Study on land use pattern change and its causes

Land use of Sylhet has changed gradually. This is found from the field survey that in 1970 the area was dominated by marshy land [645.33 katha], vacant land [430.88 katha] and crop land [336.17 katha]. By 1988 there was no university in the area. Residential area also increased. It covered 39.11% of total study area. Now in 2007 there is a radical change noticed in the area in comparison with 1988. Population has increased and accordingly residential area has also increased. Now it covers about 58.71% of the study area. A survey was conducted to judge the view of the old residents of the area about the change of the land use pattern. The impacts of land use changes are desertification, climate changes and hill cutting. Improper lands use like removal of vegetal cover brings about marked changes in the local climate of Sylhet. Deforestation changes rainfall, temperature, wind speed etc. It was observed that rainfall pattern; atmospheric window of Sylhet has been changed significantly within last ten years

Regression analysis of ground water quality data of Sunamganj district, Bangladesh

Ground water samples from different Upazilas of Sunamganj District have been analyzed for drinking and irrigation purposes. Correlation coefficients among different parameters were determined. An attempt has been made to develop linear regression equations to predict the concentration of water quality constituents having significant correlation coefficients with electrical conductivity [EC]. Calcium and EC; Bicarbonate and EC are highly correlated but not perfect. Our findings show that calcium, nitrate, and bicarbonate are significantly related with electrical conductivity at 1% level of significance. Except for the total dissolved solid, all other variables are significant at a conventional level [i.e. 5%] with expected sign. The usefulness of these linear regression equations in predicting the ground water quality is an approach, which can be applied in any other locations

Assessment of ground water quality in Sunamganj of Bangladesh

In this study, groundwater quality in Sunamganj of Bangladesh was studied based on different indices for irrigation and drinking uses. Samples were investigated for sodium absorption ratio, soluble sodium percentage, residual sodium carbonate, electrical conductance, magnesium adsorption ratio, Kelly's ratio, total hardness, permeability index, residual sodium bi-carbonate to investigate the ionic toxicity. From the analytical result, it was revealed that the values of Sodium Adsorption Ratio indicate that ground water of the area falls under the category of low sodium hazard. So, there was neither salinity nor toxicity problem of irrigation water, so that ground water can safely be used for long-term irrigation. Average total hardness of the samples in the study area was in the range of between 215 mg/L at Tahirpur and 48250 mg/L at Bishamvarpur. At Bishamvarpur, the water was found very hard. Average total hardness of the samples was in the range of between 215 mg/L at Tahirpur and 48250 mg/L at Bishamvarpur. At Bishamvarpur, the water was found very hard. It was shown based on GIS analysis that the groundwater quality in Zone-1 could be categorized of [excellent] class, supporting the high suitability for irrigation. In Zone-2 and Zone-3, the groundwater quality was categorized as [risky] and [poor] respectively. The study has also made clear that GIS-based methodology can be used effectively for ground water quality mapping even in small catchments