The ancients discovered that the use of water in mining, especially gold mining, eased extraction and washed ore from hillsides. Two main methods were employed, hushing and ground-sluicing. Hushing used large quantities of water, stored in tanks, which was poured down over the deposit. This dislodged sediment, exposed the deposit for easier mining and washed smaller deposits into sluicing boxes where they could be collected. Ground-sluicing achieved similar results but was a more controlled technique. Requiring a constant, steady flow of water, it often involved the redirection of natural streams and rivers. Both techniques left land stripped back to bedrock.
