Border Security: Additional Actions Could Strengthen DHS Efforts to Address Subterranean, Aerial, and Maritime Smuggling, Report to Congressional Requesters [open pdf - 8MB]
"As DHS has increased the security of overland smuggling routes, transnational criminal organizations have adapted their techniques to smuggle drugs and humans through alternative methods. These methods include cross-border tunnels, ultralight aircraft, panga boats, and recreational maritime vessels. While these methods account for a small proportion of known smuggling, they can be used to transport significant quantities of drugs or for terrorist activity. GAO [Government Accountability Office] was asked to review DHS's efforts to address subterranean, aerial, and maritime smuggling. This report addresses, among other things, (1) the known prevalence of the aforementioned smuggling methods, (2) efforts to address them, and (3) efforts to assess the results of activities to counter them. GAO analyzed relevant procedures, reports, and data for fiscal years 2011 through 2016. GAO also interviewed DHS officials and conducted site visits to locations in California, Arizona, and Florida, chosen based upon past detection of smuggling by the selected methods, among other things. The information from the site visits is not generalizable, but provided valuable insights."
Government Accountability Office: http://www.gao.gov/