Sdok Kok Thom is an ancient Khmer sanctuary located on the Thai-Cambodia border in Sa Khaeo Province, and dating to the 11th century CE. It was first discovered in 1901. Survey and restoration work began at Sdok Kok Thom in 1993 and was completed in 2015. In the sanctuary there is two large ancient water structures, next to the ancient monument, known as the Baray and Lalom (ancient earth-dike). According to the “Sadok Kok Thom No.II” inscription, it can be hypothesized that the structures are used for irrigation were also used in rituals as part of ancient Khmer traditional practices. Excavations of the Baray and Lalom were conducted in order to clarify the original structure of the irrigation systems. Soil samples from each layer were transferred to the TINT laboratory for Optical stimulated luminescence (OSL) measurement. The preliminary dating results indicate that the original structure is contemporary with the age of the monuments mentioned in the inscription. However, more analysis and data collection are needed to provide greater insights into the construction and function of the irrigation channels at Sdok Kok Thom.