Lake Natron is a salt lake located in northern Tanzania, close to the Kenyan border, in the eastern branch of the East African Rift. The lake is fed by the Southern Ewaso Ng’iro River and also by mineral-rich hot springs. It is quite shallow, less than three meters (10 feet) deep, and varies in width depending on its water level, which changes due to high levels of evaporation, leaving concentrations of salt and other minerals, notably sodium carbonate (natron). The surrounding country is dry and receives irregular seasonal rainfall. The lake falls within the Lake Natron Basin Wetlands of International Importance Ramsar Site. Temperatures in the lake can reach 50 degrees Celsius (120 degrees Fahrenheit), and depending on rainfall, the alkalinity can reach a pH of 9 to 10.5 (almost as alkaline asammonia).