Effect of comprehensive harnessing on water and soil conservation in SanChuanhe river basin

The paper take the SanChuanhe river basin as an example, which is located in the coarser sediment-producing area in the middle reaches of Yellow River, use “Hydrological Method” calculated the flood and sediment reduction by water and soil conservation measures in recent ten years. According to the research: during 1997 to 2006, comprehensive harnessing on water and soil conservation reduced 34.77 million m³ of flood, the rate of flood reduction is 62.7%, reduced 1.482 million tons of sediment, the rate of sediment reduction is 83.6%. Compared with the rate in the past, the flood and sediment reduction rate was raise year after year. During 1997 to 2006, the rate of flood reduction increased nearly two times than in the 1970s and 1980s; the rate of sediment reduction is also significantly higher than past years. Water and soil conservation measures have a good effect in SanChuanhe river basin.