Recharge and groundwater models: an overview |
| |
| Authors: | Ward Sanford |
| |
| Institution: | (1) US Geological Survey, 431 National Center, Reston, Virginia 20192, USA, |
| |
| Abstract: | Recharge is a fundamental component of groundwater systems, and in groundwater-modeling exercises recharge is either measured
and specified or estimated during model calibration. The most appropriate way to represent recharge in a groundwater model
depends upon both physical factors and study objectives. Where the water table is close to the land surface, as in humid climates
or regions with low topographic relief, a constant-head boundary condition is used. Conversely, where the water table is relatively
deep, as in drier climates or regions with high relief, a specified-flux boundary condition is used. In most modeling applications,
mixed-type conditions are more effective, or a combination of the different types can be used. The relative distribution of
recharge can be estimated from water-level data only, but flux observations must be incorporated in order to estimate rates
of recharge. Flux measurements are based on either Darcian velocities (e.g., stream baseflow) or seepage velocities (e.g.,
groundwater age). In order to estimate the effective porosity independently, both types of flux measurements must be available.
Recharge is often estimated more efficiently when automated inverse techniques are used. Other important applications are
the delineation of areas contributing recharge to wells and the estimation of paleorecharge rates using carbon-14.
Electronic Publication |
| |
| Keywords: | Groundwater recharge Geologic fabric Numerical modeling Inverse modeling |
| 本文献已被 SpringerLink 等数据库收录！ |
|
