Abstract
A new pumping test method has been designed around the practical requirements of those working in rural water-supply projects in developing countries. The bailer test needs only simple equipment and can be completed in under 1 h. The test involves removing 20-50 bails from a borehole over a 10-min period and then measuring the recovery. The test is analysed using large-diameter-well analysis (which accounts for well storage) and is appropriate for testing low productivity aquifers (transmissivity 0.1-10 m(2) d(-1)), where water levels are shallow (<20 m depth). The bailer test was developed and trialled in a rural water supply project in Nigeria where it was found to predict similar transmissivity to 5-h constant rate tests (r (2)=0.9). Analysis of the test was further simplified to provide guidelines for field staff such as community health workers. The likelihood of a borehole sustaining a handpump for 250 people can be indicated by measuring the maximum drawdown and time for 50 and 75% recovery from a bailer test and comparing to a simple table. This simplified test is now being used in this and other rural water-supply projects, and has been modified to indicate whether a borehole can sustain higher yields for small-scale irrigation.
Original language | English |
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Pages (from-to) | 1065-1075 |
Number of pages | 11 |
Journal | Hydrogeology Journal |
Volume | 16 |
Issue number | 6 |
DOIs | |
Publication status | Published - Sept 2008 |
Keywords / Materials (for Non-textual outputs)
- Africa
- Nigeria
- Hydraulic testing
- Water supply
- Groundwater development