[en] Full-text: Slope failures, landslide and settlement of foundation (subsidence) typically do not occur spontaneously. There is a scientific reason for each failure and usually failures do not occur without warning if such sensitive areas are well monitored. It is well known that water is one of the major factors in slope instability that can act to soften the soils and allows the slope failure or foundation to settle. This paper deals with the results obtained from geophysical and isotope hydrology techniques, with the aim on improving the hydrological conceptual model of a landslide-risked site, focusing on the hydraulic connection between water bodies. The increasing interest in using geophysical techniques in hydrogeological studies is because the ability of geophysics to provide spatially distributed models of physical properties in areas that are difficult to sample using conventional hydrological sampling methods. Information gathered from geophysical techniques can be used to differentiate and characterise lithological units and, in some cases, related hydrological properties and processes. The results of geophysical techniques are supported by the isotopic signature which may give a direct insight into the origin and distribution process within the hydrological system. Isotopic measurement was performed on water samples collected from rainwater, river water, stream water, groundwater and tap water. Environmental stable isotopes of water (¹⁸O, ²H) are primarily used in isotope hydrology to identify water bodies of different origins and determine the hydraulic connection between these water bodies. The results from geophysical techniques lead to a hypothesis of a two-layer stratigraphic model which may exhibit different hydrological systems, whereas the results from isotope technique indicated that there is no relation between the groundwater and the tap water. Based on this finding, it could be reasonably assumed that the contribution of flow pathway from a suspected broken water pipeline can be neglected. (author)

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[en] The direct CO₂ absorption method is a fast and economical sample preparation compared to benzene synthesis for ¹⁴C dating in hydrological study. This paper explains sequentially the CO₂ extraction and absorption process using the setup line unit that was recently assembled in the Environmental Tracer Application Group (e-TAG) laboratory. The setup line unit comprises of two main sections, the CO₂ extraction unit and the CO₂ absorption unit. The CO₂ extraction unit comprises of three sub-sections, reaction unit, moisture trap unit and CO₂ storage unit. The CO₂ absorption unit includes three sub-sections, CO₂ storage, flow control and the absorption units. A vacuum pump unit is directly attached to the setup line to generate the required vacuum condition for the process (author)

[en] Environmental tritium (³H) is a powerful tracer of groundwater age, and is a key tracer of groundwater movement. ³H concentrations in precipitation have exponentially declined over the past decades as the anthropogenic bomb ³H peak has all but disappeared. Today, the environmental ³H concentrations are close to natural levels of cosmic production. The current ultra-low levels therefore pose a problem for the measurement of low level ³H concentrations in natural water samples using ³H enrichment units of the past, which mostly were built for enrichment of 250 - 500 mL water samples. Therefore, a new tritium enrichment unit called as New Tritium Enrichment System (NTES) had been developed that can enrich up to 2 L of water to concentrate current levels of ³H, leading to more precise ³H analysis for hydrological applications. This paper will explained the step how to measured environmental ³H using enrichment procedure. This technique involved five steps which is primary distillation, electrolysis, neutralization, final distillation and counting. (author)