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At least 55 records · Page 3Linked to original sources
USGS1969

Geologic history of the Colorado River: Chapter C in The Colorado River region and John Wesley Powell (Professional Paper 669)

John Wesley Powell clearly recognized that the spectacular features of the Colorado River - its many grand canyons - were dependent upon the structural history of the mountainous barriers crossed by the river. He conceived of three different historical relationships between rivers and structural features: (1) Newly uplifted land surfaces have rivers that flow down the initial slope of the uplift; these relationships he termed consequent. (2) A river may be older than an uplift that it crosses because it has been able to maintain its course by eroding downward as the uplift progresses; this relationship he named antecedent. (3) An uplifted block may have been buried by younger deposits upon which a river becomes established. The river, in cutting downward, uncovers the uplifted block and becomes incised into it; this relationship he called superimposed. The geologic history of the Colorado River involves all three relationships. In addition, although the position of the river course through a particular structural barrier may have been the result of superposition, the depth of the canyon at that point may be largely due to renewed uplift of the barrier; such deepening of the canyon, therefore, is due to antecedence. The problem of the Colorado River remains today very much as G. K. Gilbert stated it nearly 100 years ago: "How much is antecedent and how much is superimposed?" The question must be asked separately for each stretch of the river.

Colorado River↗
USGS1969

The rapids and the pools - Grand Canyon: Chapter D in The Colorado River region and John Wesley Powell (Professional Paper 669)

Through the Grand Canyon the Colorado drops in elevation about 2,200 feet in 280 miles; most of this drop occurs in rapids that account for only 10 percent of the distance. Despite the importance of rapids, there are no waterfalls. Depth measurements made at 1/10-mile intervals show that the bed profile is highly irregular, but the apparent randomness masks an organized alternation of deeps and shallows. Measurement of the age of a lava flow that once blocked the canyon near Toroweap shows that no appreciable deepening of the canyon has taken place during the last million years. It is reasoned that the river has had both the time and the ability to eliminate the rapids. The long-continued existence and the relative straightness of the longitudinal profile indicate that the river maintains a state of quasi-equilibrium which provides the hydraulic requirements for carrying the debris load brought in from upstream without continued erosion of the canyon bed. The maintenance of the alternating pools and rapids seems to be a necessary part of this poised or equilibrium condition.

Colorado River↗
USGS1984

Selected papers in the hydrologic sciences 1984; July 1984

The rapid, accurate measurement of the oxygen content of soil gas in the unsaturated zone or dissolved oxygen in soil water in the saturated zone can be useful in wetland vegetation studies. A method has been devised and tested in the Great Dismal Swamp, a wetland with fine silt-clay and organic soils, that appears to provide good results. A 60-milliliter sample of soil gas or water is withdrawn from permanently installed chambers at various depths in the soil profile. The oxygen concentration of air samples is measured with a specially constructed analyzer cell fitted to the polarographic oxygen electrode of a portable oxygen meter. The dissolved oxygen concentration of water samples is measured directly with the oxygen electrode while stirring the sample in a 32-milliliter glass bottle with a portable magnetic stirrer. Field tests with duplicate chamber installations showed that consistent results are obtained for soil gas and water.

Water Supply Paper↗
USGS1985

Selected papers in the hydrologic sciences, 1985; May 1985

The University of Minnesota, the Minnesota Geological Survey, and the U.S. Geological Survey are studying the feasibility of storing water at a temperature of 150 degrees Celsius in the Franconia-Ironton-Galesville aquifer. The Aquifer Thermal-Energy Storage project has a doublet-well design with a well spacing of approximately 250 meters. One well will be used for cool-water supply, and, the other, for hot-water injection. The U.S. Geological Survey is constructing a model of ground-water flow and thermal-energy transport to aid in determining the efficiency of the Aquifer Thermal Energy Storage system. A preliminary model of radial flow and thermal-energy transport was constructed, based on hydraulic and thermal properties of the Franconia-Ironton-Galesville aquifer determined in previous studies. The model was used to investigate the sensitivity of model results to various hydraulic and thermal properties and to study the potential for buoyancy flow within the aquifer and the effect of various cyclic injection-withdrawal schemes on the relative thermal efficiency of the aquifer. Sensitivity analysis was performed assuming 8 days of injection of 150-degree-Celsius water at 18.9 liters per second, 8 days of storage, and 8 days of withdrawal of hot water at 18.9 liters per second. The analysis indicates that, for practical ranges of hydraulic and thermal properties, rock-heat capacity is the least important property and thermal dispersivity is the most important property used to compute temperature and aquifer thermal efficiency. The amount of buoyancy flow was examined for several values of hydraulic conductivity and ratios of horizontal to vertical hydraulic conductivities. For the assumed base values of hydraulic and thermal properties, buoyancy flow was negligible. The greatest simulated buoyancy flow resulted from simulations in which horizontal hydraulic conductivity was increased to 10 times the base value, and the vertical hydraulic conductivity was set equal to the horizontal hydraulic conductivity. The effects of various injection-withdrawal rates and durations on computed values of aquifer relative thermal efficiency and final well-bore temperature were studied for five 1-year hypothetical test cycles of injection and withdrawal. The least efficient scheme was 8 months injection of 150-degree-Celsius water and 4 months of withdrawal of hot water at 18.9 liters per second. The most efficient scheme was obtained with 6 months of injection of 150-degree-Celsius water at 18.9 liters per second and 6 months of withdrawal of hot water at 37.8 liters per second. The hypothetical simulations indicate that the subsequent calibrated model of the doublet-well system will be a valuable tool in determining the most efficient system operation.

Water Supply Paper↗
USGS1987

Selected papers in the hydrologic sciences, 1986

Water-quality data from long-term (24 years), fixed- station monitoring at the Cape Fear River at Lock 1 near Kelly, N.C., and various measures of basin development are correlated. Subbasin population, number of acres of cropland in the subbasin, number of people employed in manufacturing, and tons of fertilizer applied in the basin are considered as measures of basinwide development activity. Linear correlations show statistically significant posi- tive relations between both population and manufacturing activity and most of the dissolved constituents considered. Negative correlations were found between the acres of harvested cropland and most of the water-quality measures. The amount of fertilizer sold in the subbasin was not statistically related to the water-quality measures considered in this report. The statistical analysis was limited to several commonly used measures of water quality including specific conductance, pH, dissolved solids, several major dissolved ions, and a few nutrients. The major dissolved ions included in the analysis were calcium, sodium, potassium, magnesium, chloride, sulfate, silica, bicarbonate, and fluoride. The nutrients included were dissolved nitrite plus nitrate nitrogen, dissolved ammonia nitrogen, total nitrogen, dissolved phosphates, and total phosphorus. For the chemicals evaluated, manufacturing and population sources are more closely associated with water quality in the Cape Fear River at Lock 1 than are agricultural variables.

Water Supply Paper↗
USGS1961

Paper A: Terrestrial features of impact origin

Craters made by meteorites striking the earth are discussed, with attention given to geological evidence for discriminating them from craters formed by other structural processes. The major known meteorite craters are briefly described, as well as other features that are considered probable or possible meteorite craters on the basis of less conclusive evidence. Separate tabulations are given of (1) topographic features either known to be meteorite craters, or considered as possible meteorite craters through lack of conclusive evidence to the contrary, and (2) topographic features once considered to be possible meteorite impact craters, but which are now believed to be of other origin.

Conference Paper↗