ALBERT

Description: 〈p〉Hard rocks, including crystalline igneous, metamorphic and strongly cemented sedimentary and carbonate rocks cover about 50% of the earth's land surface (〈i〉Singhal and Gupta, 2010〈/i〉). Globally, the volume of groundwater contained in hard rock aquifers is not well constrained (〈i〉Comte et al., 2012〈/i〉), but locally they can be important aquifers (〈i〉MacDonald et al., 2012〈/i〉), albeit with low groundwater storage and poor primary porosity and permeability. Groundwater flow in these hard rocks is commonly observed to be associated with water bearing discontinuities, such as fractures, joints and faults (〈i〉Berkowitz, 2002; Mazurek, 2000; Font-Capo et al., 2012〈/i〉) and in the weathered regolith (〈i〉Wright 1992, Chilton and Foster 1995; Deyassa et al., 2014)〈/i〉. Structural elements such as fault zones also strongly govern the behaviour of these systems (〈i〉Forster and Evans, 1991; Lopez and Smith, 1995, Bense et al., 2013〈/i〉). The nature, abundance, orientation and connectivity of these water-bearing features are largely governed by the history and nature of structural deformation of the bedrock and commonly impose strong anisotropic flow and transport parameters on these bedrock aquifers (〈i〉Hsieh et al., 1985; Bour and Davy, 1997; Mortimer et al., 2011〈/i〉). Weathering processes furthermore lead to an alteration of bedrock composition and associated aquifer properties resulting in enhanced fracture connectivity and an overall vertical stratification/zonation of bulk aquifer properties, ranging from highly altered shallow regolith horizons to more competent sparsely fractured bedrock at depth (〈i〉Dewandel et al., 2006; Krasny and Sharp, 2007; Lachassagne et al., 2011〈/i〉).〈/p〉 〈p〉〈b〉...〈/b〉〈/p〉 〈p〉〈i〉This 250-word extract was created in the absence of an abstract.〈/i〉〈/p〉