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A number of experimental freshwater wetlands (150 m long × 75 m wide) with different ages since they were abandoned as rice fields, were used to analyze the prospects of multipurpose wetland restoration for such degraded areas. Nitrogen and phosphorus removal rate of the wetlands were determined monthly during the flooding season to estimate their efficiency as filters to remove nutrients from agricultural sewage. The number of wetland birds was recorded regularly to identify their habitat preferences. Both the temporal dynamics and changes in the spatial pattern of land use cover during the last 20 years were determined from aerial photographs and field analysis. All the wetlands appeared to be very efficient in the removal of nitrogen and phosphorus exported from rice fields. Usually 50–98% of the nitrogen and less than 50% of the soluble phosphorus were removed by the wetlands at any stage of restoration. Wetland birds preferred wetlands with intermediate plant cover for resting and sleeping activities better than rice fields and either very open wetlands or very dense ones with tall vegetation. Apart from the improvement in water quality and the restoration of natural habitats, restoration of wetland belts around lagoons will increase spatial heterogeneity and diversity of the landscape.

This paper describes the experimental assessment of lateral sloshing forces developed within scaled road tankers as a function of fill level and container shape, focusing on high fill levels (from 90 to 98 per cent) and three container shapes (oval, modified oval, and circular). The purpose of the study was to estimate the effect of sloshing forces on the lateral stability of tank trucks when operating almost fully loaded. Water was used as the working fluid while the lateral dimensional characteristics of the containers represented a reduction scale of road tankers in the range of 1:5. Containers were subjected to a lateral excitation imparted by a sinusoidal electromagnetic shaker that moved a wheeled container/support assembly at a range of frequencies. The residual after-perturbation sloshing forces were measured by means of a force transducer connected to the shaker ram, and recorded for analysis. For the 98 per cent fill level, normalized sloshing forces were found to represent up to 4 per cent of the total liquid weight. Application of these normalized forces to actual size tank trucks further suggests that the rollover threshold acceleration of a rigidly suspended tank truck, due to sloshing, can be reduced by 2 per cent for the 98 per cent fill level, and around 10 per cent for the 90 per cent fill level. These already significant reductions in the roll stability of tank trucks would be more severe for a spring suspended vehicle, thus rationalizing the rollover trend of such vehicles. The use of longitudinal sloshing suppressors is strongly recommended.

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