Résumé: In recent years, Algeria has faced increasing water stress due to climate change and rising human activities. In the Seraidi region, the overexploitation of water springs has made these resources increasingly vulnerable. This study has two main objectives: (1) to assess the depletion of springs in the Edough Massif during low-flow periods and estimate the water reserves within the surrounding aquifer, and (2) to examine changes in the pollution indicator levels of these springs. The average flow rates of these springs are below 1 l/s, categorizing most Seraidi springs as magnitude 6. The primary objective of this study is to apply Maillet’s depletion model to analyze the flow of twelve selected springs during the low-water period (May–October 2018). The model shows a strong ft to the data, as indicated by an R² value ranging from 0.62 to 0.98. This model facilitates the prediction of underground water reserve volumes during low-flow periods and helps characterize the spring discharge regime. The results indicate that the springs in Seraidi are perennial, with recession coeffcients ranging from 0.0011 d-1 to 0.0365 d-1, ensuring a consistent water supply in the study area. However, the flow rates remain very low during low-water periods. This study also monitored nine pollution indicator elements, including phosphate (PO43-), metals (Fe3+, Cu2+, Ni2+, Al3+, Mn2+), and nitrogen compounds (NO3-, NO2-, NH4+), which exhibit varying concentrations and distributions in the study area. Fe3+ concentrations ranged from 0 to 0.53 mg/L, exceeding the recommended limit of 0.3 mg/L in 2015. Ni2+ concentrations exceeded Algeria’s drinking water standards (0.02 mg/L) in some areas in 2018, with a peak value of 0.35 mg/L observed in Ain Bouhadada. Furthermore, the study highlights a notable rise in nickel levels in certain springs, primarily due to anthropogenic activities, which threaten the water quality of springs. However, the presence of heavy metals in the water, even at concentrations below drinking water standards, raises signifcant public health concerns. This study highlights the vulnerability of Seraidi’s water springs due to low flow rates and increasing pollution levels. Although the springs are perennial, their discharge becomes critically low during dry periods. The rising concentrations of pollutants, particularly heavy metals such as nickel and iron, emphasize the adverse impact of human activities on water quality. These fndings underscore the urgent need for sustainable water management strategies to protect this vital resource and ensure the region’s water security. Keywords: Seraidi springs; depletion curve; low water flow; aquifer reserves; pollution indices. Negli ultimi anni, l’Algeria ha affrontato un crescente stress idrico a causa dei cambiamenti climatici e dell’aumento dell’attività antropica. Nella regione del Seraidi, il sovrasfruttamento delle sorgenti ha reso queste risorse sempre più vulnerabili. Questo studio ha due obiettivi: (1) esaminare le curve di esaurimento delle sorgenti nel massiccio dell’Edough durante i periodi di magra e stimare le riserve idriche dell’acquifero circostante, e (2) analizzare le variazioni degli indicatori di inquinamento. Le portate medie sono inferiori a 1 l/s, classifcando la maggior parte delle sorgenti del Seraidi come di magnitudo 6. L’obiettivo principale di questo studio è applicare il modello della curva esaurimento di Maillet per analizzare il flusso di dodici sorgenti durante un periodo di magra (Maggio–Ottobre 2018). Il modello mostra una buona corrispondenza con i dati, come indicato dai valori di R2 compresi tra 0.62 e 0.98. Questo modello consente di prevedere i volumi delle riserve idriche sotterranee durante i periodi di magra e di caratterizzare il regime di deflusso delle sorgenti. I risultati indicano che le sorgenti del Seraidi sono perenni, con coeffcienti di recessione che variano da 0.0011 d-1 a 0.0365 d-1, garantendo un approvvigionamento idrico costante nell’area di studio. Tuttavia, le portate rimangono molto basse durante i periodi di magra. Lo studio ha anche monitorato nove composti chimici che posso suggerire un inquinamento, tra cui fosfati (PO43-), metalli (Fe3+, Cu2+, Ni2+, Al3+, Mn2+) e composti azotati (NO3-, NO2, NH4+). Questi ioni presentano concentrazioni e distribuzioni variabili nell’area di studio. Le concentrazioni di Fe3+ variano da 0 a 0.53 mg/L, superando il limite raccomandato di 0.3 mg/L stabilito nel 2015. Le concentrazioni di Ni2+ hanno superato in alcune aree gli standard algerini di potabilità dell’acqua (0.02 mg/L) nel 2018, con un valore massimo di 0.35 mg/L registrato ad Ain Bouhaddada. Inoltre, questo studio evidenzia un aumento signifcativo dei livelli di nichel in alcune sorgenti, attribuibile principalmente ad attività antropiche che minacciano la qualità dell’acqua delle sorgenti. Tuttavia, la presenza di metalli pesanti nell’acqua, anche a concentrazioni inferiori rispetto agli standard di potabilità, solleva importanti preoccupazioni per la salute pubblica. Questo studio mette in luce la vulnerabilità delle sorgenti del Seraidi causata da portate ridotte e dall’aumento dei livelli di inquinamento. Sebbene le sorgenti siano perenni, le loro portate diventano criticamente basse durante i periodi di siccità. L’aumento delle concentrazioni di inquinanti, in particolare metalli pesanti come nichel e ferro, sottolinea l’impatto negativo delle attività umane sulla qualità dell’acqua. Questi risultati evidenziano l’urgenza di adottare strategi

Résumé: Flood hazard prevention plans and watercourse management require a lot of data; the most important is the flood event that will serve as a reference. In practice, this reference flood is often assumed to be the greatest ever known historical flood or the 100-year flood if the latter would be greater than the recorded historical one. The purpose of this paper is to provide some data that help in the elaboration of such plans. Indeed, analysis of severe storms and extreme discharge records in the Saf Saf wadi watershed and statistical data processing (frequency analysis) revealed that the December 28th, 1984 to January 1st, 1985 heavy storm is an exceptional event with respect to the intensity (324mm in 5 days), the magnitude of the generated flood (peak discharge: 754m3/s, flood volume: 75hm3 at the Zardézas dam) and the extent of property damages and human losses (11 dead). Historical data and frequency analysis results show that this deadly well documented event could be a good reference to elaborate flood control and watercourse management plans to reduce vulnerability to flooding in the Saf-Saf wadi basin. Key words: Saf-Saf wadi, Algeria, Heavy rains, Watercourses, Flood control plans

Résumé: This study deals with short-duration precipitation, an important parameter in hydrology. These rainfalls play a significant role in triggering flash floods, landslides, and inundations,all directly impacting urban and rural areas. The Eastern Oued Kébir watershed, located in the El Tarf region (northeastern Algeria), is highly exposed to such extreme events. The analysis is based on records from the Ain Assel station, the unique site equipped with a rain gauge in the watershed, covering a continuous measurement period of 32 years. High-resolution data (ranging from 5 minutes to 24 hours) allowed for the examination of the main characteristics of rainfall (duration, height, intensity, and frequency). Two reference matrices were established: the first for annual maximum heights and the second for annual maximum intensities across 17 characteristic durations. These series form the basis for the frequency analysis of extreme rainfall in the watershed. The results highlight intense rainfalls concentrated over very short durations. At Ain Assel, 5-minute episodes reached 25 mm, corresponding to approximately 300 mm/h intensities. The cumulative height exceeds 30 mm in 2 hours, with a maximum of 109 mm. These values illustrate the severity of these rainfalls and their potential for hydrological damage. The frequency analysis led to the construction of Height-Duration-Frequency (HDF) curves. These curves are important for sizing flood protection structures and useful in urban drainage, agricultural drainage, torrent correction, and restoration of mountainous soils. The HDF model serves as a reliable tool for estimating rainfall height and intensity by evaluating any durationrecurrence period pair T, even in the absence of complete series. Keywords: El Tarf, Oued Kébir-Est, rainfall, frequency analysis, HDF model.