Sirikit Dam Reservoir

Choeng Thong Waterfall

Phu Phaya Pho

        Lam Nam Nan National Park area is a complex mountain range. It is a water source of Sirikit Dam. There are two parts; a reservior area created by Sirikit Dam over Nan Stream with its area of 203 square kilometers (126,875 rai), and a slight sloppy forest area on the western side of the reservior and another sloppy pristine forest area on the eastern side of the reservior located in Uttaradit and Prae Province. The mountains include Doi Mae Naeng, Doi San Phak Hiak, Doi San Phu Mu, Doi Pang Muang Kham, Doi Pha Tuep, Doi Cha Khan, Khao Hat La, Khao Huai Chan, Phu Mon Kratai, Phu khon Kaen and Phu Phaya Pho The highest peak (1,350 meters above sea level) which indicates the border between Uttaradit and Prae Province. It is also the water souce for Yom River in Prae Province, as well as runs to Sirikit Reservior in Uttradit Province. It is the 84th National Park in Thailand.

         The Lam Nam Nan National Park is influenced by the monsoon climate. Summer lasts from March to May, while the rainy season lasts from June to September, with an average annual rainfall of 1,440 millimeter per year. Winter lasts from October to February, and coldest temperatures are found on mountain summits. This season is especially popular with Thai tourists. 

       In Lam Nam Nan National Park there are many types of fertile forests including dry evergreen forests, mixed deciduous forest, and deciduous dipterocarp forest. These are  densely packed with many essential and economically valuable woods such as Teak, Black Rosewood, Iron Wood, Burma Padauk, Tamalin, Lagerstroemia calyculata Kurz , and Dipterocarpus alatus. It is also a habitat for wildlife such as Serows, Wild Boar, Civet, Common Palm Civet, and birds including the Red Junglefowl. There are also many types of aquatic animals in the Khuean Sirikit Reservoir.

       Dry evergreen forests are found along streamswhere water flows all year round. There are examples in Uttaradit, Phrae, and Nan. Common plants include Hopea odorata, Tetrameles nudiflora, Duabanga grandiflora, Hopea ferrea Laness, Dipterocarpus alatus, Lagerstroemia calyculata Kurz, Black Rosewood, Wild Himalayan Cherry, Cyatheaceae, and Rough Tree Fern grows in patches. There are many different types of orchids that cling to the many large trees.

        Mixed deciduous forest are  found  around the Sirikit Dam and they are home to many different types of precious wood including Teak, Iron Wood, Burma Padauk, Black Rosewood, and Dalbergia dongnaiensis.

         Deciduou dipterocarp forests are found mainly on the west bank of the Nan River, and are home to Burma Sal, Burmese Sal, Dipterocarpus tuberculatus, Terminalia alata Heyne, and Morinda coreia.

Wildlife:
       There are Mannals are33 species of mainly medium and small sized mammals including bats, Indian Muntjac, Wild Boar, Serows, and the Sun Bear, There are also reptiles, the most common of which are the Bengal Monitor Lizard, Tokay Gecko, Ground Lizard, King Cobra, Cobra, Rat Snake, Burmese Python, and Reticulated Python. Amphibians are common, including the Common Asian Toad, Green-Backed Frog, Rugosed frog, Malayan Giant Frog, Asiatic Burrowing Frog, and Siamese Large-headed Terrapin.
As Lam Nam Nan National Park includes the Khuean Sirikit Reservoir it is home to many fish species, including the White Barbodes, Gonionotus, Black-Eared Catfish, Spotted Knife Fish, Jullien’s Golden-Price Carp, Soldier River Barb, Nile Tilapia, Mekong Giant Catfish, and Sand Goby.