Groundwater is very important for the socioeconomic development of Bangladesh. Supply of safe drinking water to 97% of the population and attaining self-sufficiency in rice production are the two major successes achieved with the utilization of groundwater. Easy availability, good quality and cheap development technologies make groundwater exploitation very popular all over the country and abstraction has increased manifold over the last 30 year. This increasing trend would remain unchanged for the years to come. More than 90% of drinking water and 72% of irrigation water are provided from extensive Holocene alluvial and Pliocene Dupi Tila aquifers.
There are number of development constraints which limits use of groundwater over many parts of the country. The presence of arsenic at concentrations higher than recommended limit, excessive iron and manganese, high chloride concentrations in coastal areas and few pockets inland, lowering of water level, occurrences of gravel, occurrences of biogenic methane, and pollution from various sources are the major constraints for groundwater exploitation in Bangladesh.
Despite high dependence, the management of groundwater is not properly practiced. There are many government organizations involved in development of groundwater. Also exists number of policies and strategies to ensure integrated groundwater management. However; the lack of key legislation like National Water Code and groundwater laws limit the enforcement of policies. A separate National Groundwater Development and Management Authority and an Asian/International Center for Groundwater Studies are considered very important for ensuring proper development of groundwater in the country. Current lack of awareness about the importance of groundwater has to be overcome and people's participation has to be ensured to implement the goal of integrated water resources management for sustainable development.

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Potential field and hydraulic property distributions of sub-sea formation govern submarine groundwater discharge (SGD). In this study, a newly developed method to estimate pore pressure field and hydraulic properties of sub-sea formation using multiple-depth pore pressure measurements was applied to the sub-sea formation at the offshore Kurobe alluvial fan, Japan, where SGD has been discovered and studied well. We successfully determined the average pore pressure at 0.50 meters below sea floor (mbsf) and 0.84mbsf to be 0.23 kPa and 0.63 kPa higher than hydrostatic pressure, respectively, suggesting the existence of the upward component of groundwater flow. The hydraulic diffusivity at 0.50mbsf was determined to be 0.3-1.2 m²/s from pore pressure response to water wave load using the theory of poroelasticity. The SGD flux per unit area was estimated to be 1.8 × 10^-6 5.6 × 10^-5m/s, which was consistent with that determined from the seepage meter data.

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As the enhanced natural attenuation (E NA) technique of chlorinated aliphatic hydrocarbons (CAHs) in groundwater, a bio-barrier was installed in an aquifer by injecting the hydr ogen release compound through injection wells approximately once a year. Long term monitoring was conducted for 3 years to evaluate the effectiveness of the technology. At down-gradient of the bio-barrier, total molar concentration of CAHs has been declined, a portion of the CAHs had been degraded to ethane. First-order degradation rates of CAHs in groundwater have been significantly accelerated after bio-barrier installation, and CAHs degradation became stable along time. Groundwater quality after the second hydrogen release compound injection showed apparent different features comparing to the data after the first injection, i. e. changes of pH, DO and ORP in groundwater became small, and no apparent reduction of sulfate was observed.

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As the enhanced natural attenuation (E NA) technique of chlorinated aliphatic hydrocarbons (CAHs) in groundwater, a bio-barrier was installed in aquifer by injecting the hydrogen release compounds. Long term monitoring was conducted for 3 years to evaluate the effectiveness of the technology, and biological tests have been continuously conducted to measure the change of subsurface biological environment. After bio-barrier installation, microbial community structure in the groundwater had been obviously changed.β-subclass and γ-subclass of Proteobacteria was dominant. As time passed, changes in the microbial community structure and dominant species were observed. Degradation of CAHs was observed regardless of the change in the detection situation of Dehalococcoides sp., and so it was presumed that another bacteria was related to the degradation of CAHs.

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At present, the new campus of Kyushu University is under construction at the hilly area of Motooka and Kuwabara located in the western part of Fukuoka City, Japan. The land-use at the foot of the hilly area is used for private residence, greenhouses, paddy fields, and field farms. The shallow groundwater in this area is used for greenhouses, drinking, and Japanese sake brewery. Specifically, the pumping wells for the greenhouses are situated closed to the tip of the intruded fresh-saline water interface and some of the wells pump up the fresh water floating over the saline water. If there are no counteractions against the alteration of land-use, it is anticipated that excessive pumping of groundwater for greenhouses and the reduction in the groundwater recharge at the new campus may accelerate the saline water intrusion into the aquifer. In order to abate these problems, a project committee organized by the local farmers, municipalities and Kyushu University, monitors the variation of the electric conductivity (EC) at the pumping and observation wells.
In the present report, the variation of EC and the vertical change of fresh-saline water interface are studied. As a result, EC at the all pumping stations varies between 200 and 500μS/cm. This implies that the fresh water is carefully pumped up by the farmers to avoid the contamination of saline water. For some of the monitoring wells that are located close to the pumping wells during the summer season, the depth of EC level which shows about 20,000μS/cm rises and the variation of EC at some monitoring wells often corresponds with the increase of groundwater pumping for greenhouses irrigation. On the other hand, the monitoring wells operating from a distance from the pumping stations showed that the boundary of fresh-saline water is clear and its depth is stable.

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