2012). Formal planning and control of underground space by municipalities is a responsibility to be recognized and acted upon in the United States if sustainable urban development is to be realized. In some countries such as China, planning of underground space is a special focus for responding to urban growth, and such plans have been developed by almost every large Chinese city over the past few years (Guo et al., in press).

This chapter traces the evolution of urban underground space and illustrates how the progressive and piecemeal development of underground space poses significantly more restrictions on future development than in the cases of surface facilities and infrastructure development.

EXPANSION OF THE UNDERGROUND IN THE PAST CENTURY

Sewage systems are placed underground to use gravity to drain sewage away from buildings. Water distribution systems are often placed underground to protect them against freezing and other damage. Telecommunications and electric power supply systems may be placed below ground according to local precedent, in consideration of the value placed on maintaining a secure and resilient infrastructure, for reasons related to surface aesthetics, or to minimize the effect of installation on property values. Concern regarding uncoordinated planning of underground space is not new. In 1914, George Webster, chief engineer and surveyor of Philadelphia, lamented that few large cities planned the space beneath streets, or charted the utilities and services placed there (Webster, 1914). He noted the importance of understanding what the underground was required to accommodate and discussed the need to plan for

• water, hot water, steam, sewer, refrigerating, and gas pipes; electrical conduits; pneumatic tubes; and as yet undetermined future services;

• galleries for pipes and conduits;

• vaults under sidewalks in the public right-of-way as a part of new building construction;

• subways for transit systems and passengers;

• tunnels beneath underground services to accommodate movement of people between business establishments without the need to cross streets or venture into weather; and

• underground freight movement services to connect freight terminals with commercial businesses and industrial establishments.

Webster advocated that underground space should be planned to facilitate future installations and minimize the costs and delays caused by future installations. He advocated for an official authoritative body to regulate underground usage, and he predicted that without such controls new large underground installations



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