流域形状 meaning in English

basin shape
shape of basin
watershed form

When catchment area , average channel gradient and catchment shape factor of designed culvert or bridge are known , a user can be convenient to get local parameters c , e and b from standard contour charts and easy to calculate flood flow just by a calculator . design period of flood flow is enormously shortened as well as a high precision . estimated flood flow through culvert or small bridge by new calculation model is generally less than by traditional methods , so that much cost is cut down a s reducing the span of culvert or small bridge
以75000km ~ 2的川中丘陵地区为试点研究区，绘制了该地区新模型的参数等值线图，率定了不同设计频率的改正系数，使设计者只需在地形图上获取集水面积，河道平均坡降和流域形状系数，在参数等值线图上查得桥涵所在地的相应参数，使用计算器即可迅速计算出设计流量，大大缩短了设计周期，且精度较高，设计的洪水流量一般低于传统方法，从而可减小桥涵跨径，节省投资。