The Dez protected area, spreading over 16,000 hectares is located on the two sides of the Dez River. Some 5,000 hectares of the Dez protected area is a wild life refuge. The Dez wild life refuge is considered the most important habitat of the Iranian yellow deer. Various other animal species abound in the area. The Dez River basin has been the site of some great civilizations in history. The Elamite king, Ontash, had built a place 50 kms from Shoush city. This building is better known as Dorantash and includes Ziggurat, which functioned as a temple. Khuzestan Province possesses special climatic conditions due to its location on the slopes of the Zagros mountain chains.
Iran's major river, Karoun, has its source in the Zagros. Other important rivers that flow through Khuzestan such as Maroun, Dez, Karkheh and Hendijan, also rise in the Zagros Mountains.
Sediments from these water resources have turned Khuzestan into flat green plain rich in agriculture. The fertile soil of this area provides excellent cultivation for sugarcane, citrus fruits, and dates. The water resources in the area are the reason for dense forests in several parts of Khuzestan, particularly around the Dez and Karkheh rivers. In view of this, these areas are considered as protected.
Dez River is fed by two main tributaries, the Sezar and Bakhtiari streams that flow into Khuzestan from the neighbouring Lorestan Province. Dez River, in its meandering course to join the River Karoun, north of Ahwaz, flows past the cities of Dezfoul, Shoushtar, and Shoush. The huge Dez hydroelectric dam is built on the Dez River.
The region's vegetation is made up of various types of tropical and semi-tropical plants. This type of vegetation includes different types of trees and various plants. Due to abundant water and dense forests, the Dez area has a rich variety of birds, both migratory and local, in addition to various reptiles. The streams have several species of fishes.
The Dez Dam is a large hydroelectric dam built in Iran in 1963.
The dam is on the Dez River, the closest city being Dezful the only way to access the dam in the Northwestern province of Khuzestan. It is 214 metres high, making it one of the highest in the world, and has a reservoir capacity of 3,340 million cubic meters.
At the time of construction, the Dez Dam was Iran's biggest development project. From Andimeshk it is 15 minutes easy drive. It is also possible to visit powerhouse which is located at the left of the dam in the mountains. The powerhouse has eight vertical Francis turbines.
The current problem with this dam is annual loss of reservoir capacity due to the erosion of soil in upstream areas. The water from the reservoir irrigates 160 square km.