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,
Maskeliya Dam Maskeliya Dam The Maskeliya Dam (also known as the Maussakelle Dam) is a large gravity dam at Maskeliya, in the Central Province of Sri Lanka. Along with the Castlereigh Dam, the dams are the highest point and beginning of the Laxapana Hydropower Complex, involving a number of dams, penstocks, and hydroelectric power stations. The dam creates the Maskeliya Reservoir over the route of Maskeliya Oya, a major tributary of the Kelani River, which is the 4th longest in the country. A penstock from the Maskeliya Reservoir, measuring in diameter, transfers water directly to the Canyon Hydroelectric Power Station, located further