Gal oya is the longest and largest rever in nilgala national park.It is very beautiful and valuable rever situated in this park.It is about 106 mils long. Gal oya begin as a small stream from Dorapotha mountain and falls to sea in east cost. The farmers work thousands of acres faddy fields under this rever. The dam in Senanayaka samudraya has built across this rever. And the other thing this rever most valuable of the gems. We can find the rare and most valuable gems in Sri lanka from Gal oya. There are many gems from start to end of this rever. The gem miners find blue , red, cats-eye, yellow, white sapare and many other valuable gems in this rever. So Gal oya is the most Worth rever situated in Nilgala herbal park.
