ANALYSIS OF SEDIMENT MOVEMENT IN A RIVER DIVERSION SYSTEM
Abstract: Sediment-related
disaster especially debris flow occurs frequently in various places in
Indonesia. It has been well known in general that debris flow contents big size
of materials which huge power to destroy the river and surrounding area.
Comprehensive measures and rising awareness to prevent the toll of human lives
against sediment disaster is considered necessary. Diversion system to
proximate river aimed to lessen sediment load by considering its capacities and
sediment prevention facilities becomes an alternative counter measure of
sediment flood disaster. Information of river diversion capability and
associated phenomena due to sediment gravity flow is a fundamental desire for
establishing reasonable sediment control plans. Physical model compared to
simple mathematical model are conducted to know river diversion capacity to
convey sediment. The experiment used a channel made of masonry with 80 cm wide
in average and 400 cm length, and 10 % gradient. The proposed sediment control
facilities comprises two types, there are open type dam with 33 cm wide, 16cm
high (at +1.245m elevation of crest) and four slits in main stream river and
close type dam 41 cm wide, 15 cm high (at +1.255m elevation of spillway) for
river diversion. The distance of these facilities is 110 cm. The result of this
study is expected to be able to explain the sediment gravity flow behavior in
the field. It shows that the performance of river diversion and open type dam
control volume depend on quantity and mechanism of sediment flow from upstream,
and also elevation of crest of the open type dam. The largest amount of
sediment gravity flow entering diversion channel is about 7 % of sediment inflow
for +1245 m open dam crest elevation and +1255 m river diversion spillway
elevation.
Author: Agus Safari
Journal Code: jptsipilgg130022
