In the hydro-reclamation systems of the South of Russia and the North Caucasus, channels of open type, rectangular and trapezoidal sections are widely used. Polygonal channels are less common, although their economic and hydraulic efficiency is known. Problems of reliability and efficiency of rectangular and trapezoidal channels remain relevant to the present time. Based on the results of analytical and experimental studies of the hydraulic characteristics of the channels, a new method is proposed for the design and technology of the construction of an industrial and efficient polygonal channel structure for the conditions of the foothill zone. Standard designs of L-shaped precast concrete blocks have been developed, with the help of which it is easy to mount polygonal channels of various designs and capacities. The parameters of L-shaped precast concrete blocks and the design of channels are taken from the condition of ensuring hydraulically efficient conditions in the channel according to the method of Kurbanov S. O. In channels of polygonal cross-section, the center of gravity of the flow is concentrated at the top of the triangular base, and a quasi-uniform movement of the water flow is established. While hydrodynamic load flow distributed across the channel cross section, the hydraulic efficiency of the flow of water and the reliability of the channel are greatly increased. The results of the conducted analytical studies confirm the high efficiency and manufacturability of the proposed channels lined with typical L-shaped precast concrete blocks, confirmed by patents for inventions and for which technical conditions are being developed. The author's developments on the proposed structures of channels made of precast reinforced concrete blocks are included in the state grant program for the development of standard structures of hydraulic structures of reclamation systems.