Runoff Characteristics and Change Trends of the Chishuihe River Watershed in Recent 10 Years

Based on the hydro-meteorological data of runoff and precipitation in the upper reaches of the Chishuihe River basin from 2008 to 2017, covering the upstream of Chishui, the middle stream of Maotai, and the downstream of Lianyuxi sections, the temporal and spatial characteristics of the basin were analyzed, as well as the spatial correspondence with precipitation, industrial water intake and other influencing factors. The results showed that in the past 10 years, the annual runoff of Chishui River has demonstrated a slow increasing trend, and its amplitude increased with the increment of the basin spatial scale of the basin. The runoff presented the alternating fluctuation law of "decrease-increase-decrease-increase" within one year as the cycle, and the annual and inter annual changes were more severe. The change trend of runoff and precipitation was highly consistent, and precipitation was the dominant factor driving the inter-annual and intra-annual changes of runoff in the basin. In the past 10 years, except for the slight increase in upstream runoff coefficient, the middle and downstream showed a slight downward trend; the annual runoff coefficient was mainly affected by the precipitation in July, September, January and February, and the increase of precipitation in these months would promote the increase of runoff coefficient in wet and dry seasons, thus raising the annual runoff.