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Research about Iowa

Source-linked reports with geographic coverage including Iowa.

At least 271 records · Page 15Linked to original sources
USGS1996

Delineation of flooding within the upper Mississippi River Basin — Flood of June 18 through August 4, 1993, in Des Moines and vicinity, Iowa

This hydrologic investigations atlas shows the areas in and near Des Moines, Iowa, that were flooded by the Des Moines and the Raccoon Rivers and Walnut, Fourmile, and Beaver Creeks from June 18 through August 4, 1993. This map also depicts the Federal Emergency Management Agency 100-year flood boundaries. The area drained by the Des Moines River upstream from Des Moines received more than 100 percent of normal rainfall in May, June, and July, 1993. At Boone, which is located about 35 miles north-northeast of Des Moines, July rainfall was 424 percent of normal. The discharges at streamflow- gaging stations on the Des Moines River near Stratford, downstream from Saylorville Lake, and at Des Moines are shown. The cumulative discharge for inflow-gaging stations in the Des Moines area and discharge for the Des Moines River below the Raccoon River at Des Moines from July 8 through 21, 1993, are shown. The water-surface elevations of Saylorville Lake from June 18 through August 4, 1993, are shown. Profiles of the maximum water- surface elevations of the Des Moines and Raccoon Rivers during the 1993 flood in Des Moines and vicinity are higher than the respective Federal Emergency Management Agency 100- and 500-year flood profiles.

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USGS1996

Water-quality data of stormwater runoff from Davenport, Iowa, 1992 and 1994

The Water Quality Act of 1987 required the U.S. Environmental Protection Agency to regulate stormwater discharges under the National Pollutant Discharge Elimination System program, and guidelines for obtaining permits under this program were established for areas served by municipal separate storm sewer systems with populations greater than 100,000 (U.S. Environmental Protection Agency, 1992a, 1992b). The City of Davenport, Iowa, and the U.S. Geological Survey cooperatively conducted a study designed to meet technical conditions of the permit application and to develop criteria for ongoing monitoring during the term of the permit. During 1992 and 1994, stormwater runoff in Davenport, Iowa, was sampled from the following land use types: agricultural and vacant, residential, commercial, parks and wooded areas, and industrial. Grab samples collected within the first hour of the runoff event were analyzed for many constituents including volatile organic compounds. Flow-weighted composite samples, composed from discrete samples collected at 15-minute intervals during the first three hours of the event or until discharge returned to pre-event levels, also were analyzed for many constituents including major ions, nitrogen, phosphorus, metals, total organic carbon, acid/base-neutral organics, organochlorine pesticides, and polycyclic aromatic hydrocarbons.

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USGS1996

Survey of users of the USGS stream-gaging network in Iowa, 1996

A survey was sent to over 200 Federal, State, and local agencies that might use streamflow data collected by the U.S. Geological Survey in Iowa. A total of 181 forms were returned and 112 agencies indicated that they use streamflow data. The responses show that streamflow data from the Iowa USGS stream-gaging network, which in 1996 is composed of 117 stations, are used by many agencies for many purposes and that many stations provide streamflow data that fulfill a variety of joint purposes. The median number of respondents per station that use data from the station was 6 and the median number of data-use categories indicated per station was 9. The survey results can be used by agencies that fund the Iowa USGS stream-gaging network to help them decide which stations to continue to support if it becomes necessary to reduce the size of the stream-gaging network.

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USGS1996

Floods of June 17, 1990, and July 9, 1993, along Squaw Creek and the South Skunk River in Ames, Iowa, and vicinity

Water-surface-elevation profiles and peak discharges for the floods of June 17, 1990, and July 9, 1993, along Squaw Creek and the South Skunk River, in Ames, Iowa, are presented in this report. The maximum flood-peak discharge of 24,300 cubic feet per second for the streamflow-gaging station on Squaw Creek at Ames, Iowa (station number 05470500) occurred on July 9, 1993. This discharge was 80 percent larger than the 100-year recurrence-interval discharge and exceeded the previous record flood-peak discharge of June 17, 1990, by 94 percent. The July 9, 1993, flood-peak discharge of 26,500 cubic feet per second on the South Skunk River below Squaw Creek (station number 05471000) was also a peak of record, exceeding the previous record flood-peak discharge of June 27, 1975, by 80 percent, and the 100-year recurrence-interval discharge by 60 percent. A flood history describes rainfall conditions for floods that occurred during 1990 and 1993. The report also includes information on flood stages and discharges and floodflow frequencies for the active gaging stations in the vicinity of Ames, Iowa, and on temporary bench marks and reference points in the Squaw Creek and South Skunk River Basins near Ames, Iowa.

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USGS1996

Selected hydrogeologic data from the Cedar Rapids Area, Benton and Linn counties, Iowa, October 1992 through March 1996

The city of Cedar Rapids, Iowa, obtains its water supply from shallow wells screened in the alluvial aquifer along the Cedar River. A cooperative study between the city of Cedar Rapids, Iowa, and the U.S. Geological Survey was started in March 1992 to assess the water quality and water quantity of the ground-water resource. This report summarizes selected hydrogeologic data collected from October 1992 through March 1996. Information collected includes water quality (major ions, nutrients, and pesticides), ground-water levels, multiprobe-instrument data (water levels, specific conductance, pH, water temperature, and dissolved oxygen monitored at 15-, 30-, or 60-minute intervals), well information (location, casing type, screen interval, and depth), and geophysical seismic-refraction and seismic-reflection data (estimated depth to bedrock and alluvial thickness along the Cedar River). Geologic, hydrologic, and water-quality data were collected from domestic, municipal, observation, and industrial wells and the Cedar River. Well-construction data for more than 300 wells in the Cedar Rapids area in Benton and Linn Counties, Iowa, were compiled primarily from records on file with the Iowa Department of Natural Resources, Geologic Survey Bureau (Iowa City).

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USGS1996

Flood of May 19, 1990, along Perry Creek in Plymouth and Woodbury counties, Iowa

A water-surface-elevation profile and peak discharges for the flood of May 19, 1990, along Perry Creek in Plymouth and Woodbury Counties, Iowa, are presented in this report. The peak discharge for the May 19,1990, flood on Perry Creek at 38th Street, Sioux City (06600000) is the second largest flood-peak discharge recorded at the streamflow-gaging station for the period 1939-95. The peak discharge for May 19, 1990, of 8,670 cubic feet per second, is approximately equal to the 35-year recurrence-interval discharge. The report provides information on flood stages and discharges and floodflow frequencies for streamflow-gaging stations in the Perry Creek Basin using flood information collected during 1939-95. Information on temporary bench marks and reference points established in the Perry Creek Basin during 1990-93 is also included in the report. A flood history describes rainfall conditions for the three largest floods that occurred during 1939-95 (July 1944, September 1949, and May 1990).

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USGS1996

Floods of July 12, 1972, March 19, 1979, and June 15, 1991, in the Turkey River Basin, northeast Iowa

Water-surface-elevation profiles and peak discharges for the floods of July 12, 1972, March 19, 1979, and June 15, 1991, in the Turkey River Basin, northeast Iowa, are presented in this report. The profiles illustrate the 1979 and 1991 floods along the Turkey River in Fayette and Clayton Counties and along the Volga River in Clayton County; the 1991 flood along Roberts Creek in Clayton County and along Otter Creek in Fayette County; and the 1972 flood along the Turkey River in Winneshiek and Fayette Counties. Watersurface elevations for the flood of March 19,1979, were collected by the Iowa Natural Resources Council. The June 15, 1991, flood on the Turkey River at Garber (station number 05412500) is the largest known flood-peak discharge at the streamflow-gaging station for the period 1902-95. The peak discharge for June 15, 1991, of 49,900 cubic feet per second was 1.4 times larger than the 100-year recurrence-interval discharge. The report provides information on flood stages and discharges and floodflow frequencies for streamflow-gaging stations in the Turkey River Basin using flood information collected during 1902-95. Information on temporary bench marks and reference points established in the Turkey River Basin during 1981, 1992, and 1996 also is included in the report. A flood history describes rainfall conditions for floods that occurred during 1922, 1947, 1972, 1979, and 1991.

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USGS1996

Ground-water levels and flow at selected study sites in the Walnut Creek Management System Evaluation Area, Boone and Story counties, Iowa, 1991-93

Data collected from May 1991 through September 1993 to determine seasonal fluctuations in ground-water levels and to estimate directions of ground-water flow in the saturated zone at selected study sites at the Iowa Management Systems Evaluation Area in the Walnut Creek Watershed are presented. The Walnut Creek Watershed is located on glacial deposits of Wisconsinan age in central Iowa and includes about 20 square miles. The upper glacial materials appear to be supraglacial tills rather than basal glacial tills and contain both oxidized and unoxidized zones. Water levels were measured in 102 wells from 38 locations at 7 study sites in the watershed. Water levels fluctuated in response to local climatic conditions and ranged from at or near the land surface to more than 30 feet below land surface. In general, ground water flowed towards Walnut Creek or large drainage tiles. Potentiometric-surface maps at the selected study sites can be used to determine which locations might be affected by agricultural management practices in place at each site.

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USGS1996

Flood-plain and channel aggradation at selected bridge sites in the Iowa and Skunk River basins, Iowa

Flood-plain and channel-aggradation rates were estimated at 10 bridge sites on the Iowa River upstream of Coralville Lake and at two bridge sites in the central part of the Skunk River Basin. Four measurement methods were used to quantify aggradation rates: (1) a dendrogeomorphic method that used tree-age data and sediment-deposition depths, (2) a bridge-opening cross-section method that compared historic and recent cross sections of bridge openings, (3) a stage-discharge rating-curve method that compared historic and recent stages for the 5-year flood discharge and the average discharge, and (4) nine sediment pads that were installed on the Iowa River flood plain at three bridge sites in the vicinity of Marshalltown. The sediment pads were installed prior to overbank flooding in 1993. Sediments deposited on the pads as a result of the 1993 flood ranged in depth from 0.004 to 2.95 feet. Measurement periods used to estimate average aggradation rates ranged from 1 to 98 years and varied among methods and sites. The highest aggradation rates calculated for the Iowa River Basin using the dendrogeomorphic and rating- curve measurement methods were for the State Highway 14 crossing at Marshalltown, where these highest rates were 0.045 and 0.124 feet per year, respectively. The highest aggradation rates calculated for the Skunk River Basin were for the U.S. Highway 63 crossing of the South Skunk River near Oskaloosa, where these highest rates were 0.051 and 0.298 feet per year, respectively.

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USGS1996

Transport of agricultural chemicals in surface flow, tileflow, and streamflow of Walnut Creek Watershed near Ames, Iowa, April 1991-September 1993

The U.S. Geological Survey, in cooperation with the National Soil Tilth Laboratory of the U.S. Department of Agriculture, Agricultural Research Service, conducted a study as part of the multi-scale, inter-agency Management Systems Evaluation Area (MSEA) program to evaluate the effects of agricultural management (farming) systems on water quality. Data on surface flow, tileflow, and streamflow in the Walnut Creek watershed just south of Ames, Iowa, were collected during April 1991-September 1993 at five sites with drainage areas ranging from 366 to 5,130 hectares. Precipitation, flow discharge, and concentration, loads, and yields of nitrate as nitrogen, atrazine, and metolachlor were analyzed to relate the transport of agricultural chemicals to major water-flow processes and to examine flow and transport differences among three subwatersheds. Antecedent conditions and basin-characteristic differences had significant effects on the flow response from the subwatersheds. Monthly streamflow-to-precipitation ratios were greater than 1.0, as a result of snowmelt, and negative when streamflow was lost to the ground-water system in the downstream subwatershed. Dry antecedent conditions resulted in ratios less than 0.3 (July 1992), whereas wet antecedent conditions resulted in ratios from 0.7 to almost 1.0 (July 1993) during months with similar large rainfall amounts. Most of the streamflow from the upland subwatersheds came from tileflow. Surface flow (surface runoff, interflow, and return flow) was highly variable and intermittent, usually lasting for only a few days after a storm, although it could be the dominant source of flow when stormflow was large. Tileflow was less variable and much more persistent, ceasing only after prolonged dry periods. Large quantities of nitrate as nitrogen were transported in Walnut Creek, with concentrations often greater than the Maximum Contaminant Level of 10 milligrams per liter established by the U.S. Environmental Protection Agency for finished drinking water. In the upland subwatersheds, ground-water flow from the tiles appears to have been the primary means of transport to the streams. Concentrations in tileflow and streamflow generally were 4 to 16 milligrams per liter, with the lower concentrations often the result of dilution by surface runoff. Loss ratios, chemical yields expressed as a percentage of average application rates of nitrate as nitrogen for October 1992-September 1993, were about 10 percent for surface flow and more than 100 percent for tileflow from the 366-hectare basin and were more than 200 percent for streamflow from the downstream subwatershed. Concentrations of atrazine and metolachlor in streamflow, typically, were less than the Maximum Contaminant Level of 3.0 micrograms per liter, but were as high as 59 and 80 micrograms per liter, respectively, during stormflow. Concentrations as high as 170 micrograms per liter occurred in tileflow, but these were related to surface flow through surface inlets. The transport of herbicides was extremely variable, with most of the loads occurring during stormflow. Atrazine appeared more susceptible to transport losses to streamflow than did metolachlor. Loss ratios for streamflow from the subwatersheds for April-September periods were 0.3 to 20 percent for atrazine and 0.1 to 2.9 percent for metolachlor. Chemical loss ratios indicated differences in the transport characteristics of the three subwatersheds. The downstream subwatershed, which has steeper terrain, a more-developed natural drainage system, and fewer tiles than the two upland subwatersheds, had the largest loss rates for all three chemicals 206 percent for nitrate as nitrogen (October 1992-September 1993) and 20 percent for atrazine and 2.9 percent for metolachlor (April-September 1993). For May-July 1993, when most of the herbicides were transported, the downstream subwatershed also had the largest cumulative unit discharge and the largest streamflow-to-precipitation ratios.

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USGS1996

A dynamical-systems approach for computing ice-affected streamflow

A dynamical-systems approach was developed and evaluated for computing ice-affected streamflow. The approach provides for dynamic simulation and parameter estimation of site-specific equations relating ice effects to routinely measured environmental variables. Comparison indicates that results from the dynamical-systems approach ranked higher than results from 11 analytical methods previously investigated on the basis of accuracy and feasibility criteria. Additional research will likely lead to further improvements in the approach.

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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.

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USGS1995

Occurrence of active and inactive herbicide ingredients at selected sites in Iowa

The objective of this study was to investigate the occurrence of herbicide active and inactive ingredients (primarily volatile organic compounds) at four selected sites in Iowa representing drain tiles, observation wells, or lysimeters. Water samples were collected monthly and bi-monthly before and after herbicide applications in 1991, respectively. They were analyzed for seven herbicides and 32 volatile organic compounds using methods recommended by the U.S. Environmental Protection Agency. Commercially available herbicide formulations also were obtained and analyzed for volatile organic compounds. Herbicides were detected in 50% of water samples, ranging from 78% of water samples from the Ames site to 25% from the Walnut Creek site. Among herbicides detected, listed in decreasing order of frequency, were atrazine > alachlor > cyanazine > metolachlor > metribuzin. Volatile organic compounds were detected in 11% of water samples. Among the compounds detected, listed in decreasing order of frequency, were xylene > toluene > acetone. One sample contained a detectable amount of aliphatic compound(s), with the empirical formula of C 8 H 18 . Results from the Deer Creek site showed that herbicides were detected primarily in the top layer (1.2 m), whereas xylene and other alkylbenzenes were detected at 2.1 m or deeper. Apparently, physico-chemical and other factors are separating herbicides and volatile organic compounds in the shallow unsaturated zone.

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USGS1995

Largemouth bass response to habitat and water quality rehabilitation in a backwater of the upper Mississippi River

Severe sedimentation since lock and dam construction in the 1930s has reduced water depth in Upper and Lower Brownˈs lakes, a backwater complex in Pool 13 of the upper Mississippi River, and resulted in periods of chronic anoxia. This backwater complex was rehabilitated by construction of a deflection levee, installation of a water control structure, and excavation of canals through the area. Water quality variables inside and outside the project area, movement of radio-tagged largemouth bass in response to changing oxygen concentrations, and creel statistics were used to evaluate the success of the improvements. Turbidity was significantly less in the Brownˈs Lake complex than in the main channel. Oxygen concentrations were allowed to deteriorate to 3 ppm before the water control structures were opened during the winter; within 7 d, oxygen concentrations as high as 10 ppm were found in the top strata in most of the Brownˈs Lake complex. Chemical and thermal stratification observed in the dredge canal water column were caused by colder (32°F), highly oxygenated water from the main channel moving over denser, warmer (36–38°F) water in the dredge canals. Water in the dredge canals remained stratified until ice-out, with colder, oxygenated water in the surface stratum; warmer, but anoxic, water in the bottom stratum; and a mixture (3–7 ppm oxygen and 35–36°F) in the middle stratum. Fourteen radio-tagged largemouth bass Micropterus salmoides were located in the Brownˈs Lake complex in December before oxygen concentrations began to decline, Concurrent with oxygen declines, most radio-tagged fish exited the complex through a slough connected to the main channel and returned when the water control structure was opened and oxygen concentrations increased. Some radio-tagged largemouth bass moved 4 mi under ice to return to the complex. Estimated angler effort and catch increased 58 and 117%, respectively, in the Lower Brownˈs Lake–Lainesville Slough complex following rehabilitation. A 10-fold increase in angler effort and catch was estimated for Upper Brownˈs Lake after the project was completed.

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