Geology Reports⌕ Search

Geology topics

R.N. Oltmann

Publications and source records attributed to R.N. Oltmann.

10 recordsLinked to original sources
USGS2002

Hydrodynamic field study of a shallow estuarine subembayment, Sherman Lake, California

Sherman Lake, California, has two hydrodynamically distinct regions: a tidally forced jet located along the eastern flank that creates an important hydraulic connection between the Sacramento and San Joaquin Rivers, and a relatively quiescent area in the west. The forcing mechanisms driving circulation and transport are spatially variable in Sherman Lake, a characteristic, we are finding, that is typical of shallow-water environments in the San Francisco Bay and Delta. As interest in restoring and creating tidal wetlands and other shallow-water environments in the Delta increases (CALFED, 2001), serious consideration of the heterogeneity of the physical environment must be taken when developing restoration objectives and monitoring programs.

Conference Paper↗
USGS1996

Sediment inflow to the delta from the Sacramento and San Joaquin Rivers

USGS routinely measures the daily suspended sediment load entering the delta with the flows of the Sacramento and San Joaquin rivers. Most of the suspended sediment that flows into the delta is carried by these two rivers, but it also enters from Yolo Bypass; the Mokelumne, Calaveras, and Cosumnes rivers; and several smaller streams. This article presents suspended sediment data for the Sacramento and San Joaquin rivers, and compares the data collected during the water year 1995 to statistically analyzed data from the long-term record.

Interagency Ecological Program Newsletter↗
USGS1987

Rainfall and runoff quantity and quality characteristics of four urban land-use catchments in Fresno, California, October 1981 to April 1983

Rainfall and runoff quantity and quality were monitored for industrial, single-dwelling residential, multiple-dwelling residential, and commercial land-use catchments in Fresno, California, during 1981-82 and 1982-83 rain seasons. Storm-composite rainfall and discrete runoff samples were analyzed for physical, inorganic, organic, and biological constituents. Atmospheric dry-deposition- and street-surface particulate samples also were collected and analyzed. Except for the industrial catchment, highest runoff concentrations for most constituents occurred during initial storm runoff and then decreased throughout the remainder of the storm; constituent concentrations for the industrial catchment fluctuated greatly. Statistical testing of runoff-quality data showed higher concentration for most constituents for the industrial catchment. Lead showed lower concentrations for the industrial catchment than for the other three catchments. Event mean concentration (EMC) for most constituents for all but the industrial catchment were highest for the first two or three storms of the rain season after which they became almost constant; the industrial constituent EMC 's generally did not show any pattern. The organophosphorus compounds, parathion, diazinon, and malathion were the most prevalent pesticides detected in rainfall. Other pesticides detected in rainfall included chlordane, lindane, methoxychlor, endosulfan, and 2 ,4-D. Of these, only methoxychlor and endosulfan were not consistently detected in the runoff. (USGS)

California↗
USGS1987

Rainfall and runoff quantity and quality data collected at four urban land-use catchments in Fresno, California, October 1981-April 1983

Data were collected as part of the National Urban Runoff Program to characterize urban runoff in Fresno, California. Rainfall-runoff quantity and quality data are included along with atmospheric dry-deposition and street-surface particulate quality data. The data are presented in figures and tables that reflect four land uses: industrial, single-dwelling residential, multiple-dwelling residential, and commercial. A total of 255 storms were monitored for rainfall and runoff quantity. Runoff samples from 112 of these storms were analyzed for physical, organic, inorganic, and biological constituents. The majority of the remaining storms have pH and specific conductance data only. Ninety-two composite rain samples were collected. Of these, 63 were analyzed for physical, inorganic, and (or) organic constituents. The remaining rainfall samples have pH and specific conductance data only. Nineteen atmospheric deposition and 21 street-particulate samples were collected and analyzed for inorganic and organic constituents. The report also details equipment utilization and operation, and discusses data collection methods. (USGS)

Open-File Report↗
USGS1984

Estimation of streamflow for selected sites on the Carson and Truckee rivers in California and Nevada, 1944-80

Daily mean and monthly discharges were estimated for 10 sites on the Carson and Truckee Rivers for periods of incomplete records and for tributary sites affected by reservoir regulation. On the basis of the hydrologic characteristics, stream-flow data for a water year were grouped by month or season for subsequent regression analysis. In most cases, simple linear regressions adequately defined a relation of streamflow between gaging stations, but in some instances a nonlinear relation for several months of the water year was derived. Statistical data are presented to indicate the reliability of the estimated streamflow data. Records of discharges including historical and estimated data for the gaging stations for the water years 1944-80 are presented. (USGS)

Water-Resources Investigations Report↗
USGS1979

Application of transient-flow model to the Sacramento River at Sacramento, California

The transient-flow simulation model was applied to the Sacramento River at Sacramento, Calif. An alternative is needed to the empirical stage-fall-discharge computational method, which provides only daily mean discharges and requires frequent measurement over a 25- to 26-hour period of the tide-affected flow. Measurement of tide-affected flow involves use of a cable suspended across the river; this presents a hazardous navigational condition. Use of the model does not eliminate the hazardous navigational problem, but it significantly reduces the time that this condition exists. The model has demonstrated that it can provide reliable daily mean as well as instantaneous discharge data. The model also has the capability of providing discharge data for locations farther downstream in the tidal zone from the Sacramento stream gage; this is not possible with the stage-fall-discharge computational method. (Woodard-USGS)

Water-Resources Investigations Report↗