From purpose and objectives: The purpose of this report is to summarize the hydrologic investigation. The study objective was to provide data and a limited interpretation of surface- and ground-water flow systems.

Purpose of study and report: This study is the result of an agreement between the Denver Water Department and the U.S. Geological Survey to investigate the evaporative losses from reservoirs which are a part of the Denver water-supply system. Interim results of the study were presented by Ficke and others (1977). The subject report is a continuation of results given by Ficke and others (1977).

From introduction: The purpose of this study was to define the altitude and configuration of the water table for use by water planners and users in future development of water resources.

From introduction: The overall objective of this report is to determine the cumulative effects of mining on dissolved solids in the Yampa River basin. more specifically the approach is (1) to develop a model of streamflow and dissolved solids focused on the Trout Creek drainage and a reach of the Yampa River main stem; (2) to calibrate this model with existing data; (3) to insert into the model future mine plans as given by the Mined Land Reclamation Division to determine cumulative effects of mining on dissolved solids in the streamflow.

Purpose and scope: This report describes a preliminary reconnaissance of the water-bearing properties of the Mississippian Leadville Limestone in the western part of the White River Uplift (synonymous with the White River Plateau). The purpose of this preliminary investigation is to determine areas of the Leadville Limestone suitable for exploratory drilling and testing at relatively shallow depths to confirm the quality of water in storage.

Abstract: A reconnaissance study of eight landfills in Colorado shows that they have contaminated the shallow ground-water system. Contamination is indicated by values of specific conductance and concentrations of major ions and trace elements. Because only shallow ground water was sampled, it was not possible to determine whether deeper ground-water systems also are contaminated. The major effects on water quality caused by contaminants in the land-fills were increased salinity, nitrogen, iron, manganese, and phenols in the shallow ground-water system.

From introduction: The purpose of the investigation was to compile and interpret available hydrologic data, with principal emphasis on the hydrologic relation of the water resources with respect to the salt deposits, in order to serve as a basis for more detailed evaluations of potential repository sites.

From introduction: This report describes the results of an investigation in which three computer models were used to evaluate different levels of the proposed reservoir development. One model simulated streamflow conditions with alternative multireservoir configurations; a second model simulated the dissolved-solids concentrations at various locations in the basin; and a third model used streamflows and dissolved solids concentrations to simulate the water-quality conditions within certain proposed reservoirs. This study was designed to demonstrate the application of computer-modeling techniques in evaluating impacts of proposed reservoirs.

Abstract: The U.S. Geological Survey maintains a quality-assurance program based on the analysis of reference samples for its two water-analysis laboratories located in Atlanta, Georgia, and Denver, Colorado. Reference samples containing inorganic constituents are prepared at the U.S. Geological Survey's Ocala, Florida office and disguised as routine samples, and sent daily to each laboratory through other U.S. Geological Survey offices. The results are permanently stored in the National Water Data Storage and Retrieval System (WATSTORE), the U.S. Geological Survey's data base for all water data. These data are analyzed statistically for precision and bias. The results of these statistical analyses are presented for data collected during the 1981 calendar year. In addition, one sample containing known concentrations chlorophyll a were analyzed in both laboratories, and these results also are presented.

From abstract: "A three-year study was made to document water quality, suspended sediment, and gain-and-loss characteristics of the South Platte near Fort Morgan, Colorado, prior to construction of the construction of the proposed Narrows Reservoir." It contains maps, graphs, and tables.

Purpose and Scope: The purpose of this report is to describe the regional hydrogeologic systems in the Blanding-Durango area and to establish their relationship to help assess salt as an effective storage medium for radioactive wastes. Interpretations are based principally on existing data; however, well inventories, phreatophyte mapping and stream-flow measurements were made during 1978, 1979, and 1980.

From abstract: This report describes a refined, two-dimensional graph-plotting program that was developed for use on Tektronix 4050-series graphics computers.

From introduction: This investigation was made as part of a comprehensive geohydrologic study of the Front Range Urban Corridor in Colorado conducted by the U.S. Geological Survey. The purpose of the study was to delineate the areal extent of the aquifer, the altitude and configuration of the water table, and the gradient and underflow in various parts of the area, in order to better understand the quality of water moving into and through the aquifer.

From purpose and scope: The purpose of this report is to present an analysis of the August 14, 1980, rainstorm in Denver, Colorado, and describe its effects on the South Platte River and six of its tributaries (figure 1).

Purpose and scope: The primary purpose of the study is to determine if data on infiltration and runoff obtained from the U.S. Geological Survey rainfall simulator, are useful in defining parameters used in the PRMS, which is used to predict runoff from larger watersheds. Incidental to this purpose are determination of the spatial variability of the parameters measured over the simulation plots and over the watershed, and sensitivity of these parameters in predicting runoff.

From introduction: This report describes the results of 1980 sampling of ground-water pumpage for irrigation on the High Plains, one phase of the High Plains Regional Aquifer-System Analysis project. These data were collected to estimate the volume of irrigation water pumped during 1980 and to determine current trends in irrigation pumpage on the High Plains.

From purpose and scope: The study was designed to describe and quantify the benthic invertebrate communities in selected streams in coal mining areas. A secondary purpose was to compare the results with other data collected prior to this study and to assess possible changes in water quality reflected in the composition of the benthic invertebrate community.

Abstract: Water shortages are expected in the Upper Colorado River Basin because of increasing water demands for various uses. Ground-water supplies can help to reduce water shortages but ground-water reservoirs have not been studied in detail. The regional aquifer systems analysis of the Upper Colorado River Basin is a study of the major ground-water resources of the region. Aquifers occur in the sedimentary rock sequences in basins and uplifted regions, in volcanic-rock regions, and in stream-valley alluvium. The project work will include collection and compilation of existing geologic, geophysical, hydrologic, and geochemical data. These data will be used to assess the hydrologic characteristics of the aquifer systems and to estimate the hydrologic effects of discharge from, or recharge to, selected aquifers.