The objective of this study is to propose a new methodology for the time-domain analysis of a 2D dam-reservoir system, which considers the effects of fluid-structure interaction. The proposed method involves combining the Radial Basis Function based Differential Method (RBF-DQM) for the fluid domain with the Finite Element Method (FEM) for the solid domain. This approach is referred to as the decoupled Coupled RBF-DQM-FEM method. The RBF-DQM method is a meshless technique that utilizes Thin Plate Splines (TPS) as the test function to achieve high accuracy without requiring additional parameters. The compatibility conditions are imposed iteratively along the dam-reservoir interface to couple the solutions obtained from the fluid and solid domains. This study presents several examples in the time domain to demonstrate the accuracy and performance of the proposed method. The numerical simulations show excellent agreement with other benchmark solutions.