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The Wells Of Ann Arbor

The Wells Of Ann Arbor image
Parent Issue
Day
23
Month
May
Year
1902
Copyright
Public Domain
OCR Text

THE WELLS OF ANN ARBOR

Their Properties Explained by Mr. Leverett.

IS AN AUTHORITY

And a Member of the U. S. Geographical Survey -- His Estimate of the City Wells

The following article has been written for the Argus by Mr. Frank Leverett, of the U. S. Geological Survey, an acknowledged authority on his subjects.

For several years flowing wells have been in operation in the west part of Ann Arbor along Huron and Washington streets, which obtain their supply from a depth of 90 to 115 feet. The presence of these wells led the Ann Arbor Water Company to obtain control of a tract of ground on the south side of Washington street which includes the lowest land in the flowing well district. They began operations in 1896 and now have about 50 wells which will supply 50,000 gallons per hour when pumped to their full capacity.

This flowing well district is one of a large number which are found along or near the west border of the plain that extends from Lake St. Clair and Lake Erie westward into Oakland, northwestern Wayne, southeastern Washtenaw and central Lenawee counties. The border of this plain has a northeast to southwest trend and there is a rapid rise northwestward from it into a rolling country with loose textured soil and a large number of small lakes. The flowing wells appear to obtain their supply from this rolling upland country. Much of the rainfall is absorbed and the water which enters the ground makes its way through beds of sand and gravel far below the surface, which appear to slope or dip toward the southeast in the same general direction as the surface drainage.

WATER BEARING BEDS.

The underground flow of water is so slow that these water bearing beds are saturated to such a degree that when borings are made on the low land east of this rolling country water is forced up through the pipes and often overflows. There is usually a bed of impervious clay of such thickness that the water finds difficulty in escaping through it in the form of springs, and this impervious cover helps to hold the water at a high level beneath the country immediately west of this plain.

The wells which were first made on Huron and Washington streets are found to have had a head about 20 feet higher than the station of the Ann Arbor Railroad, or about 825 feet above sea level. Those at Jacob Laubengayer's and William Rohde's which stand on a terrace above the level of the ravines rose only a few feet above the surface, the height at Mr. Rohde's being estimated to be 6 feet, but those in the ravine at Mr. Allmendinger's and at the west side station of the Water Company are reported to have risen fully 20 feet above the surface.

INTERESTS GEOLOGISTS

A well made by the Ann Arbor Water Company the past week, just east of Seventh street is of interest to Geologists because it penetrated two sheets of glacial bowlder clay of unlike characteristics, and probably of widely different age. Like wells in regions further south the record here supports the view that there have been at least two distinct ice invasions. The following is the record of the well as given by the Company.

WATER COMPANY WELL NEAR SEVENTH STREET.

Feet

Surface alluvium ... 8

Water bearing gravel and sand ... 26

Blue clay, soft and adhesive, not very stony ... 65

Blue clay, hard and dry, very stony ... 8

Cemented clay, cobble and gravel ... 7

Hard, partially cemented, sand and clay ... 21

Gravel, waterbearing, with head rising to surface ... 2

Blue shale at 140 feet.

Of the beds penetrated the first three were made by stream action. The fourth is glacial, that is, it was deposited by the ice sheet and ice invasion. The underlying hard clay, gravel, etc, appear to be deposits made at an earlier invasion. In many places farther south a black soil has been found at the junction of the hard and soft bowlder clays, and under the buried soil there is usually a few feet of yellow sub soil.

PARTIAL RECORD.

The well made by the Water Company does not show so complete a record of events, probably because the later ice invasion here scraped off the soil and subsoil and mixed them with material in the basal portion of the ice sheet to form the bed of soft adhesive clay which was deposited when the ice melted.

The record of the Court House well, kept by Prof. Alexander Winchell, and published in Volume 5 of the Michigan Geological Survey, also shows a change from soft to hard material in the lower part of the glacial drift, as may be seen from the section which follows. In this well the first 30 feet is of similar material to the upper 27 in the Water Company's well; the adhesive blue clay, though thicker in the court house well, is apparently the same as the soft blue clay of the Water Company's well, while the compact shale-like material appears to be the hard clay of the earlier ice invasion.

COURT HOUSE WELL.

Feet.

Soil, gravel, etc. ... 30

Clay, bluish and adhesive, with alternating seams of quicksand ... 101

Quicksand ... 1/2

Compactly bedded shale-like material ... 28 1/2

Partially cemented sand ... 4

Blue shale at 164 feet.

Total depth of well, 755 feet.

Mr. Leverett, whose address is 312 North Thayer street, will be glad to obtain records of other wells in this part of Michigan which show similar variations in the material penetrated, or, better still, which show a buried soil or black muck or peat under beds of clay. He will also be glad to learn of any wells which have been sunk to bed rock. Mr. Leverett has been computing the altitude of the rock surface in several wells at Ann Arbor, and finds that it differs much less than the surface of the ground where the wells are made, as indicated in the following table. The altitudes have been determined by spirit level:

ALTITUDES AT WELLS IN ANN ARBOR.

Drift surface Feet

Rock surface Feet

Campus well ... 876 ... 644

Court House well ... 830 ... 666

Hay & Todd well ... 825 ... 662

Water Co. well east of Seventh street ... 804 ... 664

Ditto west of Seventh street ... 808 ... 654

Ditto at west side pumping station ... 800 ... 673

It is of interest to note that the level of the rock surface is in all cases below the level of Huron river, the river being 759 feet at the crossing of the Ann Arbor railroad and 749 at the bridge near the south end of the boulevard drive.