Interaction of aquifer–wetland in a zone of intensive agriculture: the case of Campo de Dalías (Almería, SE Spain)

Abstract

Artículo de publicación ISIThe Campo de Dalı´as (Almerı´a, south-eastern Spain) was the backdrop for the development of intensive agricultural activity during the 1970s. Due to the poor natural soil development, the agriculturalists opted for a system that involved quarrying silt and clay deposits that could be used as soil in the greenhouses. In parallel, poor water quality in the upper aquifer caused the gradual abandonment of boreholes and a generalised rise in piezometric levels. These factors have favoured the formation of a series of artificial wetlands in the abandoned clay pits (Onayar, Cabriles and Balsa del Sapo (‘‘Toad Pond’’) being the most significant). In Balsa del Sapo, the water column rose 3.5 m between October 2007 and February 2011. There has been a continuous fall in the electrical conductivity of the surface water, which has gone from 14,500 lS cm-1 in 2004 to 4,100 lS cm-1 in 2013. The most recent concentrations are close to those found in the groundwater. The same situation is detected for Cl, SO4 and Na ion concentrations in the surface and groundwater. These data show the groundwater–surface water interaction in the Balsa del Sapo. Nevertheless, the sharp rise in surface water level has created a flood hazard (due to the shallow topography of the area), both for people living in the vicinity and their property. This is an endorheic zone where a number of ramblas (gullies) draining the southern face of the Sierra de Ga´dor mountains converge. The Campo de Dalı´as is a spectacular example of the changes that can occur in a semiarid agricultural area as a result of intensive groundwater abstraction. These changes are directly related to the management of water resources, the most recent consequence of which is the increased risk of flooding. Hence, there is a need to consider the management of these water resources to achieve a more sustainable use, which is compatible with the environmental protection of the wetland and which will give some guarantee of flood protection for people and property.Water Resources and Environmental Geology Research Group (RNM-189) and Junta de Andalucia (Andalusian Regional Government) with the contribution of project P11-RNM-811

Groundwater Sustainability Strategies in the Sierra de Gador-Campo de Dalias System, Southeast Spain

“…The reason for this anomalous behavior lies in the suspension of groundwater extraction in the detritic aquifer as a result of the water salinization due to the irrigation return flows from the greenhouse area. These are saline waters rich in nitrates with an average conductivity of 4 mS/cm [42,43]. However, the original formation of this human-made wetland would also be linked to the irrigation return flow of pumping water from the lower carbonate aquifer, which is heavily overexploited and displays levels clearly in decline.…”

Current uses of ground penetrating radar in groundwater-dependent ecosystems research

“…The occurrence of most GDE is the result of a favourable combination of regional lithology and tectonics (Howard and Merrifield, 2010;Salvador et al, 2011;Shapouri et al, 2015), and local topography and hydrology (Henry and Fisher, 2003;Hancock et al, 2005;Howard and Merrifield, 2010;Silva et al, 2012;, as well as certain human-induced actions (Molina-Sánchez et al, 2015). Most GDE appear in extensive aquifer areas having favourable hydrogeological conditions for shallow groundwater (Hardie and Davies, 2007;Silva et al, 2012;Margat and van der Gun, 2013;Adams et al, 2015;Félix et al, 2015).…”

“…26% of the total case studies ( Fig. 7b; Table 4) such as (1) water extraction (RI3a) diminishing groundwater transference to natural systems (Endres et al, 2000;Tsoflias et al, 2001;Bevan et al, 2003); (2) point pollution (RI3b) focused mainly on monitoring contamination plumes (Corbeanu et al, 2002;Conant et al, 2004;Talley et al, 2005;Tsoflias and Becker, 2008); (3) civil works (RI3c) modifying groundwater flow of natural courses (Słowik, 2013); (4) agricultural practices (RI3d) altering aquifer recharge rates and mechanisms (Lunt et al, 2005;Lambot et al, 2008); and (5) mining and quarrying practices (RI3e) changing preferential flows (Grandjean and Gourry, 1996) and generating new GDE (Molina-Sánchez et al, 2015). Despite that shallow groundwater propitiated the existence of GDE in most of the case studies, only one study expressly addressed GDE research (Zurek et al, 2015).…”

“…Most GDE appear in geological environments favouring shallow groundwater such as coastal fluvial (Hardie and Davies, 2007), estuarine (Silva et al, 2012), lacustrine (Félix et al, 2015), inland alluvial (Hardie and Davies, 2007), proglacial moraines (Langston et al, 2011), sand dunes (Adams et al, 2015), oases in drylands (Margat and van der Gun, 2013), high-permeability carbonates (Shapouri et al, 2015), weathered and fissured siliciclastics (Howard and Merrifield, 2010), and crystalline formations (Salvador et al, 2011). Some GDE are the result of local hydraulics favouring shallow groundwater (Salvador et al, 2011) such as the presence of salinity interfaces in the freshwater discharge area of flat coastal aquifers (Hancock et al, 2005;Silva et al, 2012), alpine taluses favouring shallow groundwater drainage (Muir et al, 2011), clay-rich sediments in unsaturated (Howard and Merrifield, 2010) and hyporheic (Henry and Fisher, 2003) zones that favour the water table raising during infiltration events, and human-induced lagoons due to quarries reaching the saturated zone (Molina-Sánchez et al, 2015). Despite this experience, GDE research is still in an early phase which may lead to unsuitable management policies (Kløve et al, 2014) with environmental implications affecting the economy and social habits of the population .…”

Short-Term Effects of Changing Soil Management Practices on Soil Quality Indicators and Crop Yields in Greenhouses

“…The province of Almeria (SE Spain), with 31,034 ha, has the highest concentration of greenhouses, most of which are low or medium cost structures with plastic covers [2,3], dedicated to the cultivation of horticultural species. Conventional greenhouse management practices are characterized, in most cases, by the excessive use of agrochemicals and irrigation water [4,5], which, along with the absence of organic inputs or tillage, tends to make the soil lose quality in the long term [6][7][8][9] and has caused a series of environmental problems associated with nitrate leaching [10,11] or with the accumulation of a huge amount of crop residues at the end of the cropping season [12]. These problems, coupled with the current situation of the instability of prices perceived by the farmers, which sometimes do not cover production costs [1], endanger the future sustainability of the system.…”