Present Involvement

Project Title: Deep Aquifer Database Development

Organizations: DPHE (Bangladesh), DFID (UK), JICA (Japan)

Objective: The objective of the project is to provide support to DPHE in preparing a deep aquifer database, including lithological and water quality data, a preliminary deep aquifer map and recommendations for future development.

Activities:

      Review of available lithological logs and water quality data from DPHE, BWDB, WARPO, CEGIS and other stakeholders and selecting those that are suitable for inclusion in the database

      Make recommendations for exclusion or checking of data where required

      Input of data into the RockWorks2004 software

      Collection of data from DPHE Upazila officers if required

      Undertake any field checking of data as directed by the lead consultant

      Provide support to DPHE staff in understanding and use of the RockWorks2004 software

      Undertake analysis of the data as directed by the lead consultant

      Contribute to reports and documents prepared as part of the project as directed by the lead consultant.

Background: The uncertainty regarding the quality of the Pleistocene aquifer and the degree to which it may become arsenic contaminated has meant that exploitation of this aquifer has been limited as an arsenic mitigation option. To date, use of this aquifer is accepted in the coastal belt where there is a confirmed confining clay layer and in other areas where approved by the inter-Ministerial committee on groundwater. A further important constraint on the use of the Pleistocene aquifer is the lack of knowledge of recharge mechanisms and the sustainable level of abstraction to avoid mining of the aquifer. It is already noted that the peizometric level has decline in the coastal belt and most estimates of recharge suggest that the sustainable level of abstraction is relatively low.

Despite the restrictions on the use of the Pleistocene aquifer, large numbers of deep tube wells have been sunk across the country. In the 271 Upazilas most affected by arsenic, 78,729 deep tube wells have been sunk by various agencies. The majority (54,200) have been sunk by DPHE under the GOB IV program. The sustainable use of the Pleistocene aquifer is likely to be the largest single contribution to a national program of arsenic mitigation in the long-term. However, at present there is a lack of clean guidance regarding the use of the deep aquifer across the country, with the exception of the coastal belt. Other research has been supported which has undertaken detailed characterization of the aquifer at particular localities, but here remains a lack of clear information across the country. What are required in particular are some simple maps that show areas where the Pleistocene aquifer can and cannot be exploited (Based on the presence or absence of the confining clay layer) and areas where further data is required.

Given the numbers of deep tube wells sunk by DPHE in addition to data held by the Bangladesh Water Development Board, WARPO, GSB and others, there is significant data on the Pleistocene aquifer and lithological logs exists for a number of tube wells. This data can be used to develop initial database can be constructed and from which a preliminary aquifer map can be developed. This will be able to identify where further study is required to provide information that is more comprehensive.

© 2006 Muhammad Shahadat Hossain