The Hatillo dam is located in the province of Cotui and is one of nearly twenty such dams that provide hydroelectric power to the country. Built on the Yuna River in 1984, the reservoir is the largest in the country with a capacity of 375 million cubic meters of water; Hatillo Dam is also the largest dam in Central America and the Caribbean.
It is a nice opportunity for birdwatchers that may be based in Santiago or other interior locations to see some wading birds and waterfowl that may be more difficult to find away from the coast. There is little bird activity at the dam site itself; the interesting areas are found in the upper parts of the reservoir near the town of Maimon. Here the water has filled small valleys and created many small bays. There are large numbers of a variety of egrets and herons, and Turkey Vultures, which are absent form large parts of the country, are abundant here. In addition, by walking along the roads you can also investigate the adjoining woods, some of which has been planted in Acacia which is often favored by a wide variety of resident and migratory birds.
From the dead-end at the causeway you should first walk out along the causeway to look across the reservoir for waterfowl and other birds. You can also walk a short trail that circles up into the woods above the reservoir. Here you should look for typical woodland species such as Hispaniolan Lizard-Cuckoo, Broad-billed Tody, Hispaniolan Woodpecker, Black-whiskered Vireo, Black-crowned Palm-Tanager and a variety of over-wintering Neotropical migrants. Across from this trail is the center named NaturaBass which offers excursions on the reservoir.
After spending some time here, retrace your route about 1 km (0.6 mile) to the Club Nautica entrance on the right. Turn into this drive; stop and check here for birds along the shore, and then continue on this inner road to a point of land which yields a view of the flats. Return again to the main road and continue back towards Maimon. Stop whenever there is a view of the water, and scan for waterfowl or other birds.
Target species for this site include Blue- winged Teal, Pied- billed Grebe, Great Blue Heron, Cattle Egret, Green Heron, Turkey Vulture, Osprey, and Black- whiskered Vireo.
From Santo Domingo take the Autopista Duarte north towards Santiago. At the traffic light in Piedra Blanca take the right hand turn towards Maimon and Cotui. Arriving in Maimon there will be a sharp right-hand turn for Cotui but you will want to continue straight ahead. The road gradually becomes more rural and eventually becomes a single lane road within a tunnel of tall trees. Continue on this road until it ends at a causeway by the water. From Santo Domingo the total distance is approximately 55 km (34.2 miles) and will take you about 1.5 hr.