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Research about Iowa

Source-linked reports with geographic coverage including Iowa.

At least 289 records · Page 16Linked to original sources
USGS1995

Urban stormwater runoff study at Davenport, Iowa

Urban storm water runoff is being investigated as a nonpoint source of pollution across the country as urban areas with populations over 100,000 conduct studies designed to meet U.S. Environmental Protection Agency guidelines for National Pollutant Discharge Elimination System permits for their stormwater discharges. From 1991 through 1994, the City of Davenport, Iowa (fig. 1), and the U.S. Geological Survey cooperatively conducted a study designed to meet technical conditions of the permit application and to develop the criteria for ongoing monitoring during the term of the permit.

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USGS1995

Delineation of flooding within the upper Mississippi River Basin, 1993 — Flood of June 29-September 18, 1993, in Iowa City and vicinity, Iowa

The hydrologic investigations atlas shows the areas in and around Iowa City, Iowa, that were flooded by the Iowa River in 1993. This map also depicts the Federal Emergency Management Agency (FEMA) 100-year flood boundaries. The drainage basin of the Iowa River at Iowa City received well over 100 percent of normal rainfall in June, July, and August, 1993. At the Cedar Rapids airport, located about 20 miles north-northwest of Iowa City, July rainfall was 414 percent of normal. The discharges at U.S. Geological Survey streamflow-gaging stations on the Iowa River upstream of Coralville Reservoir, just downstream from Coralville Reservoir, and at Iowa City are shown. A profile of the maximum water-surface elevations of the 1993 flood in Iowa City and vicinity is higher than the FEMA 100-year flood profile. The water-surface elevation of Coralville Reservoir is shown from June 29-September 18, 1993.

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USGS1995

Hydrologic data from the lower Cedar River Basin, Iowa, 1989-91

Hydrologic data were collected from May 1989 through July 1991 from the Cedar River and the adjacent alluvial aquifer. The data were collected during various flow regimes of the river to evaluate the movement of agricultural chemicals between surface water and ground water. Water-quality samples from 34 surface-water sites and 95 ground-water sites were analyzed for 11 herbicides, 2 dealkylated atrazine metabolites, and nitrate. Specific conductance, pH, water temperature, and dissolved oxygen were measured at the time of sampling. Discharge and water-quality data from two seepage investigations were collected to identify gaining and losing reaches of the river and to help delineate where agricultural chemicals enter the river. Ancillary data on ground-water levels and river stage also were collected.

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USGS1995

Water resources data, Iowa, water year 1994

Water resources data for Iowa for the 1994 water year consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; ground water levels and water quality of ground-water wells. This report contains discharge records for 115 gaging stations; stage or contents for 8 lakes and reservoirs; water quality for 6 stream-gaging stations; sediment records for 11 stream-gaging stations; water levels for 232 observation wells; and chemical analyses for 101 municipal wells. Also included are data for 93 crest-stage partial-record stations. Additional water data were collected at various sites, but are not part of the systematic datacollection program and are published as miscellaneous discharge measurements and miscellaneous water-quality analyses.

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USGS1995

Effect of the Cedar River on the quality of the ground-water supply for Cedar Rapids, Iowa

The Surface Water Treatment Rule under the 1986 Amendment to the Safe Drinking Water Act requires that public-water supplies be evaluated for susceptibility to surface-water effects. The alluvial aquifer adjacent to the Cedar River is evaluated for biogenic material and monitored for selected water-quality properties and constituents to determine the effect of surface water on the water supply for the City of Cedar Rapids, Iowa. Results from monitoring of selected water-quality properties and constituents showed an inverse relation to river stage or discharge. Water-quality properties and constituents of the alluvial aquifer changed as water flowed from the river to the municipal well as a result of drawdown. The values of specific conductance, pH, temperature, and dissolved oxygen at observation well CRM-4 and municipal well Seminole 10 generally follow the trends of values for the Cedar River. Values at observation well CRM-3 and the municipal water-treatment plant showed very little correlation with values from the river. The traveltime of water through the aquifer could be an indication of the susceptibility of the alluvial aquifer to surface-water effects. Estimated traveltimes from the Cedar River to municipal well Seminole 10 ranged from 7 to 17 days. Above-normal streamflow and precipitation during the study could have increased the effect the river had on the alluvial aquifer and on the possibility of contamination by a pathogen. Microscopic particulate analysis of 29 samples found no Giardia cysts or Crytosporidium oocysts in water collected from municipal wells. Data also indicate that the aquifer is filtering out large numbers of algae, diatoms, rotifers, and nematodes as well as filtering out Cryptosporidium , Giardia , and other protozoa. The number of algae, diatoms, rotifers, protozoa, and vegetative debris for selected municipal wells tested showed at least a reduction to 1 per 1,000 of the number found in the river. A relative risk factor and a log-reduction rate were determined for the aquifer in the vicinity of selected wells. One municipal well had a high-risk factor, three other wells had a moderate-risk factor, and four wells had a low-risk factor. The filtering efficiency of the aquifer is equivalent to a 3 log-reduction rate or 99.99-percent reduction in particulates.

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USGS1995

Hydrogeologic and agricultural-chemical data for the South Skunk River alluvial aquifer at a site in Story County, Iowa, 1992-93

A reconnaissance study was conducted during 1992-93 to collect background hydrogeologic and agricultural-chemical data for the South Skunk River alluvial aquifer near Ames, Iowa. Observation wells were drilled to characterize the surficial geologic materials of a field-scale study site and to provide locations for collecting waterlevel and agricultural-chemical data. Walnut Creek, a tributary to the South Skunk River, forms a lateral boundary on the northern edge of the field site. Water-level measurements showed a hydraulic-head gradient towards the South Skunk River under both wet and dry conditions at the study site. Walnut Creek appears to be losing water to the aquifer during most hydrologic conditions. More than 20 milligrams per liter of nitrate as nitrogen were present consistently in water from the southeastern part of the study site. Nitrate-as-nitrogen concentrations in water samples from other locations routinely did not exceed 10 milligrams per liter. The herbicide atrazine was detected most often, 36 of 38 times, in water samples collected from observation wells adjacent to Walnut Creek. Atrazine was not used on the study site during 1992-93 but was found frequently in water samples from Walnut Creek. Therefore, Walnut Creek appears to be a source of herbicide contamination to the alluvial aquifer.

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USGS1995

Potential-scour assessments and estimates of maximum scour at selected bridges in Iowa

The results of potential-scour assessments at 130 bridges and estimates of maximum scour at 10 bridges in Iowa are presented. All of the bridges evaluated in the study are constructed bridges (not culverts) that are sites of active or discontinued streamflow-gaging stations and peak-stage measurement sites. The period of the study was from October 1991 to September 1994. The potential-scour assessments were made using a potential-scour index developed by the U.S. Geological Survey for a study in western Tennessee. Higher values of the index suggest a greater likelihood of scour-related problems occurring at a bridge. For the Iowa assessments, the maximum value of the index was 24.5, the minimum value was 3, and the median value was 11.5. The two components of the potential-scour index that affected the indices the most in this study were the bed-material component, which accounted for 27.1 percent of the overall total of the indices, and bank erosion at the bridge, which accounted for 18.3 percent of the overall total. Because the potential-scour index represents conditions at a single moment in time, the usefulness of potential-scour assessments is dependent upon regular assessments if the index is used to monitor potential-scour conditions; however, few of the components of the index considered in this study are likely to change between assessments. The estimates of maximum scour were made using scour equations recommended by the Federal Highway Administration. In this study, the long-term aggradation or degradation that occurred during the period of streamflow data collection at each site was evaluated. The streambed appeared to be stable at 6 of the 10sites, was degrading at 3 sites, andwas aggrading at 1 site. The estimates of maximum scour were made at most of the bridges using 100-year and 500-year flood discharges. Other discharges also were evaluated at four of the bridges. With respect to contraction scour, channel cross sections measured during floods show parts of the streambed to be scoured lower than the computed maxi mum contraction-scour depths at 4 of the 10 sites. The measured discharges at three of the sites were less than the respective 100-year floods used to compute scour. No pier-scour measurements were obtained in the study except for about 4 feet of local pier scour that was measured at the bridge over the Iowa River at Wapello, Iowa. However, the streambed was below the base of the pier footing, which is supported by piling, at the time the measurement was made. Discharge-measurement cross sections collected at two other bridges, which are not supported by piling, show the streambed between the piers to be lower than the bases of the piers. Additional investigation may be warranted at these sites to determine whether the streambed has been scoured below the bases at the upstream edges of the piers. Although the abutment-scour equation predicted deep scour holes at many of the sites, the only significant abutment scour that was measured was erosion of the embankment at the left abutment at one bridge after a flood.

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USGS1995

Agricultural chemicals in ground and surface water in a small watershed in Clayton County, Iowa, 1988-91

An investigation was conducted from October 1988 through September 1991 to (1) describe the quality of water in shallow, unconsolidated materials in the 1.09-square-mile Deer Creek watershed in Clayton County, Iowa, and to (2) define the quantity and seasonal distribution of selected agricultural chemicals in water from this watershed. Surficial unconsolidated aquifer materials that discharge water to Deer Creek include alluvium, loess, and glacial till. More than 80 percent of the watershed is used for row and cover crops. Median nitrate concentrations ranged from 16 mg/L (milligrams per liter) in water from the top of the 10-foot thick alluvial aquifer to less than 0.10 mg/L near the bottom. Atrazine was detected in more than 85 percent of the ground-water samples collected at or less than 5.5 feet below land surface. Only one sample collected at 7.0 feet below land surface in the alluvial aquifer had an atrazine concentration greater than the detection limit of 0.10 ug/L (micrograms per liter). Nitrogen and herbicide concentrations were largest in late spring and early summer. Sources of agricultural chemicals in the alluvial aquifer include vertical infiltration through the soil and lateral transport from upslope unconsolidated materials. Nitrogen was present in all water samples from Deer Creek. Nitrate concentrations ranged from 0.70 to 17 mg/L. Alachlor was detected in 11 percent of the samples, atrazine in 69 percent, cyanazine in 19 percent, and metolachlor in 33 percent. Alachlor concentrations ranged from less than 0.10 to 0.53 ug/L, atrazine ranged from less than 0.10 to 55 ug/L, cyanazine ranged from less than 0.10 to 12 ug/L, and metolachlor ranged from less than 0.10 to 69 ug/L. Herbicide detections occurred most frequently in late spring and early summer during or just following chemical application. Overland flow is an important source of nitrogen and herbicides to Deer Creek. Substantial amounts of agricultural chemicals are transported from the watershed. As much as 4,700 pounds, or 6.7 pounds per acre, of nitrogen were estimated to be transported from the watershed in 1 year. Nitrogen loads transported from the Deer Creek watershed were less during dry years than during years with average or greater than average rainfall.

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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.

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USGS1994

Hydrologic data for the Big Spring basin, Clayton County, Iowa, water year 1991

Hydrologic data were collected in the Big Spring Basin located in Clayton County, Iowa, during the 1991 water year. The data were collected by the U.S. Geological Survey in cooperation with the Iowa Department of Natural Resources, Geological Survey Bureau, to provide information on variation and movement of agricultural chemicals in the hydrologic cycle in the basin. Precipitation, surface-water, and ground-water data were collected. The largest amount of rainfall during water year 1991 (54.69 inches) was measured at the monitoring site on Unnamed Creek near Luana. The largest monthly rainfall (14.72 inches) occurred in June. Analyses of 39 rain samples indicated that calcium and sulfate were the predominant ions and that median concentrations of nitrate and ammonia as nitrogen were 0.36 and 0.49 mg/L (milligrams per liter), respectively. Stream discharge, specific conductance, pH, and water temperature were monitored continuously, and monthly water-quality samples were collected at a site on Roberts Creek and at Big Spring. Nitrite plus nitrate as nitrogen concentrations in 27 samples from Roberts Creek at the point where it leaves the study area ranged from 1.8 to 22 mg/L. Herbicide concentrations in 26 samples from the Roberts Creek site ranged from less than 0.10 μ g/L (micrograms per liter) to 43 μ g/L. Alachlor was detected in 42 percent of the samples; atrazine in 92 percent; and cyanazine and metolachlor in 35 percent of the samples. The total suspended-sediment load discharged in Roberts Creek was about 160,000 tons. At Big Spring, the ground-water discharge point, the daily mean specific conductance ranged from 414 to 788 microsiemens per centimeter at 25 degrees Celsius, the daily median pH ranged from 6.7 to 7.1, and the daily mean water temperature ranged from 8.5 to 13.0 degrees Celsius. Concentrations of nitrite plus nitrate as nitrogen in 23 samples ranged from 4.2 to 17 mg/L. The total measured suspended-sediment discharged from Big Spring was about 17,000 tons. Alachlor was detected in 26 percent; atrazine in 100 percent; cyanazine in 26 percent, and metolachlor in 9 percent of the samples. The maximum atrazine concentration was 16 μ g/L.

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USGS1994

Flood of June 17, 1990, in the Clear Creek Basin, east-central Iowa

A water-surface-elevation profile for the flood of June 17, 1990, in the Clear Creek Basin, east-central Iowa, is given in this report. The maximum flood-peak discharge of 10,200 cubic feet per second for the streamflow-gaging station on Clear Creek near Coralville, Iowa (station number 05454300), occurred on June 17, 1990. This discharge was approximately equal to the 80-year recurrence-interval discharge. A flood history describes rainfall conditions for floods that occurred during 1982, 1990, and 1993.

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USGS1994

A summary of water-resources activities of the U.S. Geological Survey in Iowa, fiscal year 1994

Water-resources programs and activities of the U.S. Geological Survey in Iowa consist principally of hydrologic data collection and investigative studies that address water-resource issues. The work is supported by direct Federal funding, by transfer of funds from other Federal agencies, and by joint-funding agreements with State or local agencies. The Iowa District of the Geological Survey's Water Resources Division conducts its hydrologic work through a District Office in Iowa City and Field Headquarters in Iowa City, Council Bluffs, and Fort Dodge. The projects currently being conducted, as summarized in this report, are operated under the general categories of data collection and investigative studies. This report describes: (1) the organization of the Iowa District; (2) the hydrologic data-collection programs; and (3) the local, statewide, regional, or national hydrologic investigations conducted by the U.S. Geological Survey in Iowa during fiscal year 1994. The report also lists reports published or released by the Iowa District since 1984.

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USGS1994

Selected nutrients in stormwater runoff from Davenport, Iowa, 1992

Flow-weighted composite samples of stormwater runoff from areas of different land use in Davenport, Iowa, were collected in the summer and fall of 1992 and analyzed for selected nutrients. Annual constituent loads were estimated for the area drained by the Davenport storm-sewer network. In all cases, the regression-equation estimate of mean annual load is less than the estimate obtained by using the method of the U.S. Environmental Protection Agency. The largest mean annual loads for total nitrite nitrogen, total nitrate nitrogen, total nitrite and nitrate nitrogen, total organic nitrogen, total ammonia and organic nitrogen, total nitrogen, and total phosphorus are associated with residential land, which covers 67.2 percent of the area drained. Using concentration data from this study, it is estimated that an average storm-producing runoff during the 7-day, 10-year low-flow discharge of the Mississippi River would contribute about 4 percent of the total ammonia and organic nitrogen load in the river. Precipitation-chemistry data indicate that substantial parts of the nitrate nitrogen and ammonia nitrogen contained in the stormwater runoff could be from precipitation.

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USGS1994

Contraction scour at a bridge over the Iowa River

Flooding of the Iowa River during July and August 1993 caused extensive contraction scour at the State Highway 99 bridge over the Iowa River at Wapello, Iowa. At least 3.3 m of piling under the footing of the second pier from the right (west) abutment were exposed. The scoured streambed did not fill in again after the flood receded, and a bathymetric survey in November 1993 showed that the streambed had been scoured for a distance of about 500 m upstream from the bridge. The bridge was closed to traffic, first because of water over the roadway when a levee failed, and then remained closed because of the exposed piling. The bridge subsequently was reopened to traffic with a weight limit of 13.6 tons.

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USGS1994

Suspended sediment and stream discharge in Bloody Run and Sny Magill watershed, water year 1992

Hydrologic data were collected in the Bloody Run and Sny Magill watersheds in Clayton County, Iowa during the 1992 Water Year (October 1, 1991 to September 30, 1992) to provide data on suspended sediment and stream discharge from these watersheds. Suspended-sediment samples were collected daily during normal flow and several times during rainstorms. Stream stage was recorded continuously and stream-discharge measurements were made monthly to develop a stage-discharge relation. Data on drainage-basin morphology and precipitation were quantified to help understand the variability in sediment and stream discharge. The total suspended-sediment discharge for Water Year 1992 was 2,720 tons at site BR1 on Bloody Run and 1,940 tons at site SN1 on Sny Magill Creek The daily median suspended-sediment discharge was 1.1 tons at both sites BR1 and SN1. The maximum daily mean stream discharge (205 cubic feet per second) at site BR1 on Bloody Run occurred on November 1, 1991. The median daily discharge at BR1 for the 1992 Water year was 24 cubic feet per second or 0.70 cubic feet per second per square mile (ft 3 /s/mi 2 ). The maximum daily mean stream discharge at site SN1 on Sny Magill Creek was 90 cubic feet per second which occurred on April 20, 1992. The median daily discharge at site SN1 for the 1992 Water Year was 15 cubic feet per second or 0.54 ft 3 /s/mi 2 .

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