The Indus Civilization c5.49

c5.49

The method of drainage adopted by the Indus Valley people is especially well preserved at Mohenjo-daro, and is certainly the most complete ancient system as yet discovered. A brick-lined channel flowed down every street, sometimes even down small lanes (Pl. C, b), and into this main drain ran smaller tributary drains from the houses on either side. The main channels varied from about twelve inches deep and nine inches wide to roughly double this size, according to the amount of water it was calculated the drain would have to carry away. They were made of ordinary bricks cemented with mud-mortar, although in better-class work lime or gypsum, or both, was mixed with the mud in order to make it more watertight. The drains were generally covered over with loose bricks laid a few inches below the level of the soil, which could be easily lifted when it became necessary to inspect or clean the channel underneath. Exceptionally wide channels were spanned with roughly hewn limestone blocks or, more rarely, with very large bricks; the latter were, however, liable to break under pressure, which explains why stone was evidently preferred for this purpose.