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The concept of Geosynthetic Cellular Systems (GCS) has recently emerged as a new method in construction of breakwaters and coastal protective structures. The method potentially has significant advantages compared to conventional systems from the standpoint of constructability, cost effectiveness, and environmental considerations. This paper presents the results of physical model testing on the hydraulic responses of GCS structures under wave action. A series of model tests were carried out in a wave flume on GCS models with different shapes and soil types, subjected to various wave characteristics. Horizontal wave forces acting on the models were measured at different elevations. The maximum horizontal force in each test was calculated and compared with conventional formula of predicting wave pressure on breakwaters. The results show that Goda’s equation overestimates the hydrodynamic water pressure on these structures. This can be attributed to the influence of seeping water through the GCS models because of relative permeability of the GCS.

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The objective of field water measurement is to conserve water by improving management of its distribution and field application. A simple mobile flume to measure a discharge through small rectangular open channels in agricultural fields has been experimentally investigated. The flume consisting of a vertical cylinder inserted axially into the horizontal prismatic rectangular channel, referred as a simple cylindrical flume, has been calibrated. The flow rate in rectangular channel can be measured by constricting the flow due to presence of cylinder, resulting in critical flow conditions. Experiments have been performed on two simple cylindrical flumes of different diameters, to evaluate the hydraulic characteristics of subcritical incoming flow under free flow conditions. The results of laboratory experiments on the flume have been analysed and two different discharge prediction models have been developed. The two models developed for the prediction of discharge for simple cylindrical flumes developed for use in rectangular channel sections, are based on the energy concept and the direct regression approach, respectively. Both the proposed models have been validated using the limited experimental data available in the literature. Formation of critical depth at the throat section has also been verified. Plots have also been developed for the dimensionless column head and the corresponding Froude number of the incoming flow. The discharge prediction model giving the least error has been proposed for use in practice.