水利工程的规划、设计工作中,经常会遇到天然河道水面线或糙率的推求工作。这类问题,在水力学中,属于非均匀流的范畴。它的计算方法很多,目前,在我省多用控制曲线法。该法实质上是忽略了局部阻力损失与流速水头。这在流速不大的平原河流或水深较大的水库回水区,是完全适用的。控制曲线可以利用水文资料或地形资料来制作。由于水文资料的限制,还要考虑应用时糙率n可能变化,控制曲线往往用地形资料制成Z～∑(nQ)~2的形式。天然河道的汇流、分汊情况是千变万化的,很难有某个方法(程序)能适应各种河 Water conservancy project planning, design work, often encounter the natural river water line or roughness of the deduction. Such problems, in hydraulics, belong to the category of non-uniform flow. It’s a lot of calculation methods, at present, in our province more control curve method. The law is essentially ignoring the loss of local resistance and velocity head. This is perfectly applicable in plain rivers or in deep reservoir backwater areas where flow rates are not high. Control curves can be generated using hydrological or topographical data. Due to the limitations of hydrological data, it is also necessary to consider the possible change of roughness n in application. The control curve is often made from topographic data in the form of Z ~ Σ (nQ) ~ 2. Confluence of natural rivers, sub-divisive situation is ever-changing, it is difficult to have a method (program) to adapt to a variety of rivers