Dating of groundwater in confined aquifer of Golestan Province using Tritium measurement

The groundwater is the most reliable and permanent source of water in arid and semi-arid regions, especially in the event of droughts. Alluvial aquifer of Golestan province having a wide area, relatively large thickness of sediments and non continuous deposits, has a large volume of water. Confined aquifer hydrograph reveals excessive consumption. This misuse can cause sand problems of wells, the salty water in the northern part of the plain and subsidence. In this situation, the necessity of the optimal management of this aquifer is obvious. For this purpose, aquifer characteristics should be known. Radioisotope dating is one of the newest methods in the field of groundwater developed based on the nuclear sciences. This study aimed to determine the age of groundwater in the confined aquifer of Golestan province using tritium radioisotope. This quantity, in turn, can be used as a tool to study flow paths, the horizontal and vertical flow rate, estimation of aquifer recharge rate, tracing of groundwater contamination, characterization of seawater intrusions and so on. This study showed that some samples collected from the aquifer have a new recharge (age 5 to 10 years) and the rest are a mix of new and before 1952 recharge (age 60 years).