Throughout the nation increasing attention is being given to the problem of pollution by discharges of waste from combined sewers. Several spe cific studies have been made including those reported by Johnson (1) for Washington, D. C. and Benjes et al. (2) for Kansas City, Mo. Weibel et al. (3) reported on studies of urban land runoff as a factor in stream pollu tion. Dunbar and Henry (4) reported recently on pollution control measures for stormwater and combined sewer overflows. Additional references re