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Geology topics

A.R. Schmidt

Publications and source records attributed to A.R. Schmidt.

7 recordsLinked to original sources
USGS1993

Water-level, velocity, and dye measurements in the Chicago tunnels

On April 13, 1992, a section of a 100-year-old underground freight tunnel in downtown Chicago, Illinois was breached where the tunnel crosses under the Chicago River, about 15 meters below land surface. The breach allowed water from the Chicago River to flow into the freight tunnels and into buildings connected to the tunnels. As a result, utility services to more than 100 buildings in downtown Chicago were lost, several hundred thousand workers were sent home, and the entire subway system and a major expressway in the Loop were shut down. The breach in the tunnel was sealed and the tunnel dewatered by the U.S. Army Corps of Engineers (Corps) and its contractors. The U.S. Geological Survey (USGS) assisted the Corps in their efforts to plug and dewater the freight tunnels and connected buildings. This assistance included the installation and operation of telemetered gages for monitoring water levels in the tunnel system and velocity measurements made in the vicinity of the tunnel breach. A fluorescent dye tracer was used to check for leaks in the plugs, which isolated the damaged portion of the Chicago freight tunnel from the remainder of the tunnel system.

Conference Paper↗
USGS1992

Floating sample-collection platform with stage-activated automatic water sampler for streams with large variation in stage

A floating sample-collection platform is described for stream sites where the vertical or horizontal distance between the stream-sampling point and a safe location for the sampler exceed the suction head of the sampler. The platform allows continuous water sampling over the entire storm-runoff hydrogrpah. The platform was developed for a site in southern Illinois.

Illinois↗
USGS1987

Assessment of water quality and factors affecting dissolved oxygen in the Sangamon River, Decatur to Riverton, Illinois, summer 1982

Water quality and processes that affect the dissolved-oxygen concentration in a 45.9 mile reach of the Sangamon River from Decatur to Riverton, Illinois, were determined from data collected during low-flow periods in the summer of 1982. Relations among dissolved oxygen, water discharge, biochemical oxygen demand, ammonia and nitrite plus nitrate concentrations, and photosynthetic-oxygen production were simulated using a one-dimensional, steady-state computer model. Average dissolved oxygen concentrations ranged from 8.0 milligrams per liter at the upstream end of the study reach at Decatur to 5.2 milligrams per liter 12.2 miles downstream. Ammonia concentrations ranged from 45 milligrams per liter at the mouth of Stevens Creek (2.6 miles downstream from Decatur) to 0.03 milligram per liter at the downstream end of the study reach. Un-ionized ammonia concentrations exceeded the maximum concentration specified in the State water quality standard (0.04 milligram per liter) throughout most of the study reach. Model simulations indicated that oxidation of ammonia to form nitrite plus nitrate was the most significant process leading to low dissolved oxygen concentrations in the river. (USGS)

Water-Resources Investigations Report↗
USGS1986

Assessment of low-flow water quality in the Du Page River, Illinois

The relations of several stream processes to concentrations of dissolved oxygen and other constituents during low-flow periods were evaluated for a 70.3-mile reach of the Du Page River in northeastern Illinois, using measured data and computer simulations. Reaeration rates and traveltimes were measured at various flow rates using a steady-state gas-tracer technique. Stream discharge, stage, temperature, and chemical constituent concentrations were measured during two 24-hour periods in July and August 1983. These data were used to describe water quality and to calibrate and verify the QUAL-II one dimensional, steady-state, water quality model. Dissolved oxygen concentrations did not meet the State water quality standards in several subreaches of the Du Page River. Concentrations were consistently below the State minimum dissolved oxygen standard in the downstream 8 miles of the East Branch Du Page River. Model simulations indicate that although ammonia oxidation played a role in the dissolved oxygen depletion, the primary factor was sediment oxygen demand. Other measured chemical constituents that did not comply with the State water quality standards in several subreaches of the river included ammonia, iron, fluoride, and total dissolved solids. (USGS)

Water-Resources Investigations Report↗
USGS1986

Assessment of low-flow water quality in Richland Creek, Illinois

To study the effects of urbanization on water quality, the relations of several stream processes to concentrations of dissolved oxygen and other constituents were evaluated during low-flow periods for a 30.1-mi reach of Richland Creek in southwestern Illinois. The study used both measured data and computer simulations. Reaeration rates and traveltimes were measured at various flow rates using a steady-state, gas-tracer technique. Sediment-oxygen demands were measured at several locations throughout the study reach. Stream discharge, stage, temperature, and chemical-constituent concentrations were measured during two 24-hr periods in July and August 1984. The data were then used to describe water quality and to calibrate and verify the QUAL-II one-dimensional, steady-state, water quality model. (USGS)

Water-Resources Investigations Report↗