hide
Free keywords:
inverse modelling; PEST; pilot points; regularisation; aquitard; hydraulic heads; waterworks; pumping test
DDC:
550 - Earth sciences
Abstract:
This paper addresses the calibration of spatial distribution of aquifer parameters using hydraulic head data. The test site is located close to a well field; the two aquifers are divided by an irregularly expres¬sed aquitard. Wells are switched with short intervals and hydraulic heads are recorded in several observation wells. The characteristic shape of the hydraulic heads at each observation well contains sensitive information about the structure of the aquifer. A numerical method is developed to extract this information. The method comprises the use of hydraulic head differences instead of absolute heads. Pilot points and a regularisation technique are used to represent the spatial distribution of the aquifer parameters. The method is applied to a transient hydraulic model. Despite of inaccuracies in the hydraulic model, cross validation shows robust determination of the spatial distribution of the aquitard. Though aquifer hydraulic conductivities could not be calibrated in a meaningful way, these are not relevant to the calibrated aquitard distribution.
