Irrigation service supply: the infrastructure
As we have seen in Figure 1.1, the irrigation cycle's supply side consists of appropriating the five base water flows, their storage, and distribution to and from storage through to farmers' fields. Chapters 3 and 4 will address the economics of irrigation service supply - first, the making of the infrastructure and, second, the year-on-year delivery of water to farming families and agribusinesses. The Report of the World Commission on Dams (WCD) has made clear just how ancient are the infrastructural works of irrigation:
The earliest evidence of river engineering is the ruins of irrigation canals over eight thousand years old in Mesopotamia. Remains of water storage dams found in Jordan, Egypt and other parts of the Middle East date back to at least 3000 B C . Historical records suggest that the use of dams for irrigation and water supply became more widespread about a thousand years later. At that time, dams were built in the Mediterranean region, China and Meso America. Remains of earth embankment dams built for diverting water to large community reservoirs can still be found in Sri Lanka and Israel. The Dujiang irrigation project, which supplied 800,000 hectares in China, is 2,200 years old.