Six watershed were identified combining the terrain elevation data and the hydrography (see Figure 3). In Santo Domingo, the principal watershed is Ozama, with a drainage surface of approximately 2,706 km², has a total rainfall rate of 2250 to 1400 mm per year. The River Ozama has important tributaries as Isabela, Savita, and Yabacao. This watershed is represented with the number 1 in Figure 3.
In San Pedro de Marcorís, the larger rivers are Higuamo and Soco. Overall, this watershed is named San Pedro de Marcorís and La Romana. In this watershed the accumulated rainfall is 2070 to 920 mm per year, and the zone drainage surface is approximately 4,629 km². The rivers of this zone are Chavón, Dulce, Cumayasa, Soco, and Marcorís. This watershed is represented with numbers 2 and 3 in Figure 3.
Samaná´s Peninsula is a wet and mountainous area with short rivers that ends in Samaná´s Bay. In this zone, the total rainfall rate has maximum of 2500 mm and minimum of 2030 mm per year. This area is represented with number 4 in Figure 3.
In Santiago, the principal watersheds are River Yaque del Norte and River Yuna. The River Yaque del Norte drains a large part of the Cordillera Central and Cordillera Septentrional. In this zone, the rainfall rate is 2500 to 550 mm per year, and the drainage surface is approximately 7053 km². The rivers that contribute to the tributaries of River Yaque del Norte are Jimenoa, Bao, Amina, Mao, and Guayubín. On the other hand, the River Yuna which runs to the northeast direction, ends in Samaná Bay. In this watershed, the accumulated rainfall rate is 3020 to 1300 mm per year, and the drainage surface is approximately 5.63 km². The major rivers in this watershed are Yuna, Camu, Licey, Maguana, Chacuey, and Payabo. These watersheds are represented with numbers 5 and 6 in Figure 3.