Artillery Impact Area Buffer Zone (AIABZ) MRS
The Artillery Impact Area Buffer Zone (AIABZ) Munitions Response Site (MRS) comprises 791 acres located along the northwestern boundary of Camp Williams. The MRS has 114 privately owned land parcels, most of which are currently undeveloped but slated for future residential housing. The northern half of the MRS includes 25 parcels with houses that are part of Area D of the Hi-Country Estates Phase II (HCE- II) residential development. The HCE-II residential development and surrounding parcels in the AIABZ MRS lie within land that is part of unincorporated Salt Lake County. The nearest urban area to these mountainous rural parcels is the city of Herriman. The AIABZ MRS is characterized by rock-covered sloping hills and deep gullies. Open grasslands and dense thickets of oak brush occupy approximately equal areas of the MRS. Based on previous feedback from landowners during the feasibility study (FS), brush removal was not permitted at the AIABZ MRS.
The current boundary of the AIABZ MRS is based on results of the remedial investigation (RI) and the nature and extent investigation conducted at two large, adjacent MRSs: The Rose Canyon Training Area MRS (approximately 5,000 acres) and the original AIABZ MRS (originally 678 acres). The RI findings for these two sites showed an area with low density munitions and explosives of concern (MEC) and munitions debris (MD) that straddled the shared boundary between the two MRSs. The boundary between these sites was revised based on computer modeling of RI results using Visual Sample Plan (VSP) software such that any locations where MEC was found in the vicinity of the shared boundary area were incorporated into the AIABZ MRS. The revised boundary is the current AIABZ MRS boundary addressed by this project.
The munitions found to date in this area are large-caliber artillery projectiles, predominantly 155mm high explosive (HE) and illumination rounds, but 8-inch HE projectiles have also been found historically. The density of these items is extremely low, currently estimated to equate to 0.04 MEC items per acre, or one MEC every 25 acres. The current hypothesis regarding the origins of these munitions is that they are related to artillery firing aimed at the Camp Williams Artillery Impact Area, located immediately south of the AIABZ MRS. All projectiles found to date were found on the surface, which is consistent with large caliber munitions and the rock-covered nature of the ground surface in this area. The RI field investigation included over 87 miles of Digital Geophysical Mapping (DGM) transects and related intrusive investigations in the Rose Canyon and AIABZ MRSs, and showed conclusively that MEC is not expected to be in the subsurface at the AIABZ MRS. For this reason, the remedial action (RA) required for the AIABZ MRS included a full surface clearance of MEC and MD.
During the summer of 2010, approximately 176 acres of the AIABZ MRS burned during a wildfire. A time-critical removal action (TCRA) was conducted over the burned ground in the AIABZ MRS during 2011. The TCRA included a full surface clearance of identified MEC and MD over 166 acres. Surface Clearance of identified MEC and MD over the remaining 625 acres of land at the AIABZ MRS was completed during the 2014 RA.
For additional information and reports of previous investigations, please visit the Repository