AVAILABLE HORSEPOWER.

The following table shows the available horsepower (80 per cent efficiency) at each power site, based on the records of flow given herewith:

The Mississippi River between the mouth of Crow Wing River and St. Anthony Falls has more undeveloped power than any other river in Minnesota. The country through which it flows is the most thickly settled portion of the State, affording the best markets for power.

The Mississippi River Commission has made a survey of the entire portion of the river lying in or adjacent to Minnesota. The results of that survey are published in a series of charts which may be obtained from the secretary of the Commission in St. Louis, Mo. A profile of the river is published in Plates IV. and V. of this report. From these sheets the following table of elevations and distances has been compiled:

Elevations and distances along Mississippi River from Lake Itasca to Minnesota

The foregoing table and the topography as shown on the Mississippi River charts indicate the following dam sites, all of which are between the Crow Wing and Minnesota rivers. Above the former the river has a gentle slope, except where power has already been developed, and the water supply is small, especially near

the source.
Line the fall is too slight for feasible development.

Between the Minnesota River and the Iowa State

At the head of Topeka Island, 9 miles above Little Falls.—A 20-foot dam, 1,500 feet long at the crest, would form a pond about 6 miles long and overflow 300 acres of land. Between the dam site at this point and the pond formed by the Little Falls dam, the river falls about 16 feet in 7 miles.

Just above Blanchards Rapids 2 miles above Two Rivers.-A 40-foot dam with a crest length of 2,000 feet and a base length of 600 feet would form a pond 8 miles long, which would extend within 2 miles of the dam at Little Falls and overflow 250 acres of land. Between this dam site and the pond formed by the Sartell dam the fall is about 20 feet.

At the foot of Sauk Rapids, 3 miles above St. Cloud.-A 15-foot dam with a crest length of 900 feet would form a pond 3 miles long, extending to Watab River and overflowing 50 acres of land. There is very little fall between this dam site and the crest of the St. Cloud dam.

At a point 2 miles below Johnson Creek.-A 20-foot dam with a crest length of 800 feet would back the water upstream 6 miles, or nearly to the St. Cloud dam, and would overflow 550 acres of land.

Just below Thompson Island and 2 miles above Monticello.-A 28-foot dam with a crest length of 800 feet would back the water 20 miles upstream, nearly to the dam site below Johnson Creek. It would overflow 900 acres of land.

At the foot of Spring Rapids, 3 miles above Otsego.-A 30-foot dam with a crest length of 800 feet would back the water 9 miles upstream to the dam site below Thompson Island. It would overflow 200 acres of land.

At the foot of Haley's Rapids, 1 mile above Crow River.-A 15-foot dam would form a pond 5 miles long extending to a point 11⁄2 miles above Elk River, and overflowing 400 acres of land. Between this dam site and Rum River, a distance of 9 miles, there is a fall of 16 feet.

Just above Rice Creek, 8 miles above St. Anthony Falls.-A 22-foot dam with a crest length of 800 feet would form a pond nearly 10 miles long, extending to the mouth of Rum River or above.

It would overflow 550 acres of land. Between this dam site and the pond above St. Anthony Falls there is a fall of about 12 feet.

At Fort Snelling, just above Minnesota River. The Federal Government is building a 30-foot dam at Fort Snelling, chiefly for the purpose of making the Mississippi navigable between Minneapolis and St. Paul. It will back the water upstream nearly to the foot of the lower dam at St. Anthony Falls. As the river flows through a deep gorge, very little land will be overflowed. When this dam is completed it will completely submerge the existing lock and dam No. 2 about 5 miles upstream.

AVAILABLE HORSEPOWER.

The following table shows the available horsepower at the sites just described, as determined from the records of flow presented herewith:

To show the sanitary quality of the water in the Mississippi River and the extent this water is used for municipal supplies, data showing the source of municipal supply and disposal of sewage have been compiled for all towns of 500 inhabitants or more located on the Mississippi or its tributaries. These data have been tabulated in order of location, beginning near the source of the river. The data for towns on the tributaries will be found under the descriptions of those tributaries, as only the location of the mouth of such streams is given here. Data showing the population per square mile exclusive of the towns listed, for various portions. of the drainage basin, have also been compiled.

Municipal water supply and sewage disposal of towns on the Mississippi River.

From the preceding table it appears that above Grand Rapids no untreated sewage from towns enters the river. The rural population for that portion of the basin is extremely small, being 3.3 per square mile. The slope of the river is very flat, much of the channel being in lakes, and therefore the chance of bacteria from sewage being found in the water is slight.

Between Grand Rapids and the Crow Wing, a distance of 186 miles by river, the Mississippi receives untreated sewage from Grand Rapids, Aitkin, and Brainerd-representing a population. of 12,000. The rural population averages 4.8 per square mile for the entire drainage basin above the Crow Wing. The average fall of the river in this stretch is 0.5 foot per mile. For 13 miles the course of the river is through the pond created by the Brainerd dam, and here sedimentation is an active factor. No untreated river water is used for municipal supplies.