lle authorities.

On December 5, 1914, Detroit appointed Mr. Clarence W. Hubbell, a consulting sanitary engineer, to review the data Cooperation of pub- and the conclusions of the commission's sanitary experts, and to report what means, if any, should be adopted by the city for the purification of its sewage, and to what extent it would be justified in incurring expense for that purpose. Mr. Hubbell's office cooperated most closely with the commission's Detroit office during the whole period of the investigation so far as the work related to Detroit; and the commission is pleased to report that his recommendations to the city and the recommendations of the consulting engineer of the commission are in substantial accord. Buffalo furnished office space and equipment for the commission's staff at that city and furthered the progress of the investigation by supplying all information in its possession and by rendering valuable assistance to the commission's engineers, in addition to making readily available all city maps and documents required.

Treatment projects.

The commission also expresses its satisfaction with the readiness and promptness with which the smaller cities and towns furnished the maps, data, and information in their possession. The Provincial and State health authorities also afforded the commission's engineers valuable assistance by providing them with maps and data in their possession relating to the sewerage systems of those cities and towns. This was particularly the case in the Province of Ontario. The reports of the Chief of Engineers of the United States Army supplied hydraulic data of great importance, especially the data dealing with Great Lakes levels, river discharges, and elevations. The investigations began in March, 1915, and were completed in March, 1916. In carrying them out it was necessary to prepare plans for treatment works adapted to local requirements and sufficient for the general needs of the situation. For economic reasons the consulting engineer adopted the existing sewerage systems as points of departure. When available, sites for treatment works were tentatively determined upon and the necessary collecting systems were planned to bring the sewage to these points. This procedure was necessarily largely experimental, as there were usually several possible and available sites for treatment works and frequently more than one possible system of main drainage. It was also necessary to plan these works with due regard to the future growth of the cities, and consequently in some instances sewer interceptors were planned for sections thereof almost wholly undeveloped. This procedure generally led to the tentative adoption of several major projects, all of them feasible and practicable, but differing in the type of treatment works, in the number and location of the concentration points for treatment, the arrangement of trunk

line interceptors, and the substitution in some cases of pumping-station plants for deeper interceptor construction. In each case these various projects were worked out in detail, the necessary structures were designed to a point sufficient for comparative cost estimates, and they were then compared upon the basis of cost and general desirability. No attempt was made to exhaust all the possibilities; and it is not assumed that the remedial works planned are the most economic or desirable. Neither time nor funds were available for field surveys, except in some minor instances, such surveys not being considered essential to the work. The engineering investigations were naturally and necessarily much less detailed than would be those in connection with a city about to construct new works. They were, however, in sufficient detail to develop in the case of all cities and towns feasible and workable plans for the collection and treatment of their sewage. The estimated cost is ample for the application of satisfactory remedial measures. Details of the proposed plans for collecting and treating the sewage of the various cities and towns are set forth in the report of the consulting engineer.1 As soon as this report was submitted to the commission it was printed, and copies were supplied to the different municipalities along the Niagara, Detroit, and St. Clair Rivers, with an invitation to attend the meetings of the commission held, as before mentioned, at Buffalo and Detroit in June, 1916.2 At these meetings the remedies suggested by the consulting engineer were discussed with the representatives of the various municipalities interested. A meeting of the commission was also held at Ogdensburg in August, 1916, at which a large number of the municipalities on the upper St. Lawrence were represented by their mayors, city engineers, and health officers.

Meetings.

The commission also devoted considerable attention to the investigation of existing methods of sewage disposal.

1 Report of the consulting sanitary engineer upon remedial measures, Mar. 8, 1916.

'Hearings of the International Joint Commission in re remedies for the pollution of boundary waters between the United States and Canada. 1916.

87873-18-2

III.—EXISTING POLLUTION.

The first question in the reference is

To what extent and by what causes and in what localities have the boundary waters between the United States and Canada been polluted so as to be injurious to the public health and unfit for domestic or other uses?

of pollution.

To enable the commission to answer this question the detailed bacteriological examination hereinbefore described was Sources and extent made by the sanitary experts. A brief epitome only of their report can be given here. An extensive examination was made of the waters in Thunder Bay and White Fish Bay of Lake Superior, the lower end of Lake Huron, and the eastern ends of Lake Erie and Lake Ontario. They were found to be practically free from B. coli in 100 c. c. quantities, and to have a bacterial count of less than 10 on agar at 37° C. This, then, is the condition of the water as it enters the St. Marys, St. Clair, Niagara, and St. Lawrence Rivers. The lower portions of Lake St. Clair and Rainy Lake, the sources of the Detroit and Rainy Rivers, respectively, while appreciably polluted by agricultural and other drainage, show a remarkable freedom from extensive bacterial pollution.

The waters of Rainy River, St. Marys River, St. Clair River, and of the Detroit and Niagara Rivers, in consequence of the unrestricted discharge of sewage from vessels and towns, are no longer fit for domestic use unless subjected to extensive treatment in water-purification plants. Below the cities of Detroit and Buffalo the waters of the Detroit and Niagara Rivers, respectively, are so intensely polluted that it is highly questionable whether by the aid of any ordinary purification plant they can be made at all suitable for drinking purposes.

River, Lake of the

Woods.

The waters of Rainy Lake, Rainy River, and Lake of the Woods were examined during the period from July 8 to Rainy Lake, Rainy July 22, 1913. In this examination 995 specimens were collected and reported upon. The waters of Rainy Lake, subjected to agricultural drainage, showed a pollution amounting to 19 B. coli per 100 c. c., presumably the effect of this drainage, and of the construction of a big fill for railway purposes. The drinking water of the towns of Fort Frances and International Falls is taken from the head of Rainy River, and

was found to be seriously contaminated owing to the discharge of polluting matter in the vicinity of the respective waterworks intakes. Below the falls a very considerable pollution, averaging about 300 B. coli per 100 c. c., exists throughout the length of the river. This is mainly attributable to the discharge of raw sewage by these towns. The polluted condition of the river is augmented by drainage from farms and small villages located at intervals along its banks, and markedly by sewage from the towns of Rainy River and Baudette.

An examination was made of the water in the Lake of the Woods in the vicinity of the mouth of Rainy River and showed an average of only 34 B. coli per 100 c. c. It appears that the self-purification and dilution had here operated to lessen pollution in the river.

Rainy River throughout its entire course has been rendered unfit for domestic uses owing to the unrestricted discharge of sewage and other wastes. The population along the banks is sparse, with the exception of that of the villages and towns. If subjected to extensive water purification, the river may be used as a source of drinkingwater supply.

The waters of Thunder Bay were examined during the period

Thunder Bay.

from July 28 to August 15, 1913. In all, 922 samples of water were collected and reported upon. Thunder Bay is extensively polluted in the neighborhood of the towns of Port Arthur and Fort William, but not to such an extent as to affect Lake Superior.

St. Marys River.

The waters of the St. Marys River were examined during the period from June 28 to July 16, 1913, 1,065 samples being collected and reported upon. The results of the investigation show that Lake Superior at the head of the St. Marys River is practically pure. In White Fish Bay the pollution measures 6.5 B. coli per 100 c. c. The discharge of sewage from vessels was shown to seriously pollute the waters in the lanes of vessel travel. Especially does vessel pollution menace the water supplies of the towns of Sault Ste. Marie (Mich.) and Sault Ste. Marie (Ontario). The average pollution at the waterworks intake of the former city during investigation was about 25 B. coli per 100 c. c., and at the waterworks intake of the latter over 200 B. coli per 100 c. c. Below the towns the pollution was shown to increase to 291 B. coli per 100 c. c. A serious condition of the river continues, although in a less pronounced degree, down to Neebish Island.

The pollution present in this river, due to the discharge of raw sewage by vessels and by the two towns of Sault Ste. Marie, affects very seriously the only available water supplies for summer residents and for pleasure boats frequenting its waters. Water examined in the Straits of Mackinac proved to be quite pure.

Lake Huron, St. Clair River, Lake St.

Clair.

The laboratories stationed at Port Huron, Detroit, and Sarnia were in operation during May, June, July, and August, 1913, for the examination of the waters of the lower end of Lake Huron, River St. Clair, and Lake St. Clair. In all, 2,336 samples were examined and reported upon. The examination showed that the waters of Lake Huron at the head of the river would be practically free from B. coli were it not for the pollution from vessel sewage. Samples taken about 10 miles up the lake showed absence of B. coli even in 100 c. c., while the water at the lower end, where vessel pollution is concentrated, showed an average of 9 B. coli per 100 C. C. Below the towns of Port Huron and Sarnia the waters of the St. Clair River for a stretch of about 34 miles are quite unfit for drinking purposes unless extensively treated, the B. Coli content found in the river water exceeding 200 per 100 c. c. The pollution below these towns is due to the combined effects of the discharge of untreated sewage from vessels and the towns along the shores. Any tendency toward self-purification of the river by natural agencies is counterbalanced by the sewage and drainage from the small villages and residences along its course.

Lake St. Clair, which receives the discharge of the river, showed less evidence of pollution. Natural agencies promote in the lake a purification not found in the river.

western end of Lake Erie.

The laboratories for the study of the Detroit River and the western end of Lake Erie stationed at Detroit, Windsor, Detroit River and Amherstburg, and on the United States revenue cutter Morrill, were operated during the months of May, June, July, August, September, and October, 1913. Some 5,353 samples were collected and examined, including those taken in the western end of Lake Erie and at the mouth of the Detroit River. The situation with reference to the Detroit River is described by the sanitary experts in their report to the commission in 1914,1 as follows:

*

The results of our analyses of samples taken above the intake for the Detroit city water supply showed this to be an unsafe source of supply without careful treatment. Samples taken along the several cross sections from this point to the site of the Michigan Central tunnel showed a marked increase of pollution in the shore samples.

The water intakes of Walkerville and Windsor are both located in dangerous situations, owing to the discharge of sewage above these intakes and to a potential danger of climatological variation diverting the intense shore pollution to points from whence it would affect the water intakes. In spite of the efforts made by these towns to protect their supplies by means of chlorination,

1 Progress report of the International Joint Commission on the Reference by the United States and Canada in re the Pollution of Boundary Waters. Including report of the sanitary experts. 1914.