The Dhaka University Journal of Earth and Environmental Sciences

Greenhouse Gas Emission Reduction through Electricity Generation from Solar Photovoltaic Systems: A Study in Dhaka

Nayeema Rashid — 2024-01-17

Though best provided with electricity, Dhaka, the capital city of Bangladesh, often experiences power outages while lacking at least 500 MW of electrical power. Given a massive shortage of electricity both in Dhaka and the country and the use of fossil fuels in power generation, the present study examines the potential of rooftop solar photovoltaics (SPVs) for electricity generation in the Dhaka Metropolitan Area (DMA) and the consequent greenhouse gas (GHG) emission reduction. It has been found that the roof area of DMA is 62 km². Considering 50% of this area (31 km²), the application of SPVs can generate 9,454 GWh of electricity yearly or 25.8 GWh per day. Such generation can reduce GHG emissions by 4.3 MtCO₂e/year, which is 26.7% of the NDC target from the power sector. The results of this study support the wide-scale application of rooftop SPVs throughout DMA.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 1-8

Exploring the Use of WRF-ARW Model for Analyzing Heatwaves in Bangladesh

Md Momin Islam — 2024-01-17

This study attempts to simulate heatwave events over Bangladesh using the WRF-ARW Model that could be used to implement a best practice strategy for predicting heatwaves in Bangladesh. In this research, 17 heatwave events were identified from the period between 2007 and 2022. The thresholds for heatwave events were considered when the maximum temperature from a weather station was above the 95^th percentile for three consecutive days. After carefully identifying the events, all the events were simulated with the WRF-ARW model. Simulated temperature, relative humidity, and wind vector (direction and speed) were analyzed for this research. The synoptic conditions were synthesized for all the heatwave events. It was found that the propagation of warm temperatures corresponded to the movement of wind and was aptly supported by the presence of humidity in the region of interest. This information could be used at the operational level for predicting heatwaves.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 9-28

Isolation, Characterization, Evaluation and Comparative Study of Beneficial Microorganisms among the Agricultural Soil, Saline Intruded Soil and Commercial Biofertilizers

Bipasha Sur — 2024-01-17

Degradation of soil health is a growing concern as both human health and soil microbial community are directly related to this. One of the main hazards to soil deterioration in Bangladesh is soil salinization. In this study, the microbiological status of two commercial biofertilizers, an agricultural soil, and saline soil in Bangladesh were analyzed and compared. Five saline soil samples from various agricultural fields in Satkhira, two commercial biofertilizer samples, and one agricultural soil from Hazi Danesh Agricultural University were collected to carry out this work. The saline soil sample's physicochemical properties, such as pH and salinity, were examined. Saline soil had a salinity range of 0.17-1.60 ppm and a pH range of 6.20-7.22. Five beneficial bacteria, three types of food-borne pathogen indicators, three types of soil quality indicators, and one plant pathogen indicator bacterium were selected for the microbiological investigation. The microbial status of the five beneficial bacteria was observed; for Rhizobium, the range was not detected to 7.62 log CFU/g, for Azotobacter, it ranged from 3.11 log CFU/g to 5.72 log CFU/g, for phosphate-solubilizing bacteria, it ranged from 3.87 log CFU/g to 4.69 log CFU/g, and for Bacillus, it was not detected to 4.65 log CFU/g. The helpful bacteria Pseudomonas spp. and the plant pathogen inhibitor Trichoderma spp., which are deemed important markers for soil health, were found to be absent in all the samples.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 29-40

Capacity Assessment of Community Clinic (CC) as an Information and Support Hub during Future Outbreaks: Lessons Learnt from the COVID-19 Outbreak

Anika Samm A — 2024-01-17

The study delves into the potential of Community Clinics (CCs) in Bangladesh to function as crucial information and support hubs during pandemics and outbreaks. By examining both internal and external factors, including organizational structure, roles, responsibilities, infrastructure, skills, tools, existing organogram, government policies, and community clinic dynamics, the research assesses the capability of CCs in this role. Through a telephonic survey of 100 Community Health Care Providers (CHCP) and Key Informant Interviews (KII) with Community Based Health Care (CBHC) officials, valuable insights were gained. While the findings reveal that CCs may not be comprehensive treatment centers for pandemics, they can effectively serve as information and support hubs, aligning with their mandates. To enhance their efficiency in this role, upgrading the WASH sensitivity of CCs is recommended, along with other measures to improve their capacity during disease outbreaks. The study underscores the significance of recognizing CCs as vital assets in combating emerging health hazards, and strategic improvements can further strengthen their contributions in addressing public health challenges.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 41-56

Evaluation of the Reservoir Characteristics of Exposed Sandstone Facies of the Bhuban Formation in Sitakund Anticline, Chittagong

Md Ashraf Ali Uzzal — 2024-01-17

This research concentrates on characterizing the sandstone reservoir features within the Bhuban Formation exposed in the Sitakund Anticline of the Chittagong Hill Tracts. Of the lack of well-qualified reservoirs, the sandstone facies in the Bhuban Formation are considered the primary reservoir source and a significant contributor to Bangladesh's hydrocarbon reserves. The Bhuban Formation showcases a pattern of alternating sandstone and shale layers. To ascertain the existence of reservoir sandstone facies in the Bhuban Formation, the study conducts analyses of exposed structures along various outcrop sections of Bariyadhala, Chandranath, Barabkunda, and Shahasradhara. Through scrutinizing lithology, sedimentary structures, bed configuration, grain size, and reservoir characteristics of rock sequences, three distinct facies types emerge: the alternating sandstone and shale layers, channel sand, and incised valley sand. These facies types signify diverse depositional environments, with the alternating sandstone and shale layers originating from tidal flats, channel sand representing sediment fill within tidal channels, and incised valley sand indicating sediment accumulation within incised valleys. The detailed petrographic analysis underscores that the incised valley fill sand exhibits the most favorable reservoir qualities, boasting an approximate porosity of 25%. The tidal channel fill and the tidal flat deposits display 20% and 8% porosity, respectively. Both channel sand and incised valley sand showcase commendable porosity and permeability. In contrast, the sample featuring the alternation of sandstone and shale has the lowest porosity and contains randomly oriented clay minerals, predominantly Kaolinite.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 57-68

Depositional Environment and Reservoir Prospect Analysis of Barail Sandstone Exposed in the Northeastern Part of Bangladesh

Muhit Alam — 2024-01-17

The study characterized the Oligocene Barail sandstone in the Surma Basin from a reservoir perspective. Data were collected by direct field observations; rock samples were collected from outcrops for detailed sedimentological, petrographic, and geochemical analysis. Collected sedimentary logs are analyzed to delineate the facies associations, sandbody architecture, and depositional environment. A total of ten facies were identified, which were further grouped into three facies associations: FA1: Tidal-influenced multistorey channel-fill deposits, FA2: Fluvial multistorey channel-fill deposits, and FA3: Overbank deposits. Facies analysis suggests that the Barail sandstone was deposited in the tidal-influenced paralic to fluvial depositional settings, and channel body dimensions increase towards the top. A petrographic study shows that these sandstones are mostly litharenite (Q₇₀F₄L₂₆) in type, and sediments were derived from quartzose recycled orogens. The average porosity of the sandstones is 16.9%; the pore spaces are of both primary and secondary origin and are mostly interconnected. Porosity distribution in the fluvial multistory channel-fill deposits (FA2)—the upper part of the sandstone succession, is less heterogeneous, while that in the tidal-influenced channel-fill deposits (FA1), occurs in the lower part is more heterogeneous. Both the depositional process and diagenesis influenced the porosity of Barail sandstones. Geochemical analysis suggests that the sandstones are chemically stable and moderately matured. The study demonstrates that the Barail sandstones may be a good petroleum reservoir.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 69-88

Spatio-Temporal Changes in the World Largest Mangrove Forest and Human Perceptions in Bangladesh: A Study Using GIS-RS and Social Survey Techniques

Muhammad Esmat Enan — 2024-01-17

Mangrove forests are disappearing at a faster rate than any other forests in many places around the world due to natural and anthropogenic causes; as a result, natural resources are decreasing. Considering these issues, present study focuses on the changing pattern of the world’s largest mangrove forest which locally known as Sundarbans, and utilized Landsat satellite imagery during the periods 2000 to 2021 as the primary data source. Using Google Earth Engine, the Normalized Difference Vegetation Index (NDVI) was applied to classify the images into 4 LULC categories (water bodies, sediment, forest, and others). The accuracies of the image classifications were between 89.76 and 92.21 percent. Classified images for the years 2000, 2010, and 2021 were then used to train and validate the ANN-CA (artificial neural network-based cellular automaton) model applied to produce the LULC scenario for the year 2031. On the other hand, a questionnaire survey was conducted in Sarankhola, and Shyamnagar Upazila to identify locals’ perceptions of the causes of LULC changes in the study area. The findings reveal a great change from 4036.92 to 3969.33 km² of forest cover between 2000 and 2021, and further degradation of 3913.03 km² by the projected year (2031). The results show that all the 13 identified causes are driving the LULC changes in Sundarbans. The study also suggests if the appropriate management practices are not implemented, the study area's forest land degradation will likely continue in the years to come.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 89-105

A Review on Remote Sensing Based Forest Vegetation Health Assessment: Bangladesh Perspective

Nazmoon Nahar Sumiya — 2024-01-17

This paper aims to present a critical review of the published scientific papers that have addressed the issue of forest health in Bangladesh using remote sensing techniques. A systematic review approach has been followed in this study where all the available papers on the application of remote sensing to assess the forest health vegetation condition of Bangladesh were considered for review. That search resulted in the selection of 48 papers. The findings indicate that remote-sensing-based studies have focused mostly on forest cover mapping and change, and landcover change detection rather than assessing the overall health condition of those forests. Also, among the major forests of the country, most studies have been conducted on Mangrove (Sundarban) forests whereas the least number of studies were found for the forests in the Chittagong Hill Tracts Forests areas and those studies were mostly conducted after the Rohingya crisis. Landsat satellite products have been most extensively used for their broader temporal resolution and availability while a few studies have worked with other products like MODIS, Sentinel, SPOT, etc. The application of advanced classification approaches incorporating machine learning algorithms and ground validation has shown effectiveness for investigating the forest or overall ecosystem health in a more detailed way. Although the RS techniques are increasingly used to study the forests of Bangladesh, forest health-specific and indicator-based research is yet to be done which can ensure sustainable forest management.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 107-121

Causes of Deforestation and Degradation of Jhau (Casuarina equisetifolia) Plantation Along the Cox’s Bazar-Teknaf Sea Beach in Bangladesh

Mosa Tania Alim Shampa — 2024-01-17

In this study, Jhau (Casuarina equisetifolia) plant degradation from the years 2006-2019 along the Cox’s Bazar-Teknaf sea beach has been conducted by remotely sensed satellite image analysis from the Google Earth platform. According to the research, roughly 16.39% of Jhau patches were lost between 2006 and 2010, 30.59% between 2010 and 2015, and 43.38% between 2015 and 2019. Deforestation in the Jhau forest has mostly been triggered by anthropogenic and natural factors. The anthropogenic causes that have been found in the current study region include structural development, road construction, water logging, and agricultural land expansion. Coastal erosion and new channel development are natural causes. Among the natural causes, on average, 65% of deforestation has occurred due to coastal erosion processes, and less is due to anthropogenic activities from the years 2006 to 2019. Among the locations where coastal deforestation has occurred, Charpara region and the Teknaf peninsula were found to have the most notable deforestation. The Teknaf peninsula is highly unstable, and the Jhau forest has been deforested every year due to this instability. The selection of vulnerable zones in these regions is highly needed and the selection of suitable locations for future Jhau plantations is very important to these regions.

The Dhaka University Journal of Earth and Environmental Sciences, Vol. 12(1), 2023, P 123-134