Identifying eroding and depositional reaches of valley by analysis of suspended sediment Transport in the Sacramento River, California

Abstract

Abstract. Spatial patterns in suspended sediment transport and storage along the Sacramento River were assessed by evaluating the suspended sediment budget for the main channel accounting for all tributaries and diversions. Time series analysis was employed to quantify the relationship between streamflow and suspended sediment concentration for gauging stations along the main channel and signature tributaries. Sediment concentration records (of 2-yr duration) were extended using Box-Jenkins transfer function models to calculate annual rates of suspended sediment discharge over a 32-year period since dam construction on the Sacramento River. The suspended sediment budget was evaluated to identify reaches of net erosion or deposition. The results of the budget suggest the influence of tectonics and anthropogenic channel modifiLation.

An empirical‐stochastic, event‐based program for simulating inflow from a tributary network: Framework and application to the Sacramento River basin, California

“…We divided this elevation difference by the number of years between the eras to arrive at an average annual erosion rate for this reach of river in intervening period. This result is 2.1 cm yr À1 (79 cm between the first year of each era, 1933 and 1970), which is close to the 1.7 cm yr À1 rate for the period 1948-1979, independently predicted in our analysis of suspended sediment transport [Singer and Dunne, 2001]. This erosion trend is corroborated by flow data from the Fremont Weir Spill.…”

“…It is noteworthy that predam peaks of flow within the leveed channel at Verona are lower than postdam ones, and this matter is discussed below. Otherwise, predam and postdam simulated flood peaks bound the historical data and illustrate the potential range of variability, especially for flows of intermediate frequencies that transport most sediment [Singer and Dunne, 2001] and drive important ecological processes [Mahoney and Rood, 1998;Milhous, 1998;Pitlick and Van Steeter, 1998;Johnson, 2000]. HYDROCARLO simulations generally bracket historical flood peaks at Verona for other exceedence probabilities.…”

“…There have been no major alterations to the flood control system [U.S. Army Corps of Engineers, 1998], and we know of no conditions that would have altered roughness. A previous study documented a decrease in specific gauge records in the Sacramento River between Knights Landing and Sacramento over $20 years [Water Engineering and Technology, 1990], and we calculated an average erosion rate for this reach of 1.7 cm yr À1 for the time period 1948-1979 from the sediment transport budget [Singer and Dunne, 2001]. 3.6.3.2.…”

Sediment-adsorbed total mercury flux through Yolo Bypass, the primary floodway and wetland in the Sacramento Valley, California

“…2-2a from LWA (2002)). Third, monthly mean discharge data dampen flood peaks that are generally responsible for the majority of the sediment/mercury flux (Singer and Aalto, 2009;Singer and Dunne, 2001).…”

“…To account for the effect of sustained extreme flows, we used the sum of Q over the previous two weeks (sumQ 2weeks ). For each site we first assess whether the specification in [1] is appropriate and then attempt to improve on the predictive power of the model by including a hysteresis variable in a multiple regression, which is a simpler, yet more transferable method than previously developed (c.f., (Singer and Dunne, 2001)). Table 3 summarizes the regression specifications used for each of the three direct tributary inputs, six weir-spilled water sources, the Bypass output and the Sacramento River gauge at Freeport.…”