## 1 Introduction  
In a glance at continental climate, it is understood that continental climates have different climatic regimes, with occasional transitions between them. These transitions could influence the occurrence of prolonged droughs, along with temporary events of moisture variations in the climate lasting for extended periods [1]. The onset of droughs in large continental regions is primarily related to anomalous features in the planet's atmospheric circulation. Therefore, predictions of drought occurrences have received significant attention, especially concerning the estimation of drought durations [2]. The reasons for drought events are so diverse that simulating the direct evolution of the physical processes leading to them is complex. [PERSON] describes this by stating that, as is the case with many meteorological and climatological phenomena, there is not a single cause but multiple factors influencing the occurrence of drought [3]. From the above, the analysis of the historical time series of recorded drought data becomes relevant. Through statistical analysis, expected future values of droughs can be provided [2], offering information for decision-making regarding the comprehensive management of water resources in the study area. In Colombia, due to the atmospheric climate variability, there is significant interannual variability in precipitation, represented by the cycles of La Nina and El Nino. These phenomena have been responsible for extreme rainfall and prolonged droughs, respectively, in the national territory and extending to other continental regions [4]. The definition of drought varies based on specific factors relevant to each location on the planet. However, in general terms, a drought can be described as the insufficient availability of water for anthropic and/or natural activities [5]. According to these anthropic and/or natural requirements, several types of droughs have been identified, each characterized by a significant variation in water demand. These categories include meteorological drought, hydrological drought, agricultural drought, and socio-economic drought [6]. Meteorological drought is defined as a precipitation deficit compared with the water demand of a region [7]. It is typically time-limited, with its duration determining its severity. Agricultural drought refers to the insufficient soil moisture required to support plant life, hindering growth and production. Hydrological drought involves abnormal decreases in minimum river flows, as well as reductions in water volumes stored in lakes and reservoirs, drops in the water table level, and diminished contributions from groundwater [8; 9; 10]. Socio-economic drought occurs when water shortage substantially impacts the economic production of communities in the affected territories, thereby affecting their sustainability [6]. Contemporary hydrology requires a comprehensive understanding of all physical processes to facilitate the efficient management of water resources. However, the existing technical conceptualization might not be suitable for assessing various extreme scenarios given that water management has historically prioritized abundance over scarcity or drought [11]. A flood hydrograph is a graphical representation illustrating the river's reaction to rainfall and aquifer contributions [12]. Conversely, a drought hydrograph is a graph that portrays the river's response to the lack of rainfall, depicting minimum flow rates where the only contributors are the aquifer or upstream reservoirs at the measurement point. Gaining insights into the future hydrological dynamics of rivers and bodies of water has long been a goal of humanity. Consequently, understanding the patterns of the dry season in the Sinu River holds significance. This research study seeks to estimate extreme dry events for varying return periods, furnishing robust information to support comprehensive water management that addresses abundance (floods) and scarcity (droughs).