Karst Recharge Areas Identified by Combined Application of Isotopes and Hydrogeological Budget

Abstract

The identification of recharge areas in karst aquifers allows us to perform sustainable management of these groundwater resources. Stable isotopes (δ18O and δ2H) have been largely used to provide information about recharge elevation in many mountainous regions. In this paper, an improved version of a recent “isotope-driven model”, for the identification of recharge areas, was applied to Capodacqua di Spigno Spring (south of the Latium region). The model upgrade consists of a preliminary check procedure to estimate the degree of influence of the rainfall’s isotopic variability on the spring water. This additional procedure gives us an indication of the reliability of the model and its applicability conditions. Moreover, the dataset of the spring was updated to analyze the degree of reliability of the isotope-driven model. The purpose of this study was to combine the previously mentioned isotope-driven model with hydrogeological tools. A quantitative study of the basin, based on the estimation of the average monthly infiltration volume, was performed by using the inverse hydrogeological water budget. In this way, the qualitative model for the recharge areas’ estimation was validated by a quantitative hydrogeological tool. Both models show that, for karst mountain basins, the recharge areas decrease as the average recharge elevations increase, including areas at high altitudes.

Groundwater recharge distribution due to snow cover in shortage conditions (2019–22) on the Gran Sasso carbonate aquifer (Central Italy)

“…In fact, many of the main springs may have been fed by not only rainfall but also by snow melt coming from the Campo Imperatore plain (Lorenzi et al 2022;Scozzafava and Tallini 2001;Amoruso et al 2014), with an estimation of about 75% of precipitation feeding the aquifer by infiltration. In this scenario, stable water isotopes are useful to understand and delineate the catchment area of the main springs (Barbieri et al 2005;Sappa et al 2018;Rusjan et al 2019;Iacurto et al 2021). Monitoring changes in stable isotopes over time and space can provide a better understanding of aquifer recharge and spring discharge links, which are critical to the study of groundwater hydrodynamics (Barbieri et al 2005).…”

Uloga nagiba padina, gustoće vrtača i analize vodne bilance u izdvajanju kompleksnog slivnog područja rijeke Slunjčice (Hrvatska)

“…The acquisition of these data typically requires a multidisciplinary study approach that includes using more specialized investigation methods to estimate the recharge or contributing areas of karst springs (Ginsberg & Palmer, 2002). Recent research also showed that if hydrogeological context in karst area wants to be fully understood, it is necessary to control hydrological factors which affect its water budget (Gil-Márquez et al, 2021), while the identification of recharge areas of karst aquifers can enable sustainable management of groundwater resources (Iacurto et al, 2021). It was shown that inclusion of different tracers in monitoring can greatly reduce ambiguity of interpretation, but also that complete certainty in hydrogeology research of karst aquifers is still very hard to achieve (Stroj et al, 2020).…”

Groundwater recharge distribution due to snow cover in shortage conditions (2019-22) on the Gran Sasso carbonate aquifer (Central Italy)

“…Infact, many of the main springs may have been fed by not only rainfall, but also by snow melting coming from the Campo Imperatore plain (Lorenzi et al, 2022;Scozzafava and Tallini, 2001;Amoruso et al, 2014), with an estimation of about 75% of precipitation feeding the aquifer by in ltration. In this scenario, stable water isotopes are useful to understand and delineate the catchment area of the main springs (Barbieri et al, 2005;Sappa et al, 2018;Rusjan et al, 2019;Iacurto et al, 2021). Monitoring changes in stable isotopes over time and space can provide a better understanding of aquifer recharge and spring discharge links, which are critical to the study of groundwater hydrodynamics (Barbieri et al, 2005).…”

“…The stable isotopes such as δ 2 H and δ 18 O, acting as conservative tracers (Calligaris et al, 2018;Iacurto et al, 2021), play a key role in the karstic aquifer. In fact, the isotopic concentration of the rainwater impacting the soil is strictly linked to the falling altitude (Giustini et al, 2016).…”