This dataset provides high-resolution porewater salinity measurements used to investigate spatial variability within subterranean estuaries (STEs) across contrasting coastal settings. Field surveys were conducted at Marine Drive beach and Siali beach along the Odisha coast, India, and at Spiekeroog Beach, Germany. Sampling campaigns were performed during the post-monsoon season (October 2024) at Marine Drive and Siali beaches, during the pre-monsoon season (March 2026) at Marine Drive beach, and in June 2025 at Spiekeroog beach. Porewater was collected from the intertidal zone at 0.5 m sediment depth using a push-point sampler following meter-scale grid-based surveys to characterize lateral variations in fresh-saline mixing. Sampling locations were mapped using QField for QGIS connected via Bluetooth to a Trimble DA2 GNSS receiver with an active Catalyst subscription, enabling high-precision positioning and simultaneous recording of spatial coordinates with field measurements. Porewater salinity, electrical conductivity, and temperature were measured in situ using a WTW multiparameter probe (Xylem Analytics Germany). The measurements capture localized freshening zones and heterogeneous mixing patterns within STEs, highlighting the spatial complexity of fresh-saline mixing. This dataset supports the evaluation of lateral variability in SGD pathways and contributes to improved understanding of the spatial heterogeneity of STEs at the beach scale.
Objective: This project is aimed at improving current methods for monitoring contaminant distribution and biodegradation in the subsurface. Currently proven methods (based on invasive sampling of soil, soil water and gaseous phase) are unable to provide sufficiently accurate data with high enough resolution. Resulting in inability to assess of bioremediation progress and quantification of the processes involved in such bioremediation at field sites. Consequently, present assessment strategies to decide on optimal remediation approach, including design of monitoring systems, and evaluation of degradation progress, are severely flawed by uncertainty. Geophysical time-lapse measurements in combination with novel ground truthing methods give the possibility to determine: absolute contamination levels, spatial spreading, and reduced concentrations of contaminants in a heterogeneous environment. Geophysical methods of data acquisition alone are presently unable to provide absolute levels of biodegradable contamination concentrations. We aim to make improvements of fundamental constitutive relations between soil physical and degradation activity parameters and geophysically measurable parameters. Despite current improvements, there is a strong need to test these theories in practical field situations. Our project is dedicated to improving both site contamination assessment and the monitoring of bioremediation processes, and changes in soil environmental conditions. We suggest combining improved conventional soil monitoring techniques with state-of-the-art geophysical approaches. Partners in the project range from microbiologists to geophysicist, all with working experience from contaminated sites. Process studies involving lysimeters, and testing of the combination of technologies at two field sites are the major aims of the project. Focus on practical field situations and strong communication with stake-holders and SMEs will ensure high relevance for society.