Assessing and Delineation of Groundwater Recharge Areas in Coastal Arid Area in Tunisia Using GIS, Remote Sensing Techniques and Self-organizing Map

In Gabès region (southeastern Tunisia), given the semi-arid to arid climate conditions, groundwater is an essential resource to supply the growth needs of the socio-economic development. To ensure sustainable development and preserve water resources, a careful estimation of the present day recharge amount and the delineation of the potential zones of rainfall precipitation are of required for an accurate evaluation of regional water balance. In this context, this study aims to a preliminary assessment of groundwater recharge in Gabes basin in regard to the delineation of the potential recharge areas of phreatic aquifers. Thus, a geological and hydrogeological collected database coupled with remote sensing techniques (RST) were used for the determination of the lateral variation of recharging zone ,Treatment by ArcGIS and Matlab softwares and Kohonen self-organizing maps (K-SOM) approaches.The obtained results indicate that five recharge potential areas have been identified and classified as 27% very low, 23% low, 40% moderate recharge, 7% good and 3 % very good potential recharge located principally on southern part of the study region .This distribution is controlled principally by the geomorphological, geologic, and hydrogeologic features of the region . Reasonable management strategies based on a perennial exploitation of these low renewable resources are required to optimize the water dependent socio-economic development. The estimated groundwater potential recharge of Gabès aquifer system using K-SOM and RST is of 11.4 Mm3.y-1. This recharging rate is very low it present 7% of the total rain, thus it must be ameliorated. K-SOM and RST approach is a useful method for groundwater potential recharge mapping and is a helpful of wells establishment and groundwater sustainable management.an isotopic analyses is recommended to ameliorate the decision maker to establish the adequate strategy.

Zoning groundwater potential recharge using remote sensing and GIS technique in the Red river delta plain

The Red River delta plain is the second largest delta in Vietnam and is located in the North of the country with an area of 14,860 km2 and residing more than 22.5 million inhabitants. Groundwater is mainly exploited in Quaternary sedimentary aquifers with a total discharge of about 3 million m3/day. Some localities have shown signs of over-exploitation such as in Hanoi and in Nam Dinh, which may lead to related problems such as depletion, subsidence, saltwater intrusion, and water pollution. In order to be able to sustainably exploit groundwater, the groundwater potential recharge needs to be estimated. There have been many studies using different methods to estimate the groundwater recharge and to zone potential recharge. In the study area, there are several studies for groundwater recharge, but some are still uncertain because of using indirect methods, some are locally estimated in specific areas. Therefore, the objective of this study is to apply remote sensing and GIS to zone the groundwater potential recharge and its verification by using radioactive isotope 3H analysis in the Red River delta plain. Various types of satellite images have been used and interpreted to detect the different thematic layers which concern the groundwater potential recharge. GIS has been applied as a platform for analysis and integration of thematic layers for zonation, finally. Field trip and water sampling for chemical and radioactive 3H analysis were also conducted. Zones with low, moderate, and high groundwater potential recharge have been delineated with good agreement from the direct estimation of groundwater recharge by radioactive isotopes 3H.

Investigation of Groundwater Potential Using Remote Sensing and Hydro-geophysical Techniques: A Case Study of the Telidjene Basin (Eastern Algeria)

The present study aims to assess groundwater potential in the Telidjene Basin located in the semi-arid part of eastern Algeria, applying an innovative approach combining both remote sensing and hydrogeophysics methods. A re-interpretation of geophysical data and vertical electrical sounding (VES) measurements were applied and calibrated with the borehole data to map the deep structures that may control the presence of groundwater and identify the geological and hydrogeological setting. Morphometric factors affecting recharge were mapped using several types of remote sensing data (SRTM DEM, Landsat-8). Thematic maps were overlaid using the multicriteria method and GIS to detect potential recharge areas. The results show that the main factors influencing recharge are fracturing and drainage density. Four potential recharge areas were identified over a 547 km2 area of the basin. 20% of the area falls in the weakest class, 32% in the weak class, 3% in the moderate, and 16% in the strongest. Furthermore, the study reveals that an alluvial aquifer with a thickness of up to 60m, spreading over the surface, along the Wadi Telijene and the alluvial soil, is deposited unconformably on Cretaceous terrain containing aquifer horizons of varying thickness and different electrical resistivities (10–150 Ωm), drawing an anticlinal structure with lithostratigraphy interrupted by a series of faults and spurs of Aptian and Triassic age. The south-western part of the basin has a high to moderate recharge and storage capacity. Its alluvial cover is directly fed by precipitation and fractured limestones deposited in a syncline outcropping on the edges forming an alluvial and carbonate bilayer aquifer. This study concluded that an integrated approach, involving recent, efficient, and inexpensive technology, such as remote sensing and conventional geophysical method, can be successfully used to identify groundwater potential in the study area.

Identification of Groundwater Potential Recharge Zones in Flinders Ranges, South Australia Using Remote Sensing, GIS, and MIF Techniques

In Australia, water resource management is a major environmental, biological, and socio-economic issue, and will be an essential component of future development. The Hawker Area of the central Flinders Ranges, South Australia suffers from a lack of reliable data to help with water resource management and decision making. The present study aimed to delineate and assess groundwater recharge potential (GWRP) zones using an integration between the remote sensing (RS), geographic information system (GIS), and multi-influencing factors (MIF) approaches in the Hawker Area of the Flinders Ranges, South Australia. Many thematic layers such as lithology, drainage density, slope, and lineament density were established in a GIS environment for the purpose of identifying groundwater recharge potential zones. A knowledge base ranking from 1 to 5 was assigned to each individual thematic layer and its categories, depending on each layer’s importance to groundwater recharge potential zones. All of the thematic layers were integrated to create a combined groundwater potential map of the study area using weighting analysis in ArcGIS software. The groundwater potential zones were categorized into three classes, good, moderate, and low. The resulting zones were verified using available water data and showed a relative consistency with the interpretations. The findings of this study indicated that the most effective groundwater potential recharge zones are located where the lineament density is high, the drainage density is low, and the slope is gentle. The least effective areas for groundwater recharge are underlain by shale and siltstone. The results indicated that there were interrelationships between the groundwater recharge potential factors and the general hydrology characteristics scores of the catchment. MIF analysis using GIS mapping techniques proved to be a very useful tool in the evaluation of hydrogeological systems and could enable decision makers to evaluate, better manage, and protect a hydrogeological system using a single platform.

Distributed groundwater recharge potentials assessment based on GIS model and its dynamics in the crystalline rocks of South India

Extensive change in land use, climate, and over-exploitation of groundwater has increased pressure on aquifers, especially in the case of crystalline rocks throughout the world. To support sustainability in groundwater management require proper understating of groundwater dynamics and recharge potential. GIS based studies have gained immense popularity in groundwater exploration in recent years because they are fast and provide recent information on the resource for future growth. Thus, the present study utilized a GIS-based Weighted Overlay Index (WOI) model to identify the potential recharge zones and to gain deep knowledge of groundwater dynamics. The in situ infiltration tests have been carried out, which is the key process in groundwater recharge and is neglected in many cases for WOI. In the WOI, ten thematic layers from the parameters influencing and involved in the recharge process are considered to identify potential recharge zones. The results suggested a significant underestimation of recharge potential without considering site-specific infiltration rates that one needs to be considered. The present WOI model considered in situ infiltration information and classified the entire area into four recharge zones, good, moderate, poor, and very poor. The final integrated map compared with the real-time field data like water level fluctuation and infiltration to analyse occurrence and quantification of recharge. The estimated average groundwater draft is 21.9 mcm, while annual renewable recharge is only 5.7 mcm that causing a continuous fall of the groundwater table. The study is useful in selecting regions with more focussed recharge studies and suggested the need of reducing groundwater demand by changing cropping patterns through a predictive decision support tool.