With the case of Lujiahe shoal reach,discussion on countermeasures to the navigation issues related to high gradient slope and large flow velocity is presented in this paper.

Along with the vigorously development of construction projects,a large number of very steep slopes (>25°) are produced by human beings,on which resulting in serious soil erosion.

Due to the limitation of terrain and culture on construction of expressways in mountainous areas,it is common to lay out lines on abrupt slope.

This paper introduces credible computing methods for discharge of starting ski jump and ending ski jump according to several cases such as abrupt slope,slope,zero slop and diffuser connecting to the front of nose of weir,which are compared with practical projects.