The Dhaka University Journal of Earth and Environmental Sciences <p>Published by the Faculty of Earth and Environmental Sciences, University of Dhaka, Dhaka, Bangladesh<strong>. </strong>Full-text articles available.</p> <p><a href="" rel="license"><img style="border-width: 0;" src="" alt="Creative Commons Licence"></a><br>Articles in the The Dhaka University Journal of Earth and Environmental Sciences are licensed under a <a href="" rel="license">Creative Commons Attribution-NonCommercial 4.0 International License</a>&nbsp;(CC BY-NC 4.0). This license permits <strong>Share</strong>— copy and redistribute the material in any medium or format, <strong>adapt</strong> — remix, transform, and build upon the material as long as it is not for commercial purposes.</p> Faculty of Earth and Environmental Sciences, University of Dhaka, Dhaka, Bangladesh en-US The Dhaka University Journal of Earth and Environmental Sciences 2220-640X Change Detection of Landuse-landcover in and around Cox’s Bazar-Teknaf Coastal Area of Bangladesh Using Satellite Images <p>The prime objective of this study is to detect changes of the biophysical resources (or landuse-landocver) of the Cox’s Bazar-Teknaf area from 1999 to 2015 using Landsat TM/ETM+/OLI sensors images after applying classifications and indices approaches. The normalized differential vegetation index (NDVI) result showed that water bodies reduced by about 20% of the study area from 1999 to 2015. Bared land or beach decreased by 6% from 1999 to 2005 and then increasing trend is observed in this study from 2005 to 2015. Mixed land was more or less an increasing trend in this study area. Vegetation cover increased from 1999 to 2005 and then suddenly decreased a lot from 2009 to 2015. The declining trend of water bodies is mostly in the northern part of the study area, which is mostly shallow area where shrimp or salt farms exist. The result of normalized differential water index (NDWI) showed that the water bodies decreased from 1999 to 2015 about 10% of the study area. Land area was increased from 1999 to 2005 and then increased a little from 2005 to 2009 and afterward it decreased. The normalized differential salinity index (NDSI) result shows that the area of non-saline zone increased from 1999 to 2015. Low saline zones reduced from 1999 to 2005 but it increased after 2005 due to absence of high and medium salinity signature from NDSI value. The low saline zone is mostly in the northern side of Cox’s Bazar where shrimp farms or salt bed exist. In unsupervised thematic maps, the water bodies increased in this region from 1999 to 2009 and then declined again. The declining trend of water bodies indicates the erosion activities from 1999 to 2009. The fallow lands including beach also decreased from 2005 to 2015, indicates more agricultural activities including fisheries, salt production in this study area. On the other hand, the vegetated region decreased but settlements area including vegetation increased in this area. In supervised thematic map, the result showed that the shrimp cultivation and salt bed increased in this region from 1999 to 2015 and agricultural land has decreasing trend. On the other hand, the vegetated region was ups and down trend from 1999 to 2009. The study indicates that the Landsat images are quite efficient to map biophysical resources of the study area with various techniques.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 1-9</p> Md Bodruddoza Mia Tanzeer Hasan Syed Humayun Akhter ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 1 9 10.3329/dujees.v8i1.50754 Surface Resistivity Sounding and Borehole Data Analysis for the Evaluation of Aquifer Characteristics of Southern Districts Barguna and Patuakhali, Bangladesh <p>The study delineates the aquifer system of the study area and determines the extension of potential fresh water aquifer and suitable locations for groundwater development through geophysical electrical resistivity method. Vertical electrical sounding with Schlumberger electrode configuration, a method for surface resistivity measurement, has been used for data collection. Resistivity data along with borelog data analyses are used for this investigation. Lithological cross section analyses show that sand and clay dominated lithology with frequent facies changes occur throughout the area and also show an aquifer system similar to the three-tier aquifer system proposed by Aggarwal for coastal area of Bangladesh. This study reveals the presence of three aquifers. 1staquifer occurs at a very shallow depth at some places &lt;5 m and thickness of the aquifer varies 10-70 m all over the region, and shows very low resistivity value indicating saline pore water. Average depth to the 2nd aquifer ranges from 60-70 m and also contaminated by saline water. In few places of 2nd aquifer resistivity values more than 20 Ωm suggest some fresh water pockets. Depth to the 3rd aquifer that spreads all over the study area is more than 220 m at maximum part of the area. Only potential fresh water aquifer is the 3rd or deep aquifer, but low resistivity values of this aquifer at Patharghata and small portion of Kalapara and Rangabali Upazilas hint that there may have saline water intrusion. More precise information for this complex geological set up require greater number of sounding points.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 11-18</p> Md Tariqul Islam ASM Woobaidullah ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 11 18 10.3329/dujees.v8i1.50755 Delineating Agricultural Landuse Change using Geospatial Techniques and Markov Model in the Tarakanda Upazila of Mymensingh, Bangladesh and Future Prediction <p>The study aims at detecting agricultural landuse change and its prediction by using the Markov model in Tarakanda Upazila of Mymensingh District during 1989-2018 which is one of the most fish farming dominated areas of Bangladesh. Therefore, agricultural landuse is converted to the fish farming sector as well as other sectors. In such a situation the study intends at identifying agricultural landuse shifting to various sectors from 1989 to 2018 and predicting it for the year of 2026 as a future vector of the Markov model. The study was conducted using multispectral data from Landsat imageries. The imageries for the years of 1989, 2000, 2010 and 2018 were collected from Landsat 4-5TM and Landsat 8 OLI-TRIS. Maximum likelihood classification and supervised classification were applied to detect landcovers of the study area. The study showed that in 1989, there was 58.55% of agricultural land, but it stood at 46.65% in 2018. About 11.9% of agricultural land has also decreased during 1989-2018. Therefore, yearly about 0.4% of agricultural land has decreased from 1989 to 2018. The predicted data shows that about 2.96% of agricultural land will be decreased from 2018-2026, hence, about 0.37% of agricultural land will be decreased in the near future in the study area. As a fish farming dominated area, the water body of the Tarakanda Upazila has increased by about 0.18% per year, similarly, other sectors have decreased at 0.21 percent per year. Therefore the landuse change dynamics should be considered seriously for future planning.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 19-31</p> Md Sofi Ullah Tarulata Shapla Md Amran Hossain Md Hasibul Hasan ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 19 31 10.3329/dujees.v8i1.50756 Relationship between Boro Rice Production and MODIS Derived NDVI for Rice Production Forecasting: A Case Study on Bangladesh <p>The present investigation illustrates an inclusive approach to extract remotely sensed Normalized Difference Vegetation Index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS) (AQUA/TERRA) imageries to find out a relationship with Boro rice production for forecasting crop production in the context of Bangladesh. This study utilizes AQUA/TERRA MODIS reflectance data (250 m resolution) for the month of March (Peak-greenness period) to calculate the average NDVI values by following MODIS based algorithm at district level during 2011-2016. The linear regression analysis of calculated average NDVI and BBS estimated Boro rice production statistics reveals a significant positive relationship due to maximize photosynthetic activities. Among the regression equations from (2011-2016), the highest regression coefficients R2=0.87 and R2=0.85 for AQUA and TERRA MODIS data have been found respectively in 2015. Therefore this regression equation can be used for future estimation of Boro rice production at country scale. However, further testing and simulation of this regression model is required to generate Boro rice production forecasting dataset on timely basis. Hence this study summarizes that, NDVI based regression equation may be an effective process to forecast the Boro rice production which can play an important role in decision-making process relevant to the food security issues of Bangladesh.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 33-40</p> BM Refat Faisal Hafizur Rahman Sukumar Dutta Nasrin Sultana Md Abu Taleb Pramanik ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 33 40 10.3329/dujees.v8i1.50759 Impacts of Flash Flood on Livelihood and Adaptation Strategies of the Haor Inhabitants: A Study in Tanguar Haor of Sunamganj, Bangladesh <p>The study evaluates the impacts of flash flood (especially 2017 massive flash flood) and explores prevailing adaptation strategies taken by haor inhabitants to subdue the impact. Primary data were collected through field visit, questionnaire survey, FGD and KII. A purposive random sampling method was applied for selecting 350 households from 10villages located in and around Tanguar Haor. The inhabitants of low-lying haor areas are extremely vulnerable to flash flood. Their coping mechanism has been strictly curved by a number of social, economic, and political factors, leading to vicious circle of debt and poverty to mohajon (money lender) and micro credit institution, perennial marginalization from haor resources by influential groups and subsequent dependency on wealthy neighbors or relatives. The haor indigent community lives with flood, suffers a loss of income and living, confronts it with food shortage and malnutrition, and survives with the circumstances by bearing considerable debt with high interest rates. This vicious circle of debt, resource loss and poverty act as a dynamic force towards their long-lasting paucity and vulnerabilities, which curve their capability to get ready, take action, and recuperate from subsequent floods, as well as any other disasters. Government should formulate combined and effectual haor management and flood management policy and implemented suitably to shield lives and livelihoods of haor inhabitants.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 41-51</p> Joynal Abedin Hafiza Khatun ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 41 51 10.3329/dujees.v8i1.50757 Non-response to Early Warning: A Comparative Study of Three Recent Cyclones in Bangladesh <p>This study aims to explore the different reasons that influence people's decision on responses to early warning. A questionnaire survey, key informant interviews and focus group discussion have been applied to obtain data from the study area for this study. The research reveals that jerry-built roads, fear of theft, disbelief and mistrust about warnings, lack of awareness about hazards and the poor state of the cyclone shelters are the main reason for nonevacuation during cyclones. Besides, past experiences of warning failures, superstitious religious beliefs, fatalism, safety issues for women also worked to influence people's decision to leave their houses during the warning periods. This study calls the attention of the disaster planners at these crucial findings for taking an immediate step to improve the conditions and save lives in future cyclones. It is highly dangerous to stay at the vulnerable houses during cyclones. The practical implementation of a good disaster preparation plan can be futile if inhabitants are no-responsive to the warning. This study recommends improvement of infrastructures, proper maintenance and construction of shelters, improved security at evacuated houses and the shelters alongside the awareness programs for the inhabitants of the vulnerable locations. It is expected that these interventions will increase the efficiency of the cyclone preparedness plan for future cyclones in Bangladesh.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 53-60</p> Fahmina Binte Ibrahim Md Marufur Rahman Nahid Rezwana ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 53 60 10.3329/dujees.v8i1.50758 Evaluation and Monitoring of Water Quantity and Quality of the Buriganga River in Bangladesh using Multi-temporal Landsat Images <p>Buriganga River, the study area, is one of the most polluted and decreasing expeditiously its area in Bangladesh due to rapid urbanization, effluents of industries and factories surrounding the river, sewage disposal from Dhaka City and some anthropogenic activities. The objective of this study is to evaluate and monitor the water quantity and quality of the river using satellite remote sensing techniques. Unsupervised and indices based classification were used to derive and monitor landuse-landcover (LULC), surface water distribution (SWD), land surface temperature(LST) and total suspended material (TSM) using four sets of Landsat TM/ETM+/OLI/TIRS images of the study area from 1989 to 2015. The indices are Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI). LULC classification results showed that the water bodies and vegetation decreased and consequently urban as well bared area increased from 1989 to 2015. Results of indices (NDVI and NDWI) analysis are similar to that of unsupervised LULC outputs, that is, the water bodies decreased with increasing urban structures of the study area. The surface water distribution monitoring results from the suitable change detection GIS model indicate that the water bodies have decreased about 31.07% and accretion rate increased rapidly from 1989 to 2015 along the river bank due to urbanization and accretion activity is more prominent in north, northeast, northwest, south, southeast and eastern part. The study also shows that the rate of TSM is sporadically increasing during the study period i.e., the maximum and minimum value of TSM was 56215.53 and 1956 mg/l in 1989 and 14188714.35 mg/l and 333942 mg/l in 2015 respectively; this indicates that the water is harmful for aquatic life. Both the analyzed satellite image outcome and in situ observations reveal that land surface temperature is also increased in some part of the study area. The study results could be used to make policy for upgrading the water quality and to maintain the extent and water quantity for agriculture, navigation and fisheries sectors of the Buriganga River.</p> <p>The Dhaka University Journal of Earth and Environmental Sciences, Vol. 8(1), 2019, P 61-69</p> Romana Afroz Md Bodruddoza Mia Md Saiful Islam ##submission.copyrightStatement## 2020-12-14 2020-12-14 8 1 61 69 10.3329/dujees.v8i1.50760