Streamflow losses to Madison Group rocks in the Little Belt and Big Snowy Mountains, Montana

Four streams originating in the Little Belt and Big Snowy Mountains in central Montana were measured in 1975 to determine streamflow losses across outcrops of the Madison Group (Mississippian age). Based on streamflow data obtained for 39 months at two streamflow-gaging stations on the Middle Fork Judith River, the average daily loss was 9.1 cubic feet per second or about 6,600 acre-feet per year. Seepage measurements on other stream reaches indicated losses of 7.6 cubic feet per second on the south Fork Judith River, 9.2 cubic feet per second in Yogo Creek, as much as 64 cubic feet per second in Dry Wolf Creek, and about 60 cubic feet per second in Rock Creek. (USGS)