Upper Arkansas Toxic-Substances Hydrology

Science Center Objects

Since 1986, the USGS Hard-Rock Mining Toxic-Substances Hydrology Project has focused on metal transport in streams affected by mining.

The approach is to study chemical processes within a hydrologic context, using a two-step approach:

  • First, the USGS used instream experimentation to provide data about the processes affecting metals.
  • Second, the USGS used the resulting data sets to develop and apply solute transport models to help quantify rates and processes.

Tracer-injection studies in St. Kevin Gulch, near Leadville, Colorado, helped the USGS design methods to characterize loading from mining activities on a watershed scale. Tracer-injection studies were done in 1995, in support of the planning needs of ederal Land Management Agencies, and as part of the USGS Abandoned Mine Land Initiative.


  1. To characterize the instream chemical processes that control the transport and transformation of metals downstream from mine drainage.
  2. To use tracer-injection methods to evaluate remediation efforts in selected basins.
  3. To quantify the time and length scales of chemical and hydrologic processes that affect the metals through development of solute-transport models.
  4. To characterize the chemistry of colloids, sediment, and bed sediments that are active in controlling the dissolved concentrations of metals.

Additional information and project results are available at: