Wide-Area Assessment

Synthetic aperture radar (SAR), Compact Airborne Spectrographic Imager II hyperspectral imaging (HSI), high-resolution color orthophotography (ortho), and Light Detection and Ranging (LiDAR) technologies are being used at the Former Lowry Bombing and Gunnery Range (FLBGR).  These platforms are being used to

1) identify previously undocumented areas of concern (AOCs) across the site, and

2) identify “presumptively clean” areas across the remainder of the site. 

(Note that the objectives of these Wide Area Assessment (WAA) efforts are to identify clusters of munitions-related items (undocumented AOCs), not identify individual, small or subsurface munitions.) 

The term “presumptively clean,” as defined in the U.S. Army Corps of Engineers (USACE) and Colorado Department of Public Health and Environment (CDPHE) Settlement Agreement, refers to areas that are:

  • Outside of any anomaly clusters identified by the WAA, and there is no other historical or technical data, which indicates the presence of unexploded ordnance (UXO);
  • In an anomaly cluster, but the cluster is not munitions related;
  • Cleared to a depth consistent with intended land use, or the Parties agree that it has been adequately addressed during previous munitions response efforts; or
  • In an anomaly cluster but, based on results of subsurface investigations, no UXO was identified, and there is no evidence to suggest that UXO exists beyond the depth of investigation.

Synthetic Aperture Radar

Both SAR and HSI data sets were collected over the 92-square-mile range in October 1999.  Initial processing and field verification of the SAR data collected at the FLBGR proved that the SAR technology is capable of detecting clusters of metallic items lying on the ground surface, indicative of military munitions debris at an AOC (i.e. former bombing target, gunnery range, demolition site, or other area where munitions were used).  The HSI data is used to discriminate vegetation-related anomalies reflected in the SAR data, as well as roads and structures that may cause false-positive SAR returns. 

Ortho and LiDAR were collected over the FLBGR in September 2002.  The ortho is used to perform quality control (QC) of the SAR/HSI results.  The LiDAR data is used for the development of a high-resolution Digital Elevation Model (DEM) and to correct distortion in the ortho.  The LiDAR is also utilized for QC of the SAR/HSI results, by providing a view of the site (without vegetation) that is useful in identifying craters and other cultural features associated with munitions usage.

Orthophoto Identifying Circle of Bricks

LiDAR Imagery Identifying Bomb Craters

An area of interest (AOI) is a cluster of anomalies identified by the WAA efforts that cannot be specifically identified or discriminated by the remote sensing data, photos, historical information, etc. and is not a known AOC. AOIs identified by the WAA efforts must be field verified in order to determine whether or not they are munitions related.  If evidence of munitions-related activities (i.e. munitions scrap, craters, other cultural features, etc.) are found at the AOI location during the field verification, then the AOI is further investigated in order to determine whether or not an AOC exists and munitions response activities are warranted.  If the AOI is not munitions related and no historical records indicate that an AOC exists in that vicinity, the area is considered presumptively clean by the USACE and the CDPHE. 

It is essential to assure the public and regulatory community that the AOIs identified by the WAA are an accurate depiction of the area being analyzed. Therefore, extensive field verifications of AOIs are being performed.  Additionally, random areas that are not identified as AOIs are also visited to ensure that AOIs are not being missed by the WAA efforts.  The field verifications are being performed jointly by representatives from the entire project team, including the USACE, CDPHE, and Technical Assistance for Public Participation (TAPP) contractor (on behalf of the stakeholders). 

Required Munitions Response

As described previously, the emphasis of the WAA is to detect potential AOCs (clusters of munitions items), as opposed to the absolute or definitive detection of individual, small or subsurface items.  If a munitions-related AOC is identified, the appropriate investigations and/or munitions response will be performed as required, including Time Critical Removal Actions (TCRAs), if needed.

Technology Limitations Summary

The use of airborne remote sensing technologies for detection of munitions clusters has never been performed at a production level and/or on a site as large as the FLBGR.  The overall goals and objectives of the WAA activities at the FLBGR include the development and refinement of parameters associated with site-specific conditions (e.g. size, terrain, funding, goals objectives, etc.) as well as identifying technology requirements and limitations (e.g. data integration, HSI discrimination of SAR anomalies, etc.)  This will provide a basis for future munitions response projects in determining the applicability of the technology(s) at any given site.  Hence, it is important to recognize that the entire process is one that is evolving and will be adjusted as necessary to produce the best, most efficient, and cost-effective results. 


©2002 - 2016 by the U.S. Army Corps of Engineers