某一研究时刻的水面线与河底线包围的面积，称过水断面。过水断面是与元流或总流所有流线正交的横断面。过水断面不一定是平面，其形状与流线的分布情况有关。只有当流线相互平行时，过水断面才为平面，否则为曲面。
为此，必须尽快扩大高集海堤的过水断面，恢复西海域生态平衡。
For all of these, quick action should be taken to widen the water-crossing section of Gaoji seawall to renew back ecological balance.
影响汊道分流比的主要因素有：两汊的比降、过水断面积、糙率、流速等。
Main factors effecting on flow rate in braided river is gradient of anabranch, area of water, roughness and velocity.
影响汊道分流比的主要因素有：两汊的比降、过水断面积、糙率、流速等。
Main factors effecting on flow rate in braided river is gardient of anabranch, area of water, roughness and velocity.
应用推荐