Application of environmental statutes to military munitions. Competition for frequency spectrum. Competition for airspace. Urban growth. Because most encroachment problems are caused by population growth and urban development, these problems are expected to increase in the future. Below are brief descriptions of some of the problems as reported by the installations and organizations we visited in the continental United States. Recently, about 10 percent of the installation has been designated as critical habitat for endangered species. DOD and military service officials said that many encroachment issues are related to urbanization around military installations. Effects of Encroachment on Training Readiness Are Not Reflected in Reported Data

Despite the loss of some training range capabilities, service readiness data do not indicate that encroachment has significantly affected training readiness. In fact, it rarely cites training range limitations at all. Although readiness reporting can and should be improved to address training degradation due to encroachment and other factors, it will be difficult for DOD to fully assess the impact of encroachment on its training capabilities and readiness without (1) obtaining more complete information on both training range requirements and the assets available to support those requirements and (2) considering to what extent other complementary forms of training may help mitigate some of the adverse impacts of encroachment. A full assessment of the effects of encroachment on training capabilities and readiness will be limited without better information on the services’ training range requirements and limitations and on the range resources available to support those requirements. Although DOD has not yet finalized a comprehensive plan of actions for addressing encroachment issues, it has made progress in several areas. According to DOD, the legislative proposals seek to “clarify” the relationship between military training and a number of provisions in various conservation statutes, including the Endangered Species Act, the Migratory Bird Treaty Act, the Marine Mammal Protection Act, and the Clean Air Act.
What GAO Found

The following eight "encroachment" issues are hampering the military's ability to carry out realistic training: endangered species' critical habitat, unexploded ordnance and munitions, competition for radio frequency spectra, protected marine resources, competition for airspace, air pollution, noise pollution, and urban growth around military installations. Officials at all the installations and major commands GAO visited in the continental United States reported that encroachment had affected some of their training range capabilities, requiring work-arounds that are unrealistic. Service officials believe that population growth is responsible for current encroachment problems in the United States and is likely to cause more training range losses in the future. Despite concerns about encroachment, military readiness reports do not indicate the extent to which encroachment is harming training. Improvements in readiness reporting can better reveal shortfalls in training, but the ability to fully assess training limitations and their impact on capabilities and readiness will be limited without (1) more complete baseline data on training range capabilities, limitations, and requirements and (2) consideration of how live training capabilities may be complemented by training devices and simulations. Progress in addressing individual encroachment issues has been made, but more will be required to comprehensively plan for encroachment. Legislation proposed by the Department of Defense to "clarify" the relationship between military training and various environmental statues may require trade-offs between environmental policy and military training objectives.