Net backward effect calculation of water conservancy investment in capital construction in main river basins of China

For research of the economic benefit of water conservancy investment in capital construction(WCICC), new concepts concerning the positive effect of the final demand on economy are put forward, i.e. the net backward effect and gross backward effect, and their calculating methods are also developed. Based on 1999's input occupancy output table of nine river basins of China compiled by the water project research group of Academy of Mathematics and Systems Science, CAS, the net backward effect and gross backward effect of WCICC are calculated for the nine river basins by use of the partially closed input output model, and the calculated results show that, except for a few river basins, WCICC has great effects on local economy as compared with the investments in other industries, especially in the river basins short of water resources. In the Songhua River and Liaohe River Basin, the effect of WCICC is significant, the net backward effect of the water conservancy construction industry ranking the second in all the departments; while in other river basins where water resources are abundant, the net backward effect of WCICC is relatively small.