Browsing by Author "RAHMAN, MD. MAHMUDUR"

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A GIS BASED DRASTIC MODEL FOR ASSESSING GROUNDWATER VULNERABILITY IN TONGI, GAZIPUR DISTRICT OF BANGLADESH
(2024-03) RAHMAN, MD. MAHMUDUR; REZA, SYED AHNAF
Groundwater resources in Tongi are currently threatened by many garments, dyeing, paper and pulp, wood, tannery, dairy, poultry, fishery, chemical and textile industries. Many of these industries release untreated heavy metals, solid and liquid wastes consisting of cadmium (Cd), chromium (Cr), and lead (Pb), threatening water resources. A model-based groundwater pollution risk assessment was conducted to address these issues. The most sophisticated among the vulnerability assessment techniques is the GIS-based DRASTIC model. The model considers parameters like depth to the water table, net recharge, aquifer and soil media and hydraulic conductivity, which were collected from Bangladesh Water Development Board (BWDB), Geological Survey of Bangladesh (GSB). This study determined the net recharge from specific yield using bore log data and water table fluctuation. The average net recharge has been calculated as 359 mm/year and varied from 105 to 614 mm/year. Determination of the DRASTIC index involves multiplying each parameter weight by its site rating and summing up the total. The higher index values symbolise a greater risk of GW pollution or greater aquifer vulnerability. Finally, for the year 2013 and 2019, two groundwater vulnerability map were developed for each year for the study area using the DRASTIC Index and GIS mapping. One of the maps was developed following typical DRASTIC weightage suggested in the model and the other map was developed by modifynig weightage for the study area. In 2013, the DRASTIC index values vary from 104 to 156 according to model suggested weightage and it was reclassified into two groups of moderate, and highly vulnerable zones. About 21% of the area is highly vulnerable and 79% area is moderately vulnerable to groundwater contamination. On the other hand, modified weightage DRASTIC index values vary between 113 and 183 and it was reclassified into two groups of moderate and high vulnerable zones. About 3.5% area is moderately vulnerable, 96.5% area is highly vulnerable. In 2019, the DRASTIC index values vary from 91 to 137 according to model suggested weightage. The whole study area is susceptible to moderate vulnerablility to groundwater contamination. On the other hand, modified weightage DRASTIC index values vary between 95 and 164 and it was reclassified into two groups of moderate and high vulnerable zones. About 20.6% area is moderately vulnerable, 79.4% area is highly vulnerable. The modified weightage map has more vulnerbility compared to typical map. Thus, the model provides important information that could be useful to city planners and decision-makers for the establishment of ETPs and putting restrictions on further industrialisation in the vulnerable zones.
IMPACT OF AGROFORESTRY SYSTEMS ON TREE SPECIES DIVERSITY AND FARMERS LIVELIHOOD OF BHOLA SADAR AND DAULAT KHAN UPAZILA IN BHOLA DISTRICT
(DEPARTMENT OF AGROFORESTRY AND ENVIRONMENTAL SCIENCE, 2022) RAHMAN, MD. MAHMUDUR
The purpose of this study was to assess the impact of agroforestry system on tree species diversity and farmers livelihood of Bhola sadar and Daulat Khan upazila in Bhola district. Assessment was done by approach of purposive random sampling. Information concentrated from an accumulation of 64 households ranging from marginal, small, medium and large categories. A total of 3032 trees representing 19 families in homestead, 671 trees with 12 families in crop land and 479 trees with 7 families in road side were identified. In the study area, fruit/food (25.58%), fuel wood (25.00%), timber (22.09%), fodder (9.30%), medicinal (8.14%), fence (4.65%) and others species (3.49%) were found in homestead. On the other hand, in crop land, mainly fruit/food species (22.22%), timber species (25.93%) and fuel wood tree species (22.22%) were found. In road side, mainly timber species (32.50%), fuel wood tree species (27.50%) and fruit/food species (15.00%) were found. Considering the abundance of tree species in the study area, the highest percentage of tree species abundance was found for mango (11.48%) followed by coconut (9.50%) and rain tree (9.10%) in homestead. Again, the highest percentage of betelnut (15.20%) followed by jackfruit (11.92%) and mango (10.73%) were found in crop land. Similarly, the highest percentage of koroi (17.54%) followed by raintree (13.99%) and mango (12.73%) were found in road side. Shannon Wiener index (H) was used to evaluate the tree diversity and the evaluation showed that tree species diversity in homestead was 1.314 thereafter 0.546 was in crop land and 0.417 in road side. Farm size, homestead size, total annual income, livelihood status of the farmers and changes of livelihood status of the farmers were significant with concerned variable in all agroforestry systems which had significant impact on livelihood status of the farmers. Among the three agroforestry systems studied, homestead agroforestry showed higher tree species diversity and facilitate better livelihood status of the farmers in the study area. The findings from this study have the potential to inform and enhance agroforestry programs, enabling the effective implementation of tree planting, initiatives tailored to diverse target populations within varying economic and environmental contexts.