Selected analytical methods for well and aquifer evaluation

Bibliography: p. 70-72.Enumeration continues from preceding title

Ground-water recharge and runoff in Illinois

Bibliography: p. 55.Enumeration continues through succeeding title.Recharge conditions in several areas of northeastern Illinois are described, and recharge rates for several aquifers in central and southern Illinois are given. Recharge rates to deeply buried bedrock and sand-and-gravel aquifers vary from 1300 to 500,000 gallons per day per square mile (gpd/sq mi). The lowest rate is for an area where the Cambrian-Ordovician Aquifer is overlain by the Maquoketa Formation consisting mostly of shale; the highest rate is for an area where a sand-and-gravel aquifer is overlain by permeable coarse-grained deposits. Groundwater recharge generally is at a maximum during wet spring months; in many years there is little recharge during the five-month period July through November. The theoretical aspects of recharge from precipitation are discussed; recharge rates vary with the coefficient of vertical permeability, the vertical head loss associated with recharge, and the saturated thickness of deposits through which vertical leakage of water occurs. Recharge rates are not constant but vary in space and time. A summary of coefficients of vertical permeability and leakage of deposits overlying aquifers within the state is presented. Coefficients of vertical permeability of glacial deposits range from 1.60 to 0.01 gallons per day per square foot (gpd/sq ft). The average coefficient of vertical permeability of the Maquoketa Formation is 0.00005 gpd/sq ft. Coefficients of leakage of glacial deposits and bedrock confining beds range from 2.3 x 10-1 to 2.5 x 10-7. Annual ground-water runoff from 109 drainage basins scattered throughout Illinois is estimated with streamflow hydrograph separation methods and flow-duration curves. The relations between groundwater runoffs during years of near, below, and above normal precipitation and basin characteristics such as geologic environment, topography, and land use were determined by statistical analysis. Groundwater runoff is greatest from glaciated and unglaciated basins having considerable surface sand and gravel and underlain by permeable bedrock. Groundwater runoff is least from glaciated basins with surface lakebed sediments and underlain by impermeable bedrock. Groundwater runoff during a year of near normal precipitation ranges from 0.06 to 0.43 cubic feet per second per square mile (cfs/sq mi). Groundwater runoff is at a maximum during spring and early summer months, and is least in late summer and fall months. Annual groundwater runoff depends upon antecedent moisture conditions as well as the amount and distribution of annual precipitation. Because many aquifers in Illinois are deeply buried, not all groundwater runoff can be diverted into cones of depression because there is some lateral as well as vertical movement of water in surface deposits. Data on groundwater runoff can be useful in estimating recharge to aquifers and in evaluating the potential yield of groundwater reservoirs. However, studies indicate that no simple relation exists between groundwater runoff and the potential or practical sustained yields of aquifers

Leaky artesian aquifer conditions in Illinois

Bibliography: p. 27.Enumeration continues through succeeding title.Leaky artesian conditions exist in many parts of Illinois where aquifers are overlain by deposits or confining beds which impede or retard the vertical movement of ground water. Under leaky artesian conditions, the cone of depression developed by a pumping well is influenced by the vertical permeability of the confining bed in addition to the hydraulic properties and geohydrologic boundaries of the aquifer. The vertical permeability of a confining bed often can be determined from the results of pumping tests by using the nonsteady-state leaky artesian aquifer equation derived by Hantush and Jacob (1955). A time-drawdown type curve method for analyzing pumping test data under nonsteady-state conditions is described in detail. A distancedrawdown type curve method for analyzing pumping test data under steady-state conditions devised by Jacob (1946) is also described. These two methods are applied to available pumping test data for Illinois. The results of a test made near the village of Dieterich in Effingham County are presented to illustrate the analysis of data. A summary of the leaky artesian test data collected to date indicates that the vertical permeability of glacial drift deposits in the southern half of Illinois ranges between 0.08 and 1.6 gallons per day (gpd) per square foot. Effects of leakage closely resemble the effects of a recharge boundary if the effects of partial penetration are excluded. The data for the Dieterich pumping test are used to show that recognition of leaky artesian conditions is critically important in predicting the water supply potential of wells and aquifers. A form of Darcy’s law is applied to data on the piezometric surface of the Cambrian-Ordovician Aquifer to determine the order of magnitude of the vertical permeability of the Maquoketa Formation. The Maquoketa Formation has a maximum thickness of about 250 feet, consists largely of beds of dolomitic shale, and confines water in the Cambrian-Ordovician Aquifer under artesian pressure. The Cambrian-Ordovician Aquifer is encountered at an average depth of 500 feet below the surface at Chicago, has an average thickness of 1000 feet, consists mainly of beds of sandstone and dolomite, and is the most highly developed source of large ground-water supplies in northeastern Illinois. Computations indicate that the average vertical permeability of the Maquoketa Formation in northeastern Illinois is about 0.00005 gpd per square foot. Leakage in 1958 through the Maquoketa Formation in northeastern Illinois is estimated to be about 8,400,000 gpd or about 11 per cent of the water pumped from deep wells.</p

Farming Credit in Texas.

86 p

Yields of shallow dolomite wells in Northern Illinois

Bibliography: p. 25.Enumeration continues through succeeding title.In northern Illinois large quantities of ground water are withdrawn from wells in shallow dolomite aquifers of Silurian and Ordovician age. The Niagaran and Alexandrian Series of Silurian age and the Galena-Platteville Dolomite of Ordovician age yield moderate to large quantities of ground water. Dolomite beds of the Maquoketa Formation of Ordovician age yield small quantities of water to wells. Silurian rocks are usually encountered at depths of between 10 and 300 feet in northeastern Illinois and between 30 and 880 feet in northwestern Illinois. These rocks exceed 450 feet in thickness at places and are often overlain by glacial drift. The average depth of shallow doIomite weIIs is about 140 feet, and most wells of recent design are finished 12 to 16 inches in diameter. About 1000 well-production tests were made, 1921-1961, on more than 800 shallow dolomite wells. Statistical analysis of specific-capacity data provided a basis for determining 1) the role of individual shallow dolomite aquifers or formations, uncased in wells, as contributors of water; 2) whether or not significant relationships exist between the yields of wells and geohydrologic controls; and 3) the effects of acid treatment on the productivities of wells. It is concluded that the Niagaran Series, Alexandrian Series, and Galena-Platteville Dolomite all have similar moderate to high yields and inconsistency of yields in areas throughout northern Illinois where these rocks directly underlie glacial drift. These Silurian and Ordovician rocks have similar low yields and inconsistency of yields in areas where these rocks are overlain by bedrock. On the other hand, the Maquoketa Formation and rocks of Devonian age yield very little water to wells. Most water-yielding openings occur in the upper one-third of the shallow dolomite aquifers. There is a good connection between glacial drift and the upper part of the shallow dolomite aquifers. Highest yielding wells are found in bedrock upland areas, in areas where the glacial drift immediately overlying the shallow dolomite aquifers is composed of sand and gravel, and in areas where reefs and associated strata are present. Most dolomite wells treated with acid show significant improvement in yield; largest improvements are recorded for rehabilitated wells. Yields are increased because water-yielding openings are enlarged and fine drill cuttings or incrustations are removed from openings. Probable ranges in yields of shallow dolomite wells in undeveloped areas are estimated from specific-capacity frequency graphs, aquifer thickness and area1 geology maps, and waterlevel data

Yields of deep sandstone wells in Northern Illinois

Bibliography: p. 27.Enumeration continues through succeeding title

Potential Yield of Aquifers in Embarras River Basin, Illinois

This work was never finalized and published, but the unpublished manuscript was assigned an RI number and was cited in: Characterization of the Study Areas for the Pilot Study : Agricultural Chemicals in Rural, Private Wells in Illinois. Cooperative Resources Report No. 15. Champaign, Ill. : Illinois State Geological Survey and Illinois State Water Survey, 1992. http://hdl.handle.net/2142/35248. Although incomplete and still in draft form it is included in the collection to ensure its continued availability for reference. Manuscript has many editorial marks, including changes to pagination and figure enumeration. Tables 10 and 16 are lacking both in the physical copy held in the University Library and digitized version.Ope

Hydrologic budgets for three small watersheds in Illinois

Bibliography: p. 40.Enumeration continues through succeeding title

Ground-water development in three areas of Central Illinois

Bibliography: p. 43.Enumeration continues through succeeding title

Ground-water development in three areas of Central Illinois

Bibliography: p. 43.Enumeration continues through succeeding title