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As a type of gate that is used to control the water level upstream, sluice gate is the gate with simple shape and outstanding ability to flush the sediment. The operation of the gate is considered an important process. The up and down movement of the gate would affect the velocity and cause local scour as the result of fluctuating rate. This research aims to assess the effects of discharge and gate-opening height variations, as well as the type of bedchannel material, on the change of depth of scour (ds). The research was conducted of open channel flow model with a sluice gate able to up and down movement. The discharges used in the research were 9 types ranging from 1.0 to 5.0 dm3·s−1. There were 5 variations in the height of gate-opening ranging from 0.5 to 2.5 cm at intervals of 0.5 and types of channel-bed material. The results of the research showed that the depth of scour can be analysed as a function of discharge, height of gate-opening, height of water level upstream and downstream, and the type of bed material used. The scour depth equation on is ds=1.7822(Qa)1.1347a$d_s = 1.7822\left( {{Q \over a}} \right)^{1.1347} a$ . Calculated coefficient of determination of the relationship between two types of channel-bed material and the depth of scour was R2 = 0.946. Consequently, it can be concluded that the equation can be applied on both types of bed-channel material.

Sluice gate operation is necessary to keep the continuity the design discharge. The mis-operation of sluice gate occurs endanger stucture and destruct the bed irrigation channel. Investigation about sluice gate operation and bed configuration are needed to avoid the destruction of the structure bed irrigation channel. The changes in bed form result from interaction of the flow, fluid and bed material. The aim of this paper is to investigate the influence of different flow parameter, height of opening gate and types of bed material. Fourty five runs were executed at different discharge started from 1.0 l/s to 5.0 l/s with an increment of 0.5 where each discharge has five different opening gate to get all characteristics of bed configuration. The material used in the experiments were sandy loam. The experimental were conducted in an acrylic side flume with recirculating water at Applied Hydraulics Laboratory in Water Resources Engineering Faculty, Brawijaya University, Malang, Indonesia. The result of investigation showed that the bed configuration of sandy loam is ripple for most of the condition. At the same opening gate and various discharge the configuration is start by plane bed (no motion) and ripplee. Meanwhile, for the same discharge at the various opening gate occurs the ripple bed configuration. The various velocity that occur during the runing process cause the changing of bed configuration. For the greater discharge at the same opening gate occur the highest velocity. This condition cause the grain sediment material of the bed channel lift up and start to moving. This result is suitable with equation approaches from the van Rijn, Simon Richardson and Garde Albertson.

In Indonesia, water is public goods so it is necessary to control water allocation. Inequity of water allocation between water users is expanding largely, including irrigation as the largest user, while the density of headworks in the river are getting higher. Considering that water is limited, the practice of irrigation water allocation needs to be refined, from the traditional equity to volumetric equity. MEQAA (Model Equalisasi Alokasi Air/Equalization Model of Water Allocation) plays a role in determining water sharing between headworks in order to meet the maximum-equal K-factor in river. MEQAA-Generic is a calculation machine with: analog-deterministic dynamic model; network equation according to mass balance and linear optimization; independent-based system; sustainability-efficiency-equity constraints; Ms. Excel-VBA. The inputs are: scheme system, local inflow, and irrigation demand. The outputs are: K-factor, release and ecosystem quote. The model performance is identified by comparing the output to the class of K-factor based on treatment of water distribution. The model test is performed in an uncontrolled and complicated system in Kukusan Tanggek watershed with 24 headworks in Lombok river basin. As long as it is adequate for water sharing, MEQAA-G can always produce maximum-equal K-factor. The output model is used to operation control.