We’re pleased to share a range of educational videos to help you deepen your understanding of decision-support modelling and to enable you to implement appropriate modelling solutions.

These videos were largely prepared by John Doherty, who is the author of PEST and a leader of the GMDSI project. Most of these videos are of general interest, describing the theoretical and conceptual outcomes of history-matching, while some are more specific.


Pilot Points

Pilot points are often employed as a parameterization device for groundwater models. This is because they can provide a sound basis for highly-parameterized inversion while

Problems with Manual Regularisation

This video extends the discussion of the preceding video, while laying the foundation for ensuing videos. It explains how calibration based on manual regularization, whether

Singular Value Decomposition

Singular value decomposition (SVD) is explained. Also explained is the important role that SVD can play in solving an ill-posed inverse problem, and the insights

Tikhonov Regularization

The importance of Tikhonov regularization in the solution of an ill-posed inverse problem in general, and in the calibration of a groundwater model in particular,

Vectors and Statistics

This video provides a short refresher on some aspects of matrix and vector algebra that we all learned at school but have since forgotten. It

Well Posed Inversion

This video shows how parameters can be estimated when model calibration constitutes a well-posed inverse problem. However, in groundwater modelling, well-posedness does not occur unless


Basic Geostatistics – Part 1

This is the first of a two-part series. It discusses correlated random variables. It shows how knowledge of one such variable conditions estimation of the

Basic Geostatistics – Part 2

In this continuation of the first video of this series, links between geostatistics and history matching of groundwater models are explored. The use of geostatistical

PEST Software

Getting the Most out of PEST

This is the first video of a two-part series whose intention is to provide PEST users with some information on how to use PEST, and

Getting the Most out of PEST – Part 2

This second video of a two-part series covers calculation of finite-difference derivatives, defences against model output numerical granularity, some aspects of observation weighting, termination criteria,

What is PEST?

This video provides an overview of PEST and the three families of utility software that accompany it. It also provides a brief discussion of the