Geology topics

C.H. Swift

Publications and source records attributed to C.H. Swift.

4 recordsLinked to original sources

USGS1985

Phase I summary and phase II plan for comparing regulated with unregulated streamflow in the Yakima River at Union Gap, Washington

A preliminary investigation of the effects of reservoir storage and canal diversion on the flow of the Yakima River at Union Gap , Washington indicates that those effects are measurable and substantial--on the average causing a reduction of roughly one-quarter from the unregulated flow. Preliminary computations of the unregulated flow of the Yakima River at Parker (near Union Gap) for the 1978 water year using the U.S. Bureau of Reclamation 's SSARR model indicate, however, that the computed flow figures contain inaccuracies. Further investigation of the model indicates that the inaccuracies can be substantially reduced by data checking and by using additional discharge records to improve the estimation of local inflows. (USGS)

Water-Resources Investigations Report↗

USGS1983

Mudflow hazards along the Toutle and Cowlitz Rivers from a hypothetical failure of Spirit Lake blockage

The debris avalanche accompanying the May 18, 1980, eruption of Mount St. Helens, in southwestern Washington, buried the former outlet of Spirit Lake, located 5 miles north of the volcano, to a depth ranging to 500 feet. Since that time, Spirit Lake has had no natural outlet and its lake level and contents have increased significantly. Erosion at the crest of the debris dam on the surface of the blockage and recent studies of theblockage stratigraphy and soil properties showing that the effective crest elevation is lower than the surface crest have led to concern that the lake may someday breach through or spill over the top of the blockage. A study was made by the U.S. Geological Survey to determine the extent of inundation that might result downstream in the Toutle and Cowlitz Rivers if a hypothetical breach should occur and generate a mudflow flood of catastrophic proportions. A hypothetical breach of Spirit Lake produced a hypothetical mudflow hydrograph with a peak discharge of 2.65 million cu ft/s and a sediment concentration of 65 percent by volume at Camp Baker on the North Fork Toutle River. Elevations determined by the hydraulic routing of the mudflow were used to prepare inundation maps, indicating depths of inundation to be about 60 feet at Castle Rock and Lexington; 30-40 feet at Toutle, Toutle Lake at Silver Lake, Kelson, and Longview; and 15-20 feet at Toledo. Travel times for the peak elevation were estimated to be about 15 hours to Kid Valley on the North Fork Toutle River, 21 hours to Castle Rock, 22 hours to Toledo, and 23 hours to Kelso and Longview on the Cowlitz River. (USGS)

Water-Resources Investigations Report↗

USGS1977

Preferred stream discharges for salmon spawning and rearing in Washington

Stream discharges preferred by salmon for spawning were determined from relationships between discharge and spawnable area at 84 study reaches on 28 streams in Washington. Preferred discharges for spawning were found statistically equivalent for chinook, pink and chum salmon. Regression equations developed for estimating discharges preferred by these species for spawning at other stream sites had standard errors of estimate of 40 percent where a relationship with toe-of-bank channel width was used, and 55 percent where basin drainage area was used. Similarly, equations for estimating the preferred discharge for spawning by sockeye and coho salmon (also statistically equivalent) had standard errors of 48 percent using channel width and 61 percent using drainage area. In general, the discharges preferred for spawning by salmon ranged in magnitude from about 0.3 to 11 times the median monthly mean discharges for September and October and about 0.1 to 6 times the median monthly means for November and December--the four months when spawning is greatest. Stream discharges preferred by salmon for rearing were determined from relationships between discharge and wetted perimeter at the study reaches. Those discharges ranged from about 0.7 to 4 times the median monthly mean discharge for September, when low flows are usually most limiting on the rearing capacity of streams. Equations developed for estimating preferred rearing discharges at other stream sites had standard errors of 57 percent using channel width and 81 percent using drainage area. Peak-unit spawnable area, or maximum area per unit length of channel that has preferred water depths and velocities, was similar for the five salmon species. Equations developed for estimating that area at other sites had standard errors of 27 percent using channel width and 47 percent using drainage area. In general, reducing discharge below the preferred spawning discharge by 25, 50, and 75 percent had the effect of reducing spawnable area by about 5, 15, and 40 percent of the peak-unit spawnable area.

Washington↗

USGS1976

Estimation of stream discharges preferred by steelhead trout for spawning and rearing in western Washington

Determined during the study of selected stream reaches used for spawning and rearing by steelhead trout were (1) stream discharges that cover the greatest areas of the streambeds with water at both the depths and the velocities preferred by spawning steelhead; (2) discharges that cover selectively reduced streambed areas with water at both the depths and velocities preferred by spawning steelhead; (3) discharges that cover the greatest streambed areas with water at velocities preferred by spawning steelhead; (4) rearing discharges that cover the streambed, but not the banks of the channel, with water; and (5) average wetted perimeters of the channels at water stages corresponding to the rearing discharges. These discharges and wetted perimeters were determined by measurements at 54 study reaches on 18 streams representative in size and location of those used by steelhead for spawning and rearing. Using multiple-regression techniques and the measured discharges and wetted perimeters, equations were developed for estimating the spawning and rearing discharges and the wetted perimeter for rearing at unmeasured stream sites. The independent parameters used were drainage area, mean altitude of the basin, reach altitude, reach slope, and average width of reach at toe of bank. Standard errors of estimate for the equations ranged from 26 to 50 percent for discharges corresponding to the greatest areas of preferred depths and velocities, from 32 to 46 percent for discharges corresponding to reduced areas of preferred depths and velocities, from 44 to 68 percent for discharges corresponding to the greatest areas of preferred velocities, from 46 to 57 percent for rearing discharges, and from 20 to 41 percent for the rearing wetted perimeter.

Washington↗