PhD Thesis

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Changing Pattern of Wetlands and its Impact on Environment of Dhaka City
(University of Rajshahi, 2010) Shahabuddin, A. K. M.; Ahmed, Raquib
Dhaka, the capital city of Bangladesh is one of the populous Mega cities in the world. High density population as well as shortage of land causes intense densification in the existing built up. Rapid population growth creates extra pressure on the land of already overcrowded Dhaka city and the city is expanding in an unplanned and uncontrolled manner. One of the major adverse impacts of unplanned growth is destruction of environmentally sensitive areas. Dhaka city had a large number of wetlands both big and small, which includes rivers, canals, lakes, lowlands etc. But the wetlands have been shrinking with the passage of time. In recent years the speed of conversion of wetlands for housing and other infrastructures emerged as an alarming issue considering its adverse impact on environment. This study mainly focuses on three issues: i) Changes of wetlands in and around Dhaka city ii) Problems appeared in the city due to wetland change iii) Government's implications regarding wetland change. This research documented the extent of wetland change since 1960. To accomplish the work top maps of 1960 and three images of different years (Land sat TM, 1988; ALOS VNIR, 2008 and Goggle earth, 2008) were used. Findings reveal that a large portion of the wetlands has been lost and the rate of destruction of wetland is alarming. During the total study period (1960-2008), the city has lost 33% of water bodies and 52% of lowlands. During the period 1960-88 the water bodies decreased about 30 hectares per year and between 1988-2008 decreased about 6 hectares per year and lowlands decreased 29 hectares per year between 1960-1988, 315 hectares per year between 1988-2008. It is clearly observed from the analysis of change in land use dimension of selected wetlands areas that wetlands are mainly converted to built-up areas. It is also revealed from this analysis that the rate of transformation of wetland is highly related with urban settlement. This research tried to apprehend the perception of local people regarding the loss of wetlands through questionnaire survey. It is evident from the views of surveyed respondent’s mainly real estate companies and government organizations are involved in wetland loss and water logging is the main impact of wetland loss. The water logging becomes a burden for the inhabitants of Dhaka city and creating adverse social, physical, economic and environmental impacts. Interruption of daily work, children's problem going to school, disruption of electricity, risk of run of motor vehicle, damage of houses, problems in getting drinking water, sanitation problem, creating unhygienic situation and suffering from the disease are the encountered effects of water logging on city life. Respondents viewed that to overcome the water logging problem, all illegal structure from the wetlands need to remove immediately. This research carried out a thorough assessment of prevailing plans, acts, rules and regulations for wetland management. The present wetland management of the public agencies has been critically analyzed and their overlapping and conflicting areas were identified. Activities of different environmental groups were also reviewed in this study. The investigation undertaken for this study reveals that the present management practices of government organizations are very weak and not at all systematic. The existing legal tools of different agencies are not exercised properly. Overlapping of functions among the agencies creates conflicts in management. The coordination status of government organizations are poor but the PLDCs, local influential people and others, those are involved in wetland change are highly organized and well coordinated. This study delivers the essence that combined effort is necessary from the part of involved stakeholders, like local people, NGOs, local government body, central government and civic organization to implement the conservation strategies of wetlands. Political will and government commitment is also needed for this purpose. In conclusion, some recommendations are made regarding proper demarcation of wetlands, strengthening the relevant GOs, strict development regulation and proper enforcement of laws towards conservation of wetlands.
Impact of Open Pit Coal Mining on Groundwater in and Around Phulbari Area, Bangladesh
(University of Rajshahi, 2014) Haque, Md. Emdadul; Ahmed, Raquib; Reza, A.H.M. Selim
This study attempts to evaluate current state of the groundwater environment considering natural and artificial system together, to better understand origin of stresses, their state, expected impact and responses made to restore healthy groundwater environment in Phulbari coal mine area. Impacts on groundwater were carried out for an open pit coal mining area located in Phulbari under Dinajpur District in Bangladesh. The exploration of coal following the open pit method will influence the ground water resources in and around the mine due to pumping of groundwater as well as precipitated water which will be accumulated in the floor of the open pit mine. Groundwater is the main source for agriculture and domestic use of that region. In this area the average groundwater level is declining 0.166m each year. During the drought season groundwater depletion rate is 0.209 m/year and during monsoon period this rate is 0.112 m/year. During the twenty-five years period (1985- 2010) total depletion of groundwater is 4.15 min Phulbari. On the other hand, during the summer season temperature ranges from 22°c to 38°C and during the winter season it varies from 5.4°C to 16°C during the 41 years period (1970-2010). The analysis reveals that due to dry up of rivers and discharge of groundwater level for irrigation, temperature increased and groundwater level decreased. Hydrographically it is also seen the close relationship between groundwater level and rainfall from the time series analysis. It is observed that temperature is increasing with time and groundwater level is decreasing with time. Here it is found a reverse relationship between groundwater level and temperature. But if open pit coal mine will be done in that area, this will abruptly change the water table, because total water of mine area has to be pumped out. As a result, drying up of wells, reduction of water in streams and lakes, deterioration of water quality, increased pumping costs and land subsidence will occur around the mine. For qualitative analysis four water san1ples out of eight showed high contamination level (Cd > 3) ranging between 4.613- 8.619 (6.6), two samples showed medium contamination level (Cd 1-3) ranging between 2.171-2.785 and two samples showed the low contamination level (Cd <1) ranging between 0.506-0.952 value before mining activities. After mining activities, the predicted concentration index for groundwater samples will show the very high contamination level (Cd > 3) ranging between 155.868- 1627.256. Before mining activities Cd ranged between 0.51 -8.62 and HPI ranged between 2.04-4.42, but after mining activities Cct values are expected to be 155.86 - 1649.7 and HPI ranges between 22.53-204.58. The DRASTIC vulnerability index is computed for evaluation of three conditions (conventional DRASTIC, Modified DRASTIC-CctHPI for before and after mining activities). For conventional DRASTIC the vulnerability index is found ranging from 81-167 of which 31 % area is highly vulnerable. Before mining activities, the vulnerability index was found ranging from 87 -182 of which 3 0% area was highly vulnerable but after mining activities the vulnerability index will be found ranging from 185 - 375 of which 24% area will be highly vulnerable, 35% will be very highly vulnerable and 41 % will be extreme vulnerable. Groundwater, temperature and rainfall were analyzed by following fitting of straight line by least square method. Selected eight heavy metals were analyzed using AAS. The prediction is done by following the data of Raniganj coal field, Maharashtra coal fired power plant in India and Poltegor coalmine, Poland. Two methods such as contamination index (Cct) and heavy metal pollution index (HPI) were used to evaluate the contamination levels. The software used for this study are Arcview 3.3 for the preparation of location map and DRASTIC vulnerability maps. Surfer software were used for 3D groundwater level map and Rockware were used for analysis of lithology and stratigraphy of the study area. The groundwater vulnerability assessment was done using DRASTIC model in GIS environment.
Landuse Change and Environmental Degradation in Dhaka City
(University of Rajshahi, 2011) Islam, Md. Shahidul; Ahmed, Raquib
The present research documents the extent and impact of land use change since 1960 to 2008. Topographical maps of 1960 and two images of different years (Landsat TM image, 1991 and Google image, 2008) were used and analyzed to accomplish the expected research outcomes. The study reveals that a large portion of land has been changed, and the rate of decrease of vegetation and wet/lowlands has appeared to be quite alarming. During 1960-2008, the Dhaka city lost 39.94% (5354 ha) of cultivated land, 66% (5026 ha) of vegetation, 44.48% (1657 ha) of water-bodies and 47.32% (42.50 ha) of wet/lowlands. During the period 1960-1991, the cultivated areas decreased to about 22.45% (97 ha/year), vegetation cover decreased to about 28.85% (71 ha/year), waterbodies to about 14.20% (17 ha/year) and wet/lowlands to about 35.10% (102 ha/year). During 1991 to 2008 Dhaka lost 22.56% (138 ha/year) of cultivated land, 52.21 % (166 ha/year) of vegetation, 35.29% (66 ha/year) of water-bodies and 18.82% (65 ha/year) of wet/lowlands. Maximum changes were found to be concentrated on certain land uses such as in cultivated land (about 112 hectares were under change per year) and vegetation (105 hectares were under change per year) during the study period 1960-2008. Rate of decrease in case of wet/lowlands 89 hectares per year during the same period. It has been observed that wet/lowlands were converted predominantly into built-up areas. The transformation of cultivated land, vegetated lands and wet/lowlands were strongly related with the high rate of growth of urban settlement. Three areas to represent the research were selected viz. Ashulia, Uttara and Amin Bazar. These areas grew and developed mostly during 1960 to 2008. It is important to observe that the increase for Ashulia was 218 .2% during 1960 to 1991. It was true also in case other two areas during 1960-2008. Growth of Uttara region was about 540.4% continuously almost steadily during the same period. It means, the rate of urbanization is much faster in Uttara than in Ashulia. It has been observed that a cultivated lands has been reduced due to urbanization in Uttara. It has also been observed that in Uttara vegetated lands increased for about (159.2%) during 1960-1991. But it has decreased in Ashulia and in Amin Bazar This research presents a dynamic change of land use in Dhaka city, based on selected physical and social factors. Land Change Modeler (LCM) was used to analyze the land use changes between various land use classes during the period 1960-1991 and 1991-2008. The land use change was assessed through evaluation of gains and losses by those classes. It was noted that most of the land use categories experienced loss and gain to some extent. But the pattern was different. During 1960-1991, cultivated/agricultural land lost 76.51 % and gained 68.45%, with a net loss of 8.06%. And in 1991-2008 it lost 78.31 % and gained 63. 72%, with a net loss of 14.59%. Vegetation lost 67.53% and gained 25.34 % in 1960-1991 with a net loss of 42.19 %. In 1991-2008 the loss was 36.28% and the gain was 19.36% with a net loss of 16.92%. Wet/lowlands lost 57.45% and gained 12.53 % in 1960-1991 with a net loss of 44.92 %. In 1991-2008 the loss was 23.57 % and the gain was 24.85% with a net gain of 1.28% and water-bodies neither gained nor lost and land (the loss of water bodies was already completed before that period). Built-up area lost to about 27.61 % and gained 93.58%, with a net gain of 65.97 % during 1960-1991. During 1991-2008 the loss was 56.42% and gain was 71.26% with a net gain of 14.84%. Net gain for bare soil/landfill was 10.58 % and in transport and communication it was 18.24% in 1960-1991. During 1991-2008 similar trends have been noticed for the rest of the classes, with the exception of bare soil/landfill, which seems to be stable. Transport, communication and others categories have gained to some extent. But however, there are always some scopes of checking the result in GIS environment. The location accuracy in land use change model using Landsat TM image of 1991 and Google Earth image of 2008 was done using the clear and visible roads. In case of classifying bare soil/landfill, cultivated/agricultural land and vegetation, the user accuracy were 59%, 49% and 61 % respectively. The prediction of land use change was done on Neural Network, a built-in module in the Andes version of ID RISI. Iterations considered were 5000, considered sufficient for running the data. The lowest accuracy obtained was 57 .30 for all the conversion types. The transition probability matrix records the probability of future changes in which each land use category indicates in relation to other category. This matrix was produced by the multiplication of each column in the transition probability matrix where the numbers of cells of corresponding land use showed the later scenario. Though this matrix can be used to predict future land use in any period, it was specially designed for the predictions for the years 2020 (short term) and 2050 (long term). This research attempted to bring light to the perception of local people regarding change of land use through questionnaire survey. It is evident from the views and opinions of the local people that real estate companies, unplanned urbanization, industrializai10n an
Sustainable Land Management: Policy Implication and Sectoral Achievement
(University of Rajshahi, 2007) Alam, Md. Shamsul; Ahmed, Raquib; Rahman, Md. Redwanur
Present investigation deals with the "Sustainable Land Management: Policy Implication and Sectoral Achievement". It was conducted from the period of three years (July'2003 to June'2006) in the Barind tract (Nachole Upazila) and Chalan Beel area (Singra Upuzila). The Chalan Beel area lies between 24°35' to 24°70' North latitude and 89° 10' to 89°35 'East longitudes. The total area of Chalan Beel area is 368 sq km. Barind tract lies between 24°20' to 25°35'North latitudes and 88°20' to 89°30' East longitudes. Total area of Barind tract is about 7,770 sq km. The investigation was designed with land management system of Bangladesh and degradation due to inadequate existing polices and improper implementation of existing laws in Bangladesh. The present study has observed that there are many laws and government policies to manage the land of Bangladesh such as The Non Agricultural Tenancy Act'1949, The Land Revenue Act’s 949, The State Acquisition and Tenancy Act' 1951, The Tax Rules'1962, The Vested Property Act'1966, The Agricultural Pesticides Ordinance'1971, The Bangladesh Irrigation and Water Rate Ordinance'1983. Most of these laws were prepared during British and Pakistan periods. These ancient laws were prepared and enacted for their own interest and in ancient time. But now the scenario is changed. The formal Bengal province is now fully independent country. The land use pattern has been changed and population has been increased. Man land ratio has been decreased. The excessive land use and improper land use change are causing land degradation. The socio-economic problems are rising due to improper land management. The population is much more than the affording capacity of the area. The people need foods, shelter and others from the limited land. The farmers are trying to produce much food from the limited land resource. They are using chemical fertilizer, insecticides, HYV seeds and other harmful things in agricultural land without considering its consequences and future. Rut there are not laws and policies to stop or to reduce of these harmful activities. Even the existing laws and policies are encouraging them to use the harmful activities such as The Canals Act' 1864, The Irrigation Act'1876, The Destructive Insects and Pests Act'1914, The Agricultural and Sanitary Improvement Act'1920, The Tanks Improvement Act'1939, The Agricultural Pesticides Ordinance'1971, The Bangladesh Irrigation and Water Rate Ordinance' 1983. Though recent policies are emphasizing! To reduce those chemical fertilizers and pesticides in agricultural land. But these policies and laws are not implemented properly. There are 24 agricultural laws and 7 policies passed by the government of Bangladesh to develop the agriculture……………………………