Time series and stochastic analyses to study the hydrodynamic characteristics of karstic aquifers

Abstract

Abstract:The regional study of hydrodynamic characteristics of karstic aquifers is challenging because of the great variety of lithology and the structural complexity found in carbonate formations. In order to improve this situation, a combined approach of time series and stochastic analyses was adopted to assess the hydrodynamic behaviour of the karstic aquifers. To achieve this, daily flow rates of 20 springs were taken from the 11 most significant aquifer units of the Basque Country. The results demonstrate the presence of memory effects, which modulated the input rainfall for short-, medium-and long-term storage capacity, resulting in hydrodynamic properties such as system memory, response time and mean delay between input and output. They reflect the storage and the manner in which these are filled and emptied, thus indicating the karstification of the aquifer. Likewise, the hydrodynamic and hydraulic classification obtained from the stochastic analysis provides a complementary approach to characterize the hydraulic behaviour of the studied karstic aquifers. The discussed examples indicate that this approach provides an excellent method to research hydrological karst systems. It is also shown that the use of hydrologic time series, alone, does not lead to a satisfactory classification of the hydrodynamic characteristics. Therefore, the general approach to hydrological regionalization in karst areas should take into account the structural complexity, heterogeneity of the lithology and the degree of karstification. Only in this case will the regionalization be physically founded, leading to a regional understanding of the hydrodynamic characteristics and flow conditions in a karst aquifer.

Assessment of groundwater quality and remediation in karst aquifers: A review

“…Karsts have the most complex system amongst terrains, causing lot of uncertainties and errors in developed models for studying and predicting their behavior (Bakalowicz, 2005). Also, the recharge and discharge rate of karst springs can vary a lot due to several reasons such as fluctuations in water table level caused by hydrological events or seasonal variations (Gárfias-Soliz et al, 2009). Table 1 elaborates hydrogeological characteristics of three main aquifer types, porous media, fractured rock and karst system based on ASTM D 5717–95 Standard (ASTM, 1995).…”

Statistical analyses and modeling approaches to hydrodynamic characteristics in alluvial aquifer

“…In karst hydrogeologic studies, autocorrelation and spectral analyses have been widely used to quantify 'memory effect' of aquifer systems and categorize aquifers in different combinations of flow paths (e.g. Angelini, 1997;Larocque et al, 1998;Rahnemaei et al, 2005;Lee et al, 2006;Massei et al, 2006;Jemcov and Petric, 2009;Gárfias-Soliz et al, 2010). In their studies, when a temporary increase of water level has a long-term influence on subsequent water level, the aquifer is regarded to have a 'memory effect' (Herman et al, 2009) The concept of 'memory effect' of aquifer is thought to be similar to the second viewpoint for recharge response, which is mentioned above, time length of aquifer's holding water.…”

Climate Variability and Groundwater Response: A Case Study in Burkina Faso (West Africa)

“…The slow decrease of the correlation highlights the big inertia of the large Mouhoun catchment. Its inertia may result from the system's high storage capacity [64], which is reflected here by the predominance of the base flow in the total flow of this station (Table 4) [65]. The catchment storage capacity is described as the most important characteristic influencing the drought development and recovery [66].…”