The limestone hills of Erawan National Park rise 165 to 996 meters above sea level. Many important streams flow from these hills. On the eastern side of the park, Mong Lai stream and Omtala stream join together above Erawan waterfall. Sadae stream flows through the north side of the park to Si- nakharindra dam. In the west, Nong Kop stream joins Sai Yok river, and these waters then flow through Sai Yok waterfall. Many small streams flow through the southern part of the park, including the Khao Phang stream which boosts the beautiful Khao Phang waterfall, also known as little Sai Yok waterfall