TY - JOUR
T1 - Groundwater salinity during 500 years of anthropogenic-driven coastline changes in the Motril-Salobreña aquifer (South East Spain)
AU - Duque, Carlos
AU - Olsen, Jonas T.
AU - Sánchez-Úbeda, Juan Pedro
AU - Calvache, María Luisa
PY - 2019/8
Y1 - 2019/8
N2 - The freshwater–saltwater interface position in groundwater at coastal aquifers is determined by the location of the coastline. Anthropogenic-driven changes as modification of the land uses in catchments or the engineering construction in rivers can alter the transport of sediments to the coastal areas affecting to the coastline shape in detrital systems. This is the case of the Motril-Salobreña aquifer where the rapid coastline progradation over the last 500 years generated new land previously covered by the sea at a fast rate, 3 m year−1 during hundreds of years. The effect of these changes in the salinity of the aquifer and the flushing time by freshwater has been examined with a paleo-hydrogeological model simulating the transient evolution of the groundwater salinity for the last 500 years with SEAWAT. The results of the model indicate a differentiated flushing time depending on the hydraulic properties in the region ranging from 50 years in the western sector to up to more than 200 years in the central sector for the shallower parts of the aquifer. In the deeper layers, the time can be highly increased but the uncertainties in the hydraulic properties generate different scenarios both in flushing time and water circulation in the aquifer. The sectors in the aquifer where changes took place at a faster rate are also the most sensitive to the effect of global changes, especially those associated to human activity as they occur at shorter time periods.
AB - The freshwater–saltwater interface position in groundwater at coastal aquifers is determined by the location of the coastline. Anthropogenic-driven changes as modification of the land uses in catchments or the engineering construction in rivers can alter the transport of sediments to the coastal areas affecting to the coastline shape in detrital systems. This is the case of the Motril-Salobreña aquifer where the rapid coastline progradation over the last 500 years generated new land previously covered by the sea at a fast rate, 3 m year−1 during hundreds of years. The effect of these changes in the salinity of the aquifer and the flushing time by freshwater has been examined with a paleo-hydrogeological model simulating the transient evolution of the groundwater salinity for the last 500 years with SEAWAT. The results of the model indicate a differentiated flushing time depending on the hydraulic properties in the region ranging from 50 years in the western sector to up to more than 200 years in the central sector for the shallower parts of the aquifer. In the deeper layers, the time can be highly increased but the uncertainties in the hydraulic properties generate different scenarios both in flushing time and water circulation in the aquifer. The sectors in the aquifer where changes took place at a faster rate are also the most sensitive to the effect of global changes, especially those associated to human activity as they occur at shorter time periods.
KW - Flushing times
KW - Groundwater numerical model
KW - Paleohydrogeological model
KW - Salinity distribution
KW - SEAWAT
UR - http://www.scopus.com/inward/record.url?scp=85069746681&partnerID=8YFLogxK
U2 - 10.1007/s12665-019-8476-9
DO - 10.1007/s12665-019-8476-9
M3 - Journal article
AN - SCOPUS:85069746681
SN - 1866-6280
VL - 78
JO - Environmental Earth Sciences
JF - Environmental Earth Sciences
IS - 15
M1 - 471
ER -