He are used as regulation reservoirs, then the elevation of the original storage level of the lakes or the lengthening of the period of high storage will have a definite effect on flood control and the drainage of excess surface water in upstream areas north of the Huai He and in southwest Shandong Province. He would rely mainly on plains and river networks for water storage. In general their water levels would be higher than the land surface. This would certainly change the runoff regimes of the surface and underground runoff and would raise the water table in adjacent areas. This could lead to widespread secondary salinization of the soil in some areas, even within the irrigated areas.
Topographical conditions are highly favourable along the proposed Middle Route.
Because it is located higher, the trunk canal would not interfere greatly with the existing irrigation and drainage systems and water could be allocated to the irrigation districts entirely by gravity. The area under control would be larger and the stretches that the main canal would pass through are mostly irrigated by wells or jointly by wells and canals. The water table is relatively deep there, the natural runoff flows unimpeded and there is little danger of secondary salinization or swamping of the soil along most of the route. If the watercourse, irrigation and drainage projects are brought about and their management perfected, this project will improve the ecosystem of the Hai He plain, and especially benefit agricultural and industrial development in the piedmont plain. However, after the water is transferred, the cropping system in the irrigated areas will be changed and the area of rice cultivation will be increased.