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Jerry G. Harmon

Publications and source records attributed to Jerry G. Harmon.

7 recordsLinked to original sources
USGS2000

Storage capacity and sedimentation of Loch Lomond Reservoir, Santa Cruz County, California, 1998

In 1998, a bathymetric survey was done to determine the storage capacity and the loss of capacity owing to sedimentation of Loch Lomond Reservoir in Santa Cruz County, California. Results of the survey indicate that the maximum capacity of the reservoir is 8,991 acre-feet in November 1998. The results of previous investigations indicate that storage capacity of the reservoir is less than 8,991 acre-feet. The storage capacity determined from those investigations probably were underestimated because of limitations of the methods and the equipment used. The volume of sedimentation in a reservoir is considered equal to the decrease in storage capacity. To determine sedimentation in Loch Lomond Reservoir, change in storage capacity was estimated for an upstream reach of the reservoir. The change in storage capacity was determined by comparing a 1998 thalweg profile (valley floor) of the reservoir with thalweg profiles from previous investigations; results of the comparison indicate that sedimentation is occurring in the upstream reach. Cross sections for 1998 and 1982 were compared to determine the magnitude of sedimentation in the upstream reach of the reservoir. Results of the comparison, which were determined from changes in the cross-sectional areas, indicate that the capacity of the reservoir decreased by 55 acre-feet.

California↗
USGS1998

Flood-inundation map and water surface profiles for floods of selected recurrence intervals, Cosumnes River and Deer Creek, Sacramento County, California

The damage caused by the January 1997 floods along the Cosumnes River and Deer Creek generated new interest in planning and managing land use in the study area. The 1997 floodflow peak, the highest on record and considered to be a 150-year flood, caused levee failures at 24 locations. In order to provide a technical basis for floodplain management practices, the U.S. Goelogical Survey, in cooperation with the Federal Emergency Management Agency, completed a flood-inundation map of the Cosumnes River and Deer Creek drainage from Dillard Road bridge to State Highway 99. Flood frequency was estimated from streamflow records for the Cosumnes River at Michigan Bar and Deer Creek near Sloughhouse. Cross sections along a study reach, where the two rivers generally flow parallel to one another, were used with a step-backwater model (WSPRO) to estimate the water-surface profile for floods of selected recurrence intervals. A flood-inundation map was developed to show flood boundaries for the 100-year flood. Water-surface profiles were developed for the 5-, 10-, 50-, 100-, and 500-year floods.

California↗
USGS1998

Potential overflow of Mojave Creek near disposal site, Edwards Air Force Base, California

Sedimentological evidence in Mojave Creek near Edwards, California, indicates that the largest discharge in the last hundred years near the disposal site of the Main Base Landfill at Edwards Air Force Base was a few hundred cubic feet per second. The distal ends of two alluvial fans on the Mojave Creek floodplain near the Main Base Landfill have not been eroded substantially since sediment supply was cut off by a railroad grade completed in 1884. Previous estimates of flood discharges were 4,000 cubic feet per second and larger in this reach; the estimates were calculated by regression equations derived from regional characteristics. However, a 100-year rainfall in 1983 failed to produce erosion in Mojave Creek commensurate with discharges of greater than about 100 cubic feet per second. To test the potential for the creek to overflow and reach the disposal site, a hypothetical discharge was used to determine the depth of flooding at local cross sections. Although the access road from Mojave Boulevard to the Main Base Landfill may be inundated during a flood, the artificial grade at the disposal site would not be reached at a discharge of 2,000 cubic feet per second, which is an order of magnitude greater than the apparent flood discharges that occurred during the past hundred years in Mojave Creek near the present Main Base Landfill.

Open-File Report↗
USGS1994

Flood data for the Sacramento River and Butte Basin, Sacramento Valley, California, 1980-90

Floodflows and peak states of floods were measured and channel cross sections were surveyed at sites along the Sacramento River and in Butte Basin, Sacramento Valley, California, during 1980-90 to document magnitudes of flooding and channel changes. The study reach extends from rivermile 200 near Hamilton City to rivermile 134 near Meridian. Data were collected for each flood at about 70 sites that include streamf-flow gages, crest-stage gages, bridges and road overflows on State Highway 162 east of Butte City, and locations of historical high- water marks. Six cross sections of the river between rivermiles 193.7 near Big Chico Creek and 183.3 near Ordbend were surveyed annually during calendar years 1981-84, and 1986-90. Floodflows (peak flow 157,000 cubic feet per second) almost equaled the design flow capacity of the river at Butte City on March 2, 1983, when the peak stage of 93.0 feet was 5 feet below the top of the levee. This was the largest flood recorded at Butte City during 1980- 90. The most recent flood occurred February 18-19, 1986, when the peak stage in the river at Butte City was 92.0 feet and the peak flow was 145,000 cubic feet per second.

California↗
USGS1983

Sediment and stream-velocity data for the Sacramento River near Hood, California, May 1978 to September 1981

Sediment and stream velocity data from the Sacramento River are required to determine the size requirements of a settling basin for the intake area of the proposed Peripheral Canal near Hood, California. Sediment and stream-velocity data were gathered from May 1978 to September 1981 over several magnitudes of streamflow at four cross sections near Hood. This report, prepared in cooperation with the California Department of Water Resources, contains data that show the vertical distribution and size of sediment, and the magnitude and direction of stream velocity measured at 25 points in each of the four cross sections on several occasions. (USGS)

Open-File Report↗