Aswan Dam assumption did not take into account the extent of perennial irrigation that was already present throughout Egypt decades before the high dam closure. By the 1950s only a small proportion of Upper Egypt had not been converted from basin (low transmission) to perennial (high transmission) irrigation. Expansion of perennial irrigation systems in Egypt did not depend on the high dam. In fact, within 15 years of the high dam closure there was solid evidence that biharzia was declining in Upper Egypt. S. haematobium has since disappeared altogether. Suggested reasons for this include improvements in irrigation practice. In the Nile Delta,
Medlow Dam 1900s for NSW country town water supplies which utilised a thin concrete arch wall, although it is a notable example of that set. Medlow Dam Medlow Dam is a heritage-listed major gated concrete-walled arch dam across the Adams Creek in the Blue Mountains region, located at Beauchamp Road, Medlow Bath in the City of Blue Mountains local government area of New South Wales, Australia. The dam was designed and built in 1907 by the NSW Department of Public Works. The dam's purpose includes is primarily for the potable water supply of the upper Blue Mountains region. The impounded reservoir is