▁hours ▁in ▁ 2 0 0 1 ▁and ▁continuous ▁water ▁supply ▁was ▁achieved ▁in ▁ 2 0 0 6 . ▁This ▁was ▁facil itated ▁by ▁the ▁expansion ▁of ▁a ▁water ▁pipeline ▁from ▁Lac ▁de ▁G ui ers ▁in ▁ 1 9 9 9 . ▁ ▁Conc ern ing ▁drink ing ▁water ▁quality , ▁in ▁ 2 0 0 4 ▁ 9 7 . 7 % ▁of ▁water ▁samples ▁were ▁in ▁conform ity ▁with ▁micro bi ological ▁water ▁norm s , ▁up ▁from ▁ 9 6 % ▁in ▁ 1 9 9 6 . ▁ ▁Water ▁resources ▁▁ ▁Sen eg al ' s ▁climate ▁is ▁tropical ▁with ▁well - defined ▁dry ▁and ▁hum id ▁seasons . ▁Dak ar ' s ▁annual ▁ra inf all ▁of ▁about ▁ 6 0 0   mm ▁occurs ▁between ▁June ▁and ▁October . ▁The ▁mean ▁annual ▁precip itation ▁ranges ▁from ▁ 2 7 0   mm / yr ▁in ▁the ▁North ▁to ▁ 1 7 9 3   mm / yr ▁in ▁the ▁South . ▁Inter ior ▁temper atures ▁are ▁much ▁higher ▁than ▁along ▁the ▁coast . ▁ ▁The ▁largest ▁water ▁resource ▁in ▁the ▁country ▁is ▁the ▁Sen eg al ▁River ▁in ▁the ▁North , ▁shared ▁with ▁Maur it ania , ▁M ali ▁and ▁Guinea . ▁Its ▁average ▁flow ▁is ▁ 3 7 ▁billion ▁cub ic ▁meters ▁per ▁year . ▁The ▁Lac ▁de ▁G ui ers ▁is ▁an ▁important ▁water ▁res er voir ▁in ▁the ▁Upper ▁D elta ▁of ▁the ▁Sen eg al ▁River ▁on ▁its ▁left ▁bank ▁with