Publications

In the mid-1990s, the Colorado Division of Water Resources (CDWR) adopted rules governing measurement of tributary ground-water pumpage for the Arkansas River Basin. The rules allowed ground-water pumpage to be determined using one of two approaches?power conversion coefficient (PCC) or totalizing flowmeters (TFM). In addition, the rules allowed a PCC to be applied to the electrical...

Current (1997?2001) and historical (1948?49, 1968?69) nitrate-concentration and water-level data collected from wells completed in the unconfined aquifer in the intensively cultivated area north of the Rio Grande in south-central Colorado were used to determine the distribution and mass of nitrate and to determine short- and long-term trends in the concentration and mass of nitrate in...

The water resources of the Upper Colorado River Basin have been extensively developed for water supply, irrigation, and power generation through water storage in upstream reservoirs during spring runoff and subsequent releases during the remainder of the year. The net effect of water-resource development has been to substantially modify the predevelopment annual hydrograph as well as the...

No abstract available.

The U.S. Geological Survey has monitored the quality and quantity of streamflow at the Rocky Mountain Arsenal (RMA) northeast of Denver, Colorado, since the early 1990s in cooperation with the U.S. Army. This report, prepared in cooperation with the U.S. Fish and Wildlife Service, documents existing surface-water-quality conditions on the RMA. All RMA water-quality data for the Irondale...

No abstract available.

Controls over nutrient supply are key to understanding the structure and functioning of terrestrial ecosystems. Conceptual models once held that in situ mineral weathering was the primary long-term control over the availability of many plant nutrients, including the base cations calcium (Ca), magnesium (Mg), and potassium (K). Recent evidence has shown that atmospheric sources of these...

Twenty-three stream sites representing a range of forested, agricultural, and urban land uses were sampled in the South Platte River Basin of Colorado from July through September 2002 to characterize water quality during drought conditions. With a few exceptions, dissolved ammonia, Kjeldahl nitrogen, total phosphorus, and dissolved orthophosphate concentrations were similar to seasonal...

We evaluated authigenic changes of Fe, Mn, V, U, Mo, Cd and Re in suboxic, periodically remobilized, tropical shelf sediments from the Amazon continental shelf and the Gulf of Papua. The Cd/Al, Mo/Al, and U/Al ratios in Amazon shelf sediments were 82%, 37%, and 16% less than those in Amazon River suspended sediments, respectively. Very large depletions of U previously reported in this...

No abstract available.

Introduction: This report is the companion data report for: Nutrients in Streams and Rivers Across the Nation - 1992-2001 (D.K. Mueller and N.E. Spahr, U.S. Geological Survey written commun., 2005). The data contained in this report were collected as part of the National Water-Quality Assessment (NAWQA) Program. Investigations were conducted in 51 large river basins and aquifer systems...

In January 1999, the U.S. Geological Survey (USGS) began an expanded monitoring program near Deer Trail, Colorado, in cooperation with the Metro Wastewater Reclamation District and the North Kiowa Bijou Groundwater Management District. Monitoring components were biosolids, soils, crops, ground water, and streambed sediment. The monitoring program addresses concerns from the public about...