GEOLOGY AND ECONOMIC MINERAL POTENTIAL OF UPPER BROWNS CREEK BASIN, CHAFFEE COUNTY, COLORADO.
AuthorCoolbaugh, Mark Franklin.
KeywordsGeology -- Colorado -- Browns Creek Watershed.
Mines and mineral resources -- Colorado -- Browns Creek Watershed.
Geology -- Colorado -- Chaffee County.
Mines and mineral resources -- Colorado -- Chaffee County.
MetadataShow full item record
PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Degree ProgramGraduate College
Mining and Geological Engineering
Degree GrantorUniversity of Arizona
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WATER QUALITY IN THE LOWER COLORADO RIVER AND THE EFFECT OF RESERVOIRSSlawson, G. C.; Department of Hydrology & Water Resources, The University of Arizona (Department of Hydrology and Water Resources, University of Arizona (Tucson, AZ), 1972-07)Comparison of the power spectra of TDS time series from different locations on the Lower Colorado River is useful in showing changes in salinity and for indicating physical factors influencing salinity. Similarities between the power spectra of the Lee Ferry and Grand Canyon tine series indicated that lateral inputs and evaporation are not greatly influencing the salinity cycle. The salinity change within this reach was approximated by a constant concentration change of 66.6 ppm. A similar model form was used for the Hoover Dam to Parker Dam reach. Dissimilarities between power spectra indicated that additional inputs are significant and must be accounted for in any model of such reaches. The model for Lake Mead required compensation for evaporation and for the inputs of the Virgin River and Las Vegas Wash. The modeled salinity increase between Parker Dam and Yuma contained a trend factor to allow for the effect of irrigation return flows and seepage. The crosscovariance function was used to approximate the time lag between data stations. Time series statistics, including coherence, response function spectra, and overall unit response, were used and are of utility in estimating salinity in a river system.
River basin administration and the Colorado: past practices and future alternativesKenney, Douglas S.,1964-; Gregg, Frank; Lord, William; Lopes, Vicente; Clarke, Jeanne N.; Ingram, Helen (The University of Arizona., 1993)The vast majority of large river systems in the United States cross (or comprise) one or more state lines, creating numerous administrative challenges. Addressing these multijurisdictional challenges in an efficient and equitable manner often requires the development of sophisticated institutional arrangements. Several types of "regional organizations" have been created for this purpose, including compact commissions, interstate councils, basin interagency committees, interagency-interstate commissions, federal-interstate compact commissions, federal regional agencies, and the single federal administrator format. These organizations feature a wide variety of authorities and responsibilities; what they inevitably share in common is a hostile political environment, a consequence of political geography and bureaucratic entrenchment. In this study, the challenges associated with the governance, administration, and management of interstate water resources are examined, using the Colorado River Basin as a case study. The Colorado is the only major river in the United States utilizing the "single federal administrator" format, an institutional arrangement that is often criticized for its subordination of the states and its concentration of policy-making authorities in the hands of administrators. When evaluated against carefully defined normative criteria, the Colorado is shown to feature many institutional deficiencies that are, in part, derivative of the Colorado's unique institutional arrangements. The primary objective of this study is to determine if the governance and management of the Colorado could be improved by the establishment of an alternative form of regional water organization. It is concluded that a type of federal-interstate compact commission, if carefully tailored to the political realities of the region, could improve many of the observed institutional deficiencies. This study also presents a widely-applicable methodology for the description and evaluation of institutional arrangements.
Vegetation dynamics in the southern Rocky Mountains: Late Pleistocene and Holocene timberline fluctuations.Fall, Patricia Lynn. (The University of Arizona., 1988)Plant macrofossils and pollen from six small basins in western Colorado are used to trace the history of vegetation and climate over the last 15,000 years. The late-glacial upper timberline was 2800 m, and sparse krummholz Picea grew up to 3200 m. Summer temperatures were 3° to 5°C cooler than today. The late Pleistocene climate was influenced by winter storms from the Pacific. Precipitation shifted to a summer-dominated pattern by at least 9000 yr B.P. with the development of the summer monsoon. Plant fossils from bogs and lakes located near modern ecotones track the elevations of the temperature-controlled upper timberline and the moisture-controlled lower forest through the Holocene. Between 9000 and 4000 yr B.P., the Picea engelmannii-Abies lasiocarpa forest covered a broader elevational range, with upper timberline 200-300 m higher than today. Mean annual temperatures were 1.8°C warmer, and mean summer temperatures were 2.1°C warmer, than today. Temperatures were still about 1°C warmer prior to 2000 yr B.P. The lower limits of the montane and subalpine forests were 100-200 m below their modern elevations from 9000-4000 yr B.P. Mean annual precipitation was 50-100 mm greater. By 2600 yr B.P. the modern lower forest borders were established. Modern pollen dispersal, transportation, and deposition was sampled in atmospheric collectors, moss polsters, and surface lake sediments. Annual accumulation rates range between 1000 and 5000 grains cm⁻²yr⁻¹. Modern influx (grains cm⁻²yr⁻¹)averages: 1100 in alpine tundra, 2700 in the subalpine forest, 3400 in the montane forest, and 200 in shrub steppe. Pollen spectra in atmospheric traps and moss polsters reflect local vegetation, and provide effective modern analogs for pollen accumulation in peat bogs. In forested environments 80-90% of the pollen deposition in small lakes (< 5 ha) with no inflowing streams comes from atmospheric input. Pollen spectra in open vegetation are distorted by pollen from other vegetation types. At least half of the pollen deposition in small alpine lakes comes from taxa growing up to 1500 m lower in elevation.