TY - JOUR A1 - Wang, Wei-shi A1 - Oswald, Sascha A1 - Gräff, Thomas A1 - Lensing, Hermann Josef A1 - Liu, Tie A1 - Strasser, Daniel A1 - Munz, Matthias T1 - Impact of river reconstruction on groundwater flow during bank filtration assessed by transient three-dimensional modelling of flow and heat transport JF - Hydrogeology journal : official journal of the International Association of Hydrogeologists N2 - Bank filtration (BF) is an established indirect water-treatment technology. The quality of water gained via BF depends on the subsurface capture zone, the mixing ratio (river water versus ambient groundwater), spatial and temporal distribution of subsurface travel times, and subsurface temperature patterns. Surface-water infiltration into the adjacent aquifer is determined by the local hydraulic gradient and riverbed permeability, which could be altered by natural clogging, scouring and artificial decolmation processes. The seasonal behaviour of a BF system in Germany, and its development during and about 6 months after decolmation (canal reconstruction), was observed with a long-term monitoring programme. To quantify the spatial and temporal variation in the BF system, a transient flow and heat transport model was implemented and two model scenarios, 'with' and 'without' canal reconstruction, were generated. Overall, the simulated water heads and temperatures matched those observed. Increased hydraulic connection between the canal and aquifer caused by the canal reconstruction led to an increase of similar to 23% in the already high share of BF water abstracted by the nearby waterworks. Subsurface travel-time distribution substantially shifted towards shorter travel times. Flow paths with travel times <200 days increased by similar to 10% and those with <300 days by 15%. Generally, the periodic temperature signal, and the summer and winter temperature extrema, increased and penetrated deeper into the aquifer. The joint hydrological and thermal effects caused by the canal reconstruction might increase the potential of biodegradable compounds to further penetrate into the aquifer, also by potentially affecting the redox zonation in the aquifer. KW - bank filtration KW - groundwater KW - surface-water relations KW - groundwater modelling Y1 - 2019 U6 - https://doi.org/10.1007/s10040-019-02063-3 SN - 1431-2174 SN - 1435-0157 VL - 28 IS - 2 SP - 723 EP - 743 PB - Springer CY - Berlin ; Heidelberg [u.a.] ER - TY - JOUR A1 - Sen, Jaydip A1 - Bogin, Barry A1 - Mondal, Nitish A1 - Dey, Sima A1 - Roy, Shreysai ED - Scheffler, Christiane ED - Koziel, Slawomir ED - Hermanussen, Michael ED - Bogin, Barry T1 - Groundwater arsenic contamination in the Bengal Delta Plain is an important public health issue BT - a review T2 - Human Biology and Public Health N2 - There is a close association between human biology, epidemiology and public health. Exposure to toxic elements is one area of such associations and global concerns. The Bengal Delta Plain (BDP) is a region where contamination of ground water by arsenic has assumed epidemic proportions. Apart from dermatological manifestations, chronic exposure to arsenic causes a heavy toll through several carcinogenic and non-carcinogenic disorders. This article provides a global overview of groundwater arsenic contamination in the BDP region, especially the sources, speciation, and mobility of arsenic, and critically reviews the effects of arsenic on human health. The present review also provides a summary of comprehensive knowledge on various measures required for mitigation and social consequences of the problem of arsenic contaminated groundwater in the BDP region. KW - public health KW - arsenic KW - groundwater KW - India KW - Bangladesh KW - Bengal Delta Y1 - 2021 U6 - https://doi.org/10.52905/hbph.v1.7 SN - 2748-9957 VL - 2021 IS - 1 SP - 1 EP - 31 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Nguyen Le Duy, A1 - Nguyen Viet Du, A1 - Heidbüchel, Ingo A1 - Meyer, Hanno A1 - Weiler, Markus A1 - Merz, Bruno A1 - Apel, Heiko T1 - Identification of groundwater mean transit times of precipitation and riverbank infiltration by two-component lumped parameter models JF - Hydrological processes N2 - Groundwater transit time is an essential hydrologic metric for groundwater resources management. However, especially in tropical environments, studies on the transit time distribution (TTD) of groundwater infiltration and its corresponding mean transit time (mTT) have been extremely limited due to data sparsity. In this study, we primarily use stable isotopes to examine the TTDs and their mTTs of both vertical and horizontal infiltration at a riverbank infiltration area in the Vietnamese Mekong Delta (VMD), representative of the tropical climate in Asian monsoon regions. Precipitation, river water, groundwater, and local ponding surface water were sampled for 3 to 9 years and analysed for stable isotopes (delta O-18 and delta H-2), providing a unique data set of stable isotope records for a tropical region. We quantified the contribution that the two sources contributed to the local shallow groundwater by a novel concept of two-component lumped parameter models (LPMs) that are solved using delta O-18 records. The study illustrates that two-component LPMs, in conjunction with hydrological and isotopic measurements, are able to identify subsurface flow conditions and water mixing at riverbank infiltration systems. However, the predictive skill and the reliability of the models decrease for locations farther from the river, where recharge by precipitation dominates, and a low-permeable aquitard layer above the highly permeable aquifer is present. This specific setting impairs the identifiability of model parameters. For river infiltration, short mTTs (<40 weeks) were determined for sites closer to the river (<200 m), whereas for the precipitation infiltration, the mTTs were longer (>80 weeks) and independent of the distance to the river. The results not only enhance the understanding of the groundwater recharge dynamics in the VMD but also suggest that the highly complex mechanisms of surface-groundwater interaction can be conceptualized by exploiting two-component LPMs in general. The model concept could thus be a powerful tool for better understanding both the hydrological functioning of mixing processes and the movement of different water components in riverbank infiltration systems. KW - bank infiltration KW - groundwater KW - lumped parameter model KW - mean transit time KW - Mekong Delta KW - stable isotopes Y1 - 2019 U6 - https://doi.org/10.1002/hyp.13549 SN - 0885-6087 SN - 1099-1085 VL - 33 IS - 24 SP - 3098 EP - 3118 PB - Wiley CY - Hoboken ER -