The Beluga, Peters Creek, and Healy coal areas in Alaska were studied during 1975-78, with major emphasis on surface-water hydrology and water quality.
In the Beluga coal area, mean annual discharge is estimated to range from 2.2 to 3.4 cubic feet per second per square mile of drainage area. The 7-day low flow having a 10-year recurrence interval is estimated to be 0.3 to 0.6 cubic feet per second per square mile. The dilute surface waters are a calcium bicarbonate type, have low concentrations of nutrients, and at times may contain dissolved iron and manganese in concentrations in excess of U.S. Environmental Protection Agency recommended limits. The pooled diversity index of the benthic invertebrate community ranges from 2.93 to 4.06. No ground-water wells have been drilled in the potential mining areas.
Water quality of streams in the Peters Creek coal area is similar to that of streams in the Beluga coal area. No attempt is made to define streamflow characteristics in the Peters Creek coal area due to poor correlations with nearby gaging stations.
In the Healy coal area, streamflow characteristics of the two major basins studied are dissimilar. Lignite Creek is estimated to have less yield than Healy Creek. Studied tributaries of Healy and Lignite Creeks have a dissolved-solids range of 111 to 636 milligrams per liter and have calcium and bicarbonate or magnesium and bicarbonate as principal ions. Iron and manganese concentrations are high at some times of the year. The concentrations of sodium and chloride increase significantly in the lower reaches of Lignite Creek.