Ground-water resources of the Alma area, Michigan

Water Supply Paper 1619-E

Prepared in cooperation with the Michigan Geological Survey and the city of Alma



The Alma area consists of 30 square miles in the northwestern part of Gratiot County, Mich. It is an area of slight relief gently rolling hills and level plains and is an important agricultural center in the State.

The Saginaw formation, which forms the bedrock surface in part of the area, is of relatively low permeability and yields water containing objectionable amounts of chloride. Formations below the Saginaw are tapped for brine in and near the Alma area.

The consolidated rocks of the Alma area are mantled by Pleistocene glacial deposits, which are as much as 550 feet thick where preglacial valleys were eroded into the bedrock. The glacial deposits consist of till, glacial-lake deposits, and outwash. Till deposits are at the surface along the south-trending moraines that cross the area, and they underlie other types of glacial deposits at depth throughout the area. The till deposits are of low permeability and are not a source of water to wells, though locally they include small lenses of permeable sand and gravel.

In the western part of the area, including much of the city of Alma, the glacial-lake deposits consist primarily of sand and are a source of small supplies of water. In the northeastern part of the area the lake deposits are predominantly clayey and of low permeability.

Sand and gravel outwash yields moderate and large supplies of water within the area. Outwash is present at the surface along the West Branch of the Pine River. A more extensive deposit of outwash buried by the lake deposits is the source of most of the ground water pumped at Alma. The presence of an additional deposit of buried outwash west and southwest of the city is inferred from the glacial history of the area. Additional water supplies that may be developed from these deposits are probably adequate for anticipated population and industrial growth.

Water levels have declined generally in the vicinity of the city of Alma since 1920 in response to pumping for municipal and industrial supplies. The declines are not excessive, and during the late 1950's water levels in parts of Alma have risen slightly, because of dispersion of the pumping stations.

The ground water in the Alma area generally is very hard and high in iron. Locally, the buried outwash that underlies the city of Alma is contaminated by phenolic substances. This limits the amount of ground water available for municipal supply within the city, although reclamation of the contaminated part of the aquifer is considered feasible.

Study Area

Additional publication details

Publication type:
Publication Subtype:
USGS Numbered Series
Ground-water resources of the Alma area, Michigan
Series title:
Water Supply Paper
Series number:
Year Published:
U.S. Government Printing Office
Publisher location:
Washington, D.C.
Contributing office(s):
Michigan Water Science Center
Document: v, 66 p.; 2 Plates: 19 x 13 inches and 15.5 x 13.5 inches
United States