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,
Lock and Dam No. 19 by a gantry crane that travels on the service bridge above the dam. At the time it was completed it was second in length only to the Aswan Low Dam on the Nile River. Construction began in 1910 and when completed in 1913 it was the largest capacity, single powerhouse electricity generating plant in the world. The Power House and spillways are owned and operated by Ameren Missouri and has a 142 MW capacity. The powerhouse contains 15 generators, originally designed to produce 25 Hz instead of the 60 Hz alternating current used today. Keokuk and Hamilton Water Power landed