Delineating flood risk areas in Greater Dhaka of Bangladesh using geoinformatics

This paper illustrates the development of flood hazard and risk maps in Greater Dhaka of Bangladesh using geoinformatics. Multi-temporal RADARSAT SAR and GIS data were employed to delineate flood hazard and risk areas for the 1998 historical flood. Flood-affected frequency and flood depth were estimated from multi-date SAR data and considered as hydrologic parameters for the evaluation of flood hazard. Using land-cover, gemorphic units and elevation data as thematic components, flood hazard maps were created by considering the interactive effect of flood frequency and flood water depth concurrently. Analysis revealed that a major portion of Greater Dhaka was exposed to high to very high hazard zones while a smaller portion (2.72%) was free from the potential flood hazard. Flood risk map according to administrative division showed that 75.35% of Greater Dhaka was within medium to very high risk areas of which 53.39% of areas are believed to be fully urbanized by the year 2010.     

Geomorphological features of Northwestern Bangladesh and some problems on flood mitigation

The northwest region of Bangladesh is divided into four geomorphological units which show different flood features. The region has suffered severe flood damage both in 1987 and 1988. After these floods Bangladesh Action Plan for Flood Control was established by the World Bank. In the northwest region the plan proposed two major projects, namely, an interceptor drain and a diversion channel. A Polder Project is also going on in this region. However these major projects are mainly on structural methods and require much cost for long embankments. The author suggests smaller but reasonable projects combining structural and non-structural methods in the region.     

Biotechnology and the future of rice production

Rice breeders are looking to basic bioscience and biotechnology for help in the solution of important problems that conventional breeding methods have not satisfactorily solved. Among these problems are durable resistance to recalcitrant pests and diseases such as yellow stem borer, gall midge, sheath blight, bacterial leaf blight, blast and tungro virus, and tolerance of abiotic stresses such as drought, salinity and submergence. Nutrient use efficiency, yield potential and efficient hybrid rice production are additional problems for which biotechnology solutions are envisioned. IRRI's biotechnology program emphasizes techniques such as molecular markers, anther culture and DNA fingerprinting that accelerate conventional breeding, and also techniques such as wide hybridization and genetic engineering that broaden the gene pool that breeders can exploit. IRRI's experience in adopting and adapting biotechnology for use in its own breeding program is shared with the national agricultural research systems of Asia through the Asian Rice Biotechnology Network.     

Challenges of value chain actors for vegetable production and marketing in North-East Bangladesh

GeoJournal - Vegetable farming in Northeast Bangladesh has developed rapidly over the last 10 years, with limitations to field management and marketing. A survey was conducted in...     

Variations in technical infrastructure and private economic activity in the rural areas of Southern Poland

Restructuring the Polish countryside is a complex and urgent task. Adapting agriculture for EU entry will mean a considerable reduction in employment and rural diversification is needed because other sectors of the national economy will not be able to absorb all the displaced people if they arrive in the towns. However, providing non-agricultural employment in rural areas depends to a large extent on the technical infrastructure available: running water, sewerage systems, gas supply and telecommunications. The paper deals with voivodeships in southern and southwestern Poland (formerly Galicia) and shows that while much progress has been made since the end of the communist period, the inherited inequalities are being perpetuated and in some cases increased. However, even where the infrastructure is satisfactory, private business does not develop at a uniform rate and action is needed to stimulate communities in remoter rural areas, particularly in the eastern part of the study region. This revised version was published online in July 2006 with corrections to the Cover Date.     

Farm income,inequality, and poverty among farm families of a flood-prone area in Bangladesh: climate change vulnerability assessment

GeoJournal - This paper examines the farm income differences, income inequality of farm households, parameters of income variability that ascertain vulnerability levels, and cost-income variability...     

Feasibility and acceptability study of rainwater use to the acute water shortage areas in Dhaka City,Bangladesh

This study explored the feasibility and acceptability of harvested rainwater in rural communities of Bangladesh as well as densely populated City like Dhaka, using simple and low-cost technology. As a part of this study, a field survey was conducted in the water-scarce Dhaka City. Four slums were selected for conducting questionnaire survey. A questionnaire was furnished to know some information such as the socio-economic condition for those slum dwellers and family information, housing condition, sanitation condition, health condition, economic condition, existing water supply condition, knowledge about rainwater, willingness to accept rainwater, etc. Two hundred people from different representative groups were selected randomly. Yield after spillage and yield before spillage models were developed to know the actual rainwater availability and storage conditions, which were used to justify the effective tank size. Cost-benefit analysis and feasibility analysis were performed using the survey results and the research findings. A sensitivity analysis was performed to check the important parameters toward the implementation of the system as well. The results showed that cost was the most sensitive parameter (48.1%), the second highest sensitive parameter was roof area (25.9%) and the lowest sensitive parameter was demand (2.2%). The study showed that the low-cost rainwater harvesting technique was feasible and acceptable to the slum dwellers as the only potential alternative source of safe drinking water.     

Tillage and farm manure affect root growth and nutrient uptake of wheat and rice under semi-arid conditions

Tillage systems affect soil properties, crop growth and nutrient uptake under various agro-ecological conditions. The uptake of water and nutrients are largely dependent on the root systems of wheat (Triticum aestivum L.) and rice (Oryza sativa L.). The application of manure has direct influence on the nutrient uptake by the crop plants. A 2 year field experiment was conducted to evaluate the impact of tillage and farm manure on root growth by measuring the root length density on a sandy clay loam (Typic calciargid soil). Three tillage systems were used; (i) minimum tillage (MT), (ii) deep tillage (DT) and (iii) conventional tillage (CT). Three farm manure levels were used; (i) FM₀ (only chemical fertilizers), (ii) FM₁₅ (farm manure at 15 Mg ha^?1) and (iii) FM₃₀ (farm manure at 30 Mg ha^?1). The incorporation of farm manure into soil markedly improved the root length density (RLD) of both wheat and rice crops. For wheat, the application of FM₃₀ increased RLD by 16% and 9% in cases of deep tillage and minimum tillage, respectively. For rice, the increase in RLD at the same farm manure rate (FM₃₀) was 13% and 17%, during first and second year, respectively. Averaged across tillage, the trend of RLD for both wheat and rice was DT > CT > MT. The incorporation of FM has increased the uptake of N, P and K significantly (P < 0.05), thereby increasing the agronomic parameters. The manure may be used to ameliorate the deleterious effects of tillage for sustainable crop yield.     

东北水稻产区土壤-作物系统锌元素生态地球化学特征

以东北主要水稻产区为研究区,以土壤-作物系统锌元素地球化学为研究对象,进行了系统的野外调查和土壤、水稻样品的采集、测试及统计分析。研究结果表明,东北水稻产区土壤表层锌含量介于11.01~94.95 mg/kg之间,平均值为43.97 mg/kg,锌含量总体处于缺乏状态;籽实锌含量介于14.27~36.92 mg/kg之间,平均值为24.70 mg/kg,样品中97.56%的籽实锌含量满足人体需要从谷物摄取到的量,品质优良;水稻籽实锌生物富集系数从高到低依次为草原风沙土、草甸土、盐渍水稻土、黑土、淹育水稻土、水稻土、暗棕壤、草甸白浆土;水稻籽实中锌元素的富集与土壤表层硼、锗、铋、镉、铅、锂、铍等元素含量呈现不同程度的显著负相关。     

Geoelectrical resistivity survey for the evaluation of hydrogeological condition of Bagerhat Sadar and the adjacent areas, Bangladesh

This study has been conducted to find out the aquifer characteristics of Bagerhat Sadar and adjacent areas in Bangladesh using geoelectrical resistivity method and borehole logs. The interpretation of resistivity soundings (14 nos.) shows that the sub-surface lithological sequence can be divided into four geoelectric units. The deepest geoelectric unit (with resistivity from 8 Ohm-m to 18 Ohm-m) represents the deep aquifer with usually fresh water. Resistivity values of 12 ?m or more for this unit may indicate formation water as acceptable for coastal people. In the study area, the shallow aquifer inferred is not suitable for groundwater development.     

Measurement of soil-gas radon in some areas of northern Rajasthan,India

The health hazards of the radioactive gas radon on general public are well known. In order to understand the level and distribution of ²²²Rn concentrations in soil-gas in Sri Ganganagar district of Rajasthan, a ²²²Rn survey was carried out for the first time using RAD7, an electronic radon detector manufactured by Durridge Company (USA), at different locations covering a total area of 10,978 km ², having a population of approximately 20 lakh. The measurement of ²²²Rn concentration in soil-gas was carried out at four different depths (10, 40, 70, and 100 cm). The radon concentration in soil-gas for 10, 40, 70, and 100 cm depths ranged from 0.09–4.25, 0.15–6.30, 0.50–9.18, and 0.72–10.40 kBq m ^?3, respectively. The minimum value of radon concentration is observed in 33 GB village at 10 cm depth and maximum for Mohanpura village at 100 cm depth. As expected, our data show an increase of soil-gas radon concentration levels with depth. The present results are compared with the available radon data from other studies.     

第四系覆盖区元素地球化学制图方法新探讨

受分析误差、成图方法以及众多人为因素的影响,根据分析测试数据制作的元素地球化学图有时并不能客观真实地反映元素区域分布起伏特征.笔者以浙北地区土壤元素资料为基础,探讨了成图处理方法对地球化学图的影响,旨在更好地利用计算机制图技术,有效削减分析误差及成图处理方法的畸变干扰,以绘制出更加准确可靠的元素地球化学图.     

A note on the weather and rice yield relationship at some stations in India

A study was conducted with four traditional photosensitive and one high yielding rice varieties grown during the kharif season under rainfed conditions. The curvilinear technique was used to examine the influence of meteorological parameters on the yield of rice. Rice varieties grown in different agroclimatic regions performed differently to climatic parameters. The maximum yield was observed when rainfall ranged between 100 and 115 cm. Maximum and minimum temperature ranges of 29–32°C and 23–25°C respectively appear ideal for optimum yield. Photoinsensitive high yielding variety performed well even at low light intensity (250-350 hours of bright sunshine).     

Mobile phone use and livelihoods: qualitative evidence from some rural and urban areas in Ghana

In sub-Saharan Africa, the past two decades have witnessed a phenomenal increase in the use of mobile phones which has attracted diverse research. This paper explores mobile phone use and livelihood activities in some urban and rural areas of Ghana. Qualitative data were extracted from a larger study that covered 24 sites ranging from urban to remote rural locations in Ghana, Malawi and South Africa. The Sustainable Livelihood Framework provided guidance for the study. The main findings of the study indicate that mobile phones provide direct phone-related employment and indirectly enable some others to secure jobs through contact with friends/relations and also facilitate marketing of farm produce in terms of reduction in transaction cost, access to ready market and contacts for better prices for produce. Additionally, phone use enhances job organization through communication between apprentices and their bosses and also facilitates the migration process of some irregular migrants. As a livelihood capital, mobile phone has the potential to reduce vulnerability and improve upon people’s livelihood outcomes. There is therefore the need to make mobile phones more affordable, expand mobile phone network coverage and improve upon service quality to facilitate livelihood activities, particularly in rural areas of the country.     

Hydrochemical anomaly of drinking waters in some endemic Kashin-Beck disease areas of Tibet,China

Kashin-Beck disease (KBD) has been identified in some areas of Tibet, China. In this work, the Sangri, Nimu, Xietongmen and Gongbujiangda counties of Tibet were selected as case study areas to understand the relationship between KBD occurrence and chemical composition of drinking water. 30 drinking water samples were collected in the KBD-affected and KBD-unaffected villages of these four counties, and the hydrochemistry of endemic and non-endemic samples was compared. The results show that HCO₃–Ca, HCO₃–Ca·Na, and HCO₃·SO₄–Ca are the major hydrochemical types of water samples from both KBD-affected and KBD-unaffected villages. Although Se deficiency in environment has been widely regarded as an important cause of KBD, the Se concentrations in the drinking water samples do not correlate with KBD occurrence in the study areas. However, there are significant differences between the concentrations of Al, Fe, Na, Mn, Cd, Co, Cu, Ba and Mo in the endemic drinking water samples and those in the non-endemic samples, indicating that these constituents may be related to the prevalence of KBD in the study areas.     

An investigation about natural radioactivity,hydrochemistry, and metal pollution in groundwater from Calabrian selected areas,southern Italy

The increasing interest in radioactivity has brought about the need for an assessment of human exposure to radiation. It is, therefore, necessary to examine naturally occurring radioactivity in the environment, especially its occurrence in groundwater. The aim of this work was then to study the levels and behavior of the most significant natural radionuclides, also in order to improve the knowledge of the hydrochemical processes involved in the selected groundwater systems. Natural radioactivity in fifteen Calabrian groundwaters for human use was investigated through high-resolution gamma spectrometry (with a negative-biased Ortec HPGe detector) and liquid scintillation measurements. Particular attention was given on those radionuclides (³H, ²³⁸U, ²²⁶Ra, and ²²⁸Ra), which contribute in a significant way to the overall effective dose received by members of the public due to the intake of drinking water originating from groundwater systems. The activity concentration of ²³⁸U varied from 1 to 51 mBq/L, as a result of the geology of the investigated area and of the oxidizing conditions that favored U dissolution. ²²⁶Ra presented a broad range of activity concentrations (0.011–0.14 mBq/L), lower than uranium ones because radium occurs in groundwater under reducing conditions. Some heavy metals (Cd, Pb, Be, Hg, Ag, As, Tl, Sb, Se, and Ni) were also investigated through ICP-MS measurements and compared with the limits set by the Italian Legislation. Metals are released into the environment by both natural and anthropogenic sources; they leach into underground waters, moving along water pathways and eventually depositing in the aquifer.     

Extent and nature of hydrocarbon occurrence in the groundwater of Kuwait

A study, aimed at characterizing the nature of anthropogenic and biogenic hydrocarbon contamination in the groundwater of Kuwait, was carried out using fluorescence spectroscopy and other analytical techniques. The results of these analyses have demonstrated that the groundwater in certain areas of northern Kuwait has been significantly impacted by contamination originating from the oil-contaminated surface soils. The study revealed that a water-soluble fraction (WSF) of the crude oil surface contamination appeared to be slowly leaching into the freshwater lenses located in the area. The study also showed that hydrocarbon pollutants were practically absent in the brackish water areas of central and southern Kuwait, except for a few isolated sites. However, nonpetroleum hydrocarbons, with ultraviolet-visible absorption characteristics and fluorescence characteristics typically associated with humic substances, were observed at a few sites in the brackish water fields.