Tam Nang Waterfall

Suan Mai Waterfall

           The general condition is that of a complex high mountain range that runs parallel to the Andaman Sea coast on a north-south axis. The National Park contains a fertile forest habitat that is home to a lot of wildlife, The main  mountains include Khao Phra Mi, Khao Pho Ta Luang Kaeo, Khao Ya, and Khao Nom Sao. It is also the origin of important streams such as Tam Nang Canal, Bang Wan Canal, and Nang Yon Canal, and much astonishing scenery.

Water resources, catchment areas, watersheds, and classification of water resources

       The main watersheds of Si Phang-Nga National Park are on the west side of the southern river basin and the Tapi River Basin. The tributary basins are the Khlong Sok Basin, Khlong Phra Saeng Basin, and the Khlong Takua Pa Basin. The watershed qualification of Si Phang-Nga National Park can be classified into 7 classes as follows:

       1. Class 1A has been in the intact forest since the year 1982. Therefore, it is needed to preserve the watershed and the country's forest resources,. Itcovers approximately 133.89 square kilometers or 83,678.35 rai, accounting for 54.41% of the National Park.

        2. Class 1 AR used to be watershed class 1A, but now rubber plantations appear in the area. It covers approximately 0.09 square kilometers or 55.18 rai, accounting for 0.04% of the national park.

        3. Class 1B is the watershed class 1 where most of forest conditions were destroyed or changed to develop for land use before 2525, with covers approximately 4 square kilometers or 2,498.88 rai (3.998208 square kilometers) accounting for 1.62% of the National Park.

        4. Class 2 is the second most suitable, and covers  73.36 square kilometers or 45,849.39 rai, accounting for 29.81% of the National Park.

        5. Class 3 is in the hillside area with a high gradient  where the soil has moderate erosion. They is generally suitable for economically valuable forests, pastures, logging, mining, and perennial farming activities, but the requires soil and water conservation measures to maintain it. It covers approximately 30.96 square kilometers or 19,351.54 rai, accounting for 12.58% of the national park.

        6. Class 4 is in the hilly area with a moderate slopes. The forest conditions have been encroached upon and cleared, which makes them suitable for crop activities, fruit plantations, and pastures that require preventive measures for soil erosion. It has an area of approximately 3.54 square kilometers or 2,213.49 rai, accounting for 1.44% of the National Park.

          7. Class 5 areas are generally flat or lowland with a slight slope that are suitable for agriculture. Most of the forests have been encroached upon and cleared for farming and other activities. It is not necessary to take preventive measures against soil erosion. The area covers approximately 0.25 square kilometers or 153.17 rai, accounting for 0.10% of the National Park. 

         The characteristics of the canals around Si Phang-Nga National Park are that they are primarily short and flowfrom east to west. They include Klang Canal, Kam Phuan Canal, Ko Ko Canal, Ta Phrom Canal, Tam Nang Canal, Triam Canal, Sai Ngam Canal, Nang Phon Canal, Bang Khrang Nuea Canal, Bang Dong Canal, Bang Daeng Canal, Bang Tong Canal, Bang Nai Sang Tai Canal, , Bang Lu Canal, Bang Yai Canal, Ban Suan Mai Canal, Phraek Khwa Canal, Phraek Sai Canal, and Suan Plu Canal. The water originates in the Nom Sao Mountain range, flowing through various canals into the Andaman Sea.

Another vital surface water source nearby Si Phang-Nga National Park is the Ban Bang Soi Reservoir.

       The volume of water from the 7 tributary basins in Si Phang-Nga National Park over a period of 30 years contains approximately 3,846.5 millimeter. From the model, the average annual water volume is about 211.61 million cubic meters or accounted for around 1,692.86 millimeters, equivalent to approximately 47.78 million cubic meters per square kilometer of water yield. The month with the highest water content in streams is September, averaging about 58.19 million cubic meters. The month with the least water volume (less than 1 million cubic meters) is February.

        There is heavy rainfall almost all year round, and the year is divided into two seasons; the rainy season runs from May to December, and summer is from January to April. The highest average temperature is 34.7 degrees Celsius, and the lowest average temperature is 20 degrees Celsius. The best time to travel is from December until April.

          The forest in Si Phang-Nga National Park is a tropical rain forest. The important plants are Dipterocarpaceae, Hopea odorata , Magnolia champaca, Diospyros transitorea., and the palm family. Various orchids, such as Lady's Slipper, Uraria acaulis Schindl, Dendrobium anosmum Lindl., Dendrobium palpebrae Lindl, and Rafflesia kerrii.
Wild animals found include elephants, chamois, barking deer, gibbons, tapirs, bears, and langurs, with more than 135 species of birds, consisting of hornbills, Malayan banded pitta, woodpeckers, Buffy fish owls, and hawks. The aquatic animals consist of Phluang fish and softshell turtles.