Determination the capture zone of wells by using meshless local Petrov-Galerkin numerical model in confined aquifer in unsteady state) Case study: Birjand Aquifer)

In this study capture zones of wells for the first time is determined and depicted with using a numerical method. Meshless local Petrov-Galerkin is one of the meshless methods which is not used in this field. In this article groundwater flow is simulated by using MLPG method in confined aquifer which has four extraction wells in transient state and the changes in groundwater head in 1-month, 1-year, 2-year and 5-year is computed. Heads in number-1, number-2, number-3 and number-4 have 267.24m, 556.62m, 432.1m and 1247.93m drawdown respectively. Finally, capture zones for nodes around the well which its drawdown is equal and greater 165m is determined. For number-1 well and number-4 well and then for all the wells, the capture zone is determined and depicted. The kind of the expansion of these wells is modeled. The results indicated that by passing the time the area and width of the capture zone get greater, in other words when number -1 well is in extraction by itself, in the second year the width of the capture zone is 2.82m and in the fifth year, it is 5.8m. The effect of the increment of both hydraulic conductivity and storage coefficient is also evaluated. With increasing hydraulic conductivity coefficient and storage coefficient, the area and width of capture zone get smaller on the other hand the number of nodes which is located in capture zones reduced.