Groundwater Quantity Research Articles

Robust clustering for assessing the spatiotemporal variability of groundwater quantity and quality

The long-term spatiotemporal assessment of groundwater resources through robust clustering techniques can be used to promote remediation measures for groundwater depletion and contamination. To fully understand the variability of groundwater quantity and quality due to anthropogenic activities and climate changes, a new ensemble clustering framework based on the Combining Multiple Clusters via Similarity Graph (COMUSA) method was developed. This new approach was applied and evaluated in the context of groundwater well systems on the Ghorveh-Dehgolan Plain (GDP), which is located in western Iran, for groundwater level (GWL) and 13 physicochemical parameters during four periods (the average of data from 1988–1990, 1997–1999, 2006–2008, and 2015–2017). The classification was confirmed by using the cluster validity index of the silhouette coefficient (SC), which indicated that the cluster ensemble method could improve the performance of individual clustering methods for groundwater quantity and quality by up to 12% and 20%, respectively. Piper plots, US Salinity Laboratory Staff (USSL) diagrams, and the pollution index of groundwater (PIG) were assessed for all clusters of physicochemical variables to analyse groundwater suitability for drinking and irrigation purposes. The results of the cluster ensemble showed that a critical pattern of groundwater depletion occurred in the western half of the GDP, while the eastern part was recognized as the most polluted zone on the plain. It could be concluded that the decline in GWL was not the only reason for the increase in groundwater quality variables, but other factors, such as noticeable cropland expansion and the overuse of chemical fertilizers and pesticides, were also influential factors related to these patterns. Taken together, the results of this study contribute to better recognizing the spatiotemporal changes in groundwater quantity and quality under the intense pressure of anthropogenic activities.

Comparative Study of Groundwater-Induced Subsidence for London and Delhi Using PSInSAR

Groundwater variation can cause land-surface movement, which in turn can cause significant and recurrent harm to infrastructure and the water storage capacity of aquifers. The capital cities in the England (London) and India (Delhi) are witnessing an ever-increasing population that has resulted in excess pressure on groundwater resources. Thus, monitoring groundwater-induced land movement in both these cities is very important in terms of understanding the risk posed to assets. Here, Sentinel-1 C-band radar images and the persistent scatterer interferometric synthetic aperture radar (PSInSAR) methodology are used to study land movement for London and National Capital Territory (NCT)-Delhi from October 2016 to December 2020. The land movement velocities were found to vary between −24 and +24 mm/year for London and between −18 and +30 mm/year for NCT-Delhi. This land movement was compared with observed groundwater levels, and spatio-temporal variation of groundwater and land movement was studied in conjunction. It was broadly observed that the extraction of a large quantity of groundwater leads to land subsidence, whereas groundwater recharge leads to uplift. A mathematical model was used to quantify land subsidence/uplift which occurred due to groundwater depletion/rebound. This is the first study that compares C-band PSInSAR-derived land subsidence response to observed groundwater change for London and NCT-Delhi during this time-period. The results of this study could be helpful to examine the potential implications of ground-level movement on the resource management, safety, and economics of both these cities.

An uncertainty-based smart market model for groundwater management

Abstract This paper presents a new water market mechanism, which can be used for selecting the best trading policy by incorporating the uncertainties of total annual available water and wholesale price of agricultural products. In this mechanism, water users are asked to submit bid packages via a web-based platform. A bid package represents the real values that a user puts on different quantities of withdrawn groundwater considering its quality. Then, the most reliable water trading policy as well as the price of water are calculated by taking the market endogenous and exogenous uncertainties into account using the regret theory. The results show that by applying the proposed uncertainty-based smart groundwater market mechanisms to the Nough Plain in Iran, the average productivity of water users increases about 18% compared to the status quo condition. Furthermore, based on the outputs of the proposed market model, groundwater is finally distributed to agricultural users almost proportional to their farm's area.

Implementation of Land Procurement for Public Green Open Space Development in Yogyakarta City, Indonesia

The provision of land to build green open spaces in urban areas as in the city of Yogyakarta is important considering that the increasing activities of urban communities will cause various environmental problems, such as an increase in vehicle smoke pollution, a decrease in the quality and quantity of groundwater, flooding, and so on. This study aims to determine how the implementation of land acquisition for the construction of public green open space in Yogyakarta City and the obstacles that arise in land acquisition for the construction of public green open space. This research is a type of empirical juridical research, which begins with understanding the legal rules or norms governing green open spaces in urban areas. Because of the limited land available to build this Public Urban Green Space, what the Yogyakarta City Government does is one of the ways to acquire land to build Public Urban Green Space is to buy people's land as allowed in the Land Acquisition Law and its implementing regulations.

A Feasibility Assessment of Potential Artificial Recharge for Increasing Agricultural Areas in the Kerbala Desert in Iraq Using Numerical Groundwater Modeling

Groundwater in Iraq is considered to be an alternative water resource, especially for areas far away from surface water. Groundwater is affected by many factors including climate change, industrial activities, urbanization, and industrialization. In this study, the effect of artificial recharge on the quantity of groundwater in the Dibdibba unconfined aquifer in Iraq was simulated using a groundwater modeling system (GMS). The main raw water source used in the artificial recharge process was the reclaimed water output (tertiary treatment) from the main wastewater treatment plant (WWTP) in Kerbala, with 20 injection wells. After calibration and validation of the three-dimensional numerical model used in this study and taking wastewater recharge rates into account, two different scenarios were applied to obtain the expected behavior of the aquifer when the groundwater levels were augmented with 5% and 10% of the daily outflow production of the WWTP in Kerbala. The model matched the observed head elevations with R2 = 0.951 for steady state and R2= 0.894 for transient simulations. The results indicate that the injection of treated water through 20 wells raised the water table in more than 91 and 136 km2 for 5000 and 10,000 m3/day pumping rates, respectively. Moreover, increasing the volume of water added to the aquifer could lead to establishing new agricultural areas, spanning more than 62 km2, extending about 20 km along the river.

Analysis of groundwater quality in Cimahi City of West Java Province

Cimahi City is currently experiencing a clean water crisis, the cause of which is increasing population growth, so that water needs increase and land conversion, which results in reduced groundwater infiltration. The primary source of clean water in this city is groundwater. Population growth and residential development have an impact on pollution originating from domestic waste. These two things cause the quality and quantity of groundwater in Cimahi City to be increasingly critical. This study aims to analyze the quality of groundwater used by residents of Cimahi City. The data used is secondary data from the Environmental Service in 2019. Sampling was carried out at thirty points in Cimahi City spread over 14 urban villages, namely Citereup, Pasir Kaliki, Cibereum, Cibabat, Cipageran, Cimahi, Leuwigajah, Setiamanah, Karang Mekar, Cibeber, Melong, Cigugur, Padasuka, and Utama. The number of sampling is 1-2 samples/urban village. Based on the results of the analysis of parameters that do not exceed the required quality standards based on the Regulation of the Minister of Health of the Republic of Indonesia No. 32 of 2017 concerning the requirements and supervision of pristine water quality, namely: turbidity, Manganese, nitrate, detergent as MBAS, and total coliform. Based on the results of calculations with the water quality index, it is stated that the quality of groundwater in Cimahi City is in the normal-poor category.

Developing a groundwater conservation area using analytical hierarchy process in Randublatung groundwater basin

Randublatung Groundwater Basin is a cross-regional Groundwater Basin located in Central Java with an area of 203 Km2. The increase of population in this area led to the increasing need for groundwater not only for freshwater sources and consumption but also for agriculture and industrial needs. The rise of uncontrolled groundwater usage can result in pollution and degradation in the quality and quantity of groundwater. There need to be conservation efforts to maintain the sustainability of groundwater utilization. This study aims to determine conservation zones and management priorities in the Randublatung groundwater basin area. Conservation zones are determined based on the value of their parameters: (a) availability and potential of groundwater, (b) groundwater depletion, (c) changes in groundwater quality, (d) land use, (e) aquifer characteristics, (f) prioritization of groundwater protection areas, and (g) water use. Those parameters are weighed using the Analytic Hierarchy Process (AHP) method and then overlaid corresponding to the weight of the parameter to acquire the matrix of conservation zones. The results indicate the type of lithology in the research area was an alluvial deposit—the development of the data processing presented in the form of a map of groundwater. There are four types of conservation zones in a confined aquifer, i.e., secured, vulnerable, and critical.

Spatial assessment of Groundwater Quantity and Quality: A case study in parts of Chidambaram Taluk, Cuddalore District, Tamil Nadu, India

Spatial assessment of Groundwater Quantity and Quality: A case study in parts of Chidambaram Taluk, Cuddalore District, Tamil Nadu, India

Water Quality, Availability, and Uses in Rural Communities in the Kurdistan Region, Iraq

Water resource management and the investigation of the quality and quantity of groundwater and surface water is important in the Kurdistan Region of Iraq. The growing population, as well as agricultural and industrial projects, consume huge amounts of water, especially groundwater. A total of 572 ground and surface water samples were collected for physicochemical analysis to determine the availability and quality of the water in the Kurdistan region. The physicochemical parameters such as pH, electrical conductivity, and total dissolved solids were analyzed to evaluate the suitability of the water for different purposes like livestock, irrigation, and agriculture. GIS-based multi-criteria decision analysis (MCDA) was used to determine the suitability map of water for irrigation purposes. Most of the groundwater samples were suitable for irrigation except for some samples from Erbil City, especially those taken in the Makhmur district, and samples from some small areas in the cities of Sulaymania and Duhok. All groundwater samples were acceptable for all types of agricultural crops, except for 15 well samples that were determined not to be usable for fruit crops. However, this water was acceptable for livestock and poultry. Most of the water wells provided freshwater except for 36 deep wells, which supplied slightly brackish to brackish water. Water samples were found to have low to medium salinity levels except for 26 well samples and one spring sample that had high salinity levels, and 2 well samples with very high salinity levels. Most of the samples had an excellent to good water classification except for 85 samples classified as permissible, 8 classified as doubtful, and 4 classified as unsuitable for irrigation according to the Todd classification. According to the Rhoades classification, all water samples were non-saline to slightly saline except for 11 samples that were moderately saline.

Estimation of water level fluctuations in groundwater through a hybrid learning machine

In the present study, a new hybrid artificial intelligence-based model is presented to simulate monthly time-series data relevant to groundwater quantity collected from an observation well located in Kermanshah, Iran. To define the hybrid AI model, the differential evolutionary is applied to optimize the Extreme Learning Machine (ELM) so that the Self Adaptive ELM (SAELM) is developed and the wavelet transform is employed to decompose the input variables of the model (WSAELM). The autocorrelation function is utilized for detecting effective lags of the time-series data. Moreover, 70% of the observed data is used to train the AI techniques and the rest (i.e. 30%) is applied in test mode. Then, using these influencing lags, different models are defined for the SAELM and WSAELM models. After that, superior models for the simulation of GWL are selected by evaluating different input combinations. For instance, the values of the Nash-Sutcliffe efficiency coefficient, variance accounted for (VAF) and correlation coefficient (R) for the superior WSAELM model are obtained to be 0.973, 97.450 and 0.988, respectively. The prediction uncertainty of the developed SAELM model for GWL is quantified with a value of ±0.081. Finally, a formula is developed for computing GWL. The obtained results show that the applied hybrid machine learning model can be utilized to estimate the groundwater quantity parameter (i.e. groundwater level) in the Karnachi well and the possible applicability of the WSAELM technique to other areas.

The 3H/3He Groundwater Age-Dating Method And Applications

Groundwater age-dating is an important tool for quantifying and managing water resources. Groundwater age is the elapsed time between recharge (at the land surface or water table) and the time when groundwater is sampled. If groundwater is sampled at the point of discharge from an aquifer, then the age represents the groundwater transit time. Groundwater that has recharged in recent decades is considered young groundwater. In many areas, the quality and quantity of young groundwater has been impacted by human activities and groundwater age-dating is useful for quantifying current and historical water and contaminant fluxes into and through aquifers. This review is focused on the tritium-helium (3H/3He) method, which is a robust and widely applied age-dating technique for young groundwater. We present the development of the 3H/3He method and practical considerations for sampling groundwater in shallow unconfined aquifers. Along the way, we highlight available resources: (1) educational software for building intuition around groundwater age-dating and selection of sampling sites and (2) software that can be used to calculate 3H/3He age from noble gas and 3H data. We also highlight strengths and potential uncertainties associated with the method. For example, while other age-dating techniques require a known historical record of tracer concentration in the atmosphere, the 3H/3He age-dating technique does not require such historical records. However, the 3H/3He method requires measurement of two tracers to produce a groundwater age estimate (“apparent age” or “tracer age”). Precise measurement of 3H and noble gases, plus careful analysis of noble gas data to calculate the tritiogenic 3He (i.e., the portion of 3He derived from decay of 3H in the aquifer) is required to calculate the groundwater apparent age. Sampling for noble gases is sometimes challenging and requires specialized sample containers and technique. We also introduce basic sampling methods in this review but highlight how practitioners should work closely with a noble gas laboratory to obtain the correct containers and assess field conditions and/or the overall feasibility of projects. Lastly, the review highlights recent applications of the 3H/3He method, including recharge rate estimation, characterization of contaminant input histories for aquifers, quantifying groundwater transit times by sampling at aquifer discharge points, and the use of isotope data to constrain and inform numerical and statistical models of groundwater and contaminant movement in the subsurface.

Results of land subsidence measurement using GPS method in the Jakarta groundwater basin in 2015-2019

The development of population and development activities in big cities in Indonesia, especially in the city of Jakarta and surrounding areas is very rapid. From several land subsidence studies, several factors have been identified that cause land subsidence, namely: excessive groundwater extraction, reduction due to building/infrastructure loads, subsidence due to natural consolidation of soft soil layers, and subsidence due to tectonic forces. At present the exploitation of ground water for industrial and residential needs is at a level that needs attention. Excessive pumping of groundwater will cause a decrease in the quantity of ground water, entry of seawater into the land (sea water intrusion) and land subsidence. Symptoms of the negative impact of land subsidence have been felt in several areas, especially in industrial areas located in the northern part of Jakarta. This land subsidence can be measured by GPS or satellite geodetic method, which have begun to develop in Indonesia in the past two decades. Measurements were made using the radial method at 53 GPS points in 2015 up to 100 measurement points in 2019 in Jakarta Groundwater Basin. The result of these campaign GPS surveys that is northern part of Jakarta relatively had higher subsidence rate than the southern. The largest subsidence almost reached 6.2 cm/year in Muara Baru in northern area which is southern area only suffered an average rate of 1.16 cm/year.

Sustainable water management using rainfall-runoff modeling: A geospatial approach

The rainfall-runoff modeling was carried out using Lacey's and rational formulas to identify the possible locations for surplus precipitation to the groundwater regime with Rain Water Harvesting (RWH) systems, evaluate total recharge potential, and impact on the groundwater regime. Our results found that the total recharge potential created by these artificial recharge systems with injection well is to the tune of 72.07 × 104 m3/annum. These recharge measures will help to improve the groundwater levels as well as control the declining water levels, helps in maintain/improve the existing quality of groundwater, and the quantity of groundwater also increase. While recharging rainfall-runoff water through these RWH systems to the groundwater regime, the overall impact on the groundwater regime will be a positive effect. Groundwater reserves will improve as per the water level fluctuation method; these effects will change the area's replenishable reserves. This phenomenon of continuous recharge of runoff water to groundwater regime, those blocks are in critical/semi-critical/overexploited maybe help to renovate them into the safe category. It may add an excellent source to the groundwater for excess water consumption for irrigation/domestic/industries/mining users. Moreover, considering the cost of installation and maintenance expenses, these systems are effective and economical. This research provides a scientific approach to arrest the extreme possibility of precipitation runoff during different rainfall events, water conservation with groundwater recharge the studied area and helps to ensure the availability of surface and subsurface water in sustainable in long-term uses even in drought period/deficit rainfall events and help mitigate the flood risk hazards.

Creation of an observation network for assessment of the impact of the pig complex on the groundwater aquifer

Ukraine, as a party to the Association Agreement, in accordance with Directive 2000/60/EC of the European Parliament and of the Council, recognizes water as the most expensive resource on our planet, which must be protected and saved. Every country and every inhabitant of the planet must do everything possible to reduce the thoughtless use of water and stop water pollution. The priority is the identification of water users and "polluters", as well as the detection and prevention of pollution of water resources, which includes the identification of water sampling points around potential sources of pollution. The aim of the research is to determine the impact of pig farms on the qualitative and quantitative characteristics of groundwater using existing water intakes to preserve natural water resources from pollution and depletion. An important point for monitoring in this situation is the use of existing water intakes (bores and wells) without additional construction of observation bores and interference in the environment. To complete the study, it is necessary to create an observation (monitoring) network of selected points and establish the frequency of their study. The observation network should determine the level (static and dynamic) as well as the quality of groundwater, which reflects background concentrations (natural or "conditionally natural"). "Conditionally natural" concentrations may indicate an excess of pollutants, associated with anthropogenic impacts that occurred prior to the activities of a particular entity, in respect of which the study is conducted. Given the changes in the quality characteristics of water, caused by external factors, "conditionally natural" concentrations can be taken as background. The obtained information will allow, depending on the quality and quantity of groundwater (their level) to make management decisions on the management of groundwater resources. Groundwater in rural settlements near enterprises is in most cases the only source of water supply. The laboratory analysis of water samples from selected points in 2020 showed an excess of color, odor at 60 °C, turbidity, total iron in bores and wells. The detected elevations are due to the peculiarity of the geological structure (aquifer of Eocene sediments). The excess in the hydrogen index is almost 10 times from the surface water body, which can be taken as "conditionally natural" (background) with further study of the specific impact of the complex on the environment. The main indicators that may indicate direct contamination of the pig complex, such as nitrates, nitrites, ammonium nitrogen and microbiological studies, do not exceed the normalized values, set for drinking water. In this case, the specific indicators are within normal limits. Petroleum products were not detected in the studied samples

Mapping Of Groundwater Zones Using Vertical Electrical Sounding (VES): A Case Study of Malwah Distributary

In the last two decades, the water requirements for agriculture sector have increased due to high food demand, changes in the cropping pattern, and the increase of evapotranspiration rate due to the climate change. The irrigation water demands are not completely fulfilled by the available surface water, which resulted an increased use of the groundwater in Pakistan. It is essential that before applying the groundwater to agriculture land, its quality should be assessed. In this study, groundwater quality and quantum have been investigated through Vertical Electrical Sounding (VES) for the command area of Malwah distributary, district Shaheed Benazirabad. Total 23 sites were selected in a grid of 3km-by-3km area for the VES survey using Terrameter up to 100-meter depth. The VES results are interpreted in terms of the resistivity and corresponding thickness of various underground zones using IX1D software. The results indicated fresh groundwater up to maximum of 50 m depth, covers 75.65 km2 i.e., 21% of the total command area of 359.94 km2. However, the freshwater is accessible up to 100 m depth near the Indus River. The study suggests that the tubewells should be installed up to 50-meter depth, where the maximum quantity of fresh groundwater is available.

Spatiotemporal variability in groundwater chemistry of a mountainous catchment with complex geologic and climate gradients in south west India

Mountainous catchments are one of the world’s important water sources that sustains a major portion of global population and a rich biodiversity. The groundwater quantity and quality of mountainous watersheds depend generally on the geologic characteristics and climate gradients. Although many groundwater studies have been carried out in the midlands and lowlands of many river basins, not enough focus has been paid to the mountainous catchments of tropical watersheds. Here we report a case study on groundwater quality and controlling factors of a mountainous catchments of the Western Ghats mountain ranges of peninsular India—the Bhavani river basin, which is identified as a testbed for long-term monitoring of the Critical Zone process. A total of 88 water samples were collected seasonally for assessing various physico-chemical parameters, solute contents and scaling properties. Standard methods were followed for the estimation of various hydrochemical parameters in the open and borewell samples. The results of the study revealed that higher pH and Total Dissolved Solids (TDS) are noticed in the talc-tremolite dominated central zone whereas low values are recorded in the charnockite dominated areas. The major cations in the water samples are of the order Ca2+ > Mg2+ > Na+ > K+ and the anions are of the order HCO3− > Cl− > SO42−. The content of Cl− shows higher values in areas close to agricultural/settlement areas. An overall evaluation shows that the hydrochemistry of groundwater in the study area is influenced by both silicate and carbonate weathering. Mineral stability indices computed for the groundwater reveal that about 52% of the samples are supersaturated with carbonate minerals and often exhibit scaling due to solute overloading. Saturation Index and mineral stability diagram also support that the incongruent dissolution of aluminosilicate minerals (silicate weathering) is an important hydrochemical process controlling the chemistry of groundwater. Langelier saturation index (LSI) and Puckorius scaling index (PSI) show that a significant number of open well and borewell samples exhibit scaling tendency. Among the contributing factors that determine water quality of groundwaters, chemical weathering and anthropogenic activities play a significant role.

Evaluation of Groundwater Resources in Minor Plio-Pleistocene Arenaceous Aquifers in Central Italy

The hilly landscape of the Periadric area in Central Italy is characterized by mainly marly–clayey foredeep basin deposits (Plio–Pleistocene age). These lithotypes are generally considered aquicludes, if compared with the regional limestone aquifers of Apennines. However, a coarsening upward trend characterizes the upper portion of this stratigraphic sequence, with arenaceous deposits and even conglomerates on the top. From a geomorphological viewpoint, the areas with coarser outcrops show a flat shape and sub-vertical slopes, like boundaries. At the base of these scarps, springs can be found at the interface between coarse and fine deposits, whereas these arenaceous bodies are actual aquifers. Until now, the hydrodynamics and hydrochemical features of this kind of aquifer have not been investigated deeply, because they have always been considered a worthy water resource. However, they could play a crucial role in integrated water management, especially to cope with climate changes and drought periods. Considering these, the main purpose of this study was to investigate from a hydrogeological point of view and to assess the groundwater quantity and quality. Five examples throughout the Abruzzo region were considered. For evaluation and comparisons between water resources, the water volume that infiltrates yearly at each squared kilometer of an aquifer (Mm3/y/km2) was applied. This value was calculated through three different approaches to provide a recharge estimation for this kind of aquifer that is as exhaustive and representative as possible. The results allowed us to characterize the hydrogeological model and to quantify the resources between 0.1 and 0.16 Mm3/y/km2, to be suitable for multi–purpose utilization.

Factors of causing seawater intrusion in Kadatua Island, Southeast Sulawesi

In the last decade, there has been an increase in the population very rapidly not only in urban areas but throughout the villages of the region in Indonesia. This led to a huge increase in the need for clean water where the availability of surface water has begun not meet the needs, and groundwater ultimately plays an important role in meeting those needs. However, along with the increase in water use soil, there are negative effects that arise when groundwater exploitation becomes excessive and one of the impacts is the occurrence of seawater intrusion which destroys the quality and quality groundwater quantity. It is hoped that the long-term objective of this research will be produced a report on the estimated intrusion of seawater that can be used as a reference to optimize the protection of groundwater resources. For that purpose short term in this research is to produce information/description regarding the current extent of seawater intrusion in Kadatua Island, Southeast Sulawesi based on data obtained from the identification results in the field.

Groundwater level oscillation analysis in shallow alluvial aquifers in Pomurje, NE Slovenia

Systematic hydrologic monitoring of groundwater quantity at the national level in Slovenia has been ongoing since 1952. An insight into long-term groundwater level data enables us to delineate parts of aquifers with similar groundwater level oscillation properties as well as to identify changes of those properties in time. We used variety of statistical methods to identify long-term behaviour of groundwater level oscillation of groundwater body (GWB) Murska kotlina. Results showed that fluctuation of groundwater level in time reflect complex set of events that originate in natural or anthropogenic interferences. Using percentile analysis in combination with cluster analysis, we were able to isolate areas with a related groundwater fluctuation. Results of long-term data trends analyses of monthly groundwater level showed the impact of the research area climate on long-term and seasonal groundwater level fluctuation. In addition to natural causes, by performing trend analysis on groundwater level data, we were able identify some human induced interventions into the environment made in the past.

Quantifying floodwater impacts on a lake water budget via volume-dependent transient stable isotope mass balance

Abstract. Isotope mass balance models have undergone significant developments in the last decade, demonstrating their utility for assessing the spatial and temporal variability in hydrological processes and revealing significant value for baseline assessment in remote and/or flood-affected settings where direct measurement of surface water fluxes to lakes (i.e. stream gauging) are difficult to perform. In this study, we demonstrate that isotopic mass balance modelling can be used to provide evidence of the relative importance of direct floodwater inputs and temporary subsurface storage of floodwater at ungauged lake systems. A volume-dependent transient isotopic mass balance model was developed for an artificial lake (named lake A) in southern Quebec (Canada). This lake typically receives substantial floodwater inputs during the spring freshet period as an ephemeral hydraulic connection with a 150 000 km2 large watershed is established. First-order water flux estimates to lake A allow for impacts of floodwater inputs to be highlighted within the annual water budget. The isotopic mass balance model has revealed that groundwater and surface water inputs account for 60 %–71 % and 39 %–28 % of the total annual water inputs to lake A, respectively, which demonstrates an inherent dependence of the lake on groundwater. However, when considering the potential temporary subsurface storage of floodwater, the partitioning between groundwater and surface water inputs tends to equalize, and the lake A water budget is found to be more resilient to groundwater quantity and quality changes. Our findings suggest not only that floodwater fluxes to lake A have an impact on its dynamics during springtime but also significantly influence its long-term water balance and help to inform, understand, and predict future water quality variations. From a global perspective, this knowledge is useful for establishing regional-scale management strategies for maintaining water quality at flood-affected lakes, for predicting the response of artificial recharge systems in such settings, and for mitigating impacts due to land use and climate changes.