By Geert Janssen & Kick Hemker
Abstract The building of groundwater flow models has become a matter of practice for many hydrologists. Originally these models were mostly regional models used for large and long-term projects, such as groundwater recharge studies for water supply companies, artificial storage and recovery, and environmental impact assessments. Nowadays numerical models are increasingly used to simulate short-term and small-scale projects, such as construction dewatering, dumping-grounds, groundwater remediation and urban hydrology. Basically, models for such small-scale projects do not differ much from models for regional projects. However, it is the limited size of the area of interest, the distribution and quality of the available data, and the influence of local heterogeneities that may produce particular problems. The small-scale groundwater systems simulated in civil engineering groundwater models are sensitive to local details in hydraulic properties and boundary conditions. Generally speaking, the finite-element method is more suitable for solving these civil engineering problems than the finite-difference method. Irregular finite-element grids allow for much more flexibility of internal and external boundaries, but a smart generator is required to create a well organized, advantageous finite-element grid.
Key words numerical modelling; finite elements; small-scale model; civil engineering