Edinburgh obtains its water supply from the Esk, the water of Leith and from the streams fed by the Pentlands. the Moorfoot Hills and from Tana Water reservoir Tails Water is tie affluent of the River In 1913 the daily consumption of water in Edinburgh and Leith was 56 gallons per capita.
The Dement Valley Water Supply under an Act of Parliament, is distributed to Derby. Leicester. Nottingham and Sheffield, the ex pense of which is borne by said several cor porations in proportion to their several allotments or percentages of water consumed, all drawing from the same source, made avail able by their joint effort. That plan might be carried out in other countries where a common supply be available for several mu:1mi In l907 the Earl of Cromer reported that the Assouan reservoir would supply one-fourth of all the water needed in Egypt. That water lowed from the upper Nile 1,800 miles to reach Egypt. The evaporation in those torrid and tropical regions was 103,000,000 cubic meters out of 2,.M,000,000 cubic meters of sup ply and the loss by absorption and filling the Nile trough was 260,000,000 cubic meters, and the consumption in middle Egypt was 850, 000,000 cubic meters, which left only 1,087,000, WO cubic meters for use in Lower Egypt at Cairo. That statement shows the great losses of river or canal waters due to evaporation and percolation or absorption. Under all conditions they are factors to be considered in determin ing the amount of water supply for a com munity. Long before the Assouan reservoir was constructed, Jacob had dug a well near the site of Cairo and still earlier the Fayum depres sion was embanked and Lake Moeris was formed, around whose shores were settlements from the Neolithic age down through many centuries.
In 1914 Cairo used for all purposes an amount equivalent to 25 gallons for each of its 700,000 residents. Its water is clarified by passing it through rapid sand filters. Alex andria has a similar pit of 12,000.000 gallons daily capacity, where sulphate of aluminum is used as a coagulant.
The importance of wholesale water supplies to communities cannot be too emphatically stated, when we recall the ravages of diseases due to the contaminated water supplies in India. Prior to the British sovereignty of that
Peninsula nearly all well, river and surface waters were unfit for potable purposes. Con ditions there were appalling. The waters of the Indus., the sacred Ganges, the Brahmaputra and of all other rivers were laden with putrescent matter and some with decomposing human remains. Esc!' the wells were con taminated and the thousands of reservoirs and tanks were used as bathing pools by thousands of dust begrimed and filthy pilgrims in their annual tours of parts of India. They were ignorant of the laws of health and oblivious of all hygienic and sanitary regulations. That was the commencement of water purification in central India. There are now many sand filtration plants in India.
The Hindus were enjoined to drink the water of the Ganges, as a sacred duty. Cholera and other deadly epidemics depopulated whole districts. When the British officials began to exercise authority, they undertook to remedy conditions wherever they were able so to do, but the superstition and prejudices of the natives were such under their Indian cults, that progress was slow, In 1893, the Balram Dass ‘\'aterworks were constructed at Raipur in the central provinces. Those consisted of an infiltration_gallery 100 feet from and paralleling the !Carom' River whose level was raised at that point six feet by a dam and its waters percolated the intervening sand layers and weeped through holes into the gallery. Thence they were pumped up through a conduit of masonry and cut through the rock into tanks for distribu tion. The supply was six and one-half gallons a day per capita. Consult Vol. 143 of Pro ceedings of Institution of Civil Engineers, pp. 262 ct seq., London.
In 1901 the British favored the construction of works for the extension of irrigation from 47,000,000 to 53,500,000 acres.
In 1905 to 1912, they aided in the con struction of the Punjab Triple Canal system, which had an excellent effect upon the quality of flowing water for the thousands dependent thereon for drinking purposes. Consult k ul. 201 of Proceedings of Institution of Civil Engineers, pp. 24 et seq.