Recent EU legislation is directed to reverse the upward trends in the concentrations of agricultural pollutants in groundwater. However, uncertainty of the groundwater travel time towards the screens of the groundwater quality monitoring networks complicates the demonstration of trend reversal. We investigated whether trend reversal can be demonstrated by relating concentrations of pollutants i...

At the European scale, nitrate concentration is the most important parameter that determines groundwater quality. Since in most cases nitrate input into the aquifer is a non-point source pollution problem, measures to reduce nitrate leaching have to be designed on the aquifer scale. In this context we have coupled the unsaturated, vertical soil water and nitrogen transport model SIMWASER/STOTRA...

[1] The water table in southwestern Niger has been rising continuously for the past decades (4 m rise from 1963 to 2007), despite a 23% deficit in monsoonal rainfall from 1970 to 1998. This paradoxical phenomenon has been linked with a change in land use from natural savannah to millet crops that have expanded in area sixfold since 1950 and have caused soil crusting on slopes that has, in turn,...

[1] Unsaturated zone salt reservoirs are potentially mobilized by increased groundwater recharge as semiarid lands are cultivated. This study explores the amounts of pore water sulfate and fluoride relative to chloride in unsaturated zone profiles, evaluates their sources, estimates mobilization due to past land use change, and assesses the impacts on groundwater quality. Inventories of water-e...

In semiarid climates, a significant component of recharge to basin aquifers occurs along the mountain front. Traditionally called “mountain-front recharge” (MFR), this process has been treated by modelers of basins as a boundary condition. In general, mountain-front recharge estimates are based on the general precipitation characteristics of the mountain (as estimated, e.g., by the chloride mas...

Groundwater has a strategic role in times of climate change mainly because aquifers can provide water for long periods, even during very long and severe drought. The reduction and/or changes on the precipitation pattern can diminish the recharge mainly in unconfined aquifer, causing available groundwater restriction. The expected impact of long-term climate changes on the Brazilian aquifers for...

Precipitation that falls in a watershed undergoes three hydrological processes: evapotranspiration, groundwater recharge, and river runoff. Using the long-term average stream discharge of a watershed, one can estimate the long-term average evapotranspiration portion of the precipitation by using the precipitation minus the normalized river discharge. In addition, by partitioning the stream disc...

Abstract The Pimpama coastal plain is situated in southern Moreton Bay, in subtropical eastern Australia. The plain is low lying and tidal and is situated behind a large sand barrier island. Largely due to recent (30 years) drainage networks within the flood plain, surface water quality has declined. Groundwater hydrographs have enabled the determination of different flow systems: a deeper syst...

Mean annual recharge in the Danube-Tisza sand plateau region of Hungary over the 2000–2008 period was estimated at a 1-km spatial resolution as the difference of mean annual precipitation (P) and evapotranspiration (ET). The ET rates were derived from linear transformations of the MODIS daytime land surface temperature (Ts) values with the help of ancillary atmospheric data (air temperature, hu...

Arsenic is a contaminant in the groundwater of Holocene aquifers in Bangladesh, where approximately 57 million people drink water with arsenic levels exceeding the limits set by the World Health Organization. Although arsenic is native to the sediments, the means by which it is released to groundwater remains unresolved. Contrary to the current paradigm, ferric (hydr)oxides appear to dominate t...