Antecedent moisture, the moisture present in the soil before a rain event, plays a crucial role in shaping a hydrograph. When the soil is already saturated from previous rainfall, its capacity to absorb more water is greatly reduced. This condition leads to increased surface runoff, as excess water cannot infiltrate into the ground. Consequently, the hydrograph of a river flowing through a saturated basin will typically have a shorter lag time and a higher peak discharge, indicating a more immediate and intense response to rainfall. Conversely, in conditions of low antecedent moisture, where the soil is dry and has a higher infiltration capacity, the hydrograph will show a longer lag time and a lower peak discharge. This scenario reflects the soil's ability to absorb a significant portion of the rainfall, reducing the volume and speed of surface runoff. Understanding antecedent moisture conditions is essential for predicting river responses to storm events, particularly in flood forecasting and management.

Vegetation significantly influences the characteristics of a hydrograph through various processes. Dense vegetation cover can reduce the speed and volume of surface runoff, leading to a more moderated and delayed peak discharge. This is primarily due to the interception of rainfall by leaves and stems, which slows down the movement of water to the ground and promotes evaporation back into the atmosphere. Additionally, vegetation enhances infiltration by stabilising the soil and increasing its porosity through root systems. This process reduces surface runoff and extends the lag time. In forested basins, the presence of leaf litter and organic matter on the forest floor further aids in absorbing rainfall, slowing down its movement and facilitating infiltration. On the other hand, areas with sparse vegetation or deforested landscapes exhibit quicker runoff, shorter lag times, and higher peak discharges, making them more prone to flooding. Therefore, the type, density, and distribution of vegetation within a drainage basin are key factors in determining the hydrological response as depicted in a hydrograph.

Recession curves, which represent the return to base flow conditions after a peak discharge, are vital in hydrology for several reasons. Firstly, they provide insights into the drainage basin's ability to store water and the rate at which this stored water contributes to river flow. A gradual recession curve indicates a significant contribution from groundwater and a high capacity for water storage within the basin, which is crucial for maintaining river flows during dry periods. Secondly, the shape of the recession curve can reveal information about the permeability and porosity of the underlying geology. For instance, a steep recession curve might suggest impermeable rock, leading to rapid runoff and minimal groundwater recharge. Lastly, understanding recession curves is essential for managing water resources, particularly in predicting the availability of water for various uses such as agriculture, industry, and domestic consumption. In the context of climate change and increasing variability in precipitation patterns, accurately interpreting recession curves becomes even more critical for sustainable water management.

The type of precipitation has a significant influence on the shape of a storm hydrograph. Convective rainfall, often intense and of short duration, typically leads to a steep rising limb and a high peak discharge. This is because convective storms dump large amounts of water in a short time, overwhelming the drainage basin's ability to absorb and process the water, leading to rapid surface runoff. On the other hand, frontal rainfall, which is usually prolonged and less intense, results in a more gradual rising limb and lower peak discharge. The extended duration of frontal rainfall allows for more infiltration, reduced surface runoff, and a more moderated response in the river discharge. Orographic rainfall, occurring when moist air is forced to rise over a mountain, can also create distinct hydrograph patterns, often with a prolonged rising limb due to the sustained nature of the precipitation. Each precipitation type interacts differently with the basin's characteristics, like soil type and land use, further modifying the hydrograph's shape.

Human activities beyond urbanisation can profoundly impact hydrograph characteristics. Agriculture, for instance, changes land cover and soil properties, influencing infiltration and runoff. Intensive farming often leads to soil compaction, reducing infiltration and increasing surface runoff, which can result in a steeper rising limb and higher peak discharge on the hydrograph. Conversely, conservation agriculture practices like contour ploughing can enhance water absorption and reduce runoff. Deforestation, another significant human activity, drastically reduces interception and evapotranspiration, leading to increased runoff and a higher peak discharge. Moreover, river channelisation, a common practice to control or direct river flow for various purposes, can alter the river's response to rainfall. By straightening and deepening river channels, the time taken for water to travel downstream is reduced, potentially leading to a shorter lag time and altered peak discharge. Dams and reservoirs significantly alter hydrographs as well. By regulating river flow, they can drastically reduce peak discharges and modify the overall shape of the hydrograph. In essence, human activities have a multifaceted impact on hydrographs, affecting every aspect from the speed of runoff to the river's ability to cope with varying water volumes. Understanding these impacts is key in managing water resources and mitigating flood risks in the context of human-altered landscapes.