Simulating Non-Darcy flow by integrating Forchheimer equation with LPF package of MODFLOW

Traditional groundwater models are mostly based on Darcy’s law that are inadequate to characterize nonlinear flow. In this study, the classic groundwater numerical model MODFLOW is modified and extended by integrating the Forchheimer equation with Layer Property Flow (LPF) package (named by FLPF) based on NLFP package for capturing nonlinear flow behavior. The performance of FLPF was assessed based on benchmark. The results showed the FLPF performed well and was viable to capture the smooth transition from linear to nonlinear flow with increasing hydraulic gradient.