Both 9mTcO4- and Rhodamine WT were employed as tracers to record the residence time distribution (RTD) in 5 segments located in the Almendares
River in Havana City. Recovery calculations showed the conservative behavior of the 99mTcO4- under the field conditions studied. The experimental residence time distribution curves from the second segment were convoluted
for the d-Dirac injection at the beginning of the section. The spatial behavior of the conservative prompt spills throughout
this river section was established for two extreme flow conditions.