Cleaning up Tenmile Creek began as a grass roots effort made up of local citizens concerned for the health of the community of Rimini. The group has been very active at the site and is now composed of agency representatives and private citizens. This group, The Upper Tenmile Watershed Steering Committee, has identified three goals in their effort address contaminant problems in the Upper Tenmile Creek Watershed. Their goals include to 1) discuss and offer suggestions on improving water quality in the basin; 2) educate the general pubic about environmental problems and the potential to improve water resources within the basin, especially drinking water for residents of Rimini and the city of Helena; and 3) guide development of land in the watershed in order to preserve its amenities for the enjoyment of all, now and in the future. The group is also concerned about identifying a potable water supply and ensuring fire protection for residents of Rimini, controlling noxious weeds, improving the quality of the fishery, abating road dust, and considering measures to specifically address adit discharges to Tenmile Creek to improve water quality. From discussions among committee members and various government agencies, the EPA has gained a broader perspective on the concerns of people directly affected by the legacy of historic mining and have been able to identify issues and potential cleanup approaches that may meet the common goals and objectives of many of the affected parties. Numerous individuals and local, state, and federal governmental representatives have been working for many years to address contaminant problems in the upper Tenmile Creek watershed. They include the following:

NRIS is a clearinghouse for all GIS data created in the state. Much of the data that existed up to that point could be acquired through their map object oriented web site. Stream flow information, census information, the MWCB program files, TIGER files, small scale ownership coverages, and USGS quads ranging in scales from 1:24000 to 1:2,000,000 are just some of the data that is available to the public. Access to these types of data clearinghouses greatly reduced our data acquisition costs. Although the state is fortunate to have the NRIS clearinghouse, much of Montana is rural which results in a lot of data that has not yet been created. For example, the USGS is just starting to provide digital ortho quarter quads for portions of the state.

Due to the readily available data from the NRIS site, much of the data had already been registered to the state mandated coordinate system which is State plane NAD83 Feet. Other data came from Federal agencies, many of which have a custom coordinate system. For example, the Region VIII EPA, which would be final clearinghouse of all the data, asked that all data be delivered in the Albers projection using a custom Northing and Easting, as well as a custom point of origin. On the other hand, the USGS provides imagery such as digital raster graphics (DRGs) in Universal Transverse Mercator (UTM) NAD83 meters. The MWCB provided mine locations in both latitude/longitude (with an unknown datum) as well as Township, Range, Section, Quarter Section format. Other Superfund data in the state of Montana used the UTM NAD83 meters projection. Due to an expedited schedule, TtEMI was tasked with finding the most efficient route to convert data so that it could be easily integrated and quickly available. Reviewing the needs of the scientists showed that calculations such as length, area, distance to stream, and distance of hauling routes would be the basis of their analysis. In the selection of a projection that maintained both area and length for a site that was only approximately 51 square miles running north to south, we found that the difference in the various projections were approximately 0.1%. Since there appeared to be no large difference in calculations for this specific area, the most efficient route to integrating the data was to leave the raster data in its original projection and convert all of the vector data. As a result, the selected projection was UTM Zone 12, NAD83 meters.

With an established base map of the site, data gaps were more easily identified. The most glaring GIS data gap was the actual location of abandoned mines. Initially, the EPA utilized all historical records, interviews with MDEQ employees and private consultants, and historical aerial photography to identify as many mine sites as possible. In addition, a majority of the USGS and USFS mine locations were provided in latitude/longitude coordinates. Many of these coordinates were calculated manually from USGS 7.5 quad maps. Although many of the lat/long locations turned out to inaccurate, we did get the names and an original count of 60 abandoned mines on record. Because the mine site locations would be the basis of analysis and assessment of risk, it was a priority to have an accurate location of the abandoned mines and adits. Since the watershed was situated on mostly USFS land, the USFS provided a source for historical aerial photography. The intention was to save time and resources by using the aerial photography to locate additional waste rock piles at known abandoned mine locations instead of having field teams hike to each site in search of these locations. Unfortunately, the aerial photography was flown at such a high elevation it provided little ground resolution and the black and white nature of the photos left room for an unacceptable margin of error. Other issues for aerial photography included using recent imagery since several sites had recently been reclaimed. The more difficult aerial photography issue was the thick canopy of evergreen trees that shrouded the watershed. Considering the size of the base map area and the fact that accurate extents of mine locations can only be found when there isn't snow on the ground, the field team had approximately three months to locate the abandoned mines and adits. It would have been very difficult to accomplish this by simply canvassing the area on foot for these types of sites.

One solution to this challenge was to first focus on the 'priority mine sites'. Acquiring color aerial photography that was flown at a low elevation (7,000 feet) and scanned at a high resolution (2500 microns) enabled the field teams to pinpoint their canvass areas more effectively. Field teams then used a combination of the written historical information for the mines, the projected lat/long locations, and a global positioning system (GPS) unit to accurately locate mines in the area. Again, the thick canopy and steep terrain of the watershed provided challenges to collecting GPS data.

Gathering GIS data in the field also meant having accurate property ownership coverage. Prior to any fieldwork, the EPA had contacted private property owners requesting access to the abandoned mines on their properties. Homes outside of the Rimini community were built on land located in USFS managed land, or private land in Lewis and Clark or Jefferson Counties. Creation of the ownership coverage required research at the county assessors office where many properties were still maintained in metes and bounds descriptions.

Establishing a base map with mine locations sped up the field effort and increased the accuracy of the map products and related assessments. Field maps were created for daily use, modified and edited, and re-created for quality control. The primary focus of the field effort was to compile a comprehensive physicochemical inventory of abandoned mines in the watershed and identify mining waste features that could have a potentially negative impact on surface water, groundwater, ecology (terrestrial and aquatic), and human health. During site reconnaissance, EPA identified a total of 150 abandoned mine sites in the watershed. The purpose of the site reconnaissance was to visit the abandoned mine sites that could be accessed, and measure and document physical characteristics of the site features. Field personnel also conducted an inspection of every tributary of upper Tenmile Creek to identify mine sites that were in direct contact with these tributaries, or that could come into direct contact during runoff events.

The following summarizes the information that was gathered during the survey of each mine site and added to the RDBMS and GIS.

1. Distance of the feature from creek or drainage