沙颍河为淮河最大支流,地处中原腹地,本干流经我省平顶山、漯河、周口三市后进入安徽省境内,省内流域面积3.44万km~2。其特点:一是上游山丘区坡面陡峻,植被差,源短流急,产汇流快,洪水峰高量大,预报时间短。进入平原地区后,河道比降变缓,泄流能力小,且沿河土质较差,险工险段较多。二是处在南北气候过渡地带,受季风影响明显。6～8月份西太平洋副热带高压影响我省,东南暖湿气团内移,冷暖气团交绥,加之西部特殊地形影响,极易造成暴雨,为我省 The Shaying River, the largest tributary of the Huai River, is located in the hinterland of the Central Plains. The trunk flows through the three cities of Pingdingshan, Luohe and Zhoukou in the province and enters Anhui Province. The drainage area in the province is 34,400 km2. Its characteristics: First, the upper reaches of the hills steep slopes, poor vegetation, short source short stream, confluence fast, large flood peak, forecast time is short. Into the plains, the river slowed down than the drop, discharge capacity is small, and the soil along the river is poor, insurance risk more. Second, in the climate transition zone between North and South, it is obviously affected by the monsoon. From June to August, the subtropical high in the western Pacific affected the province, the shift of the warm and humid air mass in the southeast and the heat and air mass transit, combined with the special terrain in the west, which easily caused heavy rainfall.