Geology topics

Edward E. Fischer

Publications and source records attributed to Edward E. Fischer.

7 recordsLinked to original sources

USGS2010

Flood of June 8-9, 2008, Upper Iowa River, Northeast Iowa

Major flooding occurred June 8-9, 2008, in the Upper Iowa River Basin in northeast Iowa following severe thunderstorm activity over the region. About 7 inches of rain were recorded for the 48-hour period ending 4 p.m., June 8, at Decorah, Iowa; more than 7 inches of rain were recorded for the 48-hour period ending 7 a.m., June 8, at Dorchester, Iowa, about 17 miles northeast of Decorah. The maximum peak discharge measured in the Upper Iowa River was 34,100 cubic feet per second at streamgage 05387500 Upper Iowa River at Decorah, Iowa. This discharge is the largest discharge recorded in the Upper Iowa River Basin since streamgaging operations began in the basin in 1914. The flood-probability range of the peak discharge is 0.2 to 1 percent. High-water marks were measured at 15 locations along the Upper Iowa River between State Highway 26 near the mouth at the Mississippi River and U.S. Highway 63 at Chester, Iowa, a distance of 124 river miles. The high-water marks were used to develop a flood profile.

Open-File Report↗

USGS2008

Flood of May 6, 2007, Willow Creek, west-central Iowa

Major flooding occurred May 6, 2007, in the Willow Creek drainage basin in Harrison County following severe thunderstorm activity over west-central Iowa. More than 7 inches of rain were recorded for the 72-hour period ending 7 a.m., May 6, at the Logan, Iowa weather station. The peak discharge in Willow Creek at Medford Avenue near Missouri Valley, Iowa, was 17,000 cubic feet per second. The recurrence interval of the flood is 160 years, which was estimated using regional regression equations. Information about the basin, the storms, the flooding, and a profile of high-water marks measured at 10 locations along Willow Creek between the mouth at the Boyer River and State Highway 37 in Monona County, a distance of almost 33 river miles, are presented in this report.

Iowa↗

USGS2000

Water-quantity and water-quality aspects of a 500-year flood - Nishnabotna River, southwest Iowa, June 1998

Flooding that occurred in southwest Iowa during June 15–17, 1998, was the worst flood ever recorded on the Nishnabotna River, exceeding the theoretical 500-year flood calculated from peak-flow records (1922 to present). This flood was a direct consequence of severe thunderstorm activity that caused more than 4 inches of rain to fall over a large part of the Nishnabotna River Basin. In fact, a new official State record for 24-hour total rainfall (13.18 inches) was set by this storm. The peak streamflow of the Nishnabotna River near Hamburg, Iowa, was 65,100 cubic feet per second, about 20 percent more than any previous recorded peak streamflow at this site. To determine the concentrations of selected contaminants that might be present in this record flooding, water-quality samples were collected within hours of the flood peak. The results from these samples documented the presence of numerous herbicide compounds (11 parent compounds and 12 herbicide degradates). The highest herbicide concentration was 5.06 micrograms per liter (µg/L) for atrazine, followed by metolachlor (1.16 µg/L), metolachlor ESA (1.04 µg/L), acetochlor OA (0.99 µg/L), and acetochlor ESA (0.95 µg/L). The total herbicide concentration (summation of the 23 herbicide compounds detected) was 15.6 µg/L. The timing of the severe thunderstorm activity and flooding, which occurred shortly after chemical application associated with planting of crops, was the principal reason for the large number and concentrations of herbicide compounds found in the flood water. At the time the water-quality samples were collected, the Nishnabotna River was transporting about 6,000 pounds of suspended sediment, 18 pounds of nitrogen, 3 pounds of phosphorus, and 0.02 pound of atrazine each second. These loads were about 10 to 150 times greater than those during a previous runoff event, and about 260 to 4,600 times greater than those during a previous base-flow condition. This sampling demonstrates the importance of collecting both water-quantity and water-quality data during flood events to estimate contaminant loads. Potential environmental effects of a flood can only be understood when both components are measured.

Iowa, Missouri↗

USGS1996

Potential-Scour Assessments at 130 Bridges in Iowa

A total of 130 highway bridges in Iowa were assessed for potential scour using a potential - scour index developed by the U.S. Geological Survey for a bridge- scour study in western Tennessee. Greater values of the index, which is composed of 11 components, suggest a greater likelihood of scour -related problems occurring at a bridge. For the Iowa assessments , the minimum value was 3, the median value was 11.5, and the maximum value was 24.5. None of the 130 bridges required immediate attention with regard to installing scour countermeasures. Based on the results of the assessments , it was concluded that assessing potential scour only once at a site would be of limited benefit in the Iowa Department of Transportation's bridge inspection program. Additional information would help determine whether repeated potential - scour assessments would enhance more timely and cost-effective implementation of scour countermeasures.

Iowa↗

USGS1995

Scour measurements at bridge sites during 1993 Upper Mississippi River Basin flood

The record flood on the upper Mississippi River basin during the summer of 1993 provided a rare opportunity for collection of data on streambed scour at bridges and for testing of scour data collection equipment under extreme hydraulic conditions. Real-time scour measurements at bridges are categorized into one of three classes according to their objective: inspection measurements, limited-detail measurements, and detailed measurements. All three types of measurements were made during the 1993 flood. Recent advances in technology and improved application of existing technology allow hydraulic and channel bathymetry data to be collected more accurately, in greater detail, and more efficiently than previously possible. Two limited-detail and two detailed data sets are presented. The observed depths of scour are consistently less than the depths of pier scour estimated by use of recommended procedures. Additional data processing, analysis, and visualization are required to characterize and understand complex processes measured by use of state-of-the-art instrumentation.

Upper Mississippi River basin↗

USGS1995

Contraction scour at a bridge over Wolf Creek, Iowa

Contraction scour at the State Highway 14 bridge over Wolf Creek in south-central Iowa was caused by a large flood on September 14 and 15, 1992. The bridge is a 30.5-m, single-span steel structure supported by vertical-wall concrete abutments with wingwalls. Approximately 6 meters of scour resulted from the flood. The peak discharge was estimated by water-surface profile analysis to be 2,200 cubic meters per second. A crude stage hydrograph is depicted by a line of gravel deposits created by water overflowing the downstream face of the highway embankment. The fall of the water surface at the bridge was 3.4 m when water began to flow over the highway.

Iowa↗

USGS1991

Source of atrazine and desethylatrazine in a river, during base flow

A budget of atrazine and desethylatrazine loads was computed for a 116-kilometer reach of the Cedar River in Iowa to determine where these compounds enter the river during base-flow conditions. Loads were determined by measuring discharge and concentrations of the compounds for four main-stem sites along the Cedar River and for 27 tributaries on September 20-22, 1989. Tributaries contributed 17 percent of the increased atrazine load and 24 percent of the increased desethylatrazine load measured between the extreme upstream and downstream sites on the Cedar River. The remaining 76 to 83 percent of the increased loads were attributed to input along the groundwater's main stem. The ground-water samples were collected at depths from 1 to 2 meters beneath the river bottom where the ground water was determined to be moving toward the river. The sources of atrazine and desethylatrazine detected in the ground water may include bank storage of river water or ground-water recharge originating at some distance from the river.

Conference Paper↗