This report summarizes the results of an initial study of historical conditions (i.e., prior to significant Euro- American modification) on the lower Salinas River (downstream of Arroyo Seco). The Salinas River was a dynamic and complex system with a broad array of habitat types. Our research suggests that there may be significant potential for increasing the ecological services of the Salinas River through restoration of historical patterns among habitat types.
This reconnaissance indicates that the river corridor consisted of a sandy active channel with little vegetation, bordered in many places by extensive stands of riparian thicket and forest. Above the riparian corridor, multiple terraces (i.e., abandoned floodplains) of different elevation and extent corresponded to different inundation frequencies and had different plant communities. The wooded riparian areas adjacent to the river were commonly thousands of feet wide, and in some places as much as a mile wide. These riparian forests have been mostly developed into agricultural areas, and are little represented today. Hydrophilic tree species such as willows and cottonwoods were more common than oaks and sycamores; perennial pools and quicksand were well-documented. Freshwater marshes and ponds commonly occupied abandoned channels adjacent to the active mainstem channel.
Historical information about dry season flow presents a complex picture of inter-annual variability and reach-scale variation. But descriptions of summertime flow correspond with riparian vegetation characteristics and aquatic habitats to suggest significant year-round aquatic resources. Preliminary evidence suggests that the Salinas maintained substantial summer baseflow in many reaches, though this would have varied greatly with inter-annual variations in rainfall. We found little early evidence that the Salinas River completely or consistently dried out in the summer, although flow was restricted such that much of the active channel was an exposed sand surface. The Salinas River appears to have had summertime pools of water fed by hyporheic flow.
This reconnaissance suggests that substantial data are available for the Salinas River, and that these data may assist in the development of a better understanding of historical characteristics and function of the river. Potential opportunities to advance this research are described at the end of the report.
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This Project was completed in August 2009.
Programs and Focus Areas:
Resilient Landscapes Program