Quantifying land use and land cover influences on surface water quality through Sentinel-2 observations in the Letaba catchment, South Africa

The loss in number and function of wet meadow ecosystems in California is often associated with reduced drought tolerance and impaired water quality in watersheds. This research focused on investigating the improvement of meadow health and water quality by implementing best management practices (BMPs), particularly wildlife-friendly, cattle-exclusion fencing (allowing passage of wildlife) along streams, in a multi-use riparian wet meadow system. This longitudinal study followed the concentration of fecal indicator bacteria and fecal pathogens in the stream water from 2017 through 2022. Total coliforms, Escherichia coli , Giardia cysts, Cryptosporidium oocysts, and hydrologic parameters were monitored. The impact of the cattle exclusion fencing was evaluated using mixed-effect negative binomial and logistic regression models. Using EPA Method 1623, the overall prevalence of exceeding water quality standards for E. coli , Giardia spp., and Cryptosporidium spp. in the stream surface waters was 12.9%, 17.7%, and 27.1%, respectively. When the cattle exclusion fencing was present in a downstream location, E. coli in stream samples was reduced by 28 organisms/100 ml . Furthermore, significantly fewer water samples exceeded the regulatory thresholds set by the California State Water Resources Control Board when exclusion fencing was present. No statistically significant association was detected between fencing and the presence of Giardia spp. or Cryptosporidium spp. The hydrologic data revealed that the valley floor held more water over time, which was released more slowly throughout the year. This indicates that the wet meadow function is recovering, and suggests that using BMPs, including wildlife-friendly cattle exclusion fencing, in a multi-use wet meadow ecosystem that includes ranching, can help improve surface water quality and ecosystem health. • Protozoal pathogens in streams were detected throughout 5 years of meadow restoration. • Cattle exclusion fencing was associated with reduced freshwater stream E. coli concentrations. • Stream E. coli concentrations decreased by 28 organisms/100 ml at riparian fencing locations. • Cattle exclusion fencing was associated with improved water quality in California meadows.

ABSTRACT River water quality is declining across tropical landscapes undergoing rapid land-use change. We tested whether landform-controlled hydrological pathways explain spatial water-quality patterns in the Southern Malang Plateau (Indonesia). At 28 sites spanning tectonic, karst, alluvial, and volcanic landforms, we computed the National Sanitation Foundation Water Quality Index (NSF-WQI) and applied multivariate analyses. Alluvial rivers were most degraded, with nitrate up to 60 mg L⁻1, COD >200 mg L⁻1, and total coliforms up to 175 MPN 100 mL⁻1, resulting in poor status (WQI <50). In contrast, volcanic catchments dominated by forest and agroforestry maintained good quality (WQI >75), while karst systems showed intermediate but spatially sensitive conditions. Multivariate structure indicates that nutrient enrichment and sediment-associated impairment are regulated by landform-specific erosion–sedimentation and flow-path connectivity rather than land use alone. Integrating landform controls into water governance supports SDG 6 (clean water and sanitation) and nature-based solutions.

Intelligent water environment diagnosis and treatment center: A machine learning framework for automated surface water pollution management.

The lakes of Polissya represent the most extensive natural complex of freshwater lakes in Ukraine. They are ecologically sensitive systems where a complex interaction between the natural landscape, geochemical conditions, and localized anthropogenic pressure controls water quality. This study aimed to provide an integrated assessment of surface water quality, trophic status, metal contamination, irrigation suitability, and water aggressiveness for nine lakes using hydrochemical parameters and composite indices. Therefore, water quality was evaluated based on in situ measurements and laboratory analyses of major ions, nutrients, organic matter indicators, and trace metals, followed by the calculation of five widely applied water quality indices, the organic pollution index, the heavy metal pollution index, the trophic state indices, the irrigation indices, and the aggressiveness index. The autumn monitoring period was selected to capture relatively stable hydrochemical conditions in the absence of pronounced thermal stratification, allowing for consistent inter-lake comparison. However, the results should be interpreted as representative of autumn conditions and not as reflecting full annual variability. The results indicate that most lakes exhibit good to excellent water quality, low mineralization, and a stable hydrocarbonate-calcium water type. Elevated organic pollution and reduced integral water quality were identified for Domashnie Lake, linked to higher nutrients, organic matter indicators under urban-agricultural land use. Increased values of the heavy metal pollution index in selected lakes were primarily associated with natural Fe enrichment and localized inputs of Ni, Zn, and Cu. Trophic conditions ranged from oligotrophic to mesotrophic, while irrigation suitability remained generally high. Overall, natural factors dominate water chemistry, whereas anthropogenic impacts are spatially limited and locally significant.

To further investigate stormwater runoff patterns, pathogenic risks of pollutants on urban roads, and mitigation of urban non-point source pollution, road runoff monitoring and sampling were conducted in selected sections of central Yinchuan, a city in the arid region of northwestern China. Processed data—including rainfall, flow rate, and water quality parameters (conventional five indicators and heavy metals)—were obtained from ten rainfall events in 2024. Through analyses of water quality characteristics, influencing factors, runoff flushing patterns, and stormwater control measures, the current status of road runoff pollution was clarified. The Nemerow pollution index method was applied to evaluate pollutant levels and assess human health risks. Results indicate that pollution levels in Yinchuan are relatively mild, with most pollutant concentrations below the Class IV surface water quality standard. Basic rainfall parameters—peak rainfall intensity (PRI), average rainfall intensity (ARI), and previous sunny days (PSD)—together with urban functional zones, significantly influence pollutants in rainfall runoff, with the antecedent dry period showing the most pronounced effect. Analysis of the runoff scouring effect reveals that scouring of the conventional five water quality indicators (SS, COD, TN, NH3-N, and TP) is substantially more evident than that of heavy metals. The runoff control depth for roads in central Yinchuan ranges from 0.9 mm to 40 mm, sufficient to manage runoff pollution from small to medium-sized rainfall events. The Nemerow pollution index remains below 8.36, with no severely polluted areas identified, indicating relatively low pollution in Yinchuan’s urban core. Quantitative human health risk assessment suggests that health risks associated with heavy metals on roads are low, with no significant exposure risk, implying that stormwater runoff in Yinchuan poses no substantial threat to human health. This study provides a valuable reference for non-point source pollution control via stormwater runoff management in arid-region cities.

ABSTRACT Lakes provide essential supporting services, making sustained monitoring studies crucial amid rising environmental stressors, which are absent in mountain lake research. To fill this gap, this study assessed surface water quality in protected lakes – Balinsasayao and Danao – in the Philippines, using data collected from 2021 to 2024 across dry (March) and wet (August–November) seasons. Temporal (interannual and seasonal) variability was analysed using Generalised Additive Mixed Models (GAMMs) and Principal Component Analysis (PCA). Results showed that temperature, coliform, and chemical parameters significantly fluctuated interannually, indicating that water quality over long years had been shaped by internal processes, catchment inputs, and climate-driven warming. Seasonal analyses revealed rainfall affects pH and dissolved oxygen dynamics. PCA Dimension 1 (38.8% variance) reflected a negative correlation between temperature and positively intercorrelated variables, including TSS, coliform, pH, colour, and rainfall, while Dimension 2 (24.4% variance) separated samples by inorganic nutrients versus organic load indicators, highlighting the physical–chemical factors and nutrient effects on water quality. Findings show climate vulnerabilities in tropical mountain lakes, urging integrated management to safeguard biodiversity and sustain the wide range of supporting services these systems provide.

Predicting water quality parameters using proximal spectral sensing technology and adaptive ensemble regression.

This study assessed the impact of pandemic-related changes in treated wastewater on surface water quality and ecological status of the Raba River within the Natura 2000 site. Particular attention to the reliability of the Kasinka Mała wastewater treatment plant operating in this protected area during the two study periods—pre-pandemic (PP) and COVID-19 (CP)—was given. For this purpose, current standard monitoring methods (ecological status of a small flysch stream, existing and potential threats to the Natura 2000 site) and extended monitoring methods (river’s utility values, technological reliability of the treatment plant operating with SBR technology, reliability rating of the river as a sewage receiver) were used. The results indicated that biodegradable carbon compounds (as dissolved and suspended forms) and ammonium nitrogen were the dominant factors determining water quality. Their presence reduced the Raba River’s utility value—determined by what is required of surface water treatment—by at least one class. During the CP, the reliability analysis showed that the river remained in a reduced class for 145 days due to elevated BOD5 and nearly one-third of the year due to elevated TSS levels. For approximately half of the year, ammonium nitrogen concentrations exceeded the threshold of 1.8 mg·dm−3, thereby further reducing the class of water quality. Technological reliability of the WWTP during PP for BOD5, COD, TSS, NH4+–N, and PO4−3–P was 43%, 100%, 30%, 86%, and 100%, respectively. This means that permitted values of COD and PO4−3–P were maintained. The exceedances of limits concerned BOD5 (25 mg O2·dm−3 for 208 days), TSS (35 mg O2·dm−3 for 256 days), and NH4+–N (15 mg O2·dm−3 for 51 days). During CP, the technological reliability of the WWTP decreased rapidly for the following pollutants to 5%, 18%, 18%, 30%, and 89%, respectively. This means that permissible concentrations of BOD5 (25 mg O2·dm−3 for 347 days), COD (125 mg O2·dm−3 for 241 days), TSS (35 mg O2·dm−3 for 299 days), NH4+–N (15 mg O2·dm−3 for 256 days), and PO4−3–P (2 mg O2·dm−3 for 40 days) were exceeded. A two-year monitoring campaign has shown that small flysch rivers receiving treated wastewater may experience prolonged changes in water quality under conditions of increased anthropopressure. Effective ecosystem protection should, therefore, include extended monitoring and stricter management of BOD5, TSS, and NH4+–N in SBR systems in protected areas.

Coastal aquifers serve as a lifeline for agriculture, drinking water and ecosystems. However, they are increasingly under threat worldwide from seawater intrusion, primarily driven by excessive groundwater extraction, intensified land use, population growth, and climate change, including sea-level rise. This study applies an integrated, multi-seasonal hydrochemical and isotopic approach to assess groundwater and surface water quality in the Metaponto coastal plain (southern Italy). Groundwater and surface water were sampled seasonally over one year and analysed for major ions, trace metals, stable isotopes (δ 18 O, δ 2 H), and radioactive isotopes ( 3 H, 14 C), supported by hydrochemical diagrams, ionic deviation analysis, seawater fraction (f sea ), and multivariate statistics. Electrical conductivity in groundwater ranged from freshwater values (<1,000 μS/cm) inland to >10,000 μS/cm in coastal and deep wells, with maximum seawater fractions reaching ∼0.41. Hydrochemical facies evolve from Ca–HCO 3 inland to Na–Cl dominance near the coast, reflecting salinization driven by seawater mixing and cation exchange. Stable isotopes indicate predominantly meteoric recharge, while enriched δ 18 O and δ 2 H values (up to −2.5‰ and −15‰, respectively) in coastal and deep groundwater reflect evaporation and saline mixing. Tritium (≤0.5–4 TU) and radiocarbon ages (<1,500 to >10,000 years BP) reveal a vertically stratified aquifer, with modern shallow groundwater overlying confined paleo-groundwater. Despite elevated salinity, Heavy Metal Pollution Index (HPI) values remained low (≈10–15), indicating negligible metal contamination. These results demonstrate that groundwater quality degradation in the Metaponto coastal aquifer is primarily controlled by salinization rather than metal pollution and highlight the value of integrated hydrochemical–isotopic tools for identifying aquifer vulnerability and supporting sustainable groundwater management in coastal plains. • Integrate methods to identify processes causing groundwater quality degradation. • Reveal inland-to-coast salinity shifts with seasonal and depth-specific variations. • Differentiates mixing and reactive processes using f sea and ionic deviation analyses. • Apply δ 18 O, δ 2 H, 3 H, and 14 C to assess recharge sources and aquifer stratification. • Reveals isolated paleo-groundwater (>10,000 yrs) beneath a vulnerable coastal aquifer.

This study is devoted to the assessment of the ecological condition of the Zhaiyk River and provides a comprehensive analysis of the chemical composition of its natural waters. As one of the largest transboundary rivers in Eurasia, the Zhaiyk River has strategic importance for maintaining regional biodiversity and ensuring the sustainable development of adjacent territories. It serves as a crucial source of water for agriculture, industry, and domestic needs of the population in Kazakhstan and neighboring countries. The river’s aquatic ecosystems provide habitats for numerous species of flora and fauna, including valuable commercial fish species. In recent decades, the ecological state of the Zhaiyk River has raised serious concerns due to increasing anthropogenic pressure. The main sources of pollution include industrial discharges, agricultural runoff containing mineral fertilizers and pesticides, as well as urbanization and the growing volume of domestic wastewater. These factors negatively affect surface water quality and the overall condition of the river ecosystem. The study is based on water sampling conducted at various sections along the river, followed by laboratory analysis of key physicochemical parameters. The analyzed indicators include pH levels, concentrations of major ions (calcium, magnesium, sodium, and chlorides), as well as the content of biogenic elements such as nitrates and phosphates. The results indicate an increase in pollution levels, particularly in areas located near industrial and agricultural zones. The study also examines potential ecological risks to aquatic organisms and human health. Based on the findings, recommendations are proposed to improve monitoring systems, promote rational water resource management, and preserve the ecological sustainability of the Zhaiyk River basin.

Reverse osmosis and nanofiltration membranes are known to remove organic micropollutants (OMPs) from water. They could be used to increase OMP removal from wastewater and improve surface water quality. However, the membrane concentrate contains elevated concentrations of OMPs and requires further treatment. In this study, recirculation of the concentrate to the preceding biological treatment is investigated to increase concentration and OMP residence time in the biological treatment, resulting in an increase in removal. A continuously operated pilot with an influent flow of 1 m 3 h −1 is used, which includes a biological treatment and a commercially available hollow fiber nanofiltration (HFNF) membrane. The system operated in a stable manner for 45 days with concentrate recirculation. Compared with the performance of the base case (no recirculation), it is found that the main functionality of the biological treatment to remove organic matter and nutrients is comparable, while the sludge properties are similar. During recirculation, a significantly increased sulfate concentration was found of up to 1200 mg L −1 in the concentrate (base case of around 300 mg L −1 ). The removal of 11 OMPs is monitored closely. The removal of amisulpride and diclofenac is significantly improved by including the HFNF with recirculation, from 30 % to 70–80 %, due to high retention by the NF. Some other OMPs hardly show an increase in removal, due to a combination of low bioremoval and low retention. A broader range of larger OMPs shows that total removals beyond 80 % can be obtained, even with low bioremoval. • Pilot-scale HFNF with concentrate recirculation tested for organic micropollutant removal from wastewater. • System operates stably for 45 days with concentrate recirculation. • Sulfate concentration in concentrate rises to 1200 mg L −1 . • Achieves over 80 % removal of larger OMPs despite low bioremoval.

Surface water quality contamination by selected residues of pharmaceuticals repurposed for Covid-19 treatment

Harmonization of Surface Water Quality Assessment Methods in Central Asia: Contemporary Approaches and Emerging Challenges

Many rural communities in Alabama’s Black Belt region lack adequate sanitation, resulting in wastewater discharges that may pose risks to residents. To understand the scope of the problem in one community, we conducted three cross-sectional surveys in a small town with limited sanitation infrastructure in 2023. We measured a range of enteric pathogens in environmental samples by multi-parallel qPCR as well as fecal indicator bacteria E. coli and Enterococcus by culture and molecular methods. We examined soil samples (n = 58) from sites near failing septic systems or suspected direct surface discharges and comparison soil (n = 10) far from potential discharges to estimate sanitation-related pathogen hazards. We examined surface water samples from community (n = 8) and localized (n = 20) sites that may have been impacted by wastewater discharges. Comparing impacted and unimpacted soil samples revealed greater fecal contamination near known or suspected discharges, compared with control samples. The mean culturable E. coli count in impacted soils was 224 MPN/g (95% CI 0-510.5 MPN/g) and in unimpacted soils was 0.5 MPN/g (95% CI 0-1.5 MPN/g). We detected several pathogens via qPCR in impacted soil and surface water, including Acanthamoeba spp., Balantidium coli , Blastocystis spp., Cryptosporidium spp., and rotavirus. In community-level surface waters, 88% of samples were positive for E. coli by culture (n = 8, mean 3.04 x 10 5 , 95% CI 0-8.96 x 10 5 MPN/100 mL); 100% were positive for Enterococcus by culture (n = 4, mean 1.10 x 10 4 , 95% CI 0-2.55 x 10 4 MPN/100 mL); and we detected Acanthamoeba spp., Blastocystis spp., Cryptosporidium spp., Plesiomonas shigelloides ., rotavirus, and Yersinia enterocolitica , suggesting community-level wastewater discharges may degrade local surface water quality. Evidence suggests sanitation failures contribute to enteric pathogen hazards in this community.

Surface water systems are increasingly exposed to multiple pressures generated by climate variability, intensified water resource exploitation, and evolving geopolitical dynamics. This study provides a novel contribution by identifying critical threshold effects and non-linear interactions that influence nitrate concentrations through an integrated information systems framework. It develops an integrated information-system-based analytical framework that combines hydrological, climatic, geopolitical, and strategic indicators to shape the broader contextual framework within which hydrological and climatic pressures operate, rather than serving as direct predictors. Considering the nitrate concentration in rivers as a key parameter of water quality, the paper goes beyond univariate analysis of nitrite concentration, examining its relationship with four explanatory variables: the Water Exploitation Index Plus (WEI+), the number of heat stress days (Heat_Stress), the Geopolitical Risk Index (GPR), and a proxy variable representing the presence of strategic infrastructure (Nuclear_State) using a Reduced Error Pruning Tree (REPTree) decision tree algorithm with 10-fold cross-validation. The results indicate that climatic stress emerges as the primary predictor, with a critical threshold of approximately 7.83 heat stress days, beyond which nitrate concentrations increase significantly. Under conditions of high climatic stress and intensive water exploitation (WEI+ ≥ 67.39), predicted nitrate levels exceed 20 mg/L and can reach extreme values of up to 58.82 mg/L. In contrast, low hydrological pressure (WEI+ &lt; 0.39) combined with moderate climatic stress is associated with very low nitrate concentrations, around 2.75 mg/L. The model demonstrates strong predictive performance, with a correlation coefficient of 0.976, a Mean Absolute Error (MAE) of 0.593, a Root Mean Squared Error (RMSE) of 2.046, and a Receiver Operating Characteristic (ROC) area exceeding 0.94 for classification tasks. While geopolitical and strategic variables do not act as direct predictors, they contribute to shaping the contextual framework influencing water resource management and environmental vulnerability. Overall, the study highlights the non-linear and systemic nature of water quality dynamics and demonstrates the effectiveness of decision tree-based models within integrated information systems for supporting environmental monitoring and decision-making under conditions of climate stress and geopolitical uncertainty.

The excessive nutrient enrichment of water bodies, primarily from agricultural runoff, is a leading cause of eutrophication worldwide. The Enkare-Narok River in Kenya faces severe nutrient pollution; however, a quantitative assessment of specific nutrient losses is critically needed to inform effective mitigation strategies. This study aimed to (1) quantify the concentrations of nitrate (NO₃⁻) and phosphorus (P) during the single rainy season (April–May 2025); (2) analyze their spatial and temporal variations at the selected points. A sampling campaign collected 200 water samples from two points: Pumping Station and downstream RGS 2K03. A total of 200 water samples were collected: 100 from the Pumping Station and 100 from the RGS 2K03 site. At each site, 50 samples were allocated for nitrate (N) analysis and 50 for phosphorus (P) analysis. The selection of the two sampling points, Pumping Station and RGS 2K03, was strategic and guided by the GIS-based land use analysis to ensure they captured the dominant pollution pathways and cumulative impacts within the Enkare-Narok River Basin. The primary criteria for selection were representativeness of key land uses, position along the pollution gradient, and practical feasibility. The N and P concentrations were analyzed in triplicate using a calibrated HACH DR900 spectrophotometer following USEPA methods. A two-way Analysis of Variance (ANOVA) tested the main effects of sampling location and time on nutrient concentrations, and linear regression quantified the relationship between water level, nitrate and Phosphorus. The results exceed regulatory thresholds, with nitrate averaging 13.9 mg/L and phosphorus maximum at 2.5 mg/L. These levels pose serious risks: the mean nitrate concentration exceeds the WHO (10 mg/L) and KEBS (10 mg/L) drinking water thresholds, elevating health risks for vulnerable populations like infants (methemoglobinemia). The extreme total phosphorus level (2.5 mg/L), which is 25 times the WHOrecommended 0.1 mg/L eutrophication threshold, signals a high potential for toxic cyanobacterial proliferation and aquatic habitat degradation through hypoxia. Statistical analyses confirmed significant spatial and temporal variations, with nitrate concentrations significantly higher downstream and spiking sharply following rainfall events (p &lt; 0.001). Regression showed a positive correlation (R² = 0.58, p &lt; 0.001) between water level and nitrate, confirming that storm runoff is a primary driver of nutrient pulses. The significantly higher nitrate levels at the Pumping Station align with its position receiving cumulative runoff from upstream agricultural and urban anthropogenic activities from the city. This study, though based on a two-month rainy season snapshot, conclusively identifies agricultural runoff and urban discharges as the primary drivers of nutrient pollution threatening both ecosystem integrity and public health. This study underscores the critical need for targeted strategies to mitigate non-point source pollution and protect surface water quality. These include implementing riparian buffers to intercept subsurface flow, a key pathway delivering nitrate to surface water, and promoting farmer-led agroforestry to reduce surface erosion and phosphorus runoff.

Surface water contamination by pesticides is intertwined to surface runoff and soil erosion from agricultural farms. This study determined the presence and levels of pesticide residue in water from Themi River which is a source of irrigation water at Fire vegetable farm located in Arusha, Tanzania. Using grabbing water sampling technique, three (3) composite samples of water were collected from three strategic locations along the Themi River. Applying liquid phase extraction method, the residual of three pesticides namely trichlorfon, dimethoate, and vamidothion were detected and quantified using Gas Chromatography Mass Spectrophotometer (GC-MS) Agilent 7890A with 2-20 ppm detection limit. Results shows that the concentration of trichlorfon in the water was averaged at 0.71±0.1 µg/l, dimethoate was at 1.64±0.31 µg/l while vamidothion was at 0.78±0.38 µg/l all exceeding the 0.1 µg/l International Union of Pure and Applied Chemistry (IUPAC) recommended limits for individual pesticides residual in irrigation water. Unsustainable application of pesticide in vegetable farms not only contaminates the river but also threatens environment, life below water and human health through trophic chain.

Background: Estuarine and mangrove ecosystems are dynamic zones where microbial processes regulate nutrient cycling and water quality but are increasingly impacted by pollution and seasonal changes. An integrated assessment of physicochemical and microbial indicators is essential to understand water quality dynamics, especially in tropical estuaries like Can Gio. Aims: To assess organic pollution, microbial indicators, and surface water quality in the Can Gio estuary, Vietnam, and to compare their seasonal and spatial variation using previously published monitoring data. Study Design: Secondary analysis of an existing surface water quality dataset. Place and Duration of Study: Can Gio estuary, Ho Chi Minh City, Vietnam, using monitoring data collected at 14 sampling sites during the dry season (March 2023) and rainy season (September 2023). Methodology: Published numerical data from previous studies were reorganized and interpreted using descriptive statistics, graphical comparison, and a simple regression to examine the five-day biochemical oxygen demand (BOD5) - dissolved oxygen (DO) pattern. The assessed parameters included DO, BOD5, chemical oxygen demand (COD), ammonium (NH4+), nitrite (NO2-), phosphate (PO43-), total coliform, and Escherichia coli. Results: Water quality showed clear seasonal and spatial variation. BOD5 and COD were generally higher in the dry season, whereas DO tended to be slightly higher in the rainy season. Organic pollution was unevenly distributed among sampling sites, with several hotspots likely influenced by aquaculture, domestic wastewater, and other local human activities. Among nutrient variables, NO2- showed the clearest seasonal fluctuation, while NH4+ and PO43- varied less consistently. Microbial indicators remained high in both seasons, and E. coli fluctuated more strongly in the rainy season. The BOD5 - DO relationship at site scale was weak, indicating that DO was influenced not only by organic loading but also by hydrodynamic and environmental conditions. Conclusion: The Can Gio estuary is under pressure from mixed organic and microbial pollution, with the dry season being more sensitive to organic load accumulation. The study provides an integrated basis for water quality monitoring and management in tropical mangrove estuaries.

Both groundwater and surface water are essential sources of freshwater worldwide. In urban and peri-urban areas of Sub-Saharan Africa, such as Dar es Salaam city (Tanzania), the scarcity of good quality surface water has led to a groundwater overexploitation in the coastal aquifer. This is due to the growing water demand driven by demographic and economic development of the city. The rapid and uncontrolled urban expansion, together with the increase of impermeable areas, have negative impacts on the aquifer recharge, water table decrease and runoff increase, causing higher risk of flooding, erosion and water shortage. This paper presents the separate assessments of land use land cover change (LULCC) and climate variability impacts on water budget in the study area, using remote sensing datasets, which have followed the evolution of Dar Es Salaam City during the period 2002-2022. The assessments show how rapid urbanization has increased runoff and reduced aquifer recharge, leading to flooding risks and groundwater degradation. In 20 years, within the hydrogeological basin, the aquifer lost 30% of the recharge water volume, on average. Climate variability has affected the specific annual recharge and runoff volumes, especially in the last decade, due to an important rainfall increase. This paper demonstrates that combining the analysis of LULCC and climate variability in catchment areas with geomorphological ones and hydrogeological water budget method can provide a thorough understanding of uncontrolled urban spread effects on water resources balance and support evidence based decision-making spatial planning and environmental management. The study is part of the WECOAdapt project (Water management through ECOhydrology for climate change ADAPTation) that focuses on the reduction of negative impacts on floods and droughts due to unsustainable urban development, aiming to reverse/reduce the degradation of water and land resources.