Forty years of climatic and Human Management Controls on Winter Flooding of Rice Fields in Albufera of Valencia wetland, Spain

The structure and ecological functions of wetlands depend on their hydrological regimes, which are influenced by various natural factors such as precipitation, geomorphology, vegetation and evapotranspiration. However, alterations caused by climate change have a significant impact on these hydrological cycles. Rice cultivation, especially in coastal lagoons, is also an activity that significantly modifies these cycles. This study analyzes the effect of human management and climate change on the winter flooding of rice fields in the Albufera Natural Park in Valencia (Spain), using four decades of Landsat imagery. The Normalized Difference Water Index (NDWI) was used to determine the flooded area and to develop an equation to estimate the flood level with an Normalized Root Mean Square Error (nRMSE) of 15.39%. The results made it possible to calculate the flooding water volume. A decreasing trend in winter precipitation was associated with climate change, as well as a reduction in flooded area not related to precipitation, suggesting a significant influence of human management of the area. Although precipitation affects the amount of water stored in winter, there is no consistent trend over time. The practice of flooding rice fields in winter benefits both agriculture and biodiversity, in addition to other activities such as hunting. The results underline the importance of integrated management involving all stakeholders in the conservation of these ecosystems. Environmental monitoring, with remote sensing as a key tool, is essential for effective and sustainable management of these areas.