Calibration and Reliability in Groundwater Modelling: Credibility of Modelling

(Proceedings of ModelCARE 2007 Conference, held in Denmark, September 2007). IAHS Publ. 320, 2008, 114-119.

Auditing as a necessary step for gaining credibility in groundwater modelling

ADOLFO CHÁVEZ^1,2, ADÁN PINALES^1,2, RICARDO DUCOING³ &
JOSÉ L. CRUZ³

1 Facultad de Ingeniería, Universidad Autónoma de Chihuahua, Nuevo Campus, Chihuahua, México

achavezr@avantel.net

2 Estudios y Proyectos en Agua Subterránea, SA de CV, C. Uruguay 310-C, Chihuahua, México

3 Comisión Estatal del Agua de Guanajuato, Autopista Guanajuato–Silao km 1, Guanajuato, México

Abstract Model auditing allows examining prediction accuracy and sources of error, such as conceptual and input data errors, and its greatest benefit consists in identifying or suggesting these errors and providing elements to determine the best way to overcome them. In 1998 and 1999, groundwater flow models were constructed for the 14 main aquifer zones in the state of Guanajuato, Mexico. Afterwards, in 2002–2005, the auditing of the original models was conducted. For this, an auditing protocol was developed and its final version is introduced in this paper. The auditing showed that none of the original numerical models was reliable enough to make sensible decisions about groundwater management; however, model auditing led to new insights into system behaviour, which was useful information for model redesign. Also, through this model development process, the amount of field information was considerably increased and data quality and representativeness were properly assessed. All these efforts contributed to improve the conceptual models and to enrich the databases with which the groundwater flow models are built.

Key words groundwater modelling; auditing protocol; conceptual and input data errors