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Groundwater resource investigations primarily involve inferring groundwater levels and recharge sources from factors such as the distributed location and range, subsurface geological structure, and flow paths of groundwater sources. This study conducted an investigation on the underground aquifer at the downstream of the Chih-Ben Creek basin, Taiwan. In addition, convenient, rapid, and accurate two-dimensional electrical resistivity tomography (ERT) was employed for evaluations. The cross-sectional ERT image indicates that the low-resistivity region in the stratum at survey line CB01 may be a groundwater deposit or fracture zone. This region can be divided into three major segments. The segment that is 0-50 m from the survey line exhibits a decreasing trend and is thus inferred to be a recharge source. Survey line CB02 can be generally divided into four layers, with the second layer containing a greater amount of groundwater. This layer is an aquifer with a depth of approximately 25-100 m below the ground surface and 75-100 m in thickness. The base of the aquifer slopes toward the east and primarily possesses a lithological composition of slate and sandstone with explicit and fractured joints. [ABSTRACT FROM AUTHOR]

The temporal and spatial distributions of precipitation are extremely uneven; so, careful management of water resources in Taiwan is crucial. The long-term overexploitation of groundwater resources poses a challenge to water resource management in Taiwan. However, assessing groundwater resources in mountainous basins is challenging due to limited information. In this study, a geographic information system (GIS) and stable base-flow (SBF) techniques were used to assess the characteristics of groundwater recharge considering the Wu River watershed in central Taiwan as a study area. First, a GIS approach was used to integrate five contributing factors: lithology, land cover/land use, lineaments, drainage, and slope. The weights of factors contributing to the groundwater recharge were obtained from aerial photos, geological maps, a land use database, and field verification. Second, the SBF was used to estimate the groundwater recharge in a mountainous basin scale. The concept of the SBF technique was to separate the base-flow from the total streamflow discharge in order to obtain a measure of groundwater recharge. The SBF technique has the advantage of integrating groundwater recharge across an entire basin without complex hydro-geologic modelling and detailed knowledge of the soil characteristics. In this study, our approach for estimating recharge provides not only an estimate of how much water becomes groundwater, but also explains the characteristics of a potential groundwater recharge zone. [ABSTRACT FROM AUTHOR]

To assess groundwater recharge, this study provided a composite method combining the recession-curve-displacement method and water-table fluctuation method. First, the initial recharge reference value was determined using the water-table fluctuation method. The corresponding groundwater discharge was then determined from the recharge reference value using the recession-curve-displacement method. Furthermore, the recession segment of the match between groundwater discharge and streamflow was computed. The recharge reference value was repeatedly adjusted to achieve a good fit with the recession segment for groundwater discharge and streamflow, thereby attaining the final groundwater recharge using the proposed method. Finally, the groundwater recharge of the Lanyang Creek basin in Taiwan was estimated as a case study. A comparison of recession-curve-displacement method and proposed composite method are presented. Estimation results show that the number of recharge events, recharge timing of these events, groundwater recharge events that satisfy recession theory, and range of transmissivity can be obtained using the proposed composite method. Comparison results demonstrate that the number of groundwater recharge events obtained with the composite method was greater than that acquired with the recession-curvedisplacement method. However, the annual recharge and seasonal recharge obtained with the recession-curve-displacement method and composite method were close. [ABSTRACT FROM AUTHOR]

Two-thirds of the total area of Taiwan is mountainous terrain, which is the main groundwater recharge source of the plains region. This study assesses groundwater recharge and exploitative potential zone in the central division of the mountain areas of Taiwan (the middle reaches of the Jhuoshuei River Basin). Basic information from remote sensing and a satellite phantom is collected to set up the basic data maps using elevation, Formosa-II images, the Normalized Difference Vegetation Index, drainage distribution, slope, aspect ratio, lineament distribution, and land cover. A geographical information system is used to integrate five contributing factors, namely lithology, land cover/land use, drainage, slope, and lineaments. The criteria for the recharge potential assessment are established to demarcate the potential groundwater recharge zone. Finally, the GOD rating system is adopted to evaluate the potential exploitation zone. Three main parameters are considered: the groundwater occurrence, the lithology of the overlying layers, and the depth to groundwater. The results show that the middle reaches of the Chenyuland River have large potential exploitation zones due to its high rainfall recharge capacity. Regions west of the Jhuoshuei River and the downstream regions of the Chingshui River are medium potential exploitation zones because of their high infiltration rates and shallow groundwater levels. [ABSTRACT FROM AUTHOR]

Rollable photonic devices that can adapt to freeform surfaces with reduced dimensions while maintaining their original functionalities are highly desirable. Among photonic devices, metamaterials with hyperbolic dispersion in momentum space, defined as hyperbolic metamaterial (HMM), possess a large photonic density of states that has been proven to boost light-matter interaction. However, these devices are mainly developed on rigid substrates, restricting their functionalities. Here, we present the attempt to integrate flexible and rollable HMMs consisting of polymer and metal multilayers on paper substrate. Quite interestingly, this design enables to exhibit high photonic density of states and scattering efficiency to enhance stimulated emission and induce pronounced laser action. The flexible and rollable HMM structure remains well its functionalities on freeform surfaces with curvature radius of 1 mm, and can withstand repeated bending without performance degradation. The intensity of laser action is enhanced by 3.5 times as compared to the flat surface. We anticipate that this flexible and rollable HMM structure can serve as a diverse platform for flexible photonic technologies, such as light-emitting devices, wearable optoelectronics, and optical communication. [ABSTRACT FROM AUTHOR]