# Groundwater Modelling

### Code

10911

### Academic unit

Faculdade de Ciências e Tecnologia

### Department

Departamento de Ciências da Terra

### Credits

3.0

### Teacher in charge

José António de Almeida, Sofia Verónica Trindade Barbosa

### Weekly hours

3

### Teaching language

Português

### Objectives

(1) To know the potential and limitations of the mathematical models used for development of hydrogeological models. (2) To acquire the skills and base knowledge necessary to the use of mathematical models and two and three dimensions hydrogeological modeling software (3) To meet the necessary conditions for the development of physical models of groundwater flow (4) To understand the most important units and properties and the potential of reactive processes and transport modeling of different types of contaminants in groundwater (5) To understand the limitations and possibilities of the particular case of hydrogeological modeling of massive fractured rocks (6) To acquire practical on hydrogeological modeling and contaminant transport and reactive processes using different practical case studies (7) To acquire practical knowledge that is necessary for the modeling processes related with active or passive treatment of groundwater, such as "pump-and-treat"; installation of "drains", "passive barriers" or "active barriers".

### Prerequisites

None.

### Subject matter

**I - Hydrogeological modeling of groundwater flow**

I.1 - Principles associated with the groundwater flow: groundwater interactions with the hydrological cycle. Review and synthesis of relevant physical properties of soil, water, vadose zone and aquifer. Soil: porosity, void ratio, water content, degree of saturation, coefficient of compressibility. Water: dynamic viscosity, kinematic viscosity, compressibility. Aquifers: Hydraulic Conductivity, Transmissivity, Storage Coefficient.

I.2 - Fundamental equations of mathematical models of groundwater flow: intrinsic permeability, validity and generalization of Darcy''''''''s Law for isotropic and anisotropic conditions. Continuity Equation (Mass Conservation) and Laplace Equation. General equations of stationary regime in heterogeneous environment, anisotropic conditions with and without continuous supply in time. General equations of transient regime in heterogeneous environment, anisotropic conditions with and without continuous supply in time.

I.3 - Concept of confined aquifer and unconfined aquifer free their combinations. Unconfined aquifer and specific yield. Confined aquifer and storage capacity. General equations for confined aquifer and unconfined aquifer.

I.4 - Other concepts and general issues associated with the mathematical modeling of flows: different type solutions of mathematical models (analytical models, numerical solutions - finite difference methods, finite element methods; hybrid models). Numerical modeling of groundwater flow - applicability and potentialities. Fundamental elements of the mathematical models (base equations, boundary conditions, departure conditions in the case of transient models). Modeling process (protocol). Importance of Calibration, Verification and Validation. Importance of input data quality.

I.5 - Software PMWin "Processing MODFLOW" – Concepts of Module "MODFLOW" and familiarization with the environment modeling software. Menus of PMWin.

I.6 - Practical exercises using the software PMWin "Processing MODFLOW" - exploitation of Module "MODFLOW"

**II - Modeling of reactive processes and contaminant transport**

II.1 - Behavior of contaminants in groundwater: Organic contaminants (hydrolysis, oxidation-reduction, biodegradation, adsorption, volatilization). Inorganic Contaminants (nutrients - nitrogen, phosphorus and sulfur, acids and bases, metal and halide (filtration, precipitation, complexation / pH / redox, adsorption).

II.2 - Effects of transport of contaminants in groundwater. Transport Processes: advection, dispersion and retardation. General concepts and equations. Behavior of the contamination plume: contaminant density, solubility of the contaminant, local flow conditions (velocity of groundwater flow and hydraulic conductivity); particular geological conditions (barrier effects, effects of conduct, crystalline or fractured limestone massifs, faults and permeable structures). Reactive transport: general transport equation with the combined effect of advection-dispersion and reactive effects of retardation, degradation and existence of an external source of contaminant. The concept of natural attenuation.

II.3 - The basic concepts and equations associated with modeling techniques transport: Darcy’s Law and advective transport, Mass conservation law and Eulerian interpretation of advective transport. Advective transport with “particle tracking” method. Dispersion and mass transfer: microscopic and macroscopic . Advection-Dispersion Equation. Advective-Diffusive Systems. Dual porosity domains. Transpor with chemical reactions – concepts and basic equations: general transport equation with reactive effects; sorption and desorption effects and equilibrium and non- equilibrium systems; Sorption isotherms (*Freundlich* e*Lagmuir*); Retardation effect: concept and basic equations; Ionic exchange – concept and isotherms (retardation nonlinear equations); Concpts of sorption kinetics, first order irreversible reactions, single-species kinetics reactions, multi-species kinetics reactions, instant reactions, first order chain reaction of “*parent-daughter”** *type. Reactions of dual-porosity domains.

II.4 - Software PMWin "Processing MODFLOW" - Concepts and main differences between Modules "MT3DMS", "PHT3D", "MT3D99", "RT3D", "MOC3D" and "PMPATH"

II.5 - Software PMWin "Processing MODFLOW" - Concepts and main differences between Modules "MT3DMS", "PHT3D", "MT3D99", "RT3D", "MOC3D" and "PMPATH" - Practical Exercises

**III - Modeling of physical and reactive processes for treating groundwater ("pump-and-treat"; installation of "drains", "passive barriers", "active barriers") -**** **practical exercises

**IV – Introduction to hydrogeological modeling of fractured rock.**** **Basic concepts and principles: the notion of massive fractured rock; perpetuation of flow on altered and heterogeneous fractured rocks; importance of knowledge of the variation of the conditions of fracturing in the medium; solutions of the flow equations for the case of heterogeneous medium; introduction to dual-porosity models.

### Bibliography

[1] Vallejo, L. , Mercedes, F., Ortuño, L., Oteo, C. (2002) Ingeneria Geológica - Parte I, Capítulo 5 Hidrogeologia”. Prentice Hall, Madrid, ISBN: 84-205-3104-9, p.264-302.

[2] Liu, D., Lipták, B. (2000) Groundwater and surface water pollution. Lewis Publishers, USA. 150 p.

[3] Zheng, C. & Bennet, G. (2002) Applied Contaminant Transport Modeling. “. 2.nd Edition. John Wiley & Sons, Inc. Publication, USA. 621 p.

[4] Custodio, E e Llamas, MR (1983a) Hidrologia Subterranea. Tomos I e II. Ediciones Omega, S. A., Barcelona, 1157 p.

[5] Marques, JM, Chambel, A e Ribeiro, L. (2007) AIH-GP and IAH - Commission on Hard Rock Hydrogeology - Iberian Regional Working Group. Proceedings of the Symposium on Thermal and Mineral Waters in Hard Rock Terrains, Lisboa, Portugal, 202 p.

[6] S. Barbosa (2014). Sebentas de apoio às aulas teórico-práticas de “Modelação de Águas Subterrâneas”

### Teaching method

The teaching model adopted is kind of theoretical and practical with: i) theoretical lectures and practical multimedia support; ii) practice with problem solving using adequate software of groundwater modelling and simulation of flow and transport and reactive processes.

### Evaluation method

Theoretical and practical component (30%) and laboratory / project (70%). Theory and practice: a test that may be substituted forexamination. Component of the project: to get with delivery andevaluation of exercises, divided into two modules (35% each module).