Mea-wong dam is the big project and created by Royal Irrigation Department. This project is located in “mea-wong” national park mea-wong district, nakhon-sawan province. this project is created to control the water, help the flood, stored the water to use in summer. The size of project is 730 meter of length, 10 meter of width and 57 meter of height. The Mae Wong Dam has the area of the resevior about 13,000 rai. It can store the water about 250 million m^3.This essay will describe about the effects to create this dam.