Flash board & stop log or needle gate
Flash board and stop log or needle gate

Flash board & stop log or needle gate

FLASH BOARD It is a temporary arrangement which is adopted to store extra water during low flows in the river. At large floods they are either removed or allowed to drop on D/S side if hinged at the crest. Flash Boards are made by joining wooden planks which are fixed against the pins. The pins are installed over the crest at suitable intervals. Flash Boards when in position may be vertical or inclined. See Fig. 14.19. STOP LOG OR NEEDLE GATES In this case, piers are located at suitable intervals on the crest and stop logs Which are nothing but timber planks fixed horizontally in the grooves of the piers, one above the other. While opening, the stop logs are removed one by one. See Fig. 14.20 (b). In the case of needle gates, wooden planks are not used horizontally but vertically. A groove is developed at the crest of…

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