Appendix B
A FORTRAN Program for Solving
Coupled Groundwater Flow and
Contaminant Transport Problems
The attached FORTRAN pro gram, MCB2D.FOR, can be used to simulate
two-dimensional groundwater flow and mass transport in confined or unconfined aquifers. It is useful not only for learning this book, but also for solving
practical problems.
B.l Features and Assumptions
The program has the following features:
1. Triangular elements are used to discrete the flow region (see Section
5.1.2).
2. Discrete equations are derived by the multiple cell mass balance method
(see Section 5.2). Both local and global mass conservations can be
maintained.
3. When solving the advection-dispersion equation, appropriate upstream
weights are added adaptively according to the value of local Peclet number (see Section 6.2.3).
4. Only non-zero elements in the coefficient matrices of the discrete equations are stored (see Section 5.4.2). The required storage space is
minimized.
5. Boundary conditions, infiltrations, pumping and recharge rates and
water quality of recharged water may vary with time.
6. A modified iteration method, the selected-node iteration method (see
Section 5.4.2), is used to solve the discrete equations. The iteration
procedure is usually convergent faster than other iteration methods.
7. The groundwater flow equation and groundwater quality equation are
solved by the same subroutines. The construction of the program is
compact.
8. The pro gram is of good universality. To solve different problems, generally, we only need to change data files without any change in the
program.
300
A FORTRAN Program for Solving
Coupled Groundwater Flow and
Contaminant Transport Problems
The attached FORTRAN pro gram, MCB2D.FOR, can be used to simulate
two-dimensional groundwater flow and mass transport in confined or unconfined aquifers. It is useful not only for learning this book, but also for solving
practical problems.
B.l Features and Assumptions
The program has the following features:
1. Triangular elements are used to discrete the flow region (see Section
5.1.2).
2. Discrete equations are derived by the multiple cell mass balance method
(see Section 5.2). Both local and global mass conservations can be
maintained.
3. When solving the advection-dispersion equation, appropriate upstream
weights are added adaptively according to the value of local Peclet number (see Section 6.2.3).
4. Only non-zero elements in the coefficient matrices of the discrete equations are stored (see Section 5.4.2). The required storage space is
minimized.
5. Boundary conditions, infiltrations, pumping and recharge rates and
water quality of recharged water may vary with time.
6. A modified iteration method, the selected-node iteration method (see
Section 5.4.2), is used to solve the discrete equations. The iteration
procedure is usually convergent faster than other iteration methods.
7. The groundwater flow equation and groundwater quality equation are
solved by the same subroutines. The construction of the program is
compact.
8. The pro gram is of good universality. To solve different problems, generally, we only need to change data files without any change in the
program.
300