A finite-element framework for reduced order modeling (ROM) in the context of variational multiscale (VMS) methods is presented. The reduced order model in the current work is based on POD-Galerkin approach. The advanced VMS-ROM formulation aims for a maximum reduction of computational cost with a minimum information loss while computing the flow dynamics. The mathematical implementation is outlined in a detailed manner. The generalized-alpha time integration technique with ROM has been implemented and investigated thoroughly for its performance and stability. The developed framework is validated on numerical benchmark cases like vortex-shedding behind a 2D cylinder, turbulence generated on a 2D backward-facing step and further applied to environmental flow problems. Higher-order NURBS basis functions are explored to generate flow snapshots for the reduced orthogonal basis for VMS-ROM.