Khao Sok National Park has a very complex high stone mountain range especially Khao Kalo Strait which has limestone spires, some cliffs are very high like a tower and exuberant tropical rain forest. The tropical rain forest is where the water starts to flow to the Sok canal and Pha Saeng canal. Both canals converge to form the Pum Duang canal which is an important branch of the Tapee River. The highest sea level of the Tapee River is about 961 meters but the average sea level is 200 meters. The soil is mostly clay and red sand but somewhere is skeletal soil.