Analysis of the effects of wet and dry seasons on a Mediterranean river basin: consequences for coastal waters and its quality management

Rivers play a major role in the delivery of nutrients to coastal ecosystems which are essential for ecosystem productivity. However, the increase of nutrients due to anthropogenic activities can cause eutrophication problems. This study analyzes the seasonal variation of phytoplankton communities in the coastal receiving waters of a Mediterranean river. Two scenarios are compared: the wet and the dry season with distinctive characteristics. During the wet season agricultural runoff and combined sewer overflows (CSO) were responsible for nutrient discharges, while during the dry season partially treated effluent from wastewater was the main nutrient source. In the receiving waters, diatoms typical seasonal cycle was modified by CSO discharges during rain episodes, while dinoflagellate abundance was higher in the dry season due to partially treated effluents discharges and low turbulence. We recommend that the design of the Water Framework Directive monitoring programs should take into account wastewater treatment plants and combined sewer systems located near the coast. Management decisions should take into account that only reductions in CSO and partially treated summer effluent are likely to be efficient in the short term. Analyzing the corrective measures cost through a cost-benefit analysis would help to determine whether the costs are excessive or not.Sebastiá Frasquet, MT.; Rodilla Alamá, M.; Falco Giaccaglia, SL.; Sanchís Blay, JA. (2013). Analysis of the effects of wet and dry seasons on a Mediterranean river basin: consequences for coastal waters and its quality management. Ocean and Coastal Management. 78(3):45-55. doi:10.1016/j.ocecoaman.2013.03.012S455578

Influence of nutrient inputs from a wetland dominated by agriculture on the phytoplankton community in a shallow harbour at the Spanish Mediterranean coast

[EN] The Safor Wetland (Western Mediterranean) is a protected ecosystem declared Site of Community Importance under the Habitats Directive. Agricultural practices have been part of this ecosystem throughout history, and its hydrology is anthropogenically manipulated to satisfy cultivation needs. Freshwater from the wetland is discharged through surface channels to Gandia Harbour, a shallow water body with high water residence time. This study evaluated the linear eutrophication gradient downstream from the freshwater inflow locations. The role of the main nutrients in determining the phytoplankton community is discussed. The predominance of agricultural practices, 48% of the watershed soil, caused an excess of nitrogen and an imbalance in the nutrient ratios at all the sampling points. Phosphorus concentrations were particularly low, and did not exceed 1.0 ¿M. Chlorophyll-a concentration was of the order of that found in other eutrophic estuarine waters. In general, flagellates dominated over diatoms at all the harbour sampling points and depths. Potentially blooming species of both phytoplankton groups were detected. The correct implementation of the existing agricultural best management practices should continue to reduce nitrogen and phosphorus loading to the estuary. It seems reasonable that for effective control of the eutrophication effects in this area, strict control over wastewater point sources should be also exercised. © 2012 Elsevier B.V.Sebastiá Frasquet, MT.; Rodilla Alamá, M.; Sanchís Blay, JA.; Altur Grau, VJ.; Gadea Pérez, MI.; Falco Giaccaglia, SL. (2012). Influence of nutrient inputs from a wetland dominated by agriculture on the phytoplankton community in a shallow harbour at the Spanish Mediterranean coast. AGRICULTURE ECOSYSTEMS & ENVIRONMENT. 152(3):10-20. doi:10.1016/j.agee.2012.02.006S1020152

Sentinel-2 analysis of flooded areas: applied case study "La Safor wetland, Spain"

[EN] La Safor wetland is a representative coastal wetland in the Valencia Region (eastern Spain, Mediterranean Sea). This wetland is recognized at an international level as a Special Protection Area (SPAs) for birds and a Site of Community Importance (SCIs) (Habitats Directive, European Council Directive). The wetland is located on a detrital plain aquifer which in turn is fed by a karstic aquifer in the near limestone reliefs. The flooded surface is variable and depends on pluviometry among other factors. The objective of this study is to analyse the effects of the flooded surface on land uses by remote sensing and Airborne LiDAR data. Sentinel-2A images processed at level 1C were obtained from Copernicus. LiDAR data was used to detect the most vulnerable areas affected by floods. In the results, we analysed the impact of the maximum flooded surface on land uses. We propose several corrective actions on the drainage net based on our analysis. This methodology can be applied to other wetland areas of similar characteristics. The advantage is the high spatial resolution which makes the methodology suitable for small sized wetlands.Pena-Regueiro, J.; Sebastiá-Frasquet, M.; Aguilar-Maldonado, JA.; Estornell Cremades, J.; Sanchís Blay, JA.; Morell-Monzó, S.; Altur Grau, VJ. (2020). Sentinel-2 analysis of flooded areas: applied case study "La Safor wetland, Spain". WIT Transactions on Ecology and the Environment (Online). 242:63-70. https://doi.org/10.2495/WP200061S637024