Hydrologic and water-quality data at selected sites in the Upper Animas River watershed, southwestern Colorado, 1997-99

Abstract

The water quality and aquatic resources of the upper Animas River watershed are affected by more than 1,500 abandoned mines from historical metal-mining activities in the late 1800's and early 1900's. In 1997, the U.S. Geological Survey implemented the Abandoned Mine Lands Initiative to provide scientific information to Federal land-management agencies responsible for remediation of abandoned mine sites on publicly owned land. This report presents hydrologic and water-quality data collected as part of the Abandoned Mine Lands Initiative during water years 1997-99 in the upper Animas River watershed, Colorado. Water-quality samples were collected from four streamflow-gaging stations, nine sites along the main stem and two major tributaries, 55 abandoned mine sites, and 194 selected stream and spring sites. Data include field measurements of streamflow, specific conductance, pH, water temperature, and dissolved oxygen and laboratory analyses of major inorganic and selected traceelement constituents. Daily mean discharge values are tabulated for the four streamflowgaging stations. A CD-ROM containing hydrologic and water-quality data is in the pocket of this report.

Contemporary geochemical composition and flux of aeolian dust to the San Juan Mountains, Colorado, United States

“…For instance, based on our estimated range of winter/spring dust deposition (5 to 10 g m −2 yr −1 ), the abundance of carbonate minerals in dust (calcite + dolomite = 5.5% mineral mass), and the average snow water equivalence at the SBBSA each season (38.5 cm yr −1 ), we estimate that carbonate dissolution from dust deposition could account for 14 to 28 meq L −1 of snowmelt acid neutralizing capacity (1 mg L −1 CaCO 3 = 20 meq L −1 ANC). This is comparable to the total acid neutralizing capacity measured in streams (∼32 meq L −1 ) of the nearby Weminuche Wilderness Area [Mast et al, 2000]. Thus, in poorly buffered alpine basins, dust deposition may be an important control of surface water ANC.…”

The effects of acidic mine drainage from historical mines in the Animas River watershed, San Juan County, Colorado—What is being done and what can be done to improve water quality?

“…Because of the combined effects of hydrothermal alteration that is directly associated with the mineral deposits and the widespread distribution of historical mine sites throughout the watershed, it is difficult to attribute low pH values and high trace-metal concentrations exclusively to either source. The pH of water samples collected at background sites ranged from 2.58 to 8.49 compared to pH of water from mine sites that ranged from 2.35 to 7.77 (Mast et al, 2000a).…”

“…This mineral suite is part of the preore propylitic hydrothermal assemblage, which has a high acidneutralizing potential (Desborough and Yager, 2000). Nearsurface spring and surface water that has interacted mainly with propylitic rock has a pH range of 6.0-7.5 (Mast, et al, 2000a).…”

A GIS and statistical approach to identify variables that control water quality in hydrothermally altered and mineralized watersheds, Silverton, Colorado, USA

“…6). The primary source of water quality data used in this analysis is from a relational database described in Sole and Rich (2007) and was populated from data collected as part of AML investigations (Mast et al 2000aLeib et al 2007;Kimball et al 2007;Wright et al 2007). Samples collected during base-flow conditions during late summer to fall, primarily between 1996 and 2002, were used for analysis.…”