Sediment deposition in the flood plain of Stemple Creek Watershed, northern California
Introduction
Over the past 150 years, major changes have occurred in the land use patterns in the Stemple Creek Watershed in northern California. Riparian forests and marshes are believed to have been more widespread in the areas adjacent to the stream channel of the Stemple Creek Watershed. Much of these lower slopes and bottomlands were cleared and drained for agriculture in the 1860s. Erosion accelerated under these conditions and stream channels and bays filled with sediment, further reducing the area occupied by riparian forests and marshes (Harvey, 1990).
Stemple Creek is part of the coastal lands in the Bodega Bay–Tomales Bay area that has a long history of erosion and sedimentation problems. Geologically, the California coastal range is young and still uplifting. A coastal uplift rate of 0.07–0.08 cm year−1 has been calculated for the Point Reyes Peninsula, CA (K. Grove, Department of Geoscience, San Francisco University, personal communication, 2001). The hills are therefore prone to landslides, slumping, and erosion contributing to high naturally occurring erosion rates. In addition, historically the combination of row crop agriculture, cultivation, and year-round grazing on moderately erodible Steinbeck (Mollic Haploxeralfs), Sebastopol (Typic Haploxerults), and Tomales (Ultic Paleustalfs) soils has resulted in erosion on the watershed with subsequent sediment deposition in the flood plains, stream channels, and bays causing loss of open water. In the late 19th and early 20th century, Estero Americano, north of Estero de San Antonio, was a navigable waterway used to ship produce from the area. Today, the Estero is too shallow for large boats.
During the middle to late 1880s, the land was used for growing a wide variety of crops. In the early to mid-1900s, potatoes were grown extensively. Farming over the last 50 years has evolved to primarily dairy operations and grazing of sheep, beef cattle, and replacement dairy heifers. Grazing pressure has been reduced from historic high levels; but where animals are concentrated for extended periods or where soils are wet, livestock continue to cause erosion problems. This is more prominent in the upper flood plain reaches of the watershed. Restoration and conservation efforts are underway by landowners on the watershed. The Marin and Southern Sonoma County Resource Conservation Districts and landowners have completed 13 km of riparian restoration projects in the last 10 years along the waterways. The U.S. Department of Agriculture (USDA), National Resource Conservation Service (NRCS) approved 24 Environmental Quality Incentives Program (EQIP) contracts to improve conservation of the land within the watershed between 1997 and 2002.
This history of land use impacting erosion is superimposed on the geological controls of erosion and sedimentation. The Stemple Creek Watershed is a truncated watershed. Travis (1952) reported that the watershed of Stemple Creek formerly extended to Santa Rosa Mountain. As a larger stream, Stemple Creek was able to keep pace with tectonic uplift and incised a deep sinuous canyon in the coastal hills before discharging to the Pacific Ocean. Later tectonic uplift occurring inland truncated the drainage (Prunuske-Chatham, 1994). The present low gradient stream system (0.000415 m m−1) is conducive to deposition, confirmed by sediment in-filled stream channels in the upper watershed. As Stemple Creek flows coastward, the fjord-like qualities of steep and twisting uplands become the dominating character of the landscape.
Finney (2002) used the AGricultural NonPoint Source (AGNPS) model to estimate soil loss for four land use scenarios and estimated that 11% of the eroded material from the uplands reached the bay. The purpose of this study is to document the recent (1954 to present) sediment deposition patterns in the flood plain area adjacent to Stemple Creek using the radioactive fallout 137Cesium (137Cs) dating technique. Using 137Cs, sediment layers deposited in 1954 and 1964 can be determined and sedimentation rates and patterns can be determined Ritchie and McHenry, 1990, Walling and He, 1993, Walling et al., 1999.
Section snippets
Setting and landscape
Stemple Creek Watershed is located in Marin and Sonoma Counties on the northern California coast and covers 134 km2. Stemple Creek flows from east to west into the Estero de San Antonio and ultimately flows into Bodega Bay and the Pacific Ocean. Stemple Creek Watershed is characterized by rolling coastal hills with slopes averaging about 30%. Elevations range from sea level at the mouth of the Estero de San Antonio to 100 m at the eastern end of the watershed, 200 m along the northern boundary,
Methods and materials
In November 2001, soil profiles were collected from four different flood plain areas (sites 1–4) along Stemple Creek (Fig. 1). Soil profile samples were collected by digging pits and collecting soil samples in 5-cm increments from the side of the pits. One sample profile was collected in each flood plain area. A description of the soil profiles was also made Table 3, Table 4, Table 5, Table 6. An engineering survey of the relative surface elevation of the flood-plain cross section from
Results and discussion
Examples of the distribution of 137Cs in the flood-plain sediment profiles are shown in Fig. 2, Fig. 3. A summary of the depth to the 1964 and 1954 deposition layers and the calculated sediment deposition rates is given in Table 7. In two of the sediment profiles, samples were not collected deep enough to reach the 1964 layer. In five of the profiles, samples were not collected deep enough to reach the 1954 layer. Therefore, sediment deposition rates for those profiles could not be determined.
Conclusions
This study shows that the flood plains in the Stemple Creek watershed are a significant sink for the soils being eroded from the upland area. Deposition rates of 1 to 2 cm year−1 were measured for the period between 1954 and 2002. Such deposition rates are not unusual for flood plains Ritchie et al., 1975, Owens et al., 1999, Walling, 1999, Walling et al., 1999, Terry et al., 2002. These rates account for more than 50% of the material estimated to be eroding from the watershed using the AGNPS
Acknowledgements
The authors would like to thank the staff of the Petaluma NRCS Field Office for assistance in interfacing with the agricultural producers of Stemple Creek Watershed and the agricultural producers who allowed us access to their farms. Special thanks goes to Charlette Sanders, NRCS District Conservationist, at the Petaluma Field Office, for her cooperation and for reviewing several early versions of this manuscript. Thanks also go to Paul Pedone, NRCS State Geologist for Oregon, who provided
References (29)
- et al.
Use of floodplain sediment cores to investigate recent historical changes in overbank sedimentation rates and sediment sources in the catchment of the River Ouse Yorkshire, UK
Catena
(1999) Terrain attributes, landform segmentation, and soil redistribution
Soil and Tillage Research
(2003)- et al.
137Cesium and soil carbon in a small agricultural watershed
Soil and Tillage Research
(2003) - et al.
Rates of floodplain accretion in a tropical river system impacted by cyclones and large floods
Geomorphology
(2002) - et al.
Using 137Cs measurements to validate the application of the AGNPS and ANSWERS erosion and sediment yield models in two small Devon catchments
Soil and Tillage Research
(2003) - California Department of Fish and Game Department (CAFG), 1977. The Natural Resources of Esteros Americano and de San...
- California Department of Water Resources (CAWR), 1986. Land Use Maps of the Valley Ford, Two Rock, Cotati, Tomales,...
- Finney, V., 2002. AGNPS Modeling of Stemple Creek Watershed, CA. NRCS Technical Report. California NRCS Watershed...
- Harvey, H.T., 1990. Evolution of Wetlands in the Estero Americano, Long-term Detailed Wastewater Reclamation Studies....
- et al.
Testing distributed soil erosion and sediment delivery models using 137Cs measurements
Hydrological Processes
(2003)
Estimating soil loss from changes in soil cesium-137
Canadian Journal of Soil Science
Soil Survey of Marin County, California
Quantifying recent erosion and sediment delivery using probability: a case study
Earth Surface Processes and Landforms
Tillage translocation and tillage erosion on shoulder slope landscape positions measured using 137Cs as a tracer
Canadian Journal of Soil Science
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