Channel intake & spillway
If there are any steel parts, protect them with an anti-corrosive paint. In case of sliding parts, such as
screw and guide paths, grease them. Paint the wooden gate or replace as required. To stop leaks from
the sluice gate, use a rubber beading or polythene at the slot of the sluice gate to proof the leak.
Channel
Check the channel base and the base of the support columns (if any) for erosion. If there is erosion,
repair with concrete or rubble work. If rain water damages the base of the channel, divert rain water by
making side walls or small storm gullies. If cement works are eroded and reinforcement gets exposed,
cover it with concrete. Pay attention to either side of the channel and look for loosen rocks, logs and
earth slips, etc. Clean any over and under crossings of the channel.
Loosened rock and eroded channel base
Settling / Forebay tank
Observe the outside base for soil erosion and the inside for cracks and deteriorated concrete. When
doing this, pay more attention to the spillway side. Ensure that the trash rack hasn’t got bigger size holes
(due to damaged or bent rods). If there is a lot of sand silting, identify from where the sand gets into the
water - whether it comes from the stream or gets added to the channel on the way. Sand or any coarse
particles can damage reaction turbines and significantly reduce their efficiency. If there is excessive silt
present, modification of the civil construction may be required. This can involve constructing one more
silting tank, enlarging go the settling tank or keeping the flush out hole open while running during rainy
seasons. If too much of vegetation blocks the trash rack (maybe during windy or ‘leave falling’ season),
an additional mesh has to be introduced at the channel intake. In practice, snakes have been found
among the leaves around the forebay tank and it is advisable to take extra precautions when cleaning
the forebay tank.
Cleaning the forebay tank
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