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Show rectly ascertained by comparison of the analytical results of the two surveys, because of a significant increase in sewage and industrial waste pollution and the much lower river flows during the latter survey. Nonetheless, certain qualitative comparisons were made and are set forth in Public Health Service Bulletin No. 205 (1933). The summary of this report is quoted, in part, as follows: Canalization, permitting sedimentation and allowing longer times of flow between points in which natural puri- fication agencies may operate, appears to have decreased the bacterial load in the river both above and below the Cincinnati and Louisville metropolitan areas during the summer and fall months when the navigation dams are usually in operation. While canalization has a tendency to decrease the bacterial load in the stream, improve the bacterial quality of the water entering the metropolitan areas, and shorten the distance downstream that the effects of pollution can be observed, it also has a tendency to move the point of probable nuisance, due to oxygen depletion and anaerobic conditions, from points downstream to within the zone of pollution in the vicinity of the sewer outlets, where sludge banks form as a result of decreased velocities in the pools. While decreased bacterial loads at the water works filtration plants make the production of an effluent of satisfactory bacterial quality less difficult, the effects of low turbidities in the river and increased numbers of microscopic organisms, with their tendency toward odor and taste production and shortened filter runs, more than offset the good effects of decreased bacterial loadings. In addition, the concentration of decomposition prod- ucts in the water from the fermentation of deposits of organic materials within the pools when the dams are in continuous operation, may have public health aspects heretofore not appreciated. Reference is made to the suspected water-borne outbreak of gastroenteritis along the Ohio River at the time of and following the low-water conditions in, the fall and winter of 1930-31. Canalization, at least between Cincinnati and Louis- ville, has had a tendency to complicate rather than sim- plify the problems connected with sewage disposal, pos- sible nuisance production, the operation of water-treatment devices, and the preservation of the public health. 53. Harriman, Tenn., in the Tennessee Valley.-The Watts Bar Dam of the TVA on the Tennessee River re- sults in back-water up the Emory River which is now an arm of the Watts Bar Reservoir. At Harriman, Tenn., located on trie arm of the reservoir, industrial and muni- cipal pollution is discharged at a point normally below the Harriman municipal water intake. However, under certain conditions when cold water from Fort Loudoun Dam is discharged into Watts Bar Reservoir it flows beneath the warmer surface waters and up the bottom of the Clinch and Emory Rivers. Pollution from the Harri- man sewage and industrial waste outlets has caused dam- age to the supply to the municipal water intake. Control measures have consisted of altering the schedule of dis- charges from Fort Loudoun Dam on the Tennessee River and Norris Dam on the Clinch River in such a way as to minimize -the difficulties plus barging of some of the industrial wastes into the center of Watts Bar Reservoir. 54. Industrial pollution creates need for new source of water supply.-The necessity for developing new sources of water supplies because of high industrial waste pol- lution is illustrated by the experiences of the cities of Saginaw and Midland, Mich. Both municipalities were using water from the Saginaw River Basin. Although the quantity of supply was adequate, modern treatment methods were used, and strict laboratory control was maintained; nevertheless it became increasingly difficult to produce a supply free from objectionable tastes and odors, as well as one reasonably low in chlorides and hardness. Following a detailed study of the water supply require- ments by representatives of the two cities in 1945, it was recommended that the local sources be abandoned and that the development of a supply from Lake Huron, about 65 miles away, be undertaken. It was also recommended that the new system have a basic capacity of 43 million gallons per day. This quantity provided for a 100 per- cent increase over the requirements at the time of the study. Construction on the pipeline was begun in early 1947 and the system placed in continuous operation on October 23, 1948. The final cost was about $10,300,000. The project was financed through the sale of water revenue bonds by the cities of Saginaw and Midland, individually. The principal physical features of the project include: (a) A 66-inch steel pipeline extending 2 miles to an intake crib in Lake Huron. (b) A pumping station, with 70-million gallons daily capacity, at the lake shore. (c) Forty-eight miles of 48-inch pipe extending from the lake shore to a second pumping station, designated as the junction pumping station and designed for 70- million-gallons-per-day capacity. (d) A 5-million-gallon-capacity reservoir at the junction pumping station. (e) Two branch lines of 36-inch prestressed rein- forced concrete pipe, from the junction pumping station, extending 17 miles to Midland and 15 miles to Saginaw, respectively. 55. A malaria outbreak near Santee Reservoir, S. C.- During the summer of 1943, while the incidence of malaria was progressively declining elsewhere throughout the United States, an explosive epidemic of this disease oc- curred in South Carolina. This significant outbreak of "man-made" malaria was directly attributable to condi- tions on the 97,000-acre Santee Reservoir. The South Carolina Public Service Authorities' Santee Reservoir project was started in 1938. The dam was completed in November 1941, and water reached the normal maximum pool elevation in September 1942. Several factors of design, construction, and operation were responsible for the increased malaria transmission po- tential which resulted in an epidemic the following 402 |
