Simplification Algorithm of the Normal Depth of the Catenary Section Canal

The normal depth of the catenary canal involved in the calculations beyond the equations,using the analytical method can not directly be the solution.The traditional method(test algorithm and chart method) calculation not only cumbersome but accuracy is not high,the use of computer solving involving programming inconvenience practical application.Deformation finishing the normal depth of the cross section formula,the introduction of the dimensionless water depth parameter optimization fitting method,the remaining difference in standard minimum objective function calculated by successive approximation in the parameter range of engineering applicable to fitting simple expressions,solving the results of high accuracy of the approximate formula(maximum relative error of only 0.257%),has some practical significance.