The National Park serves as the main catchment area for Senanayake Samudraya, the largest reservoir in Sri Lanka and was established in 1954. An elephant herd can be seen throughout the year near the tank and as it's a guaranteed site is popular among the visitors to the park. There are important herbs of the Ayurveda medicine found at the park and are amongst the notable flora of the forest. Crossing the Senanayake tank by boat from Inginiyagala is an alternative method of accessing the National Park. Bird's in abundance can be seen at Birds Island that filled with nesting birds. Where Gal Oya falls to the reservoir, water flows in a natural tunnel known as Makara Kata – native word for Dragon's mouth. Thousands of pilgrims visit Dighavapi stupa annually which is also situated in the area. The stupa was built in the 2nd century BC on the site where Buddha is supposed to have meditated on his third visit to Sri Lanka.