Analysis on the increase of runoff and sediment yield due to reclamation in the Northwest of the Shanxi Province

摘要

The increase of flood and sediment yield due to the reclamation in the Northwest part of the Shanxi Province (Hekou-Longmen section, the upper reach) is analyzed in details in this paper. Based on the field investigation and data analysis, the evolution of the reclamation and its influence on soil erosion are studied. A new method to calculate the increase of flood and sediment yield due to reclamation is put forward. Analysis shows that the reclamation do not increase the flood significantly, but increase the sediment yield apparently at the rate of 6600 t/km~2 in the study area. The paper presents the sediment yield increase due to reclamation in 8 branches of he Yellow River Calculations show that the increase of sediment yield due to reclamation accelerated gradually from the 1960s to the 1990s. The recovery of the forest and grassland from the cultivated field and prohibition of deforestation is the precondition to rebuild the green Northwest China.