Metal loading assessment of a small mountainous sub-basin characterized by acid drainage -- Prospect Gulch, upper Animas River watershed, Colorado

Wirt, Laurie; Leib, Kenneth J.; Melick, Roger; Bove, Dana J.

doi:10.3133/ofr01258

Cited by 3 publications

(3 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Precipitation of iron hydroxides requires a supply of iron and sulfate (present in ARD) and an environment in which these reduced groundwater inflows mix with shallow oxygenated waters such as in the wetland. Iron‐hydroxide deposits commonly occur near the base of steep slopes, where groundwater has discharged through talus (Wirt et al , ), as is the case along the upper Snake River. The oxidizing environment of these wetland zones has historically been a sink for iron hydroxide colloids and the other metals which sorb to this precipitate.…”

Section: Site Descriptionmentioning

confidence: 99%

Quantifying sources of increasing zinc from acid rock drainage in an alpine catchment under a changing hydrologic regime

Crouch

McKnight

Todd³

2013

Hydrological Processes

View full text Add to dashboard Cite

A major water quality concern in the Rocky Mountains is acid rock drainage (ARD), which causes acidic conditions and high metal concentrations in streams. The 30‐year water quality record for the upper Snake River in Colorado, USA, shows that summer low‐flow zinc concentrations have increased four‐ to sixfold concurrently with increases in mean annual and summer temperatures and a two‐ to three‐week advancement in spring snowmelt. We found that the main source of zinc and other metal loads to the upper Snake River was a tributary draining an alpine area rich in disseminated pyrite. By conducting a tracer experiment in this tributary of interest, we demonstrated that 30% of the trace metal loading entered in an upper steep, rocky reach where the tributary of interest is fed by an alpine spring. Another increase in flow and metal loading occurred where the tributary of interest flows through a gently sloped wetland area. Analysis of the tracer experiment indicated a significant increase in hyporheic exchange along this wetland reach, from which metals appear to be mobilized. Several potential explanations are presented that might explain this phenomenon: decreasing pH in the tributary of interest may result in mobilization of metals from the wetland and hyporheic zone; the geochemistry of groundwater inflows to the wetland may be changing; and, wetland soils may be drying out with longer, warmer summers. This study illustrates how changes in hydrologic regime may cause changes in biogeochemical processes that exacerbate the danger to aquatic ecosystems associated with ARD. Copyright © 2012 John Wiley & Sons, Ltd.

show abstract

Section: Site Descriptionmentioning

confidence: 99%

Quantifying sources of increasing zinc from acid rock drainage in an alpine catchment under a changing hydrologic regime

Crouch

McKnight

Todd³

2013

Hydrological Processes

View full text Add to dashboard Cite

show abstract

“…The northern third of Prospect Gulch is dominated by several distinct suites of acid-sulfate alteration assemblages, while the remaining area is propylitically altered (less alteration). The stream in Prospect Gulch is approximately 2.4 km with an elevation change of 800 m, and the average annual precipitation is about 114 cm with 94 cm occurring as snowfall (Wirt et al 2001). Ground water and surface water in and around Prospect Gulch are affected by historical mining, but the influence of ground water flow on metal transport and resulting water quality is poorly understood.…”

Section: Project Settingmentioning

confidence: 99%

“…Prospect Gulch (Figure 1) was selected for further study of the ground water system in the upper Animas River watershed because of the amount of data provided in and around Prospect Gulch by the AMLI (Church et al 2005), including stream tracer studies (Wirt et al 1999, 2001; Kimball et al 2002) and detailed maps of hydrothermal alteration (Bove et al 2005). Prospect Gulch lies within the Silverton caldera, and the bedrock consists of volcanic rocks that are predominantly composed of massive andesitic and dacitic flows, flow breccias, and volcaniclastic sediments (Burbank and Luedke 1969).…”

Section: Project Settingmentioning

confidence: 99%

Ground Water Flow Modeling with Sensitivity Analyses to Guide Field Data Collection in a Mountain Watershed

Johnson¹

2007

Groundwater Monitoring Rem

View full text Add to dashboard Cite

In mountain watersheds, the increased demand for clean water resources has led to an increased need for an understanding of ground water flow in alpine settings. In Prospect Gulch, located in southwestern Colorado, understanding the ground water flow system is an important first step in addressing metal loads from acid‐mine drainage and acid‐rock drainage in an area with historical mining. Ground water flow modeling with sensitivity analyses are presented as a general tool to guide future field data collection, which is applicable to any ground water study, including mountain watersheds. For a series of conceptual models, the observation and sensitivity capabilities of MODFLOW‐2000 are used to determine composite scaled sensitivities, dimensionless scaled sensitivities, and 1% scaled sensitivity maps of hydraulic head. These sensitivities determine the most important input parameter(s) along with the location of observation data that are most useful for future model calibration. The results are generally independent of the conceptual model and indicate recharge in a high‐elevation recharge zone as the most important parameter, followed by the hydraulic conductivities in all layers and recharge in the next lower‐elevation zone. The most important observation data in determining these parameters are hydraulic heads at high elevations, with a depth of less than 100 m being adequate. Evaluation of a possible geologic structure with a different hydraulic conductivity than the surrounding bedrock indicates that ground water discharge to individual stream reaches has the potential to identify some of these structures. Results of these sensitivity analyses can be used to prioritize data collection in an effort to reduce time and money spend by collecting the most relevant model calibration data.

show abstract

An approach to quantify sources, seasonal change, and biogeochemical processes affecting metal loading in streams: Facilitating decisions for remediation of mine drainage

Kimball

Runkel

Walton-Day

2010

Applied Geochemistry

View full text Add to dashboard Cite

Metal loading assessment of a small mountainous sub-basin characterized by acid drainage -- Prospect Gulch, upper Animas River watershed, Colorado

Cited by 3 publications

References 11 publications

Quantifying sources of increasing zinc from acid rock drainage in an alpine catchment under a changing hydrologic regime

Quantifying sources of increasing zinc from acid rock drainage in an alpine catchment under a changing hydrologic regime

Ground Water Flow Modeling with Sensitivity Analyses to Guide Field Data Collection in a Mountain Watershed

An approach to quantify sources, seasonal change, and biogeochemical processes affecting metal loading in streams: Facilitating decisions for remediation of mine drainage

Contact Info

Product

Resources

About