Thermal behavior of a tropical island reservoir (Hatillo Reservoir, Dominican Republic)

This work was developed to identify the stratification and mixing pattern in the Hatillo reservoir, the largest reservoir in the Greater Antilles and the reservoir with the greatest water storage capacity in the Dominican Republic, built in 1984 in the lower basin of the Yuna River for electric power generation, irrigation district and flood control. Fifty-two diurnal vertical profiles of temperature, electrical conductivity, dissolved oxygen and pH in the limnetic zone of the reservoir from 2011 to 2021 were collected. Mixing is established when the difference between surface and bottom temperature is less than 1°C, that is, gradients less than 0.06°C per meter, total values of Relative Thermal Resistance to Mixing-RTR less than 40, that is, less than 1.8 per meter. The thermal monitoring carried out for ten years has allowed us to establish that the water masses of the reservoir remain thermally stratified most of the year, with annual mixing events lasting one month between December and March. The Hatillo reservoir is defined as a Warm Monomictic Lake according to the revision made by Lewis Jr. (1983a) to the classification of Hutchinson y Löffler (1956).