Geology topics
Publications and source records attributed to E. F. LeRoux.
A simplification of the two most commonly used methods of network planning and scheduling is ideally suited to the planning and evaluation of both water resources studies and construction projects. The project planning diagrams illustrate the system for scheduling of project activities and the relation of each activity to the others.
Project descriptions, water-resources summaries, and lists of hydrologic-data stations are presented to show the status of the U.S. Geological survey water-resources studies in South Dakota. (USGS)
Project descriptions and lists of hydrologic-data stations are presented to show the status of the U.S. Geological Survey water-resources studies in South Dakota. (USGS)
Project descriptions and lists of hydrologic-data stations are presented to show the status of the U.S. Geological Survey water-resources studies in South Dakota. (USGS)
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No abstract available.
No abstract available.
Rock County is in south-central Wisconsin adjacent to the Illinois State line. The county has an area of about 723 square miles and had a population of about 113,000 in 1957 ; it is one of the leading agricultural and industrial counties in the State. The total annual precipitation averages about 32 inches, and the mean annual temperature is about 48 ? F. Land-surface altitudes are generally between 800 and 00 feet, but range from 731 feet, where the Rock River flows into Illinois, to above 1,080 feet, at several places in the northwestern part of the county. The northern part of Rock County consists of the hills and kettles of a terminal moraine which slopes southward to a flat, undissected outwash plain. The southeastern part of the county is an area of gentle slopes, whereas the southwestern part consists of steep-sided valleys and ridges. Rock County is within the drainage basin of the Rock River, which flows southward through the center of the county. The western and southwestern parts of ,the county are drained by the Sugar River und Coon Creek, both of which flow into the Pecatonica River in Illinois and thence into the Rock River. The southeastern part of the county is drained by Turtle Creek, which also flows into Illinois before joining the Rock River. Nearly all the lakes and ponds are in the northern one-third of the county, the area of most recent glaciation. The aquifers in Rock County are of sedimentary origin and include deeply buried sandstones, shales, and dolomites of the Upper Cambrian series. This series overlies crystalline rocks of Precambrian age and supplies water to all the cities and villages in the county. The St. Peter sandstone of Ordovician age underlies all Rock County except where the formation has been removed by erosion in the Rock and Sugar River valleys, and perhaps in Coon Creek valley. The St. Peter sandstone is the principal source of water for domestic, stock, and small industrial wells in the western half of the county. This sandstone also yields some water to uncased wells that tap the deeper rocks of the Upper Cambrian series. East of the Rock River the Platteville, Decorah, and Galena formations undifferentiated, or Platteville-Galena unit, is the principal source of water for domestic and stock wells. Unconsolidated deposits of glacial origin cover most of Rock County and supply water to many small wells. In the outwash deposits along the Rock River, wells of extremely high capacity have been developed for industrial and municipal use. The most significant feature of the bedrock surface in Rock County is the ancestral Rock River valley, which has been filled with glacial outwash to a depth of at least 396 feet below the present land surface. East of the buried valley the bedrock has a fiat, relatively undissected surface. West of the valley the bedrock surface is rugged and greatly dissected. Ground water in Rock County occurs under both water-table and artesian conditions; however, because of the interconnection and close relation of all ground water in the county, the entire system is considered to be a single groundwater body whose surface may be represented by one piezometric map. Recharge occurs locally, throughout the county. Nearly all recharge is derived directly from precipitation that percolates downward to become a part of the groundwater body. Natural movement of water in the consolidated water-bearing units is generally toward the buried Rock and Sugar River valleys. Movement of water in the sandstones of Cambrian age was calculated to be about 44 million gallons a day toward the Rock River. Discharge from wells in Rock County in 1957 was about 23 million gallons a day. Nearly 90 percent of this water was drawn from the area along the Rock River. Drilled wells, most of which were drilled by the cable-tool method, range in diameter from 3 to 26 inches, and in depth from 46 to 1,225 feet. Driven wells in alluvium and glacial drift are usually 1? to 2? in
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The area described is confined largely to the valley-floor and foothill lands of Solano County, which lies directly between Sacramento, the State capital, and San Francisco. The area is considered in two subareas: The Putah area, which extends from Putah Creek southward to the Montezuma Hills and from the foothills of the Coast Ranges eastward to the west edge of the Yolo Bypass; and the Suisun-Fairfield area, which is to the southwest in the notch in the Coast Ranges through which the waters of the Great Central Valley of California reach San Francisco Bay. There are no known hydrologic interconnections between the two subareas, through either surface streams or underground aquifers. The climate of the area is characterized by warm, rainless summers and by cool winters in which temperatures seldom drop much below freezing. The rainfall ranges from about 17 inches per year along the east side to perhaps 24 inches in the foothills to the west, and irrigation is necessary for all crops except dry-farmed grains, pastures, and some orchards. PUTAH AREA The Putah area occupies the southwestern corner of the Sacramento Valley, a topographic and structural basin underlain by a thick accumulation of sediments eroded from the surrounding hills and mountains by the Sacramento River and its tributaries. The eastern Coast Ranges and foothills lying west of the Sacramento Valley are a generally northward-trending belt of eastward-dipping sedimentary rocks that range in age from Cretaceous to Pleistocene. Successively younger strata are exposed eastward, and the essentially undeformed deposits of late Pleistocene and Recent age that immediately underlie the valley lap onto the tilted sediments of the foothills. Most of the streams of the Putah area rise east of the high ridge of Cretaceous rocks marking the western boundaries of Solano and Yolo Counties, but Putah Creek, the largest stream in the area, rises far west of that ridge and flows across it in a deep, narrow canyon. Putah Creek and the smaller streams have constructed an alluvial plain, herein designated the Putah plain, which slopes eastward and southeastward from the foothills toward the Sacramento River. A large part of the Putah plain is traversed by a branching set of distributary channel ridges or natural levees formed at times of overflow of Putah Creek. The rocks in the Putah area range in age from Cretaceous to Recent. For the purposes of this investigation they are divided into eight geologic or stratigraphic units, from youngest to oldest: (1) Stream-channel deposits, (2) younger alluvium, (3) older alluvium, (4) Tehama formation and related continental sediments, (5) volcanic sedimentary rocks, (6) basalt, (7) undifferentiated sedimentary rocks of Paleocene(?) and Eocene age, and (8) undifferentiated rocks of Cretaceous age. The stream-channel deposits are predominantly loose sand and gravel along the channel of Putah Creek. In part they are actively moving downstream and shifting. The younger alluvium, of Recent age, consists of flood-plain deposits underlying the Putah plain, Vaca Valley, Pleasants Valley, and the small valleys in the foothills north of Putah Creek and in the English Hills. Exposures of younger alluvium are characterized by soils lacking significant profile development and in many places by channel-ridge topography. The older alluvium occupies the stratigraphic interval between the younger alluvium and the Tehama formation and related continental sediments and is probably of late Pleistocene age. Its contact with the underlying Tehama formation and related continental sediments is unconformable near the foothills, but it may be gradational beneath much of the Putah plain. The base of the older alluvium is not well defined at many places but is inferred to be at the bottom of an irregular and ill-defined zone of coarse deposits, which ranges from about 50 feet to more than 150 feet below the land surface. Exposures of the older
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Outagamie County is in east-central Wisconsin. It has no serious groundwater problem at present, but the county is important as a recharge area for the principal aquifers supplying water to Brown County and industrial Green Bay to the east. The county is covered by glacial drift and lake deposits of the Wisconsin stage of glaciation. In the northwestern quarter of the county these deposits rest upon Precambrian crystalline rocks; throughout the remainder of the county they are underlain by sandstone, limestone, dolomite, and shale of Cambrian and Ordovician age. ·where they are sufficiently thick, and where more productive formations are absent, glacial sand and gravel are an important source of ground water. The major sources, however, are the St. Peter sandstone, of Ordovician age, and the sandstones of the Upper Cambrian series. The Precambrian crystalline rocks, which underlie all the county, yield little or no water to wells. The regional dip of the Paleozoic bedrocks is 25 to 30 feet per mile eastward and southeastward. There are no major folds, but the thickness of each geologic unit may change from place to place because of predepositional or postdepositional erosion. There is no conclusive evidence of major faulting in the area. Ground water in Outagamie County occurs under both water-table (unconfined) and artesian (confined) conditions. The source of the ground water is precipitation which falls on the surface and percolates downward into the underlying permeable materials. Regional movement of ground water in the eastern third of the county is controlled by the bedrock structure, and the discharge is toward the east and south. Throughout the rest of the county the movement of water is controlled mainly by bedrock and surface topography, and the water moves toward the streams and bedrock valleys. Water-level :fluctuations follow definite patterns. Where the effects of pumping are at a minimum, water levels reach a high in April or May, decline through the summer months owing to natural discharge, and lack of recharge, and do not begin to recover until after the ground thaws in the spring. In areas of heavy pumping where this pattern is distorted, the lowest water levels occur in the early fall and recoveries begin in October or November after the period of heaviest pumping. Pumpage in the county was estimated to be about 9.0 million gallons per day (mgd) in 1951 and 1952. Nearly half of this was for industrial, commercial, and public-supply use along the Fox River. Wells, most of which are drilled by the cable-tool method, range in diameter from 3 to 16 inches and in depth from 10 or 20 feet to 804 feet. In the alluvium and glacial drift 1~- to 2¥2-inch driven wells are common. Pumping tests were made to determine the hydraulic characteristics of the aquifers at Seymour, Appleton, and Hortonville. The average coefficient of transmissibility at Seymour is about 18,000 gpd per foot; at Appleton it is about 19,000 gpd per foot. The coefficients of storage are 0.00022 and 0.00015 at Seymour and Appleton, respectively. Movement of ground water out of the county, assuming an average transmissibility of 18,000 gpd per foot, was calculated to be more than 10 mgd toward the southeast. The ground water differs greatly in chemical quality from well to well, but it is generally a very hard calcium magnesium bicarbonate water, some of it high in iron. To aid in determining the source of well waters, 22 chemical analyses were plotted on a logarithmic diagram to obtain characteristic patterns for waters from several geologic sources.
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