Who cares? What will it cost?

Approaches to improve the value of models and to reduce total project costs. Presented by Ty Ferre, University of Arizona. Download on VIMEO

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,

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

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

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

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

What is Calibration?

This short video discusses what it means to calibrate a groundwater (or other) model. Calibration implies uniqueness. The quest for uniqueness is not a quest

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,

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

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