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Research about Iowa, Minnesota

Source-linked reports with geographic coverage including Iowa, Minnesota.

30 records · Page 2Linked to original sources
USGS2000

Physical characteristics of stream subbasins in the Des Moines River, Upper Des Moines River, and East Fork Des Moines River basins, southern Minnesota and northern Iowa

Data that describe the physical characteristics of stream subbasins upstream from selected sites on streams in the Des Moines River, Upper Des Moines River, and East Fork Des Moines River Basins, located in southwestern Minnesota, and northwestern Iowa, are presented in this report. The physical characteristics are the drainage area of the subbasin, the percentage area of the subbasin covered only by lakes, the percentage area of the subbasin covered by both lakes and wetlands, the main-channel length, and the main-channel slope. Stream sites include outlets of subbasins of at least 5 square miles, and locations of U.S. Geological Survey high-flow, and continuous-record gaging stations.

Iowa, Minnesota↗
USGS2000

Ground-water quality in alluvial aquifers in the eastern Iowa basins, Iowa and Minnesota

The quality of shallow alluvial ground water that is used for domestic supplies in the Wapsipinicon, Cedar, Iowa, and Skunk River Basins (Eastern Iowa Basins) is described. Water samples from 32 domestic-supply wells were collected from June through July 1998. This study of ground-water quality in alluvial aquifers in the Eastern Iowa Basins is part of the U.S. Geological Survey's National Water-Quality Assessment Program. Calcium and bicarbonate were the dominant ions in solution, likely derived from the dissolution of carbonate minerals in the alluvial aquifer material. Concentrations of iron exceeded the U.S. Environmental Protection Agency Secondary Maximum Contaminant Level (300 micrograms per liter) for drinking water in 53 percent of the samples, and 50 percent of the samples exceeded the Secondary Maximum Contaminant Level for manganese (50 micrograms per liter). pH and alkalinity increased and sulfate concentrations decreased with increasing well depth. Nitrite plus nitrate nitrogen was detected in 53 percent of the samples and exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level of 10 milligrams per liter for drinking water in 13 percent of the samples. Nitrite plus nitrate nitrogen concentrations were negatively correlated with well depth and positively correlated with percentage of oxygen saturation. Ammonia plus organic nitrogen concentrations were positively correlated with well depth, and ratios of nitrite plus nitrate to ammonia were positively correlated with percentage of oxygen saturation. The majority of samples, 72 percent, contained water recharged since the early 1950's. The recharge date of water was earlier in deeper wells. Nitrite plus nitrate and total pesticide concentrations were greater in more recently recharged water. Eight pesticides and eight pesticide metabolites were detected in ground-water samples. Atrazine was the most commonly detected pesticide, and metolachlor ethanesulfonic acid was the most commonly detected metabolite. No pesticide detections exceeded U.S. Environmental Protection Agency drinking-water Maximum Contaminant Levels. The effects of land use on ground-water quality also were examined. There was a positive correlation between percentage of land used for soybean production and concentrations of metolachlor, metolachlor ethanesulfonic acid, and metolachlor oxanilic acid in ground-water samples. Data from this study and from previous studies in the Eastern Iowa Basins were compared statistically by well type (domestic, municipal, and monitoring wells). Well depths were significantly greater in domestic and municipal wells than in monitoring wells. pH, calcium, sulfate, chloride, and atrazine concentrations were significantly higher in municipal-well samples than in domestic-well samples. pH and sulfate concentrations were significantly higher in municipal-well samples than in monitoring-well samples. Ammonia was significantly higher in domestic-well samples than in monitoring-well samples, chloride was significantly higher in monitoring-well samples than in domestic-well samples, and fluoride was significantly higher in domestic-well samples than in municipal-well samples.

Iowa, Minnesota↗
USGS2000

Effects of land use and hydrogeology on the water quality of alluvial aquifers in eastern Iowa and southern Minnesota, 1997

Ground-water samples were collected from monitoring wells at 31 agricultural and 30 urban sites in the Eastern Iowa Basins study unit during June–August 1997 to evaluate the effects of land use and hydrogeology on the water quality of alluvial aquifers. Ground-water samples were analyzed for common ions, nutrients, dissolved organic carbon, tritium, radon-222, pesticides and pesticide metabolites, volatile organic compounds, and environmental isotopes. Calcium, magnesium, and bicarbonate were the dominant ions in most samples and were likely derived from solution of carbonate minerals (calcite and dolomite) present in alluvial detrital deposits. Chloride and nitrate were dominant anions in samples from several wells. Sodium and chloride concentrations were significantly higher in samples from urban areas, where roads are more numerous and road salts may be more frequently applied, than in agricultural areas. Nitrate was detected in 94 percent of samples from agricultural areas and 77 percent of samples from urban areas. Nitrate concentrations were significantly higher in agricultural areas than in urban areas and exceeded the U.S. Environmental Protection Agency maximum ontaminant level for drinking water (10 milligrams per liter as N) in 39 percent of samples from agricultural areas. Nitrate concentrations in samples from urban areas did not exceed the maximum contaminant level. Greater use of fertilizers in agricultural areas most likely contributes to higher nitrate concentrations in samples from those areas. Tritium-based ages indicate ground water was most likely recharged after the 1950’s at all but one sampling site. Agricultural and urban land-use areas have remained relatively stable in the study area since the 1950’s; therefore, the effects of current land use should be reflected in ground water sampled during this study. Radon-222 was detected in all samples and exceeded the U.S. Environmental Protection Agency’s previously proposed maximum contaminant level for drinking water (300 picocuries per liter) in 71 percent of samples. Pesticides were detected in 84 percent of samples from agricultural areas and 70 percent from urban areas. Atrazine and metolachlor were the most frequently detected pesticides in samples from agricultural areas; atrazine and prometon were the most frequently detected pesticides in samples from urban areas. None of the pesticide oncentrations exceeded U.S. Environmental Protection Agency maximum contaminant levels or lifetime health advisories for drinking water. Pesticide metabolites were detected in 94 percent of samples from agricultural areas and 53 percent from urban areas. Metolachlor ethane sulfonic acid and deethylatrazine were the most frequently detected metabolites in samples from agricultural areas; metolachlor ethane sulfonic acid and alachlor ethane sulfonic acid were the most frequently detected metabolites in samples from urban areas. Total metabolite concentrations were significantly higher in samples from agricultural areas than in samples from urban areas. Total pesticide concentrations (parent compounds) tended to be higher in samples from agricultural areas; however, this difference was not statistically significant. Metabolites constituted the major portion of the total residue concentration in the alluvial aquifer. Volatile organic compounds were detected in 40 percent of samples from urban areas and 10 percent from agricultural areas. Methyl tertbutyl ether was the most commonly detected volatile organic compound and was present in 23 percent of samples from urban areas. Elevated concentrations (greater than 30 micrograms per liter) of methyl tert-butyl ether and BTEX compounds (benzene, toluene, ethylbenzene, and xylene) in two samples from urban areas suggest the possible presence of point-source gasoline leaks or spills. Factors other than land use may contribute to observed differences in water quality between and within agricultural and urban areas. Nitrate, atrazine, deethylatrazine, and deisopropylatrazine concentrations were significantly higher in shallow wells with sample intervals nearer the water table and in wells with thinner cumulative clay thickness above the sample intervals. These relations suggest that longer flow paths allow for greater residence time and increase opportunities for sorption, degradation, and dispersion, which may contribute to decreases in nutrient and pesticide concentrations with depth. Nitrogen speciation was influenced by redox conditions. Nitrate concentrations were significantly higher in ground water with dissolved-oxygen concentrations in excess of 0.5 milligram per liter. Ammonia concentrations were higher in ground water with dissolved-oxygen concentrations of 0.5 milligram per liter or less; however, this relation was not statistically significant. The amount of available organic matter may limit denitrification rates. Elevated nitrate concentrations (greater than 2.0 mg/L) were significantly related to lower dissolved organic carbon concentrations in water samples from both agricultural and urban areas. A similar relation between nitrate concentrations (in water) and organic carbon concentrations (in aquifer material) also was observed but was not statistically significant.

Iowa, Minnesota↗
USGS1999

Water-quality assessment of the eastern Iowa basins: Data, September 1995 through September 1996

The U.S. Geological Survey began data-collection activities in the Eastern Iowa Basins study unit of the National Water-Quality Assessment Program in September 1995 with the purpose of determining the status and trends in water quality. Surface-water data were collected, beginning in March 1996, on a monthly basis with occasional extra high- and low-flow samples. Data collected from 12 sites on rivers and streams in the study unit included determinations of the physical properties and concentrations of nutrients, major ions, organic carbon, trace elements, suspended sediment, and dissolved pesticides. Data collected at four additional sites included physical parameters and determination of the concentration of dissolved pesticides. In addition, bed-sediment and fish-tissue samples were collected at 16 sites and analyzed for trace elements and hydrophobic pesticides. There were two ground-water studies conducted in June and July 1996. The first looked at the quality of ground water in the Silurian-Devonian and Upper Carbonate aquifers and sampled 33 wells once, and the second examined the effects of agriculture on shallow ground water of the Iowa River alluvial aquifer and sampled 23 wells once. Ground-water samples were analyzed for physical properties, nutrients, major ions, organic carbon, trace elements, dissolved pesticides, and volatile organic compounds.

Iowa, Minnesota↗
USGS1999

Ground-water quality in the eastern part of the Silurian-Devonian and upper Carbonate aquifers in the eastern Iowa basins, Iowa and Minnesota, 1996

Ground-water samples were collected from 33 domestic wells to assess the water quality of the eastern part of the Silurian-Devonian and Upper Carbonate aquifers in the Eastern Iowa Basins National Water-Quality Assessment Program study unit. Samples were collected during June and July 1996 and analyzed for major ions, nutrients, pesticides and pesticide metabolites, volatile organic compounds, tritium, radon222, and environmental isotopes. Calcium, magnesium, and bicarbonate were the dominant ions in most samples and were likely derived from the solution of carbonate minerals (calcite and dolomite) present in the aquifer materials. The dominance of sulfate in samples from several wells suggests the dissolution of evaporite minerals. Ammonia and orthophosphorus were the most commonly detected nutrients. Nitrate was detected in about half of the samples and exceeded the U.S. Environmental Protection Agency maximum contaminant level (10 milligrams per liter) in 6 percent of samples. Atrazine and metolachlor were the only pesticides detected and were present in 18 percent and 12 percent of samples, respectively. Alachlor ethanesulfonic acid and deethylatrazine were the most commonly detected pesticide metabolites and were present in 16 percent and 9 percent of samples, respectively. Radon-222 was detected in all samples, and 47 percent had concentrations in excess of the U.S. Environmental Protection Agency previously proposed maximum contaminant level (300 picocuries per liter). Radon-222 concentrations were significantly higher in samples from wells that produced recently recharged water. This relation suggests that uranium-bearing glacial deposits (Schumann, 1993) may be a source of radon-222 in the underlying aquifers. The presence of regional confining units and thick overlying Quaternary-age deposits have an effect on water quality in the Silurian-Devonian and Upper Carbonate aquifers in the study area. Tritium-based ground-water ages were significantly older, and dissolved-solids concentrations were significantly higher in relatively well protected areas (where the aquifers are overlain by a bedrock confining unit or more than 100 feet of Quaternary-age deposits). Ammonia concentrations were significantly higher in relatively well protected areas and in samples from wells that produced older water. Higher ammonia concentrations also were observed in ground water with dissolved-oxygen concentrations of 0.5 milligram per liter or less, allowing for the anaerobic reduction of nitrate to ammonia. Nitrate concentrations were significantly higher in relatively poorly protected areas (where the aquifers are not overlain by a bedrock confining unit or are overlain by less than 100 feet of Quaternaryage deposits) and in samples from wells that produced recently recharged water. Pesticide and metabolite concentrations were significantly higher in samples from wells that produced recently recharged water. Atrazine, metolachlor, and deethylatrazine were not detected in any samples from relatively well protected areas of the aquifers.

Iowa, Minnesota↗
USGS1999

Selected nutrients and pesticides in streams of the eastern Iowa basins, 1970-95

Water-quality data from 17 surface-water monitoring sites were compiled for 1970 through 1995 and analyzed to determine historical waterquality conditions and possible trends in the Eastern Iowa Basins study unit as part of the U.S. Geological Survey's National Water-Quality Assessment Program. The Eastern Iowa Basins encompasses the Wapsipinicon, Cedar, Iowa, and Skunk River Basins and covers about 19,500 square miles. Seven of the monitoring sites were sampled by the Iowa Department of Natural Resources, three sites by the Minnesota Pollution Control Agency, three sites by the University of Iowa Institute for Hydraulic Research, and four sites by the U.S. Geological Survey. Water-quality analyses typically consisted of nitrate, ammonia, total nitrogen, and total phosphorus, with limited analyses available for organic nitrogen, dissolved phosphorus, dissolved orthophosphate, and water-soluble pesticides. Long-term historical nutrient and pesticide data were not available for the Wapsipinicon River Basin. Median concentrations for total nitrogen ranged from 4.6 to 9.4 milligrams per liter, and maximum concentrations of total nitrogen ranged from 4.6 to 31 milligrams per liter. The majority of nitrogen transported in surface waters of the Eastern Iowa Basins study unit is in the form of nitrate (nitrogen). Median concentrations of total phosphorus ranged from less than 0.10 to 0.66 milligram per liter, and maximum concentrations of total phosphorus ranged from less than 0.10 to 5.4 milligrams per liter. Nitrate varied seasonally. Median concentrations of nitrate were largest during the spring and the winter (6.0 to 7.0 milligrams per liter) compared to the summer and fall (2.0 to 4.0 milligrams per liter). Concentrations of nitrate greater than 10 milligrams per liter typically occurred during spring runoff. Median ammonia concentrations generally were highest during the winter (approximately 0.3-0.5 milligram per liter) compared to the spring and summer when ammonia concentrations were often close to the detection limit (0.01 milligram per liter). In general, the median concentrations of total phosphorus varied less than 0.1 milligram per liter between seasons. The statistical analysis of the nutrient data typically indicated a strong positive correlation of nitrate with streamflow. Total phosphorus concentrations with streamflow showed greater variability than nitrate, perhaps reflecting the greater potential of transport of phosphorus on sediment rather than in the dissolved phase as with nitrate. Ammonia and ammonia plus organic nitrogen showed no correlation with streamflow or a weak positive correlation. Seasonal variations and the relations of nutrients and pesticides to streamflow generally corresponded with nonpoint‑source loadings, although possible point sources for nutrients were indicated by the data at selected monitoring sites. Statistical trend tests for concentrations and loads were computed for nitrate, ammonia, and total phosphorus. Trend analysis indicated decreases for ammonia and total phosphorus concentrations at several sites and increases for nitrate concentrations at other sites in the study unit.

Iowa, Minnesota↗
USGS1996

Movement of agricultural chemicals between surface water and ground water, lower Cedar River basin, Iowa

Movement of agricultural chemicals alachlor, atrazine, cyanazine, deethylatrazine, deisopropylatrazine, and metolachlor between surface water and ground water is documented by data collected from May 1989 through July 1991 at an unfarmed study site adjacent to the Cedar River in Iowa. During periods of runoff, these chemicals moved from the Cedar River into the alluvial aquifer with bank-storage water. Results of simulation of ground-water flow conditions during March-April 1990 indicated that bank-storage water moving through the river bottom accounted for 70 percent of the total bank-storage water, whereas the remaining 30 percent moved through the riverbank. The largest concentrations of the chemicals in bank-storage water during 1990 were: alachlor, 2.1 micrograms per liter ( μ g/L); atrazine, 4.7 μ g/L; cyanazine, 3.2 μ g/L; deethylatrazine, 0.54 μ g/L; deisopropylatrazine, 0.33 μ g/L; and metolachlor, 2.2 μ g/L. Larger concentrations of some herbicides and their metabolites were detected in the ground water after the study site was inundated by floodwater between June and August 1990. The concentrations in a water sample from one well after this flooding on February 5, 1991, were: alachlor, 0.06 μ g/L; atrazine, 18 μ g/L; cyanazine, 1.3 μ g/L; deethylatrazine, 1.4 μ g/L; deisopropylatrazine, 0.40 μ g/L; and metolachlor, 7.0 μ g/L. During base-flow conditions, the movement of agricultural chemicals from ground water to surface water was quantified for two periods of time in 1989 and 1990 along a 117-kilometer reach of the Cedar River. The principal source of atrazine, deethylatrazine, deisopropylatrazine, and metolachlor in the Cedar River during base flow was ground water discharged directly from the alluvial aquifer adjacent to the Cedar River. This discharge exceeded the combined tributary inflow of the chemicals along the entire reach. Bank storage is probably an important source of agricultural chemicals discharged from the alluvial aquifer but becomes depleted with time after surface runoff. Herbicides discharged from the alluvial aquifer during periods of extended base flow entered the alluvial aquifer with ground-water recharge at some distance from the river. The movement of nitrate between surface water and ground water is minor, when compared to the herbicides, even though nitrite was detected in the Cedar River during runoff.

Iowa, Minnesota↗
USGS1988

Surface-water quality of the Cedar River basin, Iowa-Minnesota, with emphasis on the occurrence and transport of herbicides, May 1984 through November 1985

The surface-water quality in the Cedar River basin was evaluated by analyzing the occurrence, distribution, and transport of common inorganic constituents and selected trace inorganic and organic constituents, with emphasis on herbicides. The surface-water quality of the Cedar River basin was monitored from May 1984 through November 1985. Depth integrated surface-water samples generally were collected monthly at six stations for a considerable range of river discharge. Samples were analyzed for concentrations of common inorganic constituents in the dissolved phase and for concentrations of primary nutrients, trace elements, organic carbon, and herbicides in the dissolved and the dissolved plus suspended phases. Water in the Cedar River was determined to be a calcium bicarbonate type; suspended-sediment concentrations ranged from 3 to 676 milligrams per liter. Concentrations of dissolved fluoride, dissolved nitrite plus nitrate, dissolved arsenic, dissolved lead, and dissolved mercury were less than those of the U.S. Environmental Protection Agency's drinking-water standards for public water supplies. Generally, herbicides were detected only in the dissolved phase, which indicates that herbicides are not being adsorbed on the suspended sediment. However, the lack of detection of adsorbed herbicides also may indicate a need for re-examination of traditionally acceptable methods of treating water samples at the sampling site, separating sediment and water, and extracting organic compounds from sediment. The largest concentrations of several dissolved herbicides were detected after application on agricultural areas in the spring and early summer in both wet and dry periods. However, dissolved atrazine concentrations also increased in the winter during periods of high streamflow resulting from snow melt. The maximum concentration of dissolved herbicides detected at all sampling sites during the study were: alachlor, 21 micrograms per liter; atrazine, 16 micrograms per liter; cyanazine, 8.7 micrograms per liter; metolachlor, 11.0 micrograms per liter; and metribuzin, 3.0 micrograms per liter. Herbicides can be transported from agricultural areas to the river by overland flow, drainage from agricultural areas conveyed by tile drains, and ground water. Hydrograph separation for 10 locations in the Cedar River basin indicates that the ground-water contribution varies within the basin and probably ranges from 56 to 80 percent of the annual river discharge. The predominance of ground-water contribution, the persistent detection of dissolved atrazine even during base flow, and the variety of dissolved herbicides detected in the river during the dry spring of 1985 indicate that some herbicides are being transported to the river by ground water. Atrazine transported to the Cedar River was estimated to be about 1.4 to 4.0 percent of that applied, depending on the assumed application rate. The large river discharge in June 1984, which was predominantly overland flow, contained about 70 percent of the atrazine transported to the river during 1984.

Iowa, Minnesota↗
USGS1973

Floods in the Rock River basin, Iowa

This report contains flood information for the Rock River basin in Iowa, it updates and supersedes the 1967 report "Floods in Rock River basin, Iowa" by P. J. Carpenter. The occurrence of an outstanding flood in 1969 and the acquisition of additional flood data in the basin prompted the preparation of this report. The 1969 flood, the greatest flood on the Rock River in at least 45 years, is nearly equivalent to a flood of a 50-year recurrence interval. The 1953 flood was the greatest recorded on Otter Creek. This flood was 1.8 times the 50-year recurrence interval discharge at the gaging station near Ashton. Flood information is reported for 49.8 miles (80.1 kilometers) on the main stem, 49.6 miles (79.8 kilometers) on the Little Rock River, and 33.0 miles (53.1 kilometers) on Otter Creek. This information is useful to those concerned with the design of bridges and other structures and those involved in regulatory or planning activities on the flood plains of the streams. Included in the report are flood-peak records, frequency curves, water-surface profiles, and bench mark data. Flood profiles for the Rock River include those for the 1962, 1964, 1965, 1969, and the computed 25- and 50-year floods. On the Little Rock River and Otter Creek, profiles include those for the 1969 flood and the computed 25- and 50-year floods. Low-water profiles are shown for all reaches.

Iowa, Minnesota↗
USGS1971

Floods in the Wapsipinicon River Basin, Iowa

Flood information is reported for 338 miles of the main stem and six tributaries of the Wapsipinicon River. The information will be of use to those concerned with the design of bridges and other structures and the conduct of various operations on the flood plains of the streams. Included in the report are flood-peak records, gaging-station records, frequency curves, and water-surface profiles. Outstanding floods resulting from extremely heavy rainfall occurred in the upper basin in 1968 and 1969. Those in 1968 produced the highest flood of record at the gaging station at Independence. The flood of 26,800 cfs (cubic feet per second) at this station was the greatest in the period 1933-70. A number of the smaller tributaries experienced floods more than five times the computed 50-year flood. The flood experience on the main stem downstream from Anamosa has not been outstanding. No flood of record has exceeded the 50-year flood in this reach. Flood-profile sheets show profiles of actual flood occurrences and computed profiles of the 25- and 50-year floods at most locations. These sheets also contain tabulations of the flood discharges profiled. A low-water profile and tabulated discharge indicate the range in elevation and discharge along the streams.

Iowa, Minnesota↗