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Geology topics

J. C. Blodgett

Publications and source records attributed to J. C. Blodgett.

At least 19 recordsLinked to original sources
USGS1996

Storage capacity, detention time, and selected sediment deposition characteristics for Gull and Silver Lakes, Mono County, California

Bathymetric surveys made in September 1994 indicate the maximum storage capacity of Gull and Silver Lakes, California, is about 2,400 and 3,000 acre-feet, respectively. During March through October 1994, the lake level dropped 0.7 feet at both Gull Lake and Silver Lake. The associated change in storage was 60 acre-feet at Gull Lake and 80 acre-feet at Silver Lake. The flow detention time for average annual flow conditions at Gull Lake is about 2.5 years and for Silver Lake, the average detention time is about 19 days. Sediment deposition at the inlet to Silver Lake has been monitored since 1951 using aerial photography. During 1963 through 1994, the area of sediment deposition increased from 0.32 to about 2.4 acres. Analyses of these data indicate that the rate of deposition was lower during 1951-72 than the rate during 1973-94. Sediment deposition at the lake inlet is a continuing phenomenon.

Open-File Report↗
USGS1995

Water-quality data for selected sites on Reversed, Rush, and Alger Creeks and Gull and Silver Lakes, Mono County, California, April 1994 to March 1995

Water-quality data for selected sites on Reversed, Rush, and Alger Creeks and Gull and Silver Lakes, Mono County, California, were collected from April 1994 to March 1995. Water samples were analyzed for major ions and trace elements, nutrients, methylene blue active substances, and oil and grease. Field measurements were made for discharge, specific conductance, pH, water temperature, barometric pressure, dissolved oxygen, and alkalinity. Additional data collected include vertical water profiles of specific conductance, pH, water temperature, and dissolved oxygen collected at 3.3-foot intervals for Gull and Silver Lakes; chlorophyll-a and -b concentrations and Secchi depth for Gull and Silver Lakes; sediment interstitial- water nutrient concentrations in cores from Gull Lake; and lake surface and volume of Gull and Silver Lakes.

Open-File Report↗
USGS1995

Precipitation depth-duration and frequency characteristics for Antelope Valley, Mojave Desert, California

Methods to evaluate changes in the volume of storm runoff from drainage basins that are likely to be urbanized are needed by land-use planning agencies to establish criteria for the design of flood-control systems. To document the changes in runoff volume of basins that may be urbanized, nine small basins that are considered representative of varying hydrologic conditions in Antelope Valley, California, were selected for detailed study. Precipitation and stream-gaging stations were established and data were collected for the period 1990-93. The data collected at these U.S. Geological Survey stations were supplemented by data collected at 35 Long-term precipitation stations operated by the National Oceanic and Atmospheric Administration and the Los Angeles County Department of Public Works. These data will be used to calibrate and verify rainfall-runoff models for the nine basins. Results of the model runs will then be used as a guide for estimating basin runoff characteristics throughout Antelope Valley. Annual precipitation in Antelope Valley ranges from more than 20 inches in the mountains to less than 4 inches on the valley floor. Most precipitation in the valley falls during the months of December through March, but cyclonic storms in the fall and convectional storms in the summer sometimes occur. The duration of most storms ranges from 1 to 8 days, but most of the precipitation usually occurs within the first 2 days. Many parts of the valley have been affected by storms with precipitation depths that equal or exceed 0.60 inch per hour. The storms of January 1943 and March 1983 were the most intense storms of record, with recurrence intervals greater than 100 years in some parts of the valley. Depth-duration ratios were calculated by disaggregating daily total precipitation data for intervals of 1, 2, 3, 4, 6, 12, and 18 hours for storms that occurred during 1990-93. The hourly total precipitation data were then disaggregated at 5-minute intervals. A comparison of the depth-duration data collected during 1990-93 at the Geological Survey stations with the data collected at the other stations indicated that the 1990-93 data are not representative of historical storms. Therefore, depth-duration ratios developed using these data should be considered preliminary for use in disaggregating the historical hourly data for Antelope Valley. Annual maximum 24-hour precipitation records were used to calculate precipitation depth-frequency relations for 23 stations in the valley using the log Pearson type III distribution. These calculations indicate that the storms of January 1943 and March 1983 were the most intense of record in the valley with recurrence intervals greater than 100 years.

Water-Resources Investigations Report↗
USGS1993

Measurement of bridge scour at the SR-32 crossing of the Sacramento River at Hamilton City, California, 1987-92

A study of the State Route 32 crossing of the Sacramento River near Hamilton City, California, is being made to determine those channel and bridge factors that contribute to scour at the site. Three types of scour data have been measured-channel bed (natural) scour, constriction (general) scour, and local (bridge-pier induced) scour. During the years 1979-93, a maximum of 3.4 ft of channel bed scour, with a mean of 1.4 ft, has been measured. Constriction scour, which may include channel bed scour, has been measured at the site nine times during the years 1987-92. The calculated amount of constriction scour ranged from 0.2 to 3.0 ft, assuming the reference is the mean bed elevation. Local scour was measured four times at the site in 1991 and 1992 and ranged from -2.1 (fill) to 11.6 ft , with the calculated amounts dependent on the bed reference elevation and method of computation used. Surveys of the channel bed near the bridge piers indicate the horizontal location of lowest bed elevation (maximum depth of scour) may vary at least 17 ft between different surveys at the same pier and most frequently is located downstream from the upstream face of the pier.

Conference Paper↗
USGS1990

Monitoring land subsidence in Sacramento Valley, California, using GPS

Land subsidence measurement is usually based on a comparison of bench-mark elevations surveyed at different times. These bench marks, established for mapping or the national vertical control network, are not necessarily suitable for measuring land subsidence. Also, many bench marks have been destroyed or are unstable. Conventional releveling of the study area would be costly and would require several years to complete. Differences of as much as 3.9 ft between recent leveling and published bench-mark elevations have been documented at seven locations in the Sacramento Valley. Estimates of land subsidence less than about 0.3 ft are questionable because elevation data are based on leveling and adjustment procedures that occurred over many years. A new vertical control network based on the Global Positioning System (GPS) provides highly accurate vertical control data at relatively low costs, and the survey points can be placed where needed to obtain adequate areal coverage of the area affected by land subsidence.

California↗
USGS1989

Flood of January 1982 in the San Francisco Bay area, California

A major winter storm originating over the Pacific Ocean moved through central California in early January 1982. As much as 16 inches of rain fell in Marin County and 25 inches in the mountains bordering Santa Cruz County. The storm of January 3-5, 1982 had a stable atmospheric structure, and the layer of moist maritime air was confined to altitudes between 50 and 700 ft; this phenomenon caused the rain to fall most heavily along the lower slopes of the coastal mountains. As a result of antecedent rainfall, streamflow in the San Francisco Bay area exceeded normal from the end of October to the end of December 1981. For most streams, the January 1982 flood was the largest since the flood of December 1955, but it was not significantly large in comparison with historic peak-flow data. Damages associated with the storm were substantial, but flooding from stream runoff was not the major problem. Greater than normal antecedent rainfall, together with the prolonged heavy rain, liquified the supersaturated soil cover and caused numerous slope failures and debris flows on steep, unstable slopes. The median recurrence interval of the 1982 peak for 66 streamflow-gaging stations in the San Francisco Bay area is 10 years; for the 1955 flood, the median recurrence interval for 16 stations is 11 years. Streams with highest unit peak runoff were in the Santa Cruz Mountains and North Bay subareas. Median recurrence intervals of flood volumes for durations of 1, 3, and 8 consecutive days during the January 1982 flood are 18, 11, and 8; these recurrence intervals are comparable to those of the December 1955 flood, which are 13 , 16, and 14 years. (USGS)

Water-Resources Investigations Report↗
USGS1988

Determination of bench-mark elevations at Bethel Island and vicinity, Contra Costa and San Joaquin counties, California, 1987

Elevations of 49 bench marks in the southwestern part of the Sacramento-San Joaquin River Delta were determined during October and November 1987. A total of 58 miles of level lines were run in the vicinity of Bethel Island and the community of Discovery Bay. The datum of these surveys is based on a National Geodetic Survey bench mark T934 situated on bedrock 10.5 mi east of Mount Diablo and near Marsh Creek Reservoir. The accuracy of these levels, based on National Geodetic Survey standards, was of first, second, and third order, depending on the various segments surveyed. Several bench marks were noted as possibly being stable, but most show evidence of instability. (USGS)

Open-File Report↗
USGS1988

Profile of Sacramento River, Freeport to Verona, California, flood of February 1986

A major storm in February 1986 caused record flooding in the Sacramento River and other nearby basins in north-coastal and central California. As part of an effort to document this flood, the peak water surface profile of a 33 mi reach of the Sacramento River was surveyed between Freeport and Verona, California. Supplementary profiles in this reach include elevations of the approximate top of levee, flood plain, and the water surface on March 17, 1987. On the Sacramento River at Sacramento, the peak discharge of 117,000 cu ft/sec occurred February 19 and 20, 1986. The peak stage of 30.58 ft on February 19 is the highest on record, including the period prior to construction of large flood control dams in the Sacramento River basin beginning with Shasta Dam in 1942. The February 1986 flood profile of the Sacramento River between the mouth of the American River and the Sacramento Weir (located upstream from the American River) shows a reverse water surface slope with a corresponding drop of about 0.13 ft. On the Sacramento River at Verona, upstream from Sacramento, a peak stage of 39.11 ft occurred February 20 (peak discharge 92,900 cu ft/sec) due to runoff from upstream tributaries. The February 1986 peak stage is the highest of record for 1914-87 (no record for 1918-20, 1922-25). The previous peak stage of record at Verona, March 1, 1940, was 38.20 ft, with a discharge of 79,200 cu ft/sec.

California↗
USGS1988

A water-resources appraisal of the Mount Shasta area in northern California, 1985

Present Mount Shasta, California, area hydrologic characteristics were documented to compare future changes due to land use or volcanic activity. Lower flanks of Mount Shasta consist of broad aprons of pyroclastic-flow, debris flow, and fluvial deposits, with incised channels on upper parts of the mountain. Data include glacial areas and volumes, streamflow, sediment concentrations, temperature, and water chemistry of groundwater and springs. Many springs issue from fractures in lava and lava tubes around Mount Shasta and serve as sources of water for nearby towns. Groundwater levels fluctuate as much as 27 ft. Water sampled from wells meets U.S. Environmental Protection Agency drinking water standards. Streamflow is affected by snowfield and glacial melt and precipitation, with some streams showing diurnal variations related to daily air temperature changes. Only four streams have sufficient streamflow to travel more than about 6 mi from the summit; differences in low flows are attributed to groundwater stored in materials that compose the mountain and alluvial fans and the rain shadow effect on precipitation in northwest areas of the mountain. Most streamflow is ephemeral and percolates into channel beds on alluvial fans. (USGS)

Water-Resources Investigations Report↗
USGS1988

Channel morphology of Cottonwood Creek near Cottonwood, California, from 1940 to 1985

Proposed construction of two dams on Cottonwood Creek California , has caused concern that resulting streamflow modification may alter downstream channel morphology. Baseline information on Cottonwood Creek channel characteristics from 1982-83 field surveys and 1940-84 aerial photographs indicates an alluvial channel that consists of a braided inner main channel within a broader flood channel, with no clear topographic break between the main and flood channels. The braided channel is subject to large and rapid position shifts in the flood channel, which meanders within the valley fill; however, the position of the flood channel has remained relatively stable since 1940. Mean slope of Cottonwood Creek is 0.0017 and that of South Fork Cottonwood Creek is 0.0020. Fluctuations of mean bed elevation appear to be random with no apparent long-term trend of aggradation or degradation. Mean bed-material size ranged from 3 to 82 millimeters. Low-flow channel sinuosity ranged from 1.04 to 1.47 from 1940 to 1984. Cumulative lateral migration for Cottonwood Creek decreased upstream, while for South Fork, it remained relatively constant. Net lateral migration was toward the right bank on Cottonwood Creek whereas no trend in net lateral migration is apparent for the South Fork. (USGS)

Water-Resources Investigations Report↗
USGS1986

Water-resources data for the Mount Shasta area, northern California

This report presents water quantity and water quality data for samples collected at wells, springs, streams, and lakes in the vicinity of Mount Shasta in northern California. The data are presented in graphs and tables. Groundwater data include water level measurements made at 24 wells, analyses of water samples collected at 12 wells, discharge measurements made at 14 springs , and analyses of water samples collected at 17 springs. Surface water data include streamflow measurements and/or analyses of suspended sediment collected at 36 stream sites; analyses of water samples collected at 11 streamflow sites; profiles of temperature, specific conductance, dissolved oxygen, and pH for water samples from 6 lake sites; and analyses of water samples collected at 7 lake sites. Maps of the area show the location of data-collection sites. (USGS)

Open-File Report↗
USGS1986

Rock riprap design for protection of stream channels near highway structures; Volume 1, Hydraulic characteristics of open channels

Volume I discusses the hydraulic and channel properties of streams, based on data from several hundred sites. Streamflow and geomorphic data have been collected and developed to indicate the range in hydraulic factors typical of open channels , to assist design, maintenance, and construction engineers in preparing rock riprap bank protection. Typical channels were found to have maximum-to-mean depth ratio of 1.55 and a ratio of hydraulic radius to mean depth of 0.98, which is independent of width. Most stable channel characteristics for a given discharge are slope, maximum depth, and hydraulic radius. (See also W89-04911) (Author 's abstract)

Water-Resources Investigations Report↗
USGS1986

Rock riprap design for protection of stream channels near highway structures; Volume 2, Evaluation of Riprap design procedures

In volume 2, seven procedures now being used for design of rock riprap installations were evaluated using data from 26 field sites. Four basic types of riprap failures were identified: Particle erosion, translational slide, modified slump, and slump. Factors associated with riprap failure include stone size , bank side slope, size gradation, thickness, insufficient toe or endwall, failure of the bank material, overtopping during floods, and geomorphic changes in the channel. A review of field data and the design procedures suggests that estimates of hydraulic forces acting on the boundary based on flow velocity rather than shear stress are more reliable. Several adjustments for local conditions, such as channel curvature, superelevation, or boundary roughness, may be unwarranted in view of the difficulty in estimating critical hydraulic forces for which the riprap is to be designed. Success of the riprap is related not only to the appropriate procedure for selecting stone size, but also to the reliability of estimated hydraulic and channel factors applicable to the site. (See also W89-04910) (Author 's abstract)

Water-Resources Investigations Report↗
USGS1985

Magnitude and frequency of debris flows, and areas of hazard on Mount Shasta, northern California

Debris flows on Mount Shasta, northern California, have occurred frequently during the late Holocene in response to rapid runoff from melting snow and ice. Glacial-meltwater streams that deeply incise unstable pyroclastic and related flow deposits typically from debris flows when high discharge rates cause slope failures within steep-walled gorges. The landslide material either adsorbs streamflow quickly and becomes a slurry or it briefly dams the stream and converts to a debris flow as breaching occurs. All glacial-meltwater streams on Mount Shasta have been repeated debris-flow activity during the last 500 years. During this period, large-magnitude, potentially destructive flows on Mount Shasta have occurred at a rate of four per century, but smaller flows contained by stream channels may be 10 to 20 times more numerous. The smaller debris flows on Mount Shasta pose little hazard to human life or property, whereas larger, out-of-channel flows could cause minor damage. Only the City of McCloud and inhabited areas on the Whitney-Bolam fan appear to be threatened by possible debris-flow activity. None of the streams lacking glacial meltwater have had significant debris-flow activity during late Holocene time. Sediment yields from upper fan areas of Mount Shasta are very high, but most of the sediment, moved by debris flows from upper slopes is redeposited on lower fan areas, locally causing extensive and rapid aggradation of the fan surface. Little sediment enters a through-flowing stream network. Correspondingly high denudation rates in the sediment source areas for debris flows (the deep gorges) suggest that a high frequency of debris flows may be unique in recent centuries. (USGS)

California↗