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Research about Colorado

Source-linked reports with geographic coverage including Colorado.

At least 1,693 records · Page 94Linked to original sources
USGS1975

Thermal-infrared images as a basis for structure mapping, front range and adjacent plains in Colorado

High-altitude thermal-infrared images, taken at various times of the day over the Front Range and adjacent plains in Colorado, display many linear and circular topographic features. These features are enhanced by thermal shading effects and commonly are better displayed than in photographs. Comparison with geologic maps of a control area in the Front Range shows that most lineaments drawn from the thermal images represent geologic features, principally faults. A previously unobserved circular feature at the Central City-Idaho Springs mineral district bounds most of the area of gold mineralization; it is a topographic delineation of the most intensively altered ground in the district and may reflect extremely subtle structure related to the presence of an unexposed intrusive body. Lineaments in the plains probably mark subtle structural trends related to the Denver basin and to folds not otherwise expressed at the surface. © 1975 Geological Society of America.

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USGS1975

Long-term effects of 4-aminopyridine exposure to birds and fish

The avian frightening agent, 4-aminopyridine (4AP), was tested on five avian and two fish species to assess the effects of long-term 4AP exposure to nontarget vertebrates. Adult bobwhites ( Colinus virginianus ), mourning doves ( Zenaida macroura ), and ring-necked pheasants ( Phasianus colchicus ) were fed diets containing 3 percent 4AP-treated cracked corn diluted with various ratios of untreated corn for 7 to 35 days. Minimum dilution ratios that produced more than 50 percent mortality were 1:29 for bobwhites and 1:99 for doves. Mortality caused by 4AP could not be determined for pheasants because of their inability to subsist only on corn during the test periods. LCso's were determined for doves (316 ppm) and coturnix quail ( Coturnix coturnix ) (479 ppm) fed exclusively on uniformly treated laboratory rations for 28 to 40 days. Starlings ( Sturnus vulgaris ) treated by gavage daily for 25 days with 1.78 mg/kg 4AP showed no intoxication symptoms. Mortality in all avian species appeared to be the result of acute poisoning, and no evidence of cumulative toxicity was noted in species fed uniformly-treated rations. In 96-hour static tests, channel catfish ( Ictalurus punctatus ) and bluegill (Lepomis macrochirus) showed increasing sensitivity to 4AP with time in test waters ranging from very soft to very hard and from 12 to 22 C. The 96-hour LC 50 's for both species ranged from 2.43 to 7.56 mg/liter (ppm). Toxicity appeared to decrease with increasing water temperatures but was generally unaffected by water hardness. On the basis of the data presented, and the currently registered application rate for 4AP in agricultural crops (0.34 g/ha), long-term hazards to nontarget wildlife were judged to be minimal.

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USGS1975

Lakes in the greater Denver area, Front Range urban corridor, Colorado

The many lakes in Colorado's semiarid Front Range Urban Corridor have an especially high value. In the past they were used primarily to store water for irrigation and domestic uses. Some were used for recreation. Today, rapid suburban development in the Front Range Urban Corridor is accompanied by a shift of the principal use of many lakes to recreation and to centers of real estate developments. These same lakes are threatened with a general deterioration of chemical and biological quality caused by heavy use and development of the surrounding area. The purpose of this report is to present the results of an inventory of the lakes in the central one-third of the Colorado Front Range Urban Corridor. This inventory provides information that might be helpful in planning the best and most beneficial use of lakes in an area of rapid population growth. The report includes data on lake size and water quality. Size data are included on most of the lakes of 2 hectares (20,000 m 2 , or about 5 acres) or greater, and water-quality data are provided on most lakes larger than 10 hectares (about 25 acres). Bodies of water resulting form excavation of gravel (borrow pits) were generally not included in the inventory.

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USGS1975

Map showing availability of hydrologic data published by the U.S. Environmental Data Service and by the U.S. Geological Survey and cooperating agencies, greater Denver area, Front Range Urban Corridor, Colorado

What is the rainfall of this region? What areas are prone to periodic flooding? What is the water supply? What is the chemical quality of the ground water and water in the streams? How deep is the water table? Which streams are gaged, and where? These and similar questions are being asked regularly by land and resource developers, urban planners, industrial consultants, and governmental resource managers. This map provides the first step toward answering these questions. It shows by symbols and color the hydrologic data published as of January 1974 for the Greater Denver area by the U.S. Environmental Data Service and by the U.S. Geological Survey and cooperating agencies, and the points or areas where these data have been collected. The sources of the data are given in both the following discussion and the references.

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USGS1975

Map showing flood-prone areas, greater Denver area, Front Range Urban Corridor, Colorado

The rapid growth of population in the Front Range Urban Corridor of Colorado is causing intense competition for available land resources. One form of competition posing serious problems in indiscriminate development on flood plains along creeks and rivers. Flood plains are natural features of the landscape developed by streams in carry water in excess of channel capacity. Although not used as often by the stream, flood plains are as much a part of the stream system as is the channel. Whenever man competes with this natural function of the flood plain he must inevitably pay the price through property damage and varying degrees of human suffering Flood damages in the United States have been estimated to average about \$1 billion annually (American Public Works Association, 1966.) This tremendous waste of national resources is borne not only by those citizens in direct contact with floods but also to a lesser degree by all citizens through increased cost of public services. Thus, floods are of concern to the entire community, and solutions to existing or potential problems should be a community effort.

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USGS1975

Land-use classification of the greater Denver area, Front Range Urban Corridor, Colorado

The Greater Denver area, in the Front Range Urban Corridor of Colorado, is an area of rapid population growth and expanding land development. At present no overall land-use policy exists for this area, although man individuals and groups are concerned about environmental, economic, and social stresses caused by population pressures. A well-structured land-use policy for the entire Front Range Urban Corridor, in which compatible land uses are taken into account, could lead to overall improvements in land values. A land classification map is the first step toward implementing such a policy.

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