JWSS - Journal of Water and Soil Science

Settling basins are one of the most essential structures for the separation of inflow sediments. This structure is established to enhance the water quality after the river-basins and water channels. Numerous studies have been conducted on the design of this structure and different methods have been provided to increase its efficiency. However, the use of simple settling basins with the minimum cost which can provide the ideal targets has been the focus of designers. In this study, the effect of flow-guiding plates and the angle between these and the inflow, and the impact of water depth in the basin on the trap efficiency of the settling basins were considered. For testing, 4 blades with specific length and angle were installed. This experiment was repeated for 3 different lengths and 3 angles. The results of the experiments showed that with the enhancement of the depth of water to 10 centimeters to 30 centimeters, while the basin had no flow-guiding plates, increased the trap efficiency of the basin by 4.9 percent. Also, by the use of flow-guiding plates in the suitable and best length and angle (in this study, the suitable size of blades was 22.5 centimeters and the best position was by the angle of 30 degrees); with the maximum of the water depth of 30 centimeters, the trap efficiency was increased by 13.3 percent. The sensitivity analysis done showed that the depth of water had the most effect on the trap efficiency of the basin and the changes in the lengths and angles of the blades position had the similar effects of the basin trap efficiency.

Evaluation of groundwater hydro chemical characteristics is necessary for planning and water resources management in terms of quality. In the present study, a self-organizing map (SOM) clustering technique was used to recognize the homogeneous clusters of hydro chemical parameters in water resources (including well, spring and qanat) of Kerman province; then, the quality classification of groundwater samples was investigated for drinking and irrigation uses by employing SOM clusters. Patterns of water quality parameters were visualized by SOM planes, and similar patterns were observed for those parameters that were correlated with each other, indicating a same source. Based on the SOM results, the 729-groundwater samples in the study area were grouped into 4 clusters, such that the clusters 1, 2, 3, and 4 contained 73%, 6.2%, 6.7%, and 14.1% of groundwater samples, respectively. The increase order of electrical conductivity parameter in the clusters was as 1, 4, 3 and 2. The results of water quality index based on the entropy weighting (EWQI) showed that all of the samples with excellent and good quality (36.3% of samples) for drinking belonged to the cluster 1. According to the Wilcox diagram, 435-groundwater samples (81.7%) in the cluster 1 had the permitted quality for irrigation activities, and the other 285-groundwater samples were placed in all four clusters, indicating the unsuitable quality for irrigation. The Piper diagram also revealed that the dominant hydro chemical faces of cluster 1 were Na-Cl, Mixed Ca-Mg-Cl and Ca-HCO₃, whereas the clusters 2, 3, and 4 had the Na-Cl face. This study, therefore, shows that the SOM approach can be successfully used to classify and characterize the groundwater in terms of hydrochemistry and water quality for drinking and irrigation purposes on a provincial scale.