Geology topics

Research about Clearwater River;Snake River

Source-linked reports with geographic coverage including Clearwater River;Snake River.

3 recordsLinked to original sources

USGS2013

Use of surrogate technologies to estimate suspended sediment in the Clearwater River, Idaho, and Snake River, Washington, 2008-10

Elevated levels of fluvial sediment can reduce the biological productivity of aquatic systems, impair freshwater quality, decrease reservoir storage capacity, and decrease the capacity of hydraulic structures. The need to measure fluvial sediment has led to the development of sediment surrogate technologies, particularly in locations where streamflow alone is not a good estimator of sediment load because of regulated flow, load hysteresis, episodic sediment sources, and non-equilibrium sediment transport. An effective surrogate technology is low maintenance and sturdy over a range of hydrologic conditions, and measured variables can be modeled to estimate suspended-sediment concentration (SSC), load, and duration of elevated levels on a real-time basis. Among the most promising techniques is the measurement of acoustic backscatter strength using acoustic Doppler velocity meters (ADVMs) deployed in rivers. The U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Walla Walla District, evaluated the use of acoustic backscatter, turbidity, laser diffraction, and streamflow as surrogates for estimating real-time SSC and loads in the Clearwater and Snake Rivers, which adjoin in Lewiston, Idaho, and flow into Lower Granite Reservoir. The study was conducted from May 2008 to September 2010 and is part of the U.S. Army Corps of Engineers Lower Snake River Programmatic Sediment Management Plan to identify and manage sediment sources in basins draining into lower Snake River reservoirs. Commercially available acoustic instruments have shown great promise in sediment surrogate studies because they require little maintenance and measure profiles of the surrogate parameter across a sampling volume rather than at a single point. The strength of acoustic backscatter theoretically increases as more particles are suspended in the water to reflect the acoustic pulse emitted by the ADVM. ADVMs of different frequencies (0.5, 1.5, and 3 Megahertz) were tested to target various sediment grain sizes. Laser diffraction and turbidity also were tested as surrogate technologies. Models between SSC and surrogate variables were developed using ordinary least-squares regression. Acoustic backscatter using the high frequency ADVM at each site was the best predictor of sediment, explaining 93 and 92 percent of the variability in SSC and matching sediment sample data within +8.6 and +10 percent, on average, at the Clearwater River and Snake River study sites, respectively. Additional surrogate models were developed to estimate sand and fines fractions of suspended sediment based on acoustic backscatter. Acoustic backscatter generally appears to be a better estimator of suspended sediment concentration and load over short (storm event and monthly) and long (annual) time scales than transport curves derived solely from the regression of conventional sediment measurements and streamflow. Changing grain sizes, the presence of organic matter, and aggregation of sediments in the river likely introduce some variability in the model between acoustic backscatter and SSC.

Idaho;Washington↗

USGS1980

Sediment transport in the Snake and Clearwater rivers in the vicinity of Lewiston, Idaho

During the period 1972-79, the bedload in the Clearwater River ranged from about 50,000 tons (45,000 metric tons) per year in 1972 and 1974 to about 1,000 tons (910 metric tons) per year in the drought years of 1973 and 1977. Suspended-sediment load at the same location ranged from about 1,000,000 tons (910,000 metric tons) per year to about 50,000 tons (45,000 metric tons) per year for the same respective years. In the Snake River, bedload ranged from about 200,000 tons (180,000 metric tons) per year for 1972 and 1974 to about 10,000 tons (9,100 metric tons) per year in 1973; bedload was too low for determination in 1977. Suspended-sediment load ranged from about 5,000,000 tons (4,500,000 metric tons) per year in 1974 to about 50,000 tons (45,000 metric tons) per year in 1977. Bedload thus ranged from about 2 to 10 percent of suspended load and average about 5 percent. For either river, bedload particle size was bimodal. Modes were in the medium- to coarse-sand range and in the very coarse-gravel range. Suspended-sediment particle size was generally finer than sand.

Idaho↗

USGS1979

Suspended- and bedload-sediment transport in the Snake and Clearwater rivers in the vicinity of Lewiston, Idaho, August 1976 through July 1978

Impoundment of water in the Snake River and Clearwater River arms behind Lower Granite Dam (see cover map) began in June 1975. At this time, Lower Granite Reservoir and Lock facilities, constructed by the USACE (U.S. Army Corps of Engineers), Walla Walla District, became operational. Construction and operation of this facility necessitated collection of hydrologic data that did not exist prior to construction. The USACE requested the USGS (U.S. Geological Survey) to collect hydraulic- and channel-geometry data and describe sediment-transport characteristics, beginning in the spring of 1972. This report summarizes information collected during August 1976 through July 1978 and is the fifth in a series of reports designed to release hydrologic data on a timely basis. Although some of the data were collected during the late summer and fall periods (August through December) of 1976 and 1977, most were collected during the spring runoff periods of 1977 and 1978. Therefore, for convenience, data contained in this report will be referred to as the 1977-78 data. Because this is primarily a basic-data report, no interpretation of the data is provided. This report presents tables of selected data collected and computations compiled since the 1976 report (Seitz, 1976). Most of the tabular data are also presented on graphs. Some of the graphs show plots of data since 1972~ others show plots of only the 1977-78 data. Relatively minor amounts of bedload were transported during the 1977 drought period. Therefore, regular scheduled sampling of the bedload was impractical. Only two bedload samples were collected from the Clearwater River in 1977. The resultant data are included in tables 10, 12, and 14, and figure 6. All bedload data in this report should be considered tentative, pending completion of sampler-calibration studies and possible adjustment of the data to correct for sampler efficiency. An analysis of the middle Snake River streamflow record was made during 1977. The streamflow rating for the Snake River near Anatone, Washington, gage was found to be in error at high stages. The streamflow record for water years 1974 and 1975 was revised and published with 1976 water-year data (Water Resources Data for Idaho, Water Year 1976). The revised Snake River near Anatone streamflow rating was used to recompute the sediment-discharge rating curve (fig. 3). This study program is funded by the USACE through a cooperative agreement with the USGS. All field work, laboratory analysis, and compilation of data are being conducted by the USGS. Data collection is scheduled to terminate at the end of the 1979 runoff season. A reanalysis of all data collected since the start of the program will correct all provisional records since 1972, including the 1974, 1975, and 1976 years for the Snake River near Anatone station.

Idaho↗