valley river-stream system. Little is known about their life history. They appear to spawn in May through August, and based on observed larval distribution, they may prefer areas with sand, gravel, and decomposed granite substrate. They spawn in mainstem rivers and tributaries. Adults may be found near the surface of pools and side pools of creeks and rivers, as well as near inshore weedy areas of reservoirs and lakes. There is some potential for spawning of hardhead in the Action Area, although the bottom substrate may be too silty under most flow regimes. There is little rearing and adult habitat, as the Action Area lacks submerged and emergent vegetation. California roach is a short-lived (1-3 year) native freshwater minnow, found throughout the Sacramento/San Joaquin River system and in non-tidal freshwater tributaries to the Bay-Delta. The species spawns from March through June, congregating in small groups for spawning. Eggs are deposited in rock crevices, on coarse gravels, or on tules. Eggs hatch in about 5 days, and after egg sac absorption, juveniles move into shallow nearshore habitats along the stream. As they mature, they move into the main water column. In the Action Area, it is likely that some California roach juveniles and adults would be present, although use of the area for spawning and egg maturation is unlikely because gravels and tules are not present in large numbers and river velocities are relatively high. Pacific lamprey are an anadromous species well-distributed along the Pacific coast from Baja California to Japan. They occur in the mainstem Sacramento River and its major tributaries. Spawning occurs in nests constructed in shallow water on gravel and sandy substrates. Eggs are adhesive and are washed into crevices, where they adhere to rock. Adults die after (often multiple) spawning. Pacific lamprey ammocoetes rear within their rock crevices and then swim into the mainstream to be carried to muddy-sandy substrate, where they burrow and rear. In the Action Area, Pacific lamprey may spawn in the channel and their ammocoetes probably rear in the channel substrate. Juveniles may be found in the water column as hey migrate downstream to the ocean. As one characteristic of these non-salmonid species is a relatively long juvenile residence in the river system, these species are well-adapted to variation in flow, temperature, and turbidity. They evolved to fill a niche in the historic river/floodplain/marsh habitat of the Central Valley, characterized by repeated flood-drought cycles, highly variable flows (uncontrolled by dams), and thus cooler temperatures during snowmelt and potentially much warmer temperatures during the summer when river flows were not supplemented by reservoir releases. High flooding periods were accompanied by large plumes of turbidity from erosion in the mid-to-lower watershed areas. Current flow, temperature and turbidity regimes in the mainstem river are therefore probably more moderate (less variable) for these species than they were prior to 1850. This suite of species also evolved under conditions representative of most large river floodplains: (a) a meandering mainstem river with sand bars, natural levees, and large wetlands and marshes accessible from the mainstem river during periods of high flow, (b) high nutrient loads, and (c) few predators. Currently, the levee system that isolates the river from the floodplain has altered these conditions, and there is less variety of habitat in the river system that there was historically. There are river meander corridor restoration projects underway and being planned under the CALFED program, mostly upstream of the Action Area or in regional flood bypasses such as the Yolo Bypass and Sutter Bypass. These programs may help expand the habitat for the suite of non-salmonid species. In the Action Area, it is likely that the levees along the mainstem river will remain, and that conditions in the river channel will continue to be characterized by:
These existing conditions represent a high level of disturbance when compared to ideal conditions for these species, and the density of these species in this mainstem river habitat is likely to be relatively low, when compared to densities that probably existed historically. Given these conditions, the environmental baseline of the Action Area can be characterized as (a) generally lacking spawning habitat for all non-salmonid species addressed except for Pacific lamprey, which may be able to spawn in the rocks along the shoreline (though this is not the preferred gravel substrate) and (b) generally suitable for incidental rearing of non-salmonid species, with probable good rearing conditions for the two lamprey species which utilize sandy to silty substrate for the ammocete life stage. 3.4.4.8 Swainson’s Hawk (Buteo swainsoni) (CT) Swainson's hawks (Buteo swainsoni) are neo-tropical migrants that winter in Mexico and South America and return to California in March/early April to breed and rear young. Historically they inhabited open grasslands throughout most of lowland California. A variety of habitat changes, including the conversion of native grasslands to agricultural, urban, and industrial development have caused the Swainson's hawk population to decline by more than 90 percent from levels at the time of European settlement. Beginning in the late 1800's, levee construction and agricultural and urban development reduced the available nesting and foraging habitat for Swainson's hawks throughout the Central valley, including the project area. Swainson's hawks typically nest in large, mature trees such as valley oak, cottonwood, and black walnut typically located within the riparian areas along the Sacramento River, and they forage in open grasslands, agricultural fields, and pastures. Egg incubation and juvenile rearing occurs during the spring and summer before the juveniles fledge. Alfalfa, row crops, grain fields, and irrigated pastures are the Swainson's hawk's preferred foraging habitats, where they take advantage of the opportunities that harvesting and irrigating practices provide for the easy capture of small rodents. They do not typically forage in vineyards, orchards, or flooded rice fields. Swainson's hawk is listed as threatened under the California Endangered Species Act. Although the species is not Federally listed and there is no formal recovery plan, it is Federally protected under the Migratory Bird Treaty Act. Conservation efforts are focused on preserving existing nesting and foraging habitat and on revegetating levees to establish suitable nesting habitat. The MSCS "r" recovery goal for the species is to protect, enhance, and increase Swainson's hawk habitat sufficiently to support a viable breeding population, with an interim goal of 1,000 to 2,000 breeding pairs. Several potential nesting trees exist within 0.5 miles of Proposed Project activities associated with construction of the Combined Pumping Plant and Fish Screen and with the northern sections of new and re-constructed canals. Agricultural lands adjacent to the study area (grasslands and row crops) provide suitable foraging habitat for this species, as well as other raptors. Results of 2001 field surveys are shown on Table 3-4. Table 3-4. Data on Swainson's hawk nesting in the general study area (May and June 2001 Surveys, Miriam Green Associates 2001).
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