Recharge Zone Research Articles

An Integrated Application of Remote Sensing, GIS and VES for Artificial Recharging at Watershed from South Solapur Taluka, Solapur District, Maharashtra

Over growing demand of water has led scientific community to plan augmentation of ground water by various methods. The objectives achieved in present study are to arrest run-off and silt flow, to facilitate infiltration of water. The study area considered is a small Micro Watershed from South Solapur District which is Drought prone zone. The study was an attempt to delineate the possible recharge zone for groundwater and also to identify the suitable sites for artificial recharge structures. The remote sensing, geographic information system and electrical resistivity (VES) has played important role in investigation for identifying the probable sites for artificial recharge structures.Subsurface resistivity sounding studies have revealed to know the subsurface lithological distribution and thickness of different layers and this has been correlated with local geological setup to suggest the artificial recharge structures.

Delineation and prioritization of groundwater recharge zones in the state of Karnataka using GIS technique

Delineation and prioritization of groundwater recharge zones in the state of Karnataka using GIS technique

Application of analytical hierarchy process and integrated fuzzy-analytical hierarchy process for mapping potential groundwater recharge zone using GIS in the arid areas of Ewaso Ng'iro – Lagh Dera Basin, Kenya

The demand for freshwater has continuously increased in the arid areas of Ewaso Ng'iro – Lagh Dera basin, Kenya. This study aimed to and mapped areas of potential groundwater recharge in the basin by integrating factors that influence groundwater recharge using Analytical Hierarchical Process, and Fuzzy-Analytical Hierarchical Process in ArcGIS. The results of this study are presented in form of maps indicating the potential groundwater recharge zones. The zones are categorized as high, medium and low potential groundwater recharge zone, which were validated with the location of the fresh water boreholes. High groundwater recharge potential zones occur in the central part of the study area within the generally flat flood plains consisting of alluvium lithology. In contrast, low potential groundwater recharge zones occur in the southwestern part of the area within upland plains. The study can be helpful in the proper management of the groundwater resource.

Impact of climate change on groundwater recharge in the lake Manyara catchment, Tanzania

Groundwater account for about 60 to 80% of water supply to the population of Tanzania's semi-arid regions for domestic and agriculture uses. Despite the importance of groundwater resource in semi-arid areas, limited information exists on the recharge amount and potential recharge zones in Tanzania in the context of climate change which could result in unsustainable withdrawals. This study aimed to estimate the potential impact of climate change on groundwater recharge and identify potential recharge zones in the Lake Manyara catchment using Water and Energy Transfer between Soil, Plants and Atmosphere under the quasi-steady State (WetSpass) model. The WetSpass model was setup and calibrated using hydro-meteorological data (rainfall, temperature, wind speed, potential evapotranspiration, and groundwater depth) and biophysical data (soil, land use, topography, and slope). Simulated rainfall, temperature and potential evapotranspiration from an ensemble of four CORDEX-Africa regional climate models for the period 2021–2050 under the Representative Concentration Pathway (RCP 8.5) scenario (hereafter referred as business-as-usual scenario) were used as input in the WetSpass model for the climate change impact assessment. WetSpass model calibration using the water balance equation showed a coefficient of determination (R2) value of 0.9 and Root-Mean-Square Error (RMSE) of 0.49 mm/yr between the simulated and calculated recharge. It was determined that the mean annual recharge of 53.9 mm/year (149 MCM/year) for the period 1989–2018 would increase by 7.9% in the future (2021–2050) under the business-as-usual climate scenario, due to the increase in rainfall. Seasonality and spatial differences in recharge amount were observed, with recharge projected to increase in the dry season and at areas that receive high amount of rainfall. Potential recharge zones in the catchment were found mostly around the northern part near Ngorongoro, the south-western part, and around Mbulu region. Findings from this study would help policymakers, and local stakeholders in planning and management of the groundwater resources for sustainable development.

AN ENERGY-EFFICIENT ALGORITHM FOR SERVICE MIGRATION IN UAV NETWORKS

Research subject is developing an algorithm (sequence of actions) performed when the charge of the internal battery of the UAV is reduced to migrate services from one UAV to another and move the UAV to the charging zones of the internal battery. Research method. Studying the ways of organizing the architecture of networks with UAVs, UAV applications; consideration of various ways to implement an SDN controller: at a ground Base Station, on a fixed balloon, at the head node, on all UAVs of one cluster and implementation using several controllers of different levels; identification of the main advantages from the use of the SDN concept in UAV systems. Core results. 4 ways of using UAVs are described in detail, as well as the main functions that should be implemented in the UAV cluster to perform tasks in all 4 areas of application, as well as to implement the SDN concept in the flying segment; possible ways of implementing the SDN controller in networks with UAVs are considered; the main advantages obtained in UAV systems when implementing the SDN concept are presented; theoretically substantiated the need to migrate services from one UAV to another and the inexpediency of implementing all functions on each UAV: the charge of the internal UAV battery is limited, and the more services or functions are implemented on the UAV, the more power consumption; an algorithm (sequence of actions) is proposed that will be performed when the internal battery of the UAV is discharged. This algorithm includes the following processes: the process of determining the UAV for subsequent service migration, the process of determining the service migration route, as well as the processes for sending the UAV to recharge the built-in battery, and upon returning the UAV to the state of performing the tasks assigned to it. Practical relevance. The article contains a detailed description of the ways of organizing the UAV architecture, the main areas of UAV application, as well as the advantages obtained in UAV systems when implementing the SDN concept. Also useful is information on possible ways to implement the SDN controller. The presented algorithm (sequence of actions) for the implementation of the migration of services and the movement of the UAV to the recharge zones in the future can be applied in practice when the charge of the built-in UAV battery is reduced to a certain level.

Hydrogeological simulation of head changes of a south Benin artesian aquifer

Artesian basins include groundwater that may rise above the land surface with free-flow conditions which make it possible to exploit groundwater without pumping. The change to non-artesian conditions may have large implications for local people using artesian wells for drinking and other purposes. We applied a 3D physically based model to assess future head developments in the Turonian-Coniacian artesian (T.C.) aquifer of southern Benin under different artesian outflows and climate scenarios. A sensitivity analysis of the hydraulic and storage properties of the subsurface layers was performed to determine the importance of each property. Results revealed that artesian basins are structured into peripheral and central zones behaving differently to external stresses. Head amplitudes in the peripheral zones which are adjacent to recharge zones are higher and decrease towards the central artesian zones due to the influence of the confined aquifer's hydraulic diffusivity and the leakance of the confining layer. Based on the regional climate model (RACMO) that better reproduces the historical rainfall in the study area, lower recharge is predicted for the period until 2030 and will lead to head drops by 1 m at the peripheral artesian zone. However, such head drops will likely recover during the period 2030–2050 for which higher recharge is predicted. If the current artesian outflows double by 2050 this would cause heads to reduce by only a few centimeters both in the central and at the periphery of the artesian zone. Among all the subsurface layers properties, the hydraulic conductivity of the confined T.C. aquifer is most influencing the simulated heads across the artesian zone and its specific storage is revealed as the least influencing one.

Hydrochemical peculiarities and groundwater quality assessment of the Birimian and Tarkwaian aquifer systems in Bosome Freho District and Bekwai Municipality of the Ashanti Region, Ghana

The Birimian and Tarkwaian aquifer systems are the main sources of water supply for the Bosome Freho District and Bekwai Municipality inhabitants in the Ashanti region of Ghana. A hydrogeochemical assessment was carried out to ascertain the natural baseline chemistry of the groundwaters and the factors influencing groundwater chemistry in these two areas. A multivariate statistical tool consisting of principal component analysis (PCA) and hierarchical cluster analysis (HCA) together with hydrochemical graphical plots was applied on 64 groundwater samples. The Q–mode HCA results were used to explain the changes in groundwater chemistry along the flow paths where three spatial groundwater zones and water types were delineated. The first type consists of Ca–Mg–HCO3 freshwater (recharge zone), which transitions into Ca–Na–HCO3 or Na–Ca–HCO3 mixed waters (intermediate zone) and finally evolves to the third type of Na–Ca–Mg–HCO3–Cl water (discharge zone). The study also reveals that the natural process influencing water chemistry is groundwater–rock interaction from carbonate and silicate weathering/dissolution, aided by carbonic acid from precipitation and releases concentration of Na+, Ca2+, Mg2+, and HCO3− into the groundwaters significantly. The chloro-alkaline indices also reveal cation exchange as the principal natural factor that controls groundwater chemistry in the area. Inverse geochemical modelling shows the dissolution of primary minerals such as dolomite, plagioclase, halite, gypsum, and precipitation of calcite and chlorite along the groundwater flow path. Anthropogenic activities have little influence on groundwater chemistry. The quality of groundwater in the Bosome Freho District and Bekwai Municipality is suitable for irrigational use and drinking water consumption. The results obtained so far will contribute to research paucity in the study area and serve as a guide for decision-makers for improved water resources management.

Use of Multidisciplinary Approaches for Groundwater Recharge Mechanism Characterization in Basement Aquifers: Case of Sanon Experimental Catchment in Burkina Faso

In Burkina Faso, the basement aquifers represent a major asset in terms of quantity and quality, for both drinking and irrigation purposes for rural populations. They provide water resources that can guarantee the long-term needs of the populations, provided that a sustainable management policy for these resources is adopted. Yet, any groundwater resource management policy is necessarily linked to a better knowledge of aquifer recharge mechanisms, which is yet to be fully assessed in the Sahelian basement area. The objective of this study was to characterize the recharge mechanism within the experimental site of Sanon, located in the basement zone in Burkina Faso, using a coupling of hydrodynamic and chemical approaches. The hydrodynamic approach consisted of monitoring the spatial and temporal distribution of the piezometric levels of the aquifers along a north–south and east–west transect and determining soil infiltration capacity. The hydrochemical characterization of the aquifers was carried out through an analysis of groundwater samples from the concerned aquifers and daily tracing of the electrical conductivity of the aquifer water. The cross-analysis from the results of the implemented approaches shows a direct recharge mechanism through rainwater infiltration in the central valley, an indirect recharge mechanism in the lowlands, and a recharge mechanism by lateral transfers in the peripheral aquifers of the Sanon experimental catchment. The existence of a piezometric dome reveals in the central valley a zone of preferential recharge and water movement. The water of the central valley is the least mineralized with electrical conductivities below 100 µS/cm. This mineralization follows the direction of the water flow.

Identification of Preferential Recharge Zones in Karst Systems Based on the Correlation between the Spring Level and Precipitation: A Case Study from Jinan Spring Basin

The Jinan spring basin is located in the karst area of northern China, where springs serve as important sources of water supply. Several studies on spring protection and water supply have been carried out, and scholars have developed some laws on local groundwater flow dynamic and characteristics of aquifer structures. Unfortunately, there is a lack of detailed research on preferential recharge zones, which are the main recharge pathways of springs. Therefore, this research focuses on identifying preferential recharge zones based on the correlation between the spring level and precipitation. The results show that when precipitation is more intense or lasts longer, there is a stronger correlation between spring level and precipitation. It has been established that the precipitation at Donghongmiao station has the closest relationship with the dynamic of Baotu spring, which is found to be the most significant contribution to spring preservation. Two potential preferential recharge zones in the Jinan spring basin are detected through correlation analysis and geological exploration data. These findings support spring protection and water supply projects in karst regions.

Big data and environmental sustainability based integrated framework for isotope hydrology applications in India

Water contains environmental isotopes, which can act as tracers to study the source, origin, and distribution of water in the hydrological cycle. Recently, the environmental isotopes have been widely applied in hydrological investigations and it is established that the spatio-temporal variations in isotopic abundance provide valuable information to enhance the qualitative and quantitative understanding of hydrological processes such as mixing of different flow components and recharge rate, identify origin of water, delineation of groundwater recharge zones, geothermal dynamics, paleo-recharge and many others. Here, a review of case studies is presented to highlight the impact of isotope applications in water resource management in India. Along with a review of studies across India, a study is carried out for the assessment of groundwater interactions using isotopes of water (18O, 2H and 3H) in dry/semi-arid region (Jaipur) and wet/humid region (Guwahati). The major outcome of the study is the formulation of groundwater baseline for Guwahati (post-monsoon in 2017 and 2018: δD= 4.98 δ18O + 7.50) and Jaipur (post-monsoon and pre-monsoon in 2018: δD= 4.85 δ18O – 9.49). The results indicate that tritium has strong negative correlation (R2 = 0.59) with depth in Jaipur, indicating increasing groundwater age with depth. In Guwahati, the tritium shows weak positive (R2= 0.25) relationship which might be because of the presence of sandyclay layers in the shallow zone limiting vertical recharge to aquifer. Moreover, based upon the review and isotope results of the two study sites, a novel integrated framework for isotope hydrology application for India is proposed, incorporating the principles of environmental sustainability, economic efficiency and social equity. The isotopic techniques in hydrological investigations not only complements the traditional methods used in water resource management but also provides new insights and an enhanced understanding of the hydrological systems.

Identification of groundwater recharge potential zones in a study region of South Kerala

Groundwater is considered as a precious natural resource which serves as the main source of agriculture and domestic purposes. Kerala state is blessed with around 3000mm rainfall annually because of two prominent monsoon. But the available water is insufficient to meet the demand of people. Increase in population and water demand cause threat to overall water balance. Ground water resource must be managed well to overcome these problems. Ground water recharging is a major requirement for sustainable utilization of water resources. It also becomes highly relevant to assess the water recharge zones and to preserve water quality. This study proposes identification of suitable water recharge sites in Karamana river basin, Thiruvananthapuram, Kerala. Karamana river supplies majority of drinking water in Thiruvananthapuram district. Since its quality is deteriorating day by day, appropriate locations for recharging groundwater is identified using GIS technique. Various thematic maps like soil, slope, drainage, geomorphology and land utilization that affect the groundwater recharge is integrated and weighted overlay analysis is adopted to find the groundwater recharge potential map. Weights are assigned using Analytical Hierarchy Process (AHP) by constructing a pairwise comparison matrix. The result depicts the groundwater recharge potential zones which is divided into very high, high, moderate, low and very low potential areas.

PRZ index for identifying potential areas of recharge in alluvial aquifers and for land use planning

An index to identify potential recharge zones (PRZs) in alluvial aquifers was developed to protect these zones during land use planning. The PRZ index was designed as an additive index through the selection of five characterization indicators. The variables were then operationalized and categorized to generate a conceptual model of the physical-geological system. The PRZ index places recharge zones into four classes according to their potential. This index was applied to the Bolo River hydrogeological area (Valle del Cauca, Colombia), and the following proportions were identified for each PRZ category with a total area greater than 426 km2: very high: 23%, high: 30%; moderate: 40% and low: 7%. The areas with a very high recharge potential were found in the upper portion of the debris cones; their potential was predominantly due to the presence of sand and gravel unconfined aquifers and to aquifer outcrop layers at depths of less than 2.5 m. These PRZs were validated with piezometry, and the hydraulic gradient for 71% of the area was greater than 1%. These areas should be declared protected areas.

Identification of the Dominant Factors in Groundwater Recharge Process, Using Multivariate Statistical Approaches in a Semi-Arid Region

Identifying contributing factors of potential recharge zones is essential for sustainable groundwater resources management in arid regions. In this study, a data matrix with 66 observations of climatic, hydrogeological, morphological, and land use variables was analyzed. The dominant factors in groundwater recharge process and potential recharge zones were evaluated using K-means clustering, principal component analysis (PCA), and geostatistical analysis. The study highlights the importance of multivariate methods coupled with geospatial analysis to identify the main factors contributing to recharge processes and delineate potential groundwater recharge areas. Potential recharge zones were defined into cluster 1 and cluster 3; these were classified as low potential for recharge. Cluster 2 was classified with high potential for groundwater recharge. Cluster 1 is located on a flat land surface with nearby faults and it is mostly composed of ignimbrites and volcanic rocks of low hydraulic conductivity (K). Cluster 2 is located on a flat lowland agricultural area, and it is mainly composed of alluvium that contributes to a higher hydraulic conductivity. Cluster 3 is located on steep slopes with nearby faults and is formed of rhyolite and ignimbrite with interbedded layers of volcanic rocks of low hydraulic conductivity. PCA disclosed that groundwater recharge processes are controlled by geology, K, temperature, precipitation, potential evapotranspiration (PET), humidity, and land use. Infiltration processes are restricted by low hydraulic conductivity, as well as ignimbrites and volcanic rocks of low porosity. This study demonstrates that given the climatic and geological conditions found in the Sierra de San Miguelito Volcanic Complex (SSMVC), this region is not working optimally as a water recharge zone towards the deep aquifer of the San Luis Potosí Valley (SLPV). This methodology will be useful for water resource managers to develop strategies to identify and define priority recharge areas with greater certainty.

Application of square array configuration and electrical resistivity tomography for characterization of the recharge area of a karst aquifer: A case study from Menekşe karst plateau (Kocaeli, Turkey)

Groundwater recharge characteristics of a karst plateau which plays an important role in the recharge of a regionally important highly productive karst aquifer was revealed by combined application of Electrical Resistivity Tomography (ERT) and Square Array Configuration methods. A forward model of targeted karst features and geological structures constructed prior to ERT survey enabled a more comprehensive and more reliable interpretation of the real data. The transition between the anomalies resulted from different structures were sharp and the artifacts were distinct in the inverted sections of the synthetic data whereas a smoother transition was observed between different types of anomalies in the real data and the artifacts were harder to be distinguished from the anomalies related to the real subsurface structures. The air-filled karst shafts and caves inside the Triassic aged marbles resulted in high resistivity anomalies approximately between 3000 and 6000 Ωm. On the other hand, clay rich soil zones and water bearing fissure networks led to low resistivity anomalies ranged between 100 and 400 Ωm. ERT survey detected various well karstified fast recharge zones and indicated that the network of karstified zones dipped through northeast (NE). The method also pointed out that nonkarstified fissure networks and thick layers (10–15 m) of clay rich soil zones leading to a lagged recharge existed some regions in the plateau. Square Array Configuration survey signified that dominant fracture zones existed in SW-NE and NW-SE directions and indicated that the faults and fractures in the region (SE-NW and SW-NE oriented) extended deep inside the karst aquifer. Overall evaluation of ERT and Square Array Configuration results enabled the determination of fast and slow recharge zone distribution throughout the karst plateau and thus, distinguished the highly sensitive regions in karst plateau for groundwater contamination. Finally, this study showed that combined application of Square Array Configuration and ERT surveys could successivley characterize groundwater recharge in a complex karst terrain and could constitute a supportive method for revealing the spatial vulnerability differences of a karst region to groundwater contamination.

Groundwater Potential Zone Mapping Using Analytical Hierarchy Process and GIS in Muga Watershed, Abay Basin, Ethiopia.

Groundwater is an important resource that contributes significantly to the total annual water supply. The purpose of the present study is to assess and delineate the groundwater recharge zone using geospatial technology through an analytical hierarchal process (AHP) method in to the Muga watershed, Abay Basin. Remote sensing satellite images and the corresponding data are used for the preparation of thematic layers, viz., geology, rainfall, slope, soil, curvature, topography wetness index, elevation, drainage density, land use land cover, and lineament density of the study watershed. All thematic layers are integrated with a multicriteria evaluation technique. Weighted overlay index analysis is carried out to give rank for each parameter. The weight is assigned for each thematic layer depending on the AHP technique. The reliability of the output is checked by the calculated consistency index and consistency ratio which is reasonably acceptable (0.044 < 0.1). Verification is done by considering the groundwater well locations in the validation datasets. The receiver operating characteristic curve and area under curve (=82.9%) are used to explore the prediction accuracy.

Identification of the Groundwater Potential Recharge Zones Using MCDM Models: Full Consistency Method (FUCOM), Best Worst Method (BWM) and Analytic Hierarchy Process (AHP)

Identification of the Groundwater Potential Recharge Zones Using MCDM Models: Full Consistency Method (FUCOM), Best Worst Method (BWM) and Analytic Hierarchy Process (AHP)

Depth to water table correction for initial carbon-14 activities in groundwater mean residence time estimation

Abstract. Carbon-14 (14C) is routinely used to determine mean residence times (MRTs) of groundwater. 14C-based MRT calculations typically assume that the unsaturated zone is in equilibrium with the atmosphere, controlling the input 14C activity. However, multiple studies have shown that unsaturated zone 14C activities are lower than atmospheric values. Despite the availability of unsaturated zone 14C data, no attempt has been made to generalise initial 14C activities with depth to the water table. We utilise measurements of unsaturated zone 14C activities from 13 studies to produce a 14C–depth relationship to estimate initial 14C activities. The technique only requires the depth to the water table at the time of sampling or an estimate of depth to water in the recharge zone to determine the input 14C activity, making it straightforward to apply. Applying this new relationship to two Australian datasets (113 14C measurements in groundwater) shows that MRT estimates were up to 9250 years younger when the 14C–depth correction was applied relative to conventional MRTs. These findings may have important implications for groundwater samples that suggest the mixing of young and old waters and the determination of the relative proportions of young and waters, whereby the estimated fraction of older water may be much younger than previously assumed. Owing to the simplicity of the application of the technique, this approach can be easily incorporated into existing correction schemes to assess the sensitivity of unsaturated zone 14C to MRTs derived from 14C data.

Groundwater quality assessment using GIS, the case of Omdurman area, central Sudan

Omdurman area, located west of the River Nile and White Nile is witnessing rapid urban expansion and land use change. Several axial irrigation schemes have developed accelerating the demand for water supply. This indeed, will place more pressure over the available groundwater resources. In order to measure any change of groundwater quality it is necessary to initially evaluate the background condition. This contribution employs a GIS- based Groundwater Quality Index (GQI) which synthesizes different variable water quality data (e.g. Cl-, Na+ and SO42+) by indexing them numerically relative to the World Health Organization (WHO) standards in order evaluate the overall groundwater quality in the study area.The GQI computed for Omdurman area indicated that the water quality is generally high (mean GQI = 90 out of 100) with respect to the WHO standards. Spatially the groundwater quality of the study area increased from the central area in the northeastern direction and decrease in the southeastern direction. This result was interpreted in terms of general groundwater flow, the recharge zone, geology and soil composition. Drilling at close distances and over pumping specially in the central region might create local variations of groundwater flow resulting in mixing of waters of different qualities deteriorating the quality of water in previously safe zones. This is expected due to the low hydraulic gradient (&lt; 0.001) characterizing some parts of the study area as well as the minimum recharge far from the River Nile and the White Nile.

Evaluation of Groundwater Potential Zone Using Remote Sensing and Geographical Information System: in Kaffa Zone, South Western Ethiopia

This study focused on delineating the groundwater potential and recharge area for Kaffa Zone by the method of remote sensing and ArcGIS 10.4 software analysis techniques. There are six main influencing factors (rainfall, slope, land use/cover, lineaments, drainage density, and Lithology) selected for groundwater recharge zone mapping. The thematic maps were scanned, geo-referenced, and classified as suitable for groundwater using ArcGIS 10.4. The methods to assess the potential zone were using weight overlay analysis and hierarchy of analytical process algorithm. The result obtained the potential of ground water were discussed recharge zones into four major categories: very good, good, and moderate and low. This can help for better planning and management the potential resource of groundwater. The results analyzed the groundwater potential that were subdivided in to low, moderate, high, and very high groundwater potentials areas that cover 1664.1,7682.9, 958.27, and 192.78 km2 respectively. The prediction accuracy was checked based on the borehole yield observed and predicted data of respective locations within the selected area. The prediction accuracy obtained (68.42%) reflects that the present study's method was produced significantly reliable and precise results.

Tracing δ18O and δ2H in Source Waters and Recharge Pathways of a Fractured-Basalt and Interbedded-Sediment Aquifer, Columbia River Flood Basalt Province

The heterogeneity and anisotropy of fractured-rock aquifers, such as those in the Columbia River Basalt Province, present challenges for determining groundwater recharge. The entrance of recharge to the fractured-basalt and interbedded-sediment aquifer in the Palouse region of north-central Idaho is not well understood because of successive basalt flows that act as restrictive barriers. It was hypothesized that a primary recharge zone exists along the basin’s eastern margin at a mountain-front interface where eroded sediments form a more conductive zone for recharge. Potential source waters and groundwater were analyzed for δ18O and δ2H to discriminate recharge sources and pathways. Snowpack values ranged from −22 to −12‰ for δ18O and from −160 to −90‰ for δ2H and produced spring-time snowmelt ranging from −16.5 to −12‰ for δ18O and from −120 to −90‰ for δ2H. With the transition of snowmelt to spring-time ephemeral creeks, the isotope values compressed to −16 and −14‰ for δ18O and −110 and −105‰ for δ2H. A greater range of values was present for a perennial creek (−18 to −13.5‰ for δ18O and −125 to −98‰ for δ2H) and groundwater (−17.5 to −13‰ for δ18O and −132 to −105‰ for δ2H), which reflect a mixing of seasonal signals and the varying influence of vapor sources and sublimation/evaporation. Inverse modeling and the evaluation of matrix characteristics indicate conductive pathways associated with paleochannels and deeper pathways along the mountain-front interface. Depleted isotope signals indicate quicker infiltration and recharge pathways that were separate from, or had limited mixing with, more evaporated water that infiltrated after greater time/travel at the surface.