Groundwater behaviour in Madeira, volcanic island (Portugal)

Noble gases and coupled heat/fluid flow modeling for evaluating hydrogeologic conditions of volcanic island aquifers

“…While such basal groundwater conditions are often encountered (Hunt, 1996), high-altitude water tables have been documented in many volcanic island aquifer systems. Particular examples include a water-table altitude of more than 600 m measured in a research borehole drilled beneath the summit of the Kilauea volcano on the island of Hawaii (Keller et al, 1979); regional groundwater-table altitudes approaching 1200 m in the volcanic aquifer system of Madeira Island (Prada et al, 2005); and regional spring altitudes of up to 800 m in the Fautaua Basin on the flanks of a shield volcano in Tahiti (Hildenbrand et al, 2005). Groundwater studies of Hawaii (Macdonald et al, 1983;Oki et al, 1999) were the first to introduce the conceptual model of a regionally-connected high-altitude water table with stairstep water-table compartmentalization caused by low permeability vertical dikes acting as horizontal flow barriers (Fig.…”

“…Hawaii, USA 10 À6 -10 À2 Lab measurements and aquifer testing Nichols et al (1996), Table 2 All volcanics including both dike complexes and dike-free basalts Piton de la Fournaise La Réunion 10 À3 -10 À1 Aquifer testing Violette et al (1997) Basaltic lava flows Madeira Island a Portugal 10 À5 -10 À3 Aquifer testing Prada et al (2005) Main volcanic complex Gran Canaria a Canary Islands 10 À6 -10 À4 Aquifer testing Cabrera and Custodio (2004) Pyroclastic deposits, ash-flows and recent basalts (Summary of 5 islands) Hawaii, USA 10 À5 -10 À2 Aquifer testing Rotzoll and El-Kadi (2008a) Dike-free basalts Oahu…”

Cloud water interception in the temperate laurel forest of Madeira Island

“…Cloud water interception also plays an important role in Madeira's groundwater, the island's major water supply source and the only one during summer (Prada 2000, Prada et al 2005. There is evidence that groundwater is partly recharged by cloud water.…”

Contaminant transfer and hydrodispersiveparameters in basaltic lava flows: artificial tracertest and implications for long-term management

“…Laboratory experiments showed that hydraulic conductivity K may vary in a range com-prised between 10 −1 and 10 −15 m/s with some basalts presenting 10 ranges of magnitudes in the same formation [21] with strong variability on the vertical axis due to interflow spaces and horizontal fractures [22]. Consequently, groundwater pathways, storage and discharge may be very variable, as was pointed out in numerous systems such as the Golan heights in Israel [5], India [3], Reunion Island [2,23,24], Mayotte Island in the Comoros archipelago [1,12], Madeira Island [25] Galapagos Islands [8]. These systems may behave as fine grained systems with poorly variable discharge [9,26,27] associated with slow groundwater transit.…”