Dependable water supplies are vital to the mining industry in the Marquette Iron Range in Michigan. Development of processes that concentrate and pelletize low-grade iron ore has permitted mining to expand during the past two decades. Water demand has increased both for iron ore concentration processes and for the area 's general development.
Five main streams drain the area. Their total average annual discharge is about 700 cu ft/sec, of which, about 150 cu ft/sec is inflow from outside of this study 's limits. The Middle Branch and East Branch Escanaba River flow through the central part of the study area and drain about 60 percent of it. The combined natural flow of these two streams equals or exceeds 100 cu ft/sec 90 percent of the time. Median annual 7-day low-flows are about 0.25 cu ft/sec per sq mi in most of the area. Seven stream impoundments and 243 natural lakes provide surface water storage.
Surface water is generally of a calcium-magnesium bicarbonate type and dissolved-solids concentrations are generally less than 150 mg/L. Small streams that drain glacial outwash deposits have higher dissolved-solids concentrations than larger streams.
Large ground-water supplies may be developed from glacial outwash aquifers along the northern, southern, and eastern boundaries of the study area. Thin, unconsolidated deposits of low permeability occur in the center of the area. Metamorphosed bedrock produces moderate amounts of water only in fracture zones. Sandstones in the eastern part of the area yield water at some locations, but these deposits are seldom utilized because other ground-water sources are more readily available.
Ground water in the Marquette Iron Range is generally of suitable quality for most uses. Iron concentrations, however, are frequently high.
