For a Better Understanding and Management of Karstic Aquifers: Characterization of the Properties of the Big Spring Karstic System (Missouri)
To better study, exploit, and manage karstic aquifers, a new approach using systemic analysis is currently used by Ramboll Environ. The overall behaviour of the aquifer is no longer considered to be the result of the sum of spatially individualized behaviours, which is assumed and imposed by the differential approach, but as the sum of the interactions of these individual behaviours that most of the time are unknown. The karst is thus conceived as a set of dynamic processes (flows) whose study and understanding must lead to the identification of its properties, allow a description, and ultimately facilitate its exploitation and management. While this concept is easy to understand, and seems able to solve the difficulties encountered, its implementation remains subtle.
The Ramboll Environ approach derives from a philosophy different from the conventional hydrogeological approach and requires abundant robust collection of continuous data, using transducers of the various parameters that monitor the functioning of the karstic aquifer (discharges, water levels, rainfall, etc.). This approach involved the development of a set of methods and high-performance software to extract information from the collected data in order to recognize the physical signatures that are responsible for the observed hydrodynamic behaviour, and thus, whatever the difficulty encountered, including non-linearities, characterize the dynamics of systems and predict their behaviours. These methods are called correlative and spectral analyses, continuous or discontinuous wavelet analyses, rescaled range analysis, fractal or multifractal analyses and attractor analyses.
The application of these analyses to Big Spring, Missouri allowed the establishment of an “Identity Card” of the spring, encompassing all information necessary for an optimal management of the spring.