延河流域雨洪特性及洪水预报

延河是黄河的一级支流，流经安塞、延安、延长等陕北南部地区的重要城镇，是引发该地区城镇洪水的主要河流，因此，延河洪水预报对这些城镇的防洪安全具有重要意义。在分析延河流域雨洪特性的基础上，以提高大洪水的预报精度为主、适当兼顾中小洪水的原则，采用具有成因概念的系统模型和相关图法，建立了以延安市为重点、包括安塞及延长县城的延河区段洪水预报方案，可供作业预报试用。

The Characteristics of Storms and Floods in the Yanhe River Basin and the Flood Forecasting Scheme

Yanhe River is the first-order tributary of the Yellow River, which flows across some significant cities and towns in the southern area of the northern Shaanxi Province, such as Ansai, Yan'an, and Yanchang. It is the main river that causes floods and damages to the above-mentioned cities and towns, so it is very im-portant for flood prevention to develop flood forecasting scheme. On the base of analyzing the characterisctics of storms and floods in the Yanhe River Basin, and on the principle of increasing the forecasting accuracy of the heavy floods and properly taking the normal floods into consideration, the system model is applied with the concept of flood formation and correlation diagram to develop the Yanhe River flood forecasting scheme mainly for the sections of Yan'an City, as well as Ansai and Yanchang County. This scheme can be used tentatively in practice.