Porous Medium Typology Influence on the Scaling Laws of Confined Aquifer Characteristic Parameters

An accurate measurement campaign, carried out on a confined porous aquifer, expressly reproduced in laboratory, allowed the determining of hydraulic conductivity values by performing a series of slug tests. This was done for four porous medium configurations with different granulometric compositions. At the scale considered, intermediate between those of the laboratory and the field, the scalar behaviors of the hydraulic conductivity and the effective porosity was verified, determining the respective scaling laws. Moreover, assuming the effective porosity as scale parameter, the scaling laws of the hydraulic conductivity were determined for the different injection volumes of the slug test, determining a new relationship, valid for coarse-grained porous media. The results obtained allow the influence that the differences among the characteristics of the porous media considered exerted on the scaling laws obtained to be highlighted. Finally, a comparison was made with the results obtained in a previous investigation carried out at the field scale.

Analysis And Modelling Of Geoelectric Data Modeling For The Identication Of Groundwater aquifer At Cisarua Area, West Bandung

Groundwater is the main need of society in everyday life. Groundwater is one of renewable resources but it doesn’t mean that it can be exploitated without limit. Several factors that affect the availability of groundwater derived from nature such as geological conditions, rainfall, and green areas should be considered. Water in the soil is stored in a porous layer and has a good permeability is called an aquifer. Cisarua area is located in West Bandung regency, West Java which is a hilly area that has a topography with a slope ranging from normal to steep. The land use in this area is still dominated with plantation and forest as green area. Groundwater aquifer characteristics in that area needs to be examined and analysed for the needs of the community and agricultural business. In this research, the writer used inversion modeling technique of geoelectric data to visualize the condition of subsurface. Resistivity inversion modelling of apparent resistivity data as a result of resistivity method with Wenner-Schlumberger configuration is then carried out with least-square method. The initial model is modified in an iterative manner such that the sum of square error of the difference between the model response and the observed data values is minimized. The result of resistivity modelling is used for analysis of aquifer characteristic such as lithology, depth and structure along with considering geological reference. As the result of modelling, the area of measurement is divided into three zones which are Zone of aeration, Zone of Saturation, and endapan formasi. Zone of aeration is located at depth 0-25 m with resistivity 20-100 Ohm.m and the predicted lithology is gravel or weathered soil. Zone of Saturation (akuifer) is located at depth 25-60 m with resistivity 4-30 Ohm.m and the predicted lithology is sandstone or clay. Endapan Formasi Cibereum is located at more than 60 m from ground with resistivity more than 100 Ohm.m and the predicted lithology is sandy tuff or dry breccia.

KAJIAN RESPON DEBIT MATAAIR NGELENG TERHADAP CURAH HUJAN UNTUK KARAKTERISASI AKUIFER KARST

Karst aquifer system has heterogeneous – anisotropic characteristic. The uniqueness of karstaquifer gives different evaluation process and understanding of karst aquifer characteristic. The aims ofthis research are: (1) to understand the correlation pattern between recharge from the rainfall andspring discharge temporally; (2) to analyze spring flow components that are related with response ofdischarge from rainfall to determine the characteristic of Ngeleng Spring karst aquifer. Evaluationprocesses was carried out using hydrograph recession analysis and discharge – recharge correlationapproach is used to understand the character of aquifer system in study. This research used time seriesdata. Discharge – recharge correlation show quick response which rising discharge about 2-hours timelag after rainfall. The quick response shows that there are rapid flow components (conduit and fissure).The recession analysis also shows there are 3 flow components supply the spring flow, that are diffuse,fissure and conduit.