We have the honor to present a report upon investigations made by the Detroit office relative to remedial measures for the conditions of pollution of the St. Clair and Detroit Rivers.

DESCRIPTION OF DISTRICT.

GEOGRAPHY.

Geographically, the territory considered in this report consists of the border lands lying on both sides of the St. Clair and Detroit Rivers, which, together with Lake St. Clair, form the natural divisions between the Province of Ontario, Dominion of Canada, and the State of Michigan, U. S. A. These waters pursue a general southwesterly course, connecting Lake Huron and Lake Erie. The district may be considered as being divided into two parts by Lake St. Clair. The upper portion is formed by the St. Clair River, which flows for a distance of about 40 miles by steamer track from the extreme southern end of Lake Huron to the northeastern side of Lake St. Clair. The Detroit River, forming the lower part of the district, has its source on the southwestern side of Lake St. Clair, at a point about 17 miles distant from the southwestern end of the St. Clair Flats Canal, and follows a course which is curved for a part of the way for a distance of 31 miles, discharging finally into Lake Erie near its western end.

TOPOGRAPHY.

Topographically, the land of the district is quite flat and relatively low with respect to the water level of the rivers.

ST. CLAIR RIVER.

The St. Clair River is composed of two characteristic sections. The upper normal section is 27 miles long, varies in width from one-fourth to three-fourths of a mile, and contains two islands, namely, Stag Island and Woodtick Island. The banks are clay and sand and are quite steep. The depth, except immediately adjacent to banks, varies from 20 to 47 feet. The lower Delta section divides the river into a number of distributories, and forms what is commonly known as the St. Clair Flats. The largest of the distributories are the North, Middle, and South Chan

nels, the latter being the most important one, and the one used for navigation.

The discharge of the St. Clair River may be given by quoting from the Report of the Chief of Engineers, United States Army, 1912, Appendix FFF, Northern and Northwestern Lakes:

The flow of the St. Clair River for mean lake levels, 18601911, inclusive, by the 1910 equation is 207,750 c. f. s.

The velocity, according to the "1904 Report, Chief of Engineers, United States Army," is 5.561 feet per second for the first 0.8 of a mile, and 3.078 feet per second for the remainder of the distance. These velocities are based on a discharge of 209,450 cubic feet per second.

The water is at most times very clear, but after heavy rains is colored by the clay-bearing discharge of the Black, Pine, and Belle Rivers on the Michigan side. It has been observed on days following heavy rains that opposite St. Clair the line marking the clear water from the colored was very distinct, while a few miles downstream, but well above Algonac, the water presented a nearly uniform appearance from shore to shore. The occurrence of this phenomenon in such a swiftly flowing stream would seem to be strong evidence in support of the contention that pollution crosses the boundary in both the St. Clair and Detroit Rivers.

DETROIT RIVER.

The upper 13 miles of the Detroit River is of fairly constant cross section, except at its head, where it is divided by Peach Island and Belle Isle. The bottom is of earth and the banks for the most part quite steep. The width of the greater part of this section varies from one-half to three-quarters of a mile, and the depth from 25 to 40 feet. The lower part, from the head of Fighting Island to Lake Erie, is broken up by many islands and expanses of shallow bottom, with the bottom consisting of earth and boulders, and in some places of bed rock and boulders.

The discharge of the Detroit River may, with sufficient accuracy for practical purposes, be considered as the sum of the discharge of the St. Clair and the drainage area of Lake St. Clair. The "1904 Report of the Chief of Engineers, United States Army, Appendix EEE," says that the "St. Clair drainage area. adds on the average 4,700 cubic feet per second."

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Grosse Isle has an important effect on the course of the river in that it directs the major portion of flow close to the Canadian shore for a distance of about 3 miles just above and below Amherstberg. This island by its position also forms what is known as the "back channel," which flows between Grosse Isle and the Michigan shore. This back channel is the most heavily polluted of any of the channels in the lower part of the river. It receives a comparatively small portion of the flow of the river, but on account of the configuration of the bottom, is obliged to carry the pollution from Ecorse and Wyandotte, as well as a major portion of that from Detroit and River Rouge.

LAKE ST. CLAIR.

Lake St. Clair, which forms the middle link of the chain of waters connecting Lake Huron and Lake Erie, has a water surface of over 503 square miles. Over the greater portion, its depth is between 15 and 21 feet. These depths prevail in the central, southern, and southwestern sections, those in the northwestern section near the St. Clair Flats being somewhat less. The bottom is sandy near the shores on all sides, but is clay over a large area in the center of the lake. On account of the shallowness of the lake, strong winds will make the water quite muddy at times. The lake acts as a storage basin with attendant purifying influence on the polluted waters of its tributaries, so that the pollution which is in evidence at the mouth of the St. Clair River partly disappears before the water reaches the entrance to the Detroit River.

INDUSTRIAL CHARACTERISTICS.

Various conditions exist at different localities with respect to industrial development. Along the St. Clair River industrial pursuits are not followed very extensively, although there is some activity at Port Huron and Sarnia and a smaller amount at the communities downstream from these. The same is true of the ex

treme lower section of the Detroit River, but, on the other hand, the upper section of this river is teeming with activity of a manufacturing nature, the interests focusing at Detroit on the Michigan side and being quite active also at Windsor, Walkerville, and Ford City on the Ontario side. The principal industry of this section is that of the manufacture of automobiles, their parts and accessories. Other important industries include the manufacture of drugs, salt products, stoves, copper and brass products, metal windows, electric heating materials, boats, carbon, beer, and whisky. None of the industrial processes are likely to result in the discharge of waste products in sufficient quantity to seriously affect the condition of the river water, except possibly those of drug manufacture and the concerns depending for their raw material on the immense salt beds which underlie this section. Some of the latter, among which might be instanced the Solvay Process Co., the Michigan Alkali Co., and the Penn Salt Co., discharge quite large quantities of waste products about which there is considerable complaint in certain localities. Among other things, it is averred that fishing has been seriously interfered with. The residents of some of the villages below Detroit are reputed to feel rather keenly about the condition. that has been created, many of them having formerly depended on fishing as a part of their source of livelihood. It seems quite likely that this subject of industrial wastes may soon become sufficiently pressing to require detailed investigation and possibly some sort of regulation.

POPULATION.

The population contributing untreated sanitary sewage to the St. Clair and Detroit Rivers is confined largely to a number of municipalities which are listed in Table 13 with their respective populations in 1915. In addition to the above there is some temporary summer population at the St. Clair Flats (a summer resort on the Delta of the St. Clair River), in some of the towns on the St. Clair River, and in cottages. scattered along the rivers at various points.

WATER SUPPLY.

All these municipalities obtain their water supply from the river waters, and in each case they have taken care to locate their waterworks intake above their own sewers. In no case, however, are they afforded any protection against pollution from upstream communities except that of chlorination, which has already been introduced at most of the places. It is worthy of note that Port Huron and Sarnia, the uppermost cities on the St. Clair River, have both taken steps in recent years to purify their supplies, although coming as they do from the St. Clair headwaters they are obviously less contaminated than any other supply in the district.