The objective of the research is to substantiate fundamental new lightweight design of mountain water intake structure for rivers of Len Koran subtropical zone in Azerbaijan considering hydrologic regime, characteristics of liquid and solid runoff of the rivers. The developed water intake structure was made by using roller gate situated across the river channel and forming low-pressure water intake-spill-weir with variable threshold. At the surface of roller gate by the side of upstream along its length the slots of different width for river water intake are provided. The internal space of the gate is used for collecting and withdrawing of water to off-take cannel. The developed construction provides total deposition of large fractions of bottom sediments, and then clarified river flow overflow through the ridge of roller gate wherein partially supplied through the slot to the water intake gallery. At the model of water intake the investigation of its operation at different values of width and places of slots on the roller gate was conducted. At the experiment the water discharges of water intake were 0.60, 0.83, 1.80, 2.00, 2.20, 4.65, 11.60, and 14.65 l/sec; modeling scale was 1:15. Based on theoretical investigation and form of specific energy of flow, the equations for calculating the depth of flow along a gallery for two gallery slopes, which were equal to zero and nonzero with constant specific discharges, were found. The equations found were validated by laboratory result with accuracy 1.2–11.7 %. An equation for mean water velocity in a gallery, which was confirmed by the results of experimental data with an error of 3–8 %, was deduced.
Keywords: bottom deposits, channel, gallery, water intake slot, discharge, slope, upstream, downstream.
