Transient numerical flow models were developed and calibrated in Processing MODFLOW to quantitatively examine the groundwater-surface water interaction in a floodplain hyporheic zone. Although understanding of groundwater–surface water flux exchange in a hyporheic zone is crucial for effective water management and a variety of scientific purposes, it is a difficult place to study. Our numerical modelling of Danube River and Surány aquifers interaction revealed that there was a strong relationship between the response time lag (of river level change and groundwater level change) and the distance of wells from the river; the response time between a river rise (flooding) and GW level rise increased with increasing distance from the river and vice versa. Further, there were bigger depressions due to pumping in production wells located farther away from the river as a result of decreasing recharge from the river. The water budget from the models showed that the river seepage was the biggest contributor of inflow into the aquifer with over 70% contribution. The analysis of bank filtrate demonstrated that the level of river stage influenced the length of particle travel time; higher river stages led to shorter particle travel times. For the wells closer to the Danube River, the calculated travel times were shorter and increased with wells located farther away from the river. The numerical modelling results imply a strong hydraulic and hydrogeological connection between the permanent river and the adjacent alluvial aquifer. This investigation directly contributes to the implementation of the Danube River basin-wide water resources management and Flood Risk Management Plan developed in 2015 and the European Union Floods Directive requirements. Our models may be used in advancing understanding of the groundwater-surface water hydrogeological and hydraulic connectivity processes and mechanisms in floodplain environments.

The increasing salinization of coastal areas of Bangladesh reduces options for rice intensification but offers a suitable environment for shrimp and salt farming. Under these contested land use settings, adaptation decisions to address salinity require an understanding of the salinity perspectives of all farmer types. Primary data was collected from randomly selected rice, shrimp and salt farmers in two coastal sub-districts through semi-structured interviews at household level. Also, key informant interviews (KIIs) were conducted with personnel from research and extension organisations from different levels (e.g. national and local). Salinity perceptions among the various types of farmer differed. While the majority of rice farmers (87%) perceived increased salinity, just over half of the salt and shrimp farmers perceived that salinity has decreased over the past 20 years. Most rice farmers (62%) perceived anthropogenic factors as the main cause of increased salinity, while the majority of shrimp and salt farmers focused more on natural factors. Rice farmers perceived under saline conditions a yield loss (42%), followed by less income (30%). In contrast, shrimp farmers (70%) and salt farmers (55%) perceived production gains when high salinity prevailed. Rice farmers’ adaptation preferences to cope with salinity is development of salinity-tolerant rice varieties that have greater tolerance at the reproductive stages, while shrimp and salt farmers’ preferences are engineering-based solutions. Thus, research and extension services on integrated coastal resources management need to consider all livelihood perspectives, as this approach could accelerate the pace of achieving the SDGs (i.e.. SDG-1, SDG-2 and SGD-3).