Pictured Rocks National Lakeshore has abundant picturesque and useful water resources. These resources include 12 inland lakes that range in size from 6 to 765 acres, 10 small streams that flow to Lake Superior, 40 miles of Lake Superior lakeshore, and aquifers capable of yielding water to wells in most places.
The Jacobsville Sandstone, Munising Sandstone, and glacial deposits are the sources for domestic water supplies. The Jacobsville Sandstone is the principal source of water from Miners Castle to Au Sable Point, the Munising Sandstone is the source of water in the vicinity of Grand Sable Lake, and glacial deposits provide water for Park Headquarters at Sand Point. Specific capacities range from 0.1 to 1 (gal/min)/ft (gallons per minute per foot) of drawdown for the Jacobsville Sandstone and from 1 to 14 (gal/min)/ft for the glacial deposits. Specific capacity for the Munising Sandstone is about 1 (gal/min)/ft of drawdown.
Water from both surface- and ground-water sources generally is suitable for human consumption. Concentrations of dissolved solids range from 43 to 112 mg/L (milligrams per liter) in water from lakes, from 53 to 155 mg/L in water from streams, and from 68 to 313 mg/L in ground water. The amount of suspended-sediment particles in streams is generally less than 17 mg/L.
