The Gulf of Thailand is relatively shallow. Its average depth is 45 m, and the maximum depth only 80 m. This makes water exchange slow. The strong water inflow from the rivers make the Gulf low in salinity (3.05-3.25%) and rich in sediments. The main rivers which empty into the gulf are the Chao Phraya (including its distributary Tha Chin River), Mae Klong and Bang Pakong Rivers at the Bay of Bangkok, and the Tapi River into Bandon Bay in the southwest of the gulf.