The regulating function of mountain forest landscape on fluvial runoff discharge in the arid areas of China

We selected the northern slope of Qilian Mountain as typical study area, so as to detailed study the influence of forest on runoff. Firstly, we divided the study area into different basin-based units( a total of 20 basins from southeast to northwest), then we classified all basins into 7 groups though clustering analysis based on basin features, meteorological and hydrological features data, forest coverage and other relative data needed, and determined two contrast basins in each group. According to comparative analysis results of contrast basins in the study area, we found that forest has a significant effect on the mountain runoff. The mountain forest ecosystem plays a significant “reduction” runoff role in wet season, for each additional 1 square kilometers of the forests, mountains will much self-restraint 0.76 mm of precipitation, while the conserved water of forestland will complement the steam flow in the dry season, these regulation effects make the mountain runoff change tends to be gentle in general. Because of the significant effect of forest on runoff, according to the different distribution characteristics of the mountainous landscape and forest growth optimal conditions, we optimized landscape structure of study area, and calculated the regulation discharge on runoff doubled on average, the ups and downs of runoff became more quietly.