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Rhea P. Williams

Publications and source records attributed to Rhea P. Williams.

13 recordsLinked to original sources
USGS2002

Estimated flood flows in the Lake Tahoe basin, California and Nevada

Lake Tahoe, the largest alpine lake in North America, covers about 192 square miles (mi 2 ) of the 506-mi 2 Lake Tahoe Basin, which straddles the border between California and Nevada (Fig. 1). In cooperation with the Nevada Department of Transportation (NDOT), the U.S. Geological Survey (USGS) estimates the flood frequencies of the streams that enter the lake. Information about potential flooding of these streams is used by NDOT in the design and construction of roads and highways in the Nevada portion of the basin. The stream-monitoring network in the Lake Tahoe Basin is part of the Lake Tahoe Interagency Monitoring Program (LTIMP), which combines the monitoring and research efforts of various Federal, State, and regional agencies, including both USGS and NDOT. The altitude in the basin varies from 6,223 feet (ft) at the lake's natural rim to over 10,000 ft along the basin's crest. Precipitation ranges from 40 inches per year (in/yr) on the eastern side to 90 in/yr on the western side (Crippen and Pavelka, 1970). Most of the precipitation comes during the winter months as snow. Precipitation that falls from June through September accounts for less than 20 percent of the annual total.

California, Nevada↗
USGS1997

Flood of January 1997 in the Carson River Basin, California and Nevada

Northern California and western Nevada were devastated by floods during January 1-3, 1997. Flood waters in the Carson River Basin (fig. 1) contributed to $55 million in projected damages in Douglas County and $19.5 million in Lyon County (Reno Gazette-Journal, 1997). Flooding in Douglas and Lyon Counties was extensive along the levee and irrigation systems, and agricultural land. In Carson City, damage to public facilities was estimated at $6.4 million (Reno Gazette-Journal, 1997). In late December 1996, storms built up a large snowpack (more than 180 percent of normal) in the higher altitudes of the Sierra Nevada (Daniel Greenlee, Natural Resource Conservation Service, oral commun., 1997) and also covered the valleys along the eastern Sierra Nevada. Then, a subtropical storm system originating in the central Pacific Ocean near the Hawaiian Islands brought heavy, unseasonably warm rain to the Sierra Nevada from December 30, 1996, through January 2, 1997. During this period, the Natural Resource Conservation Service recorded 16.4 inches (provisional data; Daniel Greenlee, oral commun., 1997) of precipitation at Ebbetts Pass, Calif. (8,700 feet above sea level), and the National Weather Service recorded 3.5 inches (National Oceanic and Atmospheric Administration, National Climate Data Center, written commun., 1997) at Minden (4,710 feet above sea level). Rain falling below about 10,000 feet depleted about 20 percent of the high-altitude snowpack and melted about 80 percent of the snowpack below about 7,000 feet.

California;Nevada↗
USGS1994

Problems with indirect determinations of peak streamflows in steep, desert stream channels

Many peak streamflow values used in flood analyses for desert areas are derived using the Manning equation. Data used in the equation are collected after the flow has subsided, and peak flow is thereby determined indirectly. Most measurement problems and associated errors in peak-flow determinations result from (1) channel erosion or deposition that cannot be discerned or properly evaluated after the fact, (2) unsteady and non-uniform flow that rapidly changes in magnitude, and (3) appreciable sediment transport that has unknown effects on energy dissipation. High calculated velocities and Froude numbers are unacceptable to some investigators. Measurement results could be improved by recording flows with a video camera, installing a recording stream gage and recording rain gages, measuring channel scour with buried chains, analyzing measured data by multiple techniques, and supplementing indirect measurements with direct measurements of stream velocities in similar ephemeral streams.

Conference Paper↗
USGS1982

Water resources of Rockland Basin, southeastern Idaho

Rockland basin comprises about 320 sq mi of the Snake River drainage in southeastern Idaho. Mountain ranges bordering the basin are composed predominantly of limestone and are complexly faulted. Major aquifers include Holocene alluvium, Quaternary-Tertiary volcanic rocks, and Tertiary sedimentary rocks. Groundwater occurs under water table conditions except where it is locally confined. Groundwater discharges to springs in the Deep Creek Mountains and maintains perennial streamflow. Near the mouth of Rock Creek, groundwater movement is northward toward the Snake River. Underflow is estimated to be 51,000 acre-ft/yr. Total water yield available to Rockland basin is estimated to be 5.0 in. (85,000 acre-ft) of the estimated 17.3 in. of annual precipitation. Evapotranspiration ranges from 9.9 to 17 in./yr, depending, in part, on altitude of the land surface. An estimated 12,000 acre-ft of surface water and 3,500 acre-ft of groundwater are used annually for irrigation. Less than 100 acre-ft of water is used for public supply, domestic, and stock supplies. East Fork Rock Creek supplies the most surface water for irrigation of agricultural lands. At the present (1980) state of groundwater development in Rockland basin, streams and aquifers are hydraulically connected. Pumping of groundwater in increased quantities from wells near streams will affect groundwater movement and may diminish streamflow. There are no long-term regional water table declines at present. Continued water level monitoring of selected wells may aid in documenting effects of future management practices on the groundwater system.

idaho↗
USGS1979

Sediment discharge in the Santa Clara River Basin, Ventura and Los Angeles Counties, California

Sediment data collected in the Santa Clara River basin during the 1967-75 water years were analyzed to determine the particle size and quantity of sediment transported past three gaging stations. The total sediment discharge of the basin, computed from records of Santa Clara River at Montalvo for water years 1968-75, was 63 . 5 million tons, of which 59.5 million tons was carried in suspension and an estimated 4 million tons was transported as unsampled sediment discharge. About 17. 7 million tons, or 28 percent of the total sediment discharge, was coarse sediment (particles larger than O. 062 millimeter). Most of the sediment was transported during only a few days of floodflow each year. During the 1968-75 water years, approximately 55 percent of the total sediment was transported in 2 days and 92 percent was transported in 53 days. The long-term (1928-75) average annual sediment discharge of the Santa Clara River at Montalvo is estimated at 3.67 million tons. Of that quantity, 2.58 million tons consisted of fine sediment and 1.09 million tons consisted of coarse sediment. A sediment budget for the Santa Clara River basin was estimated for sediment discharges under both natural and actual conditions. The major difference between natural and actual sediment discharges of the Santa Clara River basin is the sediment intercepted upstream from Lake Piru. The combined trap efficiency of Lake Piru and Pyramid Lake approaches 100 percent. Sediment deposited in these reservoirs resulted in about a 6-percent reduction of sediment to the Santa Clara River basin during the historical period (1928-75) and a 12-percent reduction during the period most affected by dams (1953-75). Sediment losses to the basin by gravel mining, diversion of flows, and interception of sediment in the Castaic Creek basin resulted in additional reductions of 2 percent during the period 1928-75 and 4 percent during the period 1953-75.

California↗
USGS1978

Erosion and sediment yields in the Transverse Ranges, Southern California

Major-storm and long-term erosion rates in mountain watersheds of the western Transverse Ranges of Ventura County, Calif., are estimated to range from low values that would not require the construction of catchments or channel-stabilization structures to values as high as those recorded anywhere for comparable bedrock erodibilities. A major reason for this extreme variability is the high degree of tectonic activity in the area--watersheds are locally being uplifted by at least as much as 25 feet per 1,000 years, yet the maximum extrapolated rate of denudation measured over the longest available period of record is 7.5 feet per 1,000 years adjusted to a drainage area of 0.5 square mile. Evidence of large amounts of uplift continuing into historic time includes structurally overturned strata of Pleistocene age, active thrust faulting, demonstrable stream antecedence, uplifted and deformed terraces, and other results of base-level change seen in stream channels. Such evidence is widespread in the Transverse Ranges, and aspects of the landscape are locally more a function of tectonic activity than of the denudational process. (Woodard-USGS)

Professional Paper↗
USGS1975

Erosion and sediment transport in the Owens River near Bishop, California

Closure of Pleasant Valley Dam in 1954 has almost eliminated the supply of gravel to the 16-mile (25.7-kilometre) study reach of the Owens River. Because of armoring of the channel, scour has been limited to approximately 1 foot (0.3 metre) in the upper 2.3 miles (3.7 kilometres). This report presents information useful in determining long-term erosion effects below Pleasant Valley Dam, in assessing the feasibility of a proposed bypass channel versus retention of the main channel in its present state, and in determining man's influence on river morphology. Bedload transport is dependent on the hydraulics of a section and the availability of material. Ninety-eight percent by weight of the sampled bedload transported between sites 1 and 6 in the study reach was finer than 8 millimetres, although only 6 to 12 percent of the material in the bed available for transport was finer than 8 millimetres. Bank material, a prime source of new material for transport, is predominantly finer than 16 millimetres. Bank erosion is accelerated by wide ranges in flow release. The bank-erosion rates interpreted from aerial photographs indicate average annual erosion rates of 750 tons (680 tonnes) from 1947 to 1967, 1,970 tons (1,790 tonnes) from 1967 to 1968, and 2,020 tons (1,830 tonnes) from 1968 to 1971. These rates are compatible with the water discharge-sediment discharge relation developed from field data collected during 1972-73. Hydraulic geometry of the six sites indicates a shift in the river system regime since 1954. These changes have progressed downstream from the dam to a point between sites 4 and 5. Farther downstream channel changes will occur until the channel stabilizes.

California↗