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Show program. In general, this activity was beneficial in re- ducing the mine acid load on surface streams. However, at the inception of the program the exact fundamentals of the mechanism of mine acid production and methods of preventing its formation were not completely understood. A better understanding might have resulted in somewhat different program emphasis with resultant greater benefits per dollar spent. Of even greater importance was the fact that no provision was made for maintenance work on sealed mines and at present most of the benefits of the $7 million sealing program have been lost through lack of maintenance. 49. Effect of flow increases on water pollution.-In- creasing low flow in polluted streams is an important con- tribution to the solution of water pollution problems. However, this is only a partial solution, as at least primary sedimentation is needed to remove sludge deposits, floating sewage solids, and scum. Additional benefits also accrue from reduction of hardness and reduction in temperatures when the stream is used for cooling water. Under conditions of partially regulated flow after con- struction by private interests of Milton Reservoir on the Mahoning River, an Ohio tributary of the Beaver River, the minimum expected flow at Youngstown was 145 cubic feet per second during the summer months and 110 cubic feet per second in the winter. Nuisance conditions ex- isted frequently in the stream in the Youngstown area. It was estimated that it would be necessary to remove ap- proximately 96 percent of the combined municipal and industrial pollution load to prevent this nuisance. Such a high degree of waste treatment is impractical, both technically and economically. Under flow conditions in the current operating schedule after Corps of Engineers construction of Berlin and Mos- quito Creek Reservoirs in the Mahoning Basin, the mini- mum monthly average flow at Youngstown is 470 cubic feet per second in July and 185 cubic feet per second during winter months. While conditions are not now satisfactory, inasmuch as raw sewage and industrial wastes are being discharged, the stream has improved to such a condition that it is estimated that it can be cleaned up to a satis- factory degree by practical known treatment and other pollution abatement methods. Greatly improved temperature conditions have been reported by the many industrial users of the river. Hard- ness has been reduced and acidity due to the discharge of acid pickle liquor has been reduced. 50. Water supply reservoir drainage areas.-Complete control of catchment areas has been the ideal of water- works officials for many years. The principal motivating factors are the desire for minimizing pollution, reducing water color and turbidity, controlling erosion with ac- companying maintenance of reservoir storage capacity, and regulating yield from a catchment area. The presence of lakes and ponds in the areas, farming operations, fores- tation or forest cover, and the spread and type of water- shed population will influence these factors. A far-sighted policy of acquiring drainage areas needed for current and future water-supply development has been practiced by the city of Akron, Ohio, since 1912, when the community purchased the holdings of a private water company then furnishing the supply. As of 1949 the municipal water-supply system was serving a popula- tion of about 250,000 and had an average output of about 35 million gallons per day. The city is now drawing its supply from three reservoirs located in the Cuyahoga River Basin. These involve a total catchment area of about 5,000 acres, all of which the city owns. Reservoirs cover 2,200 acres of the 5,000 acres. The drainage area surrounding these reservoirs is devoted mainly to forests, the growing of fruit, wild fowl and game preservation, and fish breeding. As the orchards become too old to be profitable the areas are cleaned and either covered by grass or reforested. In the early 1920's it became apparent that the city would at some future time require further storage areas for water-supply purposes. The purchase of additional lands in the same watershed was begun. To date about 8,000 acres have been acquired under this program. The areas are now devoted mainly to farming, forests and wood lots, pasture for sheep and cattle, and to the production of maple sugar. These various activities produce an in- come which is sufficient to offset the cost of maintaining the property. The Akron Water Bureau has worked closely with the several State agencies interested in the conservation and development of natural resources. This procedure, in addition to making the various projects self-supporting, has had a high public relations value. Since these various lands were not originally purchased primarily for farming, recreational, or other similar pur- poses, the items of taxes, interest, and land retirements are not charged to the cost of operating the various proj- ects. Such items are more properly charged ta the op- eration of the water-supply system as a whole. 51. Mississippi River below Minneapolis and St. Paul.- The construction of Hastings Dam on the Mississippi River below Minneapolis and St. Paul changed a section of the river from a running stream to a slow-moving, navi- gable waterway. The discharge of sewage from both cities subjected the river to marked pollution, particularly de- noted by the prevailing low dissolved oxygen content. Extensive laboratory data were collected both before and after 1931 when the dam was constructed. Prior to 1931, the summer laboratory results with flows between 5,000 and 7,000 cubic feet per second over a 4-year period showed a monthly average dissolved oxygen content of 3.4 parts per million. Similar data, with the same range in flows, and collected after 1931 showed an average dissolved oxygen content of 2.1 parts per million. Pollution loads changed very little during the period. From an analysis based on these values together with stream flows, it was found that the magnitude of pollution must be reduced by approximately 25 percent more in order that equivalent stream quality conditions be main- tained. 52. Ohio River between Cincinnati and Louisville.- The Public Health Service conducted sanitary surveys of the Ohio River between Cincinnati and Louisville during the periods 1914-16 and 1929-31. To facilitate navi- gation in this 164-mile section, two dams between the two cities were constructed and a third dam at Louisville was heightened 8 feet during the period between these surveys. The resulting change in channel conditions created a series of pools when the dams were in operation, thereby increasing the time of flow and permitting sedimentation to take place. The effect of this change cannot be di- 401 |
