河流比降变缓；
The slope of the river became gentle ;
并且由于海平面高度相对稳定在较高位置，河流纵比降较小，流速也较小。
The sea level stops in a high position for a long time , so both drop of water and current velocity are small .
我国西南地区崇山峻岭，河流水量大、比降大，水力资源极为丰富。
Southwest of our country water resources is very abundance .
河流比降