Report of a committee on a plan for cleansing the drains of Black Town.

Date:
1856
Catalogue details

Licence: Public Domain Mark

Credit: Report of a committee on a plan for cleansing the drains of Black Town. Source: Wellcome Collection.

    92/105 (page 84)
    SJ, •ground that was within the heel of the tank. Were it not for these villages an immense tank might he formed, hut even without raising the water so high as to-cover any village, we might have a large reservoir. But further, the bed of the Adyar in the hreach of this bund is only ahout 30 feet above the mean level of the sea, so that a bund of that height at the head of tide water, viz., at the bed of the Adyar nearest the long tank, would throw the water back to the old tank, and a few feet more would make it stand hack to the head of the basin which it occupied, a distance of 15 or 16 miles. This is amost remarkable fact when it is considered that the general rise of the country from the coast is 6 or 8 feet a mile. In this respect I have never seen any site for a tank to be compared with this, it might be supposed to have been provided for the very purpose of supplying Madras with water. The chief expense would be the compensation for cultivated land that would be flooded. Probably the best way would be to repair the old bund so as to retain only a moderate depth of water in it and to make a second bund either at the Mount or between that and Marmalono- bridge O D 9 of such a height as to retain the water to as great a height as the Cantonment of Palaveram would allow, the Parade ground of which is about 40 feet above the jnean level of the sea. I should however mention that these levels have not yet been checked, though I believe there is no considerable error in them. How very slight the rise of the country is on the line of the Adyar will be understood from the fact that the bed of that river at the head of the old tank ahout 7 miles above Palaveram is not 30 feet above the top of the bund of the long tank, 19 miles distant. If ten feet depth of water were retained in the old tank, it would only require about 4i locks of 10 feet rise each, to form the navigation from tide water, making a water communication of 25 miles from Olive's battery. 19. I append a rough estimate to give some idea of the value and re- turns of the different uses to which the water may be applied, independently of its sanitary effects.