Suspended sediment in selected streams of southeastern Montana

The relatively flat Badger Road area near Fairbanks occupies part of the alluvial plain of the Chena and Tanana Rivers and is underlain by scattered areas of permafrost. The water table of the high-transmissivity aquifer that underlies the area is generally shallower than 15 feet, fluctuates seasonally about 2 feet, and slopes northwesterly, the direction of ground-water flow. Private domestic-supply wells obtain water from the upper part of the aquifer. Septic systems used to dispose of waste water are installed at or only slightly above the water table in the same aquifer. Analyses of samples from 16 observation wells in undeveloped parts of the study area and from 33 domestic wells indicated that water quality has not been significantly degraded by on-site waste disposal. Three samples had detectable but minor contamination by fecal coliform bacteria. Anomalous values of chloride and ammonia in one third of the domestic wells may indicate incipient degradation of ground-water quality by septic-tank effluent. (USGS)