Residence Time Analysis in the Albufera of Valencia, a Mediterranean Coastal Lagoon, Spain

Abstract

The Albufera of Valencia is a coastal lagoon located in the western area of the Mediterranean Sea, in the Iberian Peninsula. It has an area of 23.1 km2 and an average depth of only 1 m, with a maximum depth of 1.6 m. This lagoon is the remnants of an original and more extensive wetland of about 220 km2 which is now mostly dedicated to rice cultivation. Surface water is supplied through several main and many secondary canals for a total of 64 water entry points and three exit points to the sea. It is difficult to evaluate the residence time due to the lack of reliable measurements of the inflow or outflow, as well as continuous measurements. Between 1988 and 2018, several procedures were used, the results of which are outlined in this document. Overall, a decrease in the inflow during these thirty years was observed and, therefore, it can be concluded that the residence time is increasing. There is a temporal variation during the year due to rainfall and cultivation periods. Likewise, the results found that the natural hydrological zoning of the lagoon causes a spatial heterogeneity with small Northern areas with low residence time of 4.7 days, almost on a weekly basis and large Western extensions with high residence time of 222.9 days. It is impossible to know this information if individual flow measurements are not taken from each of the main watercourses.

Continuous Monitoring of the Flooding Dynamics in the Albufera Wetland (Spain) by Landsat-8 and Sentinel-2 Datasets

“…Winter flooding starts around the end of October and lasts until the beginning of March. The purposes of winter flooding are to provide habitats for water-related animals and to support recreational activities such as hunting [40]. The winter flooding is economically supported by the European Agricultural Fund for Rural Development (EAFRD).…”

“…We calibrated and validated the classification method in the Albufera wetland, located in the western area of the Mediterranean Sea, in the Iberian Peninsula. Previous research on the satellite remote sensing of Albufera wetland had objectives other than the one presented here, such as water quality estimation [37][38][39][40]. The Albufera wetland can be used as an example of a natural wetland that was transformed into an artificially managed one over the years.…”

“…The Albufera wetland can be used as an example of a natural wetland that was transformed into an artificially managed one over the years. It has an extensive area of approximately 220 km 2 , which is now mostly dedicated to rice cultivation [40]. Despite its transformation, Albufera was designated on 5 December 1989 as a "Wetland of International Importance" under the Ramsar Convention, because, during the winter flooding, it offers habitats for migratory birds.…”

Diffuse Anthropization Impacts in Vulnerable Protected Areas: Comparative Analysis of the Spatial Correlation between Land Transformation and Ecological Deterioration of Three Wetlands in Spain

“…In the case of very large basins, this area of impact can be reduced by computing only Horton indices greater than or equal to 4 [45]. [17,34,42] ISPRS Int. J. Geo-Inf.…”

“…Nevertheless, the impact caused by diffuse anthropization phenomena motivated by land transformation from activities such as agriculture or urban growth not geographically adjacent to the protected area is less common in the scientific literature [14]. In this regard, water loss is currently one of the main environmental problems in the management of wetlands in semi-arid environments [15][16][17]. The objective diagnosis of this complex problem is one of the main challenges at the scientific level for the survival of these protected spaces in developed countries such as Spain.…”