An ad hoc committee of the National Academies will conduct a study to explore the potential advantages of underground development in the urban environment, to identify the research needed to take advantage of these opportunities, and to develop an enhanced public and technical community understanding of the role of engineering of underground space in the sustainability of the urban built environment, specifically the minimization of consumption of nonrenewable energy resources, construction materials, and negative impact on the natural, built, and social environments. In particular the study will: • Summarize current geological and geotechnical engineering knowledge about underground development in the urban environment and how utilization of underground could increase sustainability, including knowledge of geologic site characterization, construction and geotechnical monitoring techniques, energy requirements, use of excavated materials, and lifecycle costs and benefits of underground infrastructure development.• Identify the research needed to capitalize on opportunities for enhancing sustainable urban development through underground engineering, in the following areas:• Underground characterization, prediction of the geologic environment, and ground response critical for successful design and construction of underground projects and critical facilities to maximize sustainability and resiliency;• Construction and monitoring methodologies and enhanced excavation methods, including tunneling, conducive to sustainable and resilient underground development;• Smart underground structures and conduits that report their status;• Health and safety considerations, such as cost-effective ventilation, light, and concerns related to radon exposure or fire control;• Lifecycle cost and benefit issues, including reduced energy needs for heating and cooling, reduced construction material use, use of excavated materials, increased longevity of underground structures and reduced maintenance associated with stable temperatures and isolation from surface weathering effects; • The potential sustainability benefits of increased use of underground space for human transportation systems, including roadways and mass transit, and freight;• The potential for integrating of energy, water, and waste systems for certain urban regions to improve sustainability; and• How underground development might address concerns related to the impacts of climate change on the urban environment.The committee will recommend directions for a new underground engineering research track focused on earth systems engineering and management to ensure future human resources for sustainable underground development, will analyze the advantages and disadvantages of establishing a new research center in this area, and consider other potential options for enhancing the human resource capacity for sustainable underground development (including the status quo). The committee also will consider from a social science point of view, the policy, economic, and human behavioral drivers that promote or inhibit the development of the subsurface in a sustainable manner, but will not make policy or funding recommendations.The project is sponsored by the National Science Foundation.The approximate start date for the project is 09/01/2009