Box 22, Folder 11: Water Levels-Various Data, 1865-1873

108

Levels on Dam Oct 13. 1867 Length between abutments 363 feet- West abutment 4.00 ft high- east one 3.25 ft.

[Table of Data].

See p. 96

109 Water Levels Continued from page 107

[Table]

Continued on page 117

110

Pewaukee Lake-

Sept. 9th 1869. Measured the flow of water in Head race of mill, outlet of Lake, which has a regular rectangular form.

[Measurements and Calculations of Lake]

The owner of the mill represents that this flow could be maintained for 12 hours each day, all the year-or half the time-hence-the daily flow that can be relied upon for a water supply is half of the above or 1,944,000 cubic feet. Allowing 7 cubic feet or 50 gallons pr day for each individual, this is sufficient for 277,700 people or three times the population of Milwaukee.

The same miller informs us that he uses an equivalent of about 400 inches of water, under a head of 4 feet. [calculations for cubic feet pr second using superficial feet and velocity of water under 4 feet]

Thus agreeeing very nearly with the discharge found on the preceeding page-

The wheel used at this mill is believed to be not of the best kind-a proper wheel would doubtless do the same work with 1/3 less water. If so there is sufficent for this mill and for Milwaukee, both.

The water of the lake is now at a medium stage, being 2 1/2 lower than the highest, & 2 1/2 above the lowest stage-

Whole change of level 5 feet.

112

The area drained into this lake is about 26 square miles, and the annual rainfall about 32 inches (2.6667 feet)

Hence [Calculations]

Daily fall of rain upon the 26 miles 5,295,600 cubic feet.

This would indicate that 363 ft/ 4 pr cent of the rain is carried off through the outlet of the lake. This unusually large proportion may be owing to the loose gravelly nature of the soil. which readily absorbs the rain water & supplies the numerous copious springs on the margin of the lake.

[calculations]