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,
Tsiazompaniry Dam Tsiazompaniry Dam The Tsiazompaniry Dam is a buttress dam on the Varahina-South River, a tributary of the Ikopa River, near Tsiazompaniry in the Analamanga Region of Madagascar. The dam was constructed by a French firm in 1956. It creates Lake Tsiazompaniry, the largest reservoir in the country, which has a surface area of and a storage volume of . A second buttress dam, northwest of the main dam helps withhold the reservoir. Water released from the dam supplies a regulated flow to hydroelectric power station at the Antelomita Dam downstream. Efforts to install a 5.25 MW power station at the