摘要：Canada, the United States and Mexico are adjacent coastal nations. They share numerous important transboundary natural resources, including a significant number of international fresh water drainage basins. Bilateral institutions have been established over the years to deal with the conservation and management of these international drainage basins. Prominent among these have been the International Joint Commission (IJC) between Canada and the United States, and the International Boundary and Water Commission (IBWC) between the United States and Mexico. The geographic scopes of the IJC and the IBWC are enormous. "Canada and the United States share a 6,400 km boundary between the main portions of their provinces and states, and an additional 2,400 km between the Canadian Northwest Territories and Alaska." Crossing these boundaries are some of the richest and most prolific waterways in the world, not least of which are the vast water resources of the five Great Lakes. In comparison, the United States and Mexico share a 3,141 km long boundary not including maritime areas. The United States/Mexico boundary follows the middle of the Rio Grande from its mouth on the Gulf of Mexico a distance of 1,254 miles (2,019 kin) to a point just upstream of El Paso, Texas and Ciudad Judrez, Chihuahua; then it follows an alignment westward overland and marked by monuments a distance of 533 miles (858 km) to the Colorado River; thence it follows the middle of that river northward a distance of 24 miles (38 In); and then it again follows an alignment westward overland and marked by monuments a distance of 141 miles (226 Iam) to the Pacific Ocean. The region along the boundary is characterized by deserts, rugged mountains and abundant sunshine. The two main rivers, the Colorado River and the Rio Grande, provide life-giving waters to the largely arid but fertile lands along the rivers in both countries. Although sparsely settled, the region rapidly developed, beginning with the coming of the railroads in the 1880s and the development of irrigated agriculture after the turn of the century. In 1981, more than 810,000 hectares were irrigated in the border area with waters of the boundary rivers. Today, the United States/Mexico boundary is singularly characterized by fourteen pairs of sister cities sustained by agriculture, import-export trade, service and tourism, and, in recent years, a growing manufacturing sector. The borderlands population has grown to over eleven million people and is expected to reach 19.4
