Investigating the effect of a skimming wall on controlling
the sediment entrance at lateral intakes
Amir Moradinejad, Amir Hamzeh Haghiabi, Mojtaba Saneie
and Hojjatallah Yonesi
ABSTRACT
Sediment entering lateral intakes depends on the flow pattern at the intake entrance. Using a
structure in front of the intake entrance can change this pattern and as a result the entering
sediment. One of the effective method to change the pattern and manage sediment entering a lateral
intake is to use a skimming wall. The removal of sediments from the intake entrance using a
skimming wall led to reduction of sediment volume at the intake. To guide flow into the diversion
canal and increase skimming wall performance a spur dike was utilized at the opposite side of the
intake channel. In this study, the effect of the skimming wall’s angle with the bank, a combination of
spur dike and skimming wall and discharge changes on controlling sediments entering the intake,
intake ratio and bed topography were investigated experimentally. The effect of a skimming wall with
three angles (10
W
, 14
W
, and 18
W
) and a combination of skimming wall and spur dike on opposite sides
of the intake were investigated. Conducting dimensional analysis, non-dimensional ratios were
extracted and test variables were specified. Results showed that in the case of having a skimming
wall combined with a spur dike, the amount of sediment entering the intake decreased by 81%,
78.5% and 76% on average for walls with angles of 10
W
, 14
W
and 18
W
respectively. Combining a
skimming wall and spur dike has a higher effect on reducing sediments entering the intake compared
with a skimming wall alone by about 15%.
Amir Moradinejad
Amir Hamzeh Haghiabi (corresponding author)
Hojjatallah Yonesi
Water Engineering Department, Faculty of
Agriculture,
Lorestan University,
Khorramabad,
Lorestan Province,
Iran
E-mail: haghiabi.a@lu.ac.ir
Mojtaba Saneie
Soil Conservation and Watershed Management
Institute (SCWMRI),
Agricultural Research Education & Extension
Organization (AREEO),
Tehran,
Iran
Key words | intake efficiency, sediment control, skimming wall, spur dike
INTRODUCTION
With regard to the importance of rivers as major sources of
water supply, taking water from rivers and branching flow
from it is an issue encountered in hydraulics and river engin-
eering (Habibi et al. ). Diverting water using lateral
intake is always accompanied by the problem of sediments
entering channels and water transport systems (Raudkivi
; Wang et al. ). As the flow approaches the intake,
it accelerates along the transverse direction and is divided
into two sections as a result of the suction produced by
the lateral intake (Best & Reid ; Hashid et al. ; Her-
rero et al. ). One part enters the intake and the rest flows
in the main downstream channel. One of the problems
occurring in most intakes is the accumulation and entrance
of sediments into the intake entrance (Weber et al. ;
Barbhuiya & Dey ; Odgaard ; Mirzaei et al. ).
Failure in controlling sediments entering intakes will result
in their being transferred into irrigation channels and instal-
lations, which creates many problems because of the
sediments being carried or settling in various sections
(Nakato et al. ; Voisin & Townsend ; Mahgoub
). Complexity of flow and sediment control around the
intake entrance has caused research in that area to continue.
In this study, angle changes of the skimming wall and its
role in controlling sediment entering intakes have been
1121 © IWA Publishing 2017 Water Science & Technology: Water Supply | 17.4 | 2017
doi: 10.2166/ws.2017.007
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