Optimization of the shape of a triangular unlined canal

1. Within the scope of the adopted model, the solution of the indicated optimization problems for triangular canals is unique. 2. The best angle of the side slopes in problems 1-3 is respectively equal to 38, 42, and 42.36°. 3. In a practically rather large interval of values of α the corresponding triangular canals are close in seepage losses to an optimal canal, and moreover the canals optimal in the sense of statements 1-3 are close in losses to each other. 4. On departing from the "fork" of optimal canals (for sufficiently large or small α) the corresponding canals differ in losses from optimal.