Mapping the dynamics of the Lagunas de Ruidera wetland (Spain) using remote sensing

Wetlands protect and improve water quality, store floods, maintain surface water during dry periods and provide valuable habitats for wildlife. However, wetlands may be very sensitive to climate change and appropriate monitoring works and modelling activities are needed in order to design sustainable management strategies. In this work we aim to analyze the dynamics of the Lagunas de Ruidera wetland (Spain) for the period 1984−2015. We applied the supervised classification method to LANDSAT satellite images (missions 5, 7 and 8) with a spatial resolution of 30 m and a temporal resolution of around 16 days. In this case study two different water bodies in terms of surface reflectance have been detected. Both zones have been considered for the calibration of the water detection algorithm through a non-steady threshold. We have also analysed daily surface reflectance data from MODIS (MOD09GQ) to complete the temporal dynamic of the wetland. We obtained some correlations between surface reflectance of LANDSAT and MODIS but the efficiency to detect water surfaces of the second is considerably lower due to its 250 m spatial resolution. The results show a minimum and a maximum wetland surface of around 2.7 and 6.3 km² for the considered period. We have also analysed the relationship of the wetland surface with precipitation and aquifer discharge (obtained from a groundwater flow model). For the mean year at monthly scale, the maximum correlation between the wetland surface and precipitation is obtained for a lag of one month. The wetland surface has a similar monthly trend to the aquifer discharge and the maximum correlation is obtained without lag.

This research has been partially supported by the SIGLO-AN project (RTI2018-101397-B-I00) from the Spanish Ministry of Science, Innovation and Universities (Programa Estatal de I+D+I orientada a los Retos de la Sociedad) and by the GeoE.171.008-TACTIC project from GeoERA organization funded by European Union’s Horizon 2020 research and innovation program.