Effect of Water Withdrawal on Hydraulics and Morphology of Pumduang River, Thailand
Abstract The HEC-6 river morphological mathematical model is applied to predict the effect of water withdrawal from the Pumduang River on its water surface and bed profiles. The river is situated in the Surat Thani province in the south of Thailand. The HEC-6 model is calibrated and verified based on field data. After the model calibration and verification, the HEC-6 is applied to predict the effect of water withdrawal on changes in water level and bed level of the river. The predicted changes are compared with the results of a physical movable bed hydraulic model of scale 1:60. The agreement is found to be satisfactory. The equilibrium river bed and water surface profiles are determined for the annual average flow and the 2-, 10-, 25- and 100-year return period floods for the cases with and without water withdrawal. The water withdrawal of 16 percent of the average annual discharge of the Pumduang river is found to have no endangering effect on the flow and morphological condition of the river
Mathematical Modeling of Scour and Deposition
Electronic computers are opening up the field of sedimentation engineering by permitting the analysis of problems which heretofore have required too much time and effort. Movable stream bed profiles are being calculated in addition to water surface profiles. The initial gradation of sediment material in the stream bed may be prescribed to facilitate the calculation of an armor layer. This gradation is continually changed by the computer program in response to sediment particles being deposited on the stream bed and material on the stream bed being removed to satisfy transport capacity. Hydraulic sorting of sediment by grain size is accomodated. The stream bed does not have to be represented by a single grain size. Retardance of motion because of armor layer is calculated.
Study on the gaseous emissions from a landfill
Abstract Emissions from landfills contain a variety of compounds, organic and inorganic, which can create problems with human health. Here we examine the pollutants methane, hydrogen sulphite, mercaptans, sulphur dioxide, nitrogen dioxide and certain volatile organic compounds (VOCs) that are expected to be found in landfill emissions, in order to assess the environmental impact on the surrounding area. Results indicate that the concentrations in the landfill itself are quite high and in most cases above the ambient air quality limits, while for the surrounding area they are low. The problem is created by H 2 S and the mercaptans which, although in low content, have a distinct odour and cause problems to the neighbouring dwellings.