Geology topics
Research about Iowa
Source-linked reports with geographic coverage including Iowa.
The water resources of southeast Iowa
Water is vital in the lives of the people and the economy of any area. In order to utilize this natural resource in the most efficient and beneficial manner, a basic knowledge and understanding of its sources and the occurrence and potential of each source must be gained. To provide this knowledge, the Water Resources Division of the U.S. Geological Survey in cooperation with the Iowa Geological Survey compiled this atlas describing the water resources available for development in an 11-county area in southeast Iowa. The report contains information on the availability, quality, and utilization of water from all known sources and the future demands upon the water resources in southeast Iowa. The information is presented to aid water users and other persons searching for and evaluating sources of water in a particular place, and planners and water managers who must consider water resources on a regional basis.
Flood of March 3, 1970, on Old Mans Creek, Johnson County, Iowa
The purpose of this report is to provide information on a large flood on an 18-mile reach at the lower end of Old Mans Creek in Johnson County, Iowa, (see figure 1).
Flood profile study, Hoosier Creek, Linn County, Iowa
The purpose of this report is to present the results of a flood-profile study made for Hoosier Creek and its tributary, South Hoosier Creek. The reaches studied extend from near the south Linn County line upstream to U.S. Highway 218 on Hoosier Creek, and from the mouth to U.S. Highway 218 on South Hoosier Creek. A total of about 11 miles of stream is included in the two reaches. The profiles shown in the report are computed for a very large flood under existing valley conditions and for a smaller flood under two assumed conditions of encroachment. This information can be used to supplement the existing county zoning ordinances for flood plains and to aid in future flood-plain management when part or all of the area is urbanized. This report is the result of a cooperative agreement between Linn County, Iowa, and the U.S. Geological Survey that provides for the collection and analysis of hydrologic data in Linn County.
Flood profile study, Morgan Creek, Linn County, Iowa
The purpose of this report is to present the results of a study made for a 35,000-foot reach of Morgan Creek. The report shows profiles computed for a large flood under existing conditions and for a smaller flood for two assumed conditions of encroachment. Flood-plain management can benefit from this type of information during future expansion of the urban area. This report is a result of a cooperative agreement between the City of Cedar Rapids and the U.S. Geological Survey that provides for the collection and analysis of flood data in, and near, the City of Cedar Rapids.
The streamflow-data program in Iowa, evaluation of the past, proposal for the future
No abstract available
Geology and ground-water resources of Linn County, Iowa
Linn County, in east-central Iowa, covers about 713 square miles and lies in the Western Young Drift section of the Central Lowlands physiographic province. The normal annual rainfall in the county is about 88 inches and the annual mean temperature is about 48°F. The population in 1960 was 136,899, of which 75 percent was urban. Ground water is a vital natural resource in Linn County-all municipal, farm-domestic, livestock, and most industrial supplies are obtained from this source. An estimated 24 mgd (million gallons per day) of ground water was used in the county in 1964. The principal aquifers are alluvium, buried channel deposits, Silurian-Devonian limestones and dolomites, and the Jordan Sandstone. All yield fair-to-good quality water, although the water is hard and locally contains high concentrations of iron. All are capable of yielding as much as 500 gallons or more per minute to wells. Alluvium has been developed for water supplies only at Cedar Rapids, where withdrawals in 1964 averaged 12 mgd for municipal supplies and 2.7 mgd for industrial supplies. The alluvial aquifer yields up to 2,000 gpm (gallons per minute) to wells in the Cedar Rapids well field. Similar yields from alluvium may be available along several reaches of the Cedar and Wapsipinicon Rivers. Smaller quantities are available from the alluvium of Prairie Creek. Alluvial aquifers are readily recharged by precipitation and induced infiltration. Buried channel deposits occur in preglacial or interglacial valleys that were carved into the bedrock. These old valleys, whose trends roughly parallel the present Cedar River and Prairie Creek, contain water-bearing alluvial deposits that are covered by glacial drift. Data from a few wells tapping these deposits indicate that yields of up to 500 gpm of good-quality water are available from this source. The most favorable areas for development of water supplies are those areas where the channel deposits underlie and receive recharge from the alluvium of the Cedar River and Prairie Creek. The Silurian-Devonian aquifer's county-wide occurrence, near-surface position, and ability to yield as much as several hundred gallons per minute of good-quality water makes it the most widely used aquifer in Linn County. During 1960-64, withdrawals averaged about 1.5 mgd for domestic-livestock use, about 0.6 mgd for small community use, and about 4 mgd for industrial-commercial use. Withdrawals are concentrated in the Cedar Rapids area, where 65 percent of the withdrawals from the aquifer occur. This concentrated pumpage has caused a progressive lowering of the aquifer's piezometric surface in downtown Cedar Rapids. During the past 70 years, water levels in wells in this locality have declined about 105 feet in the center of the cone of depression and about 26 feet about one mile from the cone's center. Water level in the center of the cone presently is declining at an average rate of 1 foot per year. Because the rate of decline in the same area was determined to have been 2 to 3 feet per year during the 1940's and 50's, the cone is believed to be stabilizing or pumpage is being reduced. The aquifer probably could withstand an additional 150 to 200 feet of piezometric lowering in the Cedar Rapids area, but individual wells would be adversely affected. The Jordan aquifer, which underlies the entire county, is considered to be the most isotropic and homogeneous aquifer in Linn County. Yields of 1,000 gpm or more of fair-to-good quality water from this source are believed to be available anywhere in the county. The aquifer is not yet developed extensively; an average of about 2.4 mgd was pumped during 1964 for industrial and municipal use in the Cedar Rapids-Marion area. The shallow bedrock and glacial drift aquifers yield only small quantities of good quality water. Their widespread extent and shallow depth, however, make them suitable for the development of small supplies for domestic and livestock use.
Geology and ground-water resources of Cerro Gordo County, Iowa
The basic geologic framework underlying Cerro Gordo County consists of an igneous or metamorphic Precambrian basement complex overlain by, in ascending order, consolidated sedimentary rocks of Precambrian, Cambrian, Ordovician, Devonian, Mississippian, and Cretaceous age, and unconsolidated sand, gravel, and clay of Quaternary age. Structurally the county is in the northern part of the Iowan Basin, and the sedimentary units of Cambrian through Devonian age dip southward at 9 to 14 feet per mile. Three major glacial advances, the Nebraskan, Kansan, and Wisconsin, covered all or part of the county during the Pleistocene Epoch and left behind glacial drift consisting of 0 to 125 feet of till and related outwash deposits. De posits of Holocene age, aside from surficial soil, are thin and scattered. Ground water occurs in the sedimentary units of Cambrian through Mississippian age and in the glacial drift and outwash deposits of Quaternary age. The chief aquifers, in ascending order, are the deep Cambrian sandstones, Jordan aquifer, St. Peter Sandstone, Devonian and Mississippian limestones and dolomites, and the Pleistocene glacial drift and related interglacial deposits. Units between the St. Peter Sandstone and the Devonian limestones, the Platteville, Decorah, Galena, and Maquoketa Formations, are of low permeability and are considered to be an aquiclude in comparison to the overlying and under lying units. The deep Cambrian sandstones will yield about 60 gpm (gallons per minute) to an individual well; the Jordan aquifer about 1,200 gpm; the St. Peter Sandstone 30 to 200 gpm; the Devonian limestones and dolomites 120 to 200 gpm; and the glacial outwash or shallow bedrock generally will yield 10 gpm or more. The Jordan aquifer supplies large quantities of water for municipal and industrial use at Mason City. Pumping tests on wells tapping the Jordan in that area show that the aquifer has a transmissibility of about 35,000 gallons per day per foot and a storage coefficient of 2 x 10 -4 Pumping in the Mason City area from 1912 to 1969 has produced about 200 feet of draw down in the areas of maximum withdrawal. Ground water in Cerro Gordo County is of suitable chemical quality for domestic, industrial, or municipal use. The total dis solved solids ranges from 152 mg/l (milligrams per liter) in water from the shallow bedrock to 885 mg/l in water from the deep Cambrian sandstones. Water from the Jordan, which is the most productive aquifer in the county, generally contains less than 500 mg/l dissolved solids. Ground water is the major source of water supplies throughout Cerro Gordo County. The majority of wells in the county are used for domestic and stock supplies, but the largest withdrawals of water are for municipal and industrial supplies. Municipal pumpage in the county in 1968 was about 1.5 billion gallons; industrial pumpage was about 1.8 billion gallons and most of the water was obtained from the Jordan aquifer. If future development of water from the Jordan aquifer is to be to the best economical advantage, careful consideration should be given to the location, capacity, and pumping schedules of proposed wells and nearby existing wells so that local overdevelopment or excessive interference do not occur.
Flood profile study, Squaw Creek, Linn County, Iowa
This report is the result of a cooperative agreement between the city of Cedar Rapids and the U.S. Geological Survey that provides for the collection of hydrologic data by the Geologic Survey on small streams in and near the city. The city furnished the large-scale topographic map showing a stream reference line marked off in 100-foot stations and a part of the data on valley cross sections used in the preparation of this report. The purpose of this report is to show, for an 18,000-foot reach of Squaw Creek, (1) flood-inundation limits for a large flood under present channel and valley conditions, and (2) water-surface profiles for the above flood and for a lesser flood contained in a waterway restricted by two assumed degrees of encroachment. Mean velocities are also given at many places for the selected conditions. The information provided can be useful to State and local agencies involved in floodplain management. The purpose of this report is to show, for an 18,000-foot reach of Squaw Creek, (1) flood-inundation limits for a large flood under present channel and valley conditions, and (2) water-surface profiles for the above flood and for a lesser flood contained in a waterway restricted by two assumed degrees of encroachment. Mean velocities are also given at many places for the selected conditions. The information provided can be useful to State and local agencies involved in flood-plain management.