Areal exploitation of groundwater in coastal dunes

CARRETERO SILVINA, KRUSE EDUARDO

Oslo. Noruega

Congreso; 33rd International Geological Congress.; 2008

In the study area, the groundwater of low salinity is restricted to the fringe the onlydrinking water source for a permanent population that is superior summer, the regionpresents a tourist high which multiplies de population by In this paper the currentgroundwater exploitation is described and future management evaluated in front of thenecessary increase in water demand.The coastal dunes have a morphological expression between 0.5 to 3.5 m.a.limited by seawater and brackish continental water. To avoid the salt water exploitation is carried out.There is a pumping field, located outside of the urbanized by 7 horizontal wells, Ranneytype, (flow 7 m3/h) and for 21 well point systems, to 10 wells (flow 13 m3/h).Theextraction depth varies between 4 m & 6 m.The system recharge only takes place from the precipitations (1000 mm/year), dischargeis by the evapotranspiration (640 mm/year), with hydric excesses current situation adirect relationship between the precipitations and the variations level is observed.That is evidenced for a quick answer before the recharge from the excesses Theextraction flows have a maximum value in January and February (1200 with the touristbiggest affluence. In the minimum extraction period, between (300 m3/day) a recovery ofgroundwater levels is manifested while they are summer months with the increaseddemand. Given the methodology of exploitation deepen below 0 m.a.s.l. oscillatingbetween 0.7 and 3.1 m.a.s.l.The extracted flows are in the range of the regulating reserves and therefore modificationof the natural water cycle. It is necessary to increase the drinking the needs of a biggernumber of inhabitants. The management pattern should new exploitation areas includinga detailed water input and output quantification system. It is also recommended an arealexploitation to scarce depth, being areas should be declared reservation areas to conservethe recharge areas contamination of the groundwater.