The importance of monitoring for the determination of aquifer vulnerability and spring protection areas

Spring water resources are an irreplaceable source of drinking water supply and therefore must be adequately protected in terms of quality and quantity. The assessment of an aquifer’s vulnerability to pollution is the key stage for the sizing of protection areas. The information regarding the type of aquifer and its behavior is rather poor and, with the exception of data related to geological surveys, few hydrogeological data are available (aquifer tests, geological surveys, etc….). A suitable method to analyze the behavior of an aquifer is to monitor the three parameters of spring water: flow rate, temperature and electric conductivity. The temporal variations of these parameters, especially during major infiltrative events, allow us to acquire basic data to assess the aquifer’s vulnerability. This paper describes the hydrogeological situation and the monitoring data of 12 springs fed by different types of aquifers (karstic, fractured and porous), equipped with automatic data loggers that measure flow rate, temperature and electric conductivity. For each spring the vulnerability of the aquifer was evaluated through a detailed hydrogeological study (monitoring data, site surveys, chemical analysis of water, tracer tests). Next, using the monitoring data the vulnerability index to pollution was calculated using the half-life time and the VESPA methods. The overall results of the study have been compared in order to highlight the main issues raised by the different methods used

Estimation of spatio-temporal recharge of aquifers in mountainous karst terrains: Application to Sierra de las Nieves (Spain)

We describe a method for estimating the daily, spatially distributed recharge of aquifers in mountainous karst terrains using a water balance. Water recharge into an aquifer is a highly variable process over both time and space. Many methods have been developed to assess aquifer recharge although most have been applied to detrital aquifers. Many karst aquifers, especially in Mediterranean areas, occur in mountainous environments where rainfall and evapotranspiration can vary considerably over space and time and where there are usually few rainfall and temperature monitoring stations. We have used an advanced geostatistical method to estimate daily rainfall and temperature. The method involves kriging with an external drift using a climatological semi-variogram model inferred by modified maximum-likelihood. The depth of the soil-epikarst layer is estimated from remote sensing and terrain analysis data together with field observations and electrical resistivity tomography. Because of the karst nature of the mountainous terrain, concentrated infiltration is allowed for in some places. The parameters are calibrated against the cumulative discharge of various springs. The method is illustrated by a case study of the Sierra de las Nieves aquifer in the mountainous karst region of southern Spain. © 2012 Elsevier B.V.E. Pardo-Igúzquiza, J.J. Durán-Valsero, P.A. Dowd, C. Guardiola-Albert, C. Liñan-Baena, P.A. Robledo-Ardil

The challenge of tunneling through Mediterranean karst aquifers: the case study of Trieste (Italy)

After the 1st May 2004, when new countries joined the European Union, the need was felt to link these states through an infrastructure network of motorway and railway link (high speed—HS/high capacity—HC) easily able to transport all possible goods throughout Europe. Within this framework, 14 different projects were developed with the aim of linking important cities. One of these link is the Corridor V connecting Lisbon (Portugal) to Kiev (Ukraine) and assigning a strategic role to Italy with respect to the integration process of these countries. In detail, part of the Corridor V is expected to start from Venice, reaching Trieste and from here on to Ljubljana (Slovenia) before proceeding to Budapest and finally reaching Kiev in Ukraine. The whole development (from Portugal to Ukraine) is approximately 4,000 km long of which, about 30 km (less than 1 % of the entire route), falls within the Italian Classical Karst area, a highly karstified zone, renowned worldwide as one of the best karst landscapes on the planet. The present paper regards the GIS statistical methodological approach used to identify the degree of karstification of the Italian Classical Karst providing the stakeholders all the necessary information while planning possible railway HS/HC solutions