In response to numerous releases of hazardous substances from leaks in underground storage tanks and pipelines, the EPA requires monitoring so that leaks are detected, located and repaired as quickly as possible. Acoustic leak location offers the possibility of locating leaks which have been identified by other methods but which are not appropriate for performing location. The successful application of acoustic leak location requires that existing data analysis approaches be improved so that the smallest leaks of interest be locatable with the widest possible sensor spacing. Part of developing such approaches requires that the physical conditions which affect the amplitude, frequency, and dispersion of the leak signal as it propagates between source and sensor be better understood.