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| Effect of forest-grass vegetation on reducing flood and sediment from 1997 to 2006 in Yanhe basin |
| Ran Dachuan1, Yao Wenyi1, Wu Yonghong2, Li Xuemei3, Lv Xizhi1 |
1.Yellow River Institute of Hydraulic Research,Yellow River Conservancy Commission,450003,Zhengzhou,China;
2.Xifeng Soil and Water Conservation Experimental Station,Yellow River Conservancy Commission,745000,Qingyang,Gansu,China;
3.Hydrological Bureau of Technology,Yellow River Conservancy Commission,450003,Zhengzhou,China) |
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Abstract The effect of forest-grass vegetation on reducing flood and sediment from 1997 to 2006 was studied based the long-term hydrologic data of Yanhe basin. The results were as follows: 1) Compared to the baseline period from 1956 to 1969, the precipitation, runoff and sediment discharge decreased by 15.1%, 45.6% and 67.2% respectively from 1997 to 2006. Up to 2006, the total saved area with soil and water conservation measures in Yanhe basin (including uncontrolled area) summed up to 371 751 hm2, in which the total saved area with forest-grass planting measures was 307 412 hm2, accounting for 82.7%. 2) The annual average flood and sediment were reduced by 28 850 000 m3 and 16 950 000 t respectively by forest-grass vegetation, which accounted for 63.6% and 58.2% of the annual average amount of reduced flood and sediment caused by soil and water conservation measures. Among the measures, the effect of forest land on reducing flood and sediment was the most obvious, whose annual average amounts of reduced flood and sediment were 4.9 and 4.7 times that of the sum of grassland and blockading administration measures. 3) The upward trend of the effect of forest-grass vegetation on reducing flood and sediment from 1997 to 2006 was obvious, which had became the major part of the soil and water conservation measures to reduce flood and sediment. The ratio of the amount of reduce flood by forest-grass vegetation to engineering measures was 64% :36% and that of reduced sediment was 58% : 42%.
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Received: 07 August 2013
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