Recharge Estimates Research Articles

Isotope mass balance estimation of groundwater recharge in a hard rock tropical river basin in Kerala, India

To better assess the groundwater recharge pattern of the Kuttiyadi River Basin (KRB) situated in Northern Kerala, the oxygen (δ18O ‰) and hydrogen (δD‰) isotopic compositions of river water, reservoir water and groundwater were determined. Isotopic characterization of the waters of the basin showed that river water experienced altitude effect from lowland (elevation: <7 m) to midland (elevation: 7–75 m) and highland (elevation: >75 m). Isotopic enrichment of river water near the mouth during premonsoon and post-monsoon can be due to the influence of sea water ingress especially during tidal events. Additionally, correlation of 18O and electrical conductivity (EC) further highlights the role of evaporation in isotopic modification of surface water. The regression plot of δ18O and δD of groundwater with LMWL (Local Meteoric Water Line) and surface water samples clearly showed the meteoric origin of groundwater. Using oxygen isotope mass balance method it is estimated that surface water contribution to groundwater was up to 17% in the lowland physiographic zone and it was up to 14% in the midland zone and only 7% surface water is contributing to groundwater regime in highland zone of the KRB. This study demonstrates the usefulness of stable isotopic ratios for baseline assessments of water resources of a river basin or watershed.

Scenarios analysis using water-sensitive urban design principles: a case study of the Cape Flats Aquifer in South Africa

A feasibility assessment was undertaken on the application of water-sensitive urban design (WSUD) for the Cape Flats Aquifer in Cape Town, South Africa, at the local scale. The study contributes towards the planning of water-sensitive cities in the future. A three-dimensional steady-state groundwater flow model was applied to the Cape Flats Aquifer to predict WSUD scenarios by incorporating managed aquifer recharge (MAR). Analysis of the scenarios of varying recharge estimates and groundwater abstraction rates, predicted using the model, indicated that the water-table distribution and outflows from identified groundwater balance components show direct proportionality to the varying recharge scenarios. A notable increase in these outflows was observed when the recharge rate was increased by 50%. Varying groundwater abstraction scenarios indicated that with increasing abstraction rates, water levels and outflows from groundwater balance components also decreased accordingly. A notable decline in water levels and outflows was established at an abstraction rate of 2.5 and 5 L/s, respectively. Similar to the previous regional studies in the area, the results from the predicted scenarios show that there is a potential for applying WSUD, particularly MAR, at site-specific scale within the Cape Flats Aquifer. However, shallow groundwater levels during wet seasons limit the opportunities for application of WSUD in the area. This finding would provide an important reference to the ongoing debate on the Cape Town water crisis and similar environmental conditions where WSUD is considered.

Multi-method groundwater recharge estimation at Eshito micro-watershed, Rift Valley Basin in Ethiopia

ABSTRACT Understanding recharge processes is fundamental to improve sustainable groundwater resource management. Shallow groundwater (SGW) is being developed for multiple purposes in Ethiopia without consideration of monitoring. We established a citizen science-based hydro-meteorological monitoring network, with a focus on SGW recharge estimation, in Eshito micro-watershed, Ethiopia. Citizen scientists collected rainfall, groundwater-level and stream water-level data. We characterized the shallow aquifer using pumping tests. The data were used to estimate SGW recharge using three methods: chloride mass balance, water-level fluctuation (WLF) and baseflow separation. Approximately 20% and 35% of annual rainfall amount contributes to recharge based on the chloride mass balance and WLF results, respectively. Baseflow separation showed recharge values for the watershed vary from 38% to 28% of annual rainfall at the upstream and downstream gauging stations, respectively. This study shows that the recharge in previously unmonitored micro-watersheds can be studied if citizens are involved in data generation.

Recharge Estimation Using CMB and Environmental Isotopes in the Verlorenvlei Estuarine System, South Africa and Implications for Groundwater Sustainability in a Semi-Arid Agricultural Region

Groundwater recharge remains one of the most difficult hydrogeological variables to measure accurately, especially for semi-arid environments where the recharge flux is much smaller than in humid conditions. In this study, groundwater recharge was estimated using chloride mass balance (CMB) in the Verlorenvlei catchment, South Africa where the effects of recent severe drought conditions in an already semi-arid environment have impacted both agricultural activity as well as the RAMSAR-listed Verlorenvlei estuarine system. Chloride, 18O and 2H tracers were used to improve understanding of the groundwater flow patterns and allowed the fresh parts of the groundwater system, defined by Ca2+-HCO3− groundwater types, to be separated from those where additional salts were being introduced through groundwater mixing, and thus characterized as Na+-Cl− groundwater types. Recharge rates calculated from CMB in the fresh parts of the system were between 4.2–5.6% and 11.4–15.1% of mean annual precipitation for the headwater valley and mountains of the Krom Antonies and are largely consistent with previous studies. However, much lower recharge rates in the valleys where agriculture is dominant contrasts with previous results, which were higher, since groundwater-mixing zones were not recognised. Although the chloride concentration in precipitation is based on only one year of data between 2015 and 2016, where 2015 had on average 28% less precipitation than 2016, the results provide a snapshot of how the system will respond to increasing drought frequency in the future. The results suggest that low rates of groundwater recharge under dry spell conditions will impact on low flow generations which are required to sustain the Verlorenvlei estuarine lake system. Overall, the study highlights the importance of combining hydrochemical tracers such as bulk chloride and stable isotopes with numerical modelling in data-scarce catchments to fully understand the nature of hydrological resilience.

Modelling Recharge from Irrigation Developments with a Perched Water Table and Deep Unsaturated Zone

Modelling of recharge under irrigation zones for input to groundwater modelling is important for assessment and management of environmental risks. Deep vadose zones, when coupled with perched water tables, affect the timing and magnitude of recharge. Despite the temporal and spatial complexities of irrigation areas; recharge in response to new developments can be modelled semi-analytically, with most outputs comparing well with numerical models. For parameter ranges relevant to the western Murray Basin in southern Australia, perching can reduce the magnitude of recharge relative to irrigation accessions and will cause significant time lags for changes to move through vadose zone. Recharge in the vicinity of existing developments was found to be similar to that far from existing developments. This allows superposition to be implemented spatially for new developments, thus simplifying estimation of recharge. Simplification is further aided by the use of exponential approximants for recharge responses from individual developments.

Derivation mathematical equations to estimate water surplus and groundwater recharge in Iraq

Climate and hydrological conditions in any hydrological basin are multi-combined reflection of natural factors of morphology and soil nature, as well as the changing in climate factors that affect directly the hydrological cycle. The water balance equation for any natural area or water body indicates the relative values of inflow, outflow, and change in water storage for the area or water body. Estimation of water surplus and natural groundwater recharge in Iraq depending on water balance equation and meteorological data was the aim of this research. Corrected potential evapotranspiration were compared with annual and monthly rainfall in (32) meteorological stations to obtain actual evapotranspiration using water balance equation. Water surplus was divided into runoff and natural groundwater recharge where runoff coefficient method was used to estimate runoff. The obtained mathematical relationship between rainfall with both water surplus and actual evapotranspiration can be used to estimate these two parameters directly from rainfall. The results indicate that water surplus increased toward northeast direction of Iraq, while the minimum values of runoff and groundwater recharge located in western desert of Iraq. The climate conditions of desert were the major influence on reducing rainfall and rising temperature resulting decreasing water surplus, runoff, and groundwater recharge.

Influence of Agricultural Irrigation Activity on the Potential Risk of Groundwater Pollution: A Study with Drastic Method in a Semi-Arid Agricultural Region of China

Agricultural irrigation strongly affects groundwater pollution in cultivated areas. Groundwater vulnerability was evaluated using the DRASTIC method by considering agricultural activities that affect water infiltration and pollutant transport to the groundwater. Three scenarios, using different water recharge sources and calculation methods, were considered for the Tongliao area of northern China. For Scenario 1, only precipitation contributed to the net recharge estimation and ~33.77% of the area was under high pollution risk. For Scenarios 2 and 3, both precipitation and irrigation return water were considered for net recharge estimations. The fractional areas of high pollution risk regions were 40.60% and 19.22% for Scenarios 2 and 3, respectively. The modified infiltration coefficients for this study area were used in Scenario 3, and the fractional area of the high-risk region was 21.38% lower than for Scenario 2. The use of empirical infiltration coefficients in Scenario 2 overestimated the water infiltration ability in the cultivated areas, which also overestimated the fractional area of high-risk regions in this study. Accurate assessment of the impact of agricultural activities on the groundwater pollution risk is essential for cultivated areas. Emphasis should be placed on the calculation method of proper parameters for DRASTIC model construction.

The Sensitivity of Groundwater Recharge to the Rock Pore Connectivity Parameter in the Vadose Zone

Data on groundwater recharge is necessary for solving different classes of hydrogeological problems. One of the recharge estimation methods is flow simulation in the vadose zone. Soil hydraulic parameters are used to estimate the recharge by flow in the vadose zone. One of these hydraulic parameters is the pore connectivity l. The estimated recharge sensitivity to the pore connectivity, especially under humid climate conditions, has not been studied thoroughly. In this study, the experimental values of soil hydraulic parameters of samples from two different sites with various landscape conditions and vadose zone structure (forest conditions on sand and field conditions on loam) have been used to estimate the groundwater recharge. The recharge was also estimated at l = 0.5 and at reported values of the l parameter for a certain type of sediment. According to the calculation results, the use of a fixed value of l = 0.5 leads to a significant overestimation of recharge under both forest and field conditions, which emphasizes the importance of experimental determinations of soil hydraulic parameters for the groundwater recharge estimation. According to the data from an analysis on water balance components, the increase in the estimated recharge with an increase in l is mainly related to a decrease in a top soil evaporation.

Evaluation of groundwater recharge estimation methods in a watershed in the Brazilian Savannah

The Brazilian Savannah Biome is strategic for Brazilian agriculture and for maintaining Brazil's hydrological balance, contributing to river flows from eight of the twelve Brazilian hydrographic regions. In recent years, there has been a continuous growth of irrigated agriculture, the main activity that uses the water resource, and the emergence of conflicts over water use. Thus, to improve water resource management in the Brazilian Savannah, it is important to better understand groundwater recharge rates to determine the magnitude of the sustainable groundwater resource in the region. The study aimed to evaluate groundwater recharge estimation methods in a watershed located in the Brazilian Savannah region. For this, recharge rates were calculated for the period from October 2009 to September 2011 using the methods of baseflow separation, water table fluctuation, and a sequential water balance (BALSEQ). The recharge rates estimated by the baseflow separation, and water table fluctuation methods were, respectively, 23.7% and 26.6% of the total rainfall of 1753.8 mm in the watershed. Using the BALSEQ water balance method, the potential recharge for the period was estimated to be 31.5% of annual average precipitation. The recharge estimates calculated by the methods were consistent with those observed in other agricultural watersheds in the Brazilian Savannah Biome. Also, the evaluated methods can be used as a tool by water resource managers for the rational use of groundwater.

Sensitivity of recharge estimation to the pore connectivity parameter of vadose zone rocks

Information on recharge value is necessary for solving different classes of hydrogeological problems. One of the methods of recharge estimation is simulation of flow in vadose zone. Soil hydraulic parameters are used to estimate recharge by flow in vadose zone. One of the hydraulic parameters is the pore connectivity parameter l. The sensitivity of estimated recharge to the value of pore connectivity parameter, especially under humid climate conditions, is studied insufficiently. In present study, the experimental values of soil hydraulic parameters of samples from two different sites with various landscape conditions and vadose zone structure (forest landscape on sand and field landscape on loam) were used to estimate recharge.Recharge estimation was also carried for the value of l=0,5 and for reported values of l parameter for certain type of sediment. Analysis of calculation results demonstrated that using fixed value of l=0,5 leads to significant overestimation of calculated recharge both for forest and filed landscapes, which emphasizes the importance of experimental definitions of soil hydraulic parameters for recharge estimation. The analysis of the water balance components showed that the increase of estimated recharge with enhancement of l value is mainly associatedwith the decrease of evaporation from the upper soil layer.

Analysis and quantification of groundwater recession characteristics in regolith-bedrock aquifers: a case study in the mid- and upper-Choshuei river basin in central Taiwan

Investigating the groundwater recession characteristics and its relation with geological conditions is of critical importance to the estimation of groundwater recharge in regolith-bedrock aquifers, which commonly occur in the mountainous areas of Taiwan. This paper examines the role of geological and hydrogeological factors in controlling rainfall-induced recharge processes. Groundwater and rainfall data were compiled from 29 monitoring wells and rainfall stations situated in the mid- and upper-Choshuei river basin in central Taiwan. In light of analyzing the outcome of the groundwater-level response to rainfall, the relation between the effective rainfall and groundwater-level fluctuation tends to be positive, and rainfall events with high intensity firmly control the groundwater recharge process in Taiwan mountainous areas. Permeable geological units likely dominate the groundwater-level variations. Besides, recession rates in the vertical direction varying with geological conditions were obviously found in each well site. To improve the efficiency of the water table fluctuation (WTF) method on extrapolating recession rates, two rating systems for evaluating hydraulic properties of regolith and fractured bedrock, respectively, were proposed and applied to develop the effective techniques linked to the quantification of recession characteristics varying with depths for each well. By regression analysis, the dependence of the hydraulic property rating system on the recession rate was performed, and the derived regression equation for each well can be used to estimate the recession rate with depths. Finally, the recharge estimation with the above techniques in Taiwan mountainous areas was established, and the present method of estimating recharge was compared with the existing method. The difference between the two methods was obviously found. Thus, recharge estimation in mountainous areas should take account of complex geological conditions.

Monitoring groundwater heads and estimating recharge in multi-aquifer systems illustrated by an irrigated area in north-west Bangladesh

The impact of groundwater abstraction in multi-aquifer systems can be identified by monitoring variations of groundwater heads with depth and with time. Equally important are estimates of recharge to the groundwater system including contributions from irrigation. A case study from the Rajshahi Barind in Bangladesh illustrates the methodologies. Abstraction of groundwater from deep tubewells has resulted in substantial increases in agricultural production but also significant falls in groundwater heads in the aquifers. Monitoring of the groundwater heads at different depths and relating these to the lithology has indicated the formation of an additional water table in an intermediate aquifer; this leads to the conceptualisation of the aquifer system as two Units, Upper and Lower. Estimates of the potential recharge to the aquifer system are obtained from a daily soil water balance which is enhanced to include the representation of recharge from standing water in flooded ricefields. Detailed fieldwork, over a period of more than 2 years, includes daily records of groundwater heads, rainfall, temperature and hours of pumping for irrigation; information about the crops grown in the command area is also collected. Individual, but interconnected, conceptual and computational models for the two Units are developed. The outputs of the computational models show good agreement with measured groundwater head fluctuations. Using information from the computational models, the sustainability of the current abstraction patterns is considered.

On the sensitivity of modelled groundwater recharge estimates to rain gauge network scale

Rainfall is often the largest component of the water budget and even a small uncertainty percentage may lead to challenges for accurately estimating groundwater recharge as a calculated residual within a water budget approach. Watersheds are a common scale for water budget assessment, and rainfall monitoring networks typically have widely spaced gauges that are frequently outside the watershed of interest. The effects of rainfall spatial variability and uncertainty on groundwater recharge estimates have received little attention and may influence water budget-derived recharge estimations. In the present study, the influence of spatial density in rainfall measurement on the numerical estimation of groundwater recharge was investigated through a series of modelling scenarios utilizing field data obtained from progressively denser rain gauge networks associated with a typical watershed in southern Ontario. The uncertainty of the recharge component of the water budget was used as a metric to aid interpretation of results. The scenarios employed networks composed of: 1) one nearby national weather station (within 3 km), 2) a regional network of six stations (within 30 km), and 3) a local network of six stations, five of which were within the selected watershed. A coupled and fully distributed hydrologic model (MIKE SHE) was used in the scenario analysis and applied to the Alder Creek watershed on the Waterloo Moraine near Kitchener-Waterloo, Ontario. Rainfall showed poor spatial correlation, even at the daily time scale. Average annual results over a three-year period showed that recharge rates varied up to 140 mm per year (~40% of previously estimated annual recharge) among scenarios, with differences between scenarios greater than the water budget uncertainty during one of the years. These findings suggest that the availability of local rainfall measurements has the potential to influence the calibration of transient watershed hydrogeological models.

Assessment of groundwater recharge in carbonate aquifers based on a modified KARSTLOP–AHP method (case study: Dorfak region, Iran)

Determination of recharge from precipitation and its distribution in karst areas is of great importance in water budget calculations. Several multi-parameter weighting-rating methods have been proposed to determine the recharge into karst aquifers; one of the most precise methods used in this field is the KARSTLOP. It is always necessary that the weight of recharge estimation method becomes calibrated by new techniques due to the diversity conditions of each area. Therefore, in this study, the analytical hierarchy process (AHP) technique has been used as a powerful decision-helping subjective tool. Using this method, the weights of the original KARSTLOP method were modified and improved based on the comments from water experts in the area. The mean annual recharge in the study area was 27.5% and 34.5% for the KARSTLOP-AHO and KARSTLOP methods, respectively. The results of KARSTLOP–AHP method are in accordance with the discharge of selected springs in the study area and budget reports.

Estimation of groundwater recharge in savannah aquifers along a precipitation gradient using chloride mass balance method and environmental isotopes, Namibia

The quantification of groundwater resources is essential especially in water scarce countries like Namibia. The chloride mass balance (CMB) method and isotopic composition were used in determining groundwater recharge along a precipitation gradient at three sites, namely: Tsumeb (600 mm/a precipitation); Waterberg (450 mm/a precipitation) and Kuzikus/Ebenhaezer (240 mm/a precipitation). Groundwater and rainwater were collected from year 2016–2017. Rainwater was collected monthly while groundwater was collected before, during and after rainy seasons. Rainwater isotopic values for δ18O and δ2H range from −10.70 to 6.10‰ and from −72.7 to 42.1‰ respectively. Groundwater isotopic values for δ18O range from −9.84 to −5.35‰ for Tsumeb; from −10.85 to −8.60‰ for Waterberg and from −8.24 to −1.56‰ for Kuzikus/Ebenhaezer, while that for δ2H range from −65.6 to −46.7‰ for Tsumeb; −69.4 to −61.2‰ for Waterberg and −54.2 to −22.7‰ for Kuzikus/Ebenhaezer. Rainwater scatters along the GMWL. Rainwater collected in January, February and March are more depleted in heavy isotopes than those in November, December, April and May. Waterberg groundwater plots on the GMWL which indicates absence of evaporation. Tsumeb groundwater plots on/close to the GMWL with an exception of groundwater from the karst Lake Otjikoto which is showing evaporation. Groundwater from Kuzikus/Ebenhaezer shows an evaporation effect, probably evaporation occurs during infiltration since it is observed in all sampling seasons. All groundwater from three sites plot in the same area with rainwater depleted in stable isotopic values, which could indicates that recharge only take place during January, February and March. CMB method revealed that Waterberg has the highest recharge rate ranging between 39.1 mm/a and 51.1 mm/a (8.7% – 11.4% of annual precipitation), Tsumeb with rates ranging from 21.1 mm/a to 48.5 mm/a (3.5% – 8.1% of annual precipitation), and lastly Kuzikus/Ebenhaezer from 3.2 mm/a to 17.5 mm/a (1.4% – 7.3% of annual precipitation). High recharge rates in Waterberg could be related to fast infiltration and absence of evaporation as indicated by the isotopic ratios. Differences in recharge rates cannot only be attributed to the precipitation gradient but also to the evaporation rates and the presence of preferential flow paths. Recharge rates estimated for these three sites can be used in managing the savannah aquifers especially at Kuzikus/Ebenhaezer where evaporation effect is observed that one can consider rain harvesting.

Diffuse groundwater recharge estimation confronting hydrological modelling uncertainty

Diffuse recharge is vital in determining the availability of renewable groundwater. Estimating diffuse recharge, however, is a great challenge plagued with uncertainty due to limitations in direct observation and process understanding. Hydrological model is functional for diffuse recharge estimation at catchment scale. It can be used independently or in combination with flow recession analysis to estimate recharge but it is accompanied with uncertainties owing to model structures and parameterization schemes. Confronting the uncertainties in hydrological modelling, in this paper, we used three models (GR4J, SIMHYD and IHACRES) together with nine parameterization schemes to investigate the effectiveness and uncertainties in the estimates of diffuse recharge for unregulated headwater catchments. The parameterization schemes were configured by three objective functions and three calibration periods conditioned on climate. It was found that the capability of hydrological model in yielding more reasonable groundwater recharge estimates largely depended on the objective function used and the calibration period configured. Model calibrated using inverse NSE (NSEInv) was judged to be more likely to yield better recharge estimates. The uncertainties due to the choice of parameterization scheme were found to be comparable with those from model structures. The use of different models, objective functions and calibration periods allowed reflection on the level of uncertainties one can minimally expect in estimating catchment scale recharge.

Estimation of Natural and Artificial Recharge of Shahreza Plain Groundwater in Isfahan Using CRD and Hantush Models

Cumulative Rainfall Departure model (CRD) is widely used for estimation of ground natural recharge. This model is based on the groundwater balance and it requires random parameters. Moreover, an increase in the static level under artificial recharge facility is simulated using diffusion equations. Since Shahreza Plain is located in an arid and semi-arid area and given that rainfall is the major recharge source in such regions, in this study CRD model is applied in order to estimate natural recharge of Shahreza Plain groundwater. The amount of groundwater basin fed by rainfall was estimated about 177.2 million cubic meters using the CRD model. Also, by investigating and comparing available artificial recharge plans in Shahreza Plain it was known that in Kohrouyeh Project due to high soil permeability the increase in water table depth was higher than other projects and it achieves the maximum level of the water table within less time. By investigating the course of groundwater quality change in upstream and downstream boreholes of artificial recharge plans and given dewatering periods, we found that artificial recharge plans are generally effective in improving groundwater quality in the direction of groundwater movement but these changes are not significant. Hence, it is demonstrated that groundwater change mostly depends on the groundwater drop.

Estimation groundwater total recharge and discharge using GIS-integrated water level fluctuation method: a case study from the Alaşehir alluvial aquifer Western Anatolia, Turkey

The estimation of groundwater recharge is an essential process for hydrogeological study. Realistic determination approach is crucial for assessing groundwater potential in an aquifer system and estimating of groundwater levels and/or changes in dry periods. Based on these matters, we employ a GIS-integrated groundwater level fluctuation method to determine the groundwater recharge for a hydrological period in the Alasehir alluvial aquifer (W. Anatolia). The method basically takes into account both increasing and decreasing of the groundwater levels due to the recharge and discharge mechanisms in the aquifer. In this study, 16 pumping and monitoring wells were drilled with a total depth of 1300 m, and water level data loggers were installed into the monitoring wells to determine the groundwater level changes. The spatial distribution of the monthly groundwater level change map was multiplied by the aquifer storage distribution map and then the accurate water volume is calculated by using the 3-D spatial analysis. According to our evaluation in the aquifer, positive volume change of the groundwater is 187 hm3 in a year, which is considered as a recharge value of groundwater. It is concluded that the GIS-integrated water table fluctuation method gave rise to estimate the total recharge amount of the groundwater in the Alasehir aquifer. The total groundwater recharge indicates that total inflow in the aquifer from precipitation, leakage from surface water and irrigation waters. It can be stated that the recharge estimation of groundwater in a surficial aquifer, like the Alasehir aquifer, is fairly easy using the GIS-integrated water table fluctuation method.

A global-scale dataset of direct natural groundwater recharge rates: A review of variables, processes and relationships

Groundwater recharge indicates the existence of renewable groundwater resources and is therefore an important component in sustainability studies. However, recharge is also one of the least understood, largely because it varies in space and time and is difficult to measure directly. For most studies, only a relatively small number of measurements is available, which hampers a comprehensive understanding of processes driving recharge and the validation of hydrogeological model formulations for small- and large-scale applications.We present a new global recharge dataset encompassing >5000 locations. In order to gain insights into recharge processes, we provide a systematic analysis between the dataset and other global-scale datasets, such as climatic or soil-related parameters. Precipitation rates and seasonality in temperature and precipitation were identified as the most important variables in predicting recharge. The high dependency of recharge on climate indicates its sensitivity to climate change. We also show that vegetation and soil structure have an explanatory power for recharge. Since these conditions can be highly variable, recharge estimates based only on climatic parameters may be misleading.The freely available dataset offers diverse possibilities to study recharge processes from a variety of perspectives. By noting the existing gaps in understanding, we hope to encourage the community to initiate new research into recharge processes and subsequently make recharge data available to improve recharge predictions.

Can Soil Hydraulic Parameters be Estimated from the Stable Isotope Composition of Pore Water from a Single Soil Profile?

Modeling water and solute transport in the vadose zone for groundwater resource management requires an accurate determination of soil hydraulic parameters. Estimating these parameters by inverse modeling using in situ observations is very common. However, little attention has been given to the potential of pore water isotope information to parameterize soil water transport models. By conducting a Morris and Sobol sensitivity analysis, we highlight the interest of combining water content and pore water isotope composition data in a multi-objective calibration approach to constrain soil hydraulic property parameterization. We then investigate the effect of the sampling frequency of the observed data used for model calibration on a synthetic case. When modeling is employed in order to estimate the annual groundwater recharge of a sandy aquifer, it is possible to calibrate the model without continuous monitoring data, using only water content and pore water isotopic composition profiles from a single sampling time. However, even if not continuous, multi-temporal data improve model calibration, especially pore water isotope data. The proposed calibration method was validated with field data. For groundwater recharge estimate studies, these results imply a significant reduction in the time and effort required, by avoiding long-term monitoring, since only one sampling campaign is needed to extract soil samples.