Isotopic measurement interpretation in the Rio Sonador springs and the Rio Aguacate spring, in the north of the Dominican Republic

Isolated karstified limestone blocks in a clay formation are found in the Yasica River valley. A small amount of groundwater is stored in clay and runoff is high. On the contrary, the infiltration in limestone amounts approximately to 48 1/s-km2 or 1510 mm/a, which is the difference between precipitation (2110 mm/a) and evaporation (605 mm/a). Groundwater flows from springs at the basis of the limestone blocks. The main objective of this investigation is the determination of the discharge stability of Sonador River, for hydroelectrical purposes. The isotopic and conventional investigations show that the mean residence time of groundwater is about one year. As a consequence, the discharge of springs feeding the Sonador River does not decrease in a short time after the rainy period, because the aquifer has good storing capacity and large recharge. The spring discharge decreases to values of 0.6 m3/s in 140 days and 0.3 m3/s in 310 days of drought. The minimum discharge of Sonador River was 0.5 m3/s during 11 years of monitoring. (author). 5 figs, 2 tabs