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IV. Vegetation Monitoring: Vegetation monitoring (riparian survey) for the 16-Right and 17-Right panels was performed during the second week of September. The vegetation monitoring report, which evaluates any changes in riparian vegetation conditions and characteristics for Fish Creek relative to the measured baseline conditions, is included with the Second-Half 2004 Subsidence Report. V. Hydrologic Monitoring: Hydrologic monitoring of potential subsidence impacts from the 16-Right panel utilizes two alluvial wells and two surface sites. The upstream alluvial well is designated as AVF-13 and the downstream alluvial well as AVF -14. The upstream surface site is designated as SW-13 and the downstream site as SW-14. Note that AVF-14 and SW-14 were subsided in the summer of 2003. Period of record data tables for these sites are attached. Hydrologic monitoring of potential subsidence impacts from the 17-Right panel also utilizes two alluvial wells and two surface sites. These include alluvial well AVF-15 (downstream of AVF-14) and associated surface site SW-15 (downstream of SW-14), which are located in an area currently being subsided, and downstream surface site 305 and it's associated alluvial well, 008-AU3. Sites 305 And 008-AU3 represent non- subsidence downstream sites. These sites (with exception of downstream sites 305 and 008-AU3 which are off the map) are shown on the attached Second-Half 2004 Subsidence Map. Period of record data tables for these sites are also attached. Prior to subsiding the SW-15/AVF15 area (summer 2004), the Union Pacific Railroad raised the section of track crossing Fish Creek and extended the two existing Fish Creek culverts running under the track. Following installation of the extensions, flow was temporarily halted along Fish Creek (below the culverts), and resumed in late September 2004. The SW-15/AVF-15 area has subsequently ponded (winter of 2004 - 2005). 2004 Hydrologic monitoring did not indicate significant water quality impacts to Fish Creek, however, elevated iron and manganese concentrations were detected at alluvial water site AVF-15 in June and September 2004. These elevated concentrations do not appear be reflected at sites located upstream and downstream of AVF-15. A similar anomaly was detected in alluvial wells in August 2003. Subsequent sampling following August 2003 yielded significantly lower iron concentrations. At the time it this was suspected to be a laboratory error. Hydrologic monitoring of these sites will continue in 2005, and this anomaly will be monitored and further assessed. V. Conclusions: Structures remained essentially unaffected during the period with the exception of the predicted impacts to the Union Pacific Railroad and Fish Creek from first-half 2004 2004_2ndHalfSubReport.doc Page 2 of 3 03/01/05