SAG-30306 Characterisation of Regional Subsurface Water

Vak

Studiepunten 6.00

Language of instruction:

English

Assumed knowledge on:

SAG-20804 Soil physics and agrohydrology; HWM-20806 Hydrogeology

Contents:

Remote Sensing
The remote sensing component introduces the physical basis of remote sensing, with special attention to microwave (both active and passive) and thermal infrared remote sensing. Emphasis will be put on applications within hydrology and forestry. Remote sensing offers the unique possibility to acquire information over large and difficult by accessible areas. This makes it a perfect tool for monitoring purposes in general and in particular for watersheds at various scales and forested areas. Within this course the linkage between terrestrial measurements and airborne or spaceborne observations is explored. Measurement principles for different parts of the electromagnetic spectrum and interpretation techniques for remotely sensed data are explained. Various small case-studies are being presented that will highlight the possibilities of remote sensing for practical purposes.

Soil Physics
The Soil Physics component focuses on solute transport to the groundwater in soils at scales ranging from the sample scale to the field scale (and beyond). The background of this focus is the need to understand and assess the risk of groundwater pollution by substances applied to the soil surface (pesticides, fertilizers, atmospheric contaminants), especially in humid climates. The importance of soil heterogeneity for water flow and solute transport is demonstrated with experimental data and model results. Different methods to model the effect of soil heterogeneity at different scales are discussed, and illustrated with example calculations. Various alternatives to the classical convection-dispersion equation (CDE, introduced in SAG-20804) are presented and evaluated. Novel tools to analyse solute transport in heterogeneous soils are explored.

Groundwater Modelling
On a regional scale, the saturated zone can in general be described as a sequence of horizontal layers, where conductive aquifers are separated by low-conductive confining layers. On this scale, the groundwater flow in the aquifers can be assumed to be 2-dimensional horizontal, while the flow in the confining layers is 1-dimensional vertical. The groundwater flow, and hence the transport of solutes, on a regional scale will be affected by heterogeneities over scales that range from centimeters to hundreds of meters. Modelling the groundwater flow and solute transport on this scale will therefore require upscaling of the processes that govern the flow and transport on a smaller scale. In this component, the combined modelling of groundwater flow and the transport of solutes on a regional scale will be discussed.

Aims:

At the end of the course, students:
a. understand the laws of physics that apply to radiation and how the energy, radiation and water balance are linked;
b. are able to describe the interaction of radiation with the earth's surface and objects at that surface;
c. are able to do simple calculations with soil moisture estimation algorithms;
d. are able to understand and interpret remote sensing imagery from a more physical perspective;
e. have an appreciation of the effect of soil variability on the plot and the field scale on the fluxes of water and solutes to the groundwater;
f. can indicate the limitations of the applicability of different model concepts for solute transport in soils, based on the underlying assumptions of these concepts;
g. are able to calculate solute leaching in heterogeneous soils for simplified flows using various methods;
h. can calculate and interpret the spatial and temporal distribution of solute leaching in a soil at a given depth from experimental data;
i. will be familiar with the processes that play a role in regional scale groundwater flow and transport;
j. will be able to explain the assumptions that form the basis for regional scale modelling of groundwater flow and transport;
k. will be able to estimate upscaled hydrological parameter values for groundwater flow from small scale data;
l. will be able to explain why groundwater modelling results will be different from measurements.

Activities:

Attending lectures, practical training with computer models, and self-study of lecture notes and papers handed out during the lectures.

Examination:

Written exam.

Literature:

Lecture notes and papers handed out during the lectures.