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Abstract. Soil processes are characterized by a great degree of heterogeneity, which may be assessed by scaling properties. The aims of the current study were to describe the dynamics of soil water content at three depths in a vineyard under rain-fed and irrigation conditions and to assess the multifractality of these time data series. Frequency domain reflectometry (FDR) sensors were used for automatically monitoring soil water content in a vineyard located in Leiro (Ourense, northwest Spain). Data were registered at 30 min intervals at three depths (20, 40, and 60 cm) between 14 June and 26 August 2011 and 2012. Two treatments were considered: rain-fed and irrigation to 50 % crop evapotranspiration. Soil water content data series obeyed power laws and tended to behave as multifractals. Values for entropy (D1) and correlation (D2) dimensions were lower in the series from the irrigation treatment. The Hölder exponent of order zero (α0) was similar between treatments; however, the widths of the singularity spectra, f(α), were greater under irrigation conditions. Multifractality indices slightly decreased with depth. These results suggest that singularity and Rényi spectra were useful for characterizing the time variability of soil water content, distinguishing patterns among series registered under rain-fed and irrigation treatments.

Groundwater availability, management and protection are great challenges for the sustainability of groundwater resources in the scattered rural areas of the Atlantic regions of Europe where groundwater is the only option for water supply. This report presents a hydrogeological study of the coastal granitic area of Oia in northwestern Spain, which has unique geomorphological and hydrogeological features with steep slopes favoring the erosion of the weathered granite. The hydrogeological conceptual model of the study area includes: (1) the regolith layer, which is present only in the flat summit of the mountains; (2) the slope debris and the colluvial deposits, which are present in the intermediate and lowest parts of the hillside; (3) the marine terrace; and (4) the underlying fractured granite. Groundwater recharge from rainfall infiltration varies spatially due to variations in terrain slope, geology and land use. The mean annual recharge estimated with a hydrological water balance model ranges from 75 mm in the steepest zone to 135 mm in the lowest flat areas. Groundwater flows mostly through the regolith and the detrital formations, which have the largest hydraulic conductivities. Groundwater discharges in seepage areas, springs, along the main creeks and into the sea. The conceptual hydrogeological model has been implemented in a groundwater flow model, which later has been used to select the best pumping scenario. Model results show that the future water needs for domestic and tourist water supply can be safely provided with eight pumping wells with a maximum pumping rate of 700 m3/day.

Water supply deficits in droughts, groundwater pollution and climate change are the main challenges for the sustainability of groundwater resources from hard rock aquifers in the rural areas of Galicia (Spain). Here we address the sustainability of groundwater resources of weathered and fractured schists in the rural areas of Abegondo municipality. The conceptualization of the hydrogeology of the study area includes: 1) The regolith, 2) The fractured rock layer; and 3) The underlying fresh bedrock. Groundwater flows mostly through the regolith and the fractured rock. Rainfall infiltration is the source of aquifer recharge. Groundwater discharges in seepage areas, springs and along creeks and valleys. The water table is generally shallow and shows seasonal oscillations of up to 4 m. The equivalent transmissivity ranges from 15 to 35 m2/d. Electrical resistivity tomography identifies a shallow water table and attests that the contact of the fractured rock and the fresh bedrock is highly heterogeneous. Groundwater resources were quantified with a hydrological water balance model. The mean annual recharge is approximately equal to 185 mm. Groundwater recharge at the end of the 21st century could decrease from 6% to 10% due to climate change. The decline in groundwater table could aggravate the shortages during droughts. Groundwater quality data show bacteriological and nitrate contamination due to a poor management of the manure in the fields and occasional discharges of slurry from pig and mink farms. Groundwater management and protection actions are proposed to prevent groundwater pollution and achieve a sustainable groundwater supply in the study area.