Hydrogeology and siting of micro-dams around Léo Burkina Faso

Hydrogeology and siting of micro-dams around Léo, Burkina Faso14 June 2010The measurements show a steadily declining water level from December 2008 until February 2009.After February 2009 one well falls dry and in the other wells the water declines further, but lessrapidly.109876DanfinaWell 1 (2008-2009)Well 2 (2008-2009)Well 3 (2008-2009)Well 1 (Feb. 2010)Well 2 (Feb. 2010)Well 3 (Feb. 2010)543210dec jan feb mrt apr meiFigure 12 Water level measurements in 3 wells at Danfina, the Danfina micro-dam wasconstructed between November 2008 and March 2009However there is uncertainty on how the water levels were measured and whether or not (and how)any conversions or calculations have been done on the measured values.The measurements taken during the field visit in February 2010 (the dots in Figure 12) are 4 to 7meters higher than the values measured a year earlier. This seems a rather large difference, too largeto be accounted for by the construction of the micro-dam. So probably also here something wentwrong with the measurements or calculations/conversions afterwards.TabouIn Tabou, the measurements were carried out in three open hand dug wells/scoopholes in anagricultural plot just upstream of the dam.The measurements show a declining water level from December 2008 until April 2009 when all threewells are almost dry. The measurement in May 2009 show an increase in the water level of all threewells, probably because of the first rains.12