The rate of growth of the water volume in the reservoir varies with each charging season. The accuracy of the predictions is required in sustainable reservoir management. Its intrinsic growth rate as an ecological parameter plays a role in determining this speed. This study aimed to analyze the dynamics of water volume growth based on its intrinsic growth rate to assess the potential for hydrometeorology disasters. The population growth models proposed to be tested for suitability and goodness is the Verhulst, Richards, Comperzt, and modified Malthus model. Test suitability and model goodness were subjected to stages of verification, parameter estimation and model validation based on daily water volume data in the Gembong Reservoir, Pati, Indonesia for the period 2007-2020. A good model is determined based on the Mean Average Percentage Error (MAPE) criteria. The Richards model with b = 2 and r = 0.063/day had consistently low MAPE values during training and testing. This model was chosen as a new approach to understand the dynamics of water volume growth in a reservoir. The ecological implication of these dynamics of water volume growth is that reservoirs experience an abundance of water during the charging season. Reservoir normalization can be prioritized as a mitigation strategy for potential flood disasters.