TY - JOUR
T1 - A hydrogeological and hydrochemical explanation of the groundwater composition under irrigated land in a Mediterranean environment, Algarve, Portugal.
AU - Stigter, T.Y
AU - Ooijen, S.P.J.
AU - Post, V.E.A.
AU - Appelo, C.A.J.
AU - Carvalho Dill, A.M.M.
PY - 1998
Y1 - 1998
N2 - In the Campina de Faro, in the south of Portugal, agricultural practices have a large impact on groundwater composition. These practices involve pumping of water for irrigation from combinations of large diameter, shallow wells (noras) and small diameter, deep boreholes (furos). Excess irrigation water returns to the aquifer and mixes with water from the regional groundwater flow system. This irrigation return flow is concentrated by strong evapotranspiration and by flushing of fertilisers. The concentration increase induces cation exchange, whereby Ca on the soil exchanger is replaced by Na. The mixing in the aquifer allows application of a mixing cell model which may then be used to calculate transmissivities from the Cl mass balance. The calculations are complicated by the time-variant behaviour of Cl and the method is adjusted to calculate the change of chloride in time. Results from the calculations appear to be in good agreement with hydrochemical observations.
AB - In the Campina de Faro, in the south of Portugal, agricultural practices have a large impact on groundwater composition. These practices involve pumping of water for irrigation from combinations of large diameter, shallow wells (noras) and small diameter, deep boreholes (furos). Excess irrigation water returns to the aquifer and mixes with water from the regional groundwater flow system. This irrigation return flow is concentrated by strong evapotranspiration and by flushing of fertilisers. The concentration increase induces cation exchange, whereby Ca on the soil exchanger is replaced by Na. The mixing in the aquifer allows application of a mixing cell model which may then be used to calculate transmissivities from the Cl mass balance. The calculations are complicated by the time-variant behaviour of Cl and the method is adjusted to calculate the change of chloride in time. Results from the calculations appear to be in good agreement with hydrochemical observations.
U2 - 10.1016/S0022-1694(98)00168-1
DO - 10.1016/S0022-1694(98)00168-1
M3 - Article
SN - 0022-1694
VL - 208
SP - 262
EP - 279
JO - Journal of Hydrology
JF - Journal of Hydrology
ER -