Infrastructuras y eutrofización en l'Albufera de València. El modelo Cabhal

Abstract

This research has two parts. First we built a model of the water system of the Albufera Natural Park, a wetland located in the Spanish Mediterranean coast whose most characteristic feature is its central lake. We have called this model Cabhal, an acronym for Calidad de aguas y balance hídrico en L'Albufera (Water Quality and Water balance in L'Albufera). This model includes: 1) a quantification of water inputs from the natural cycle 2) a quantification of changes caused by the irrigation system and urban pressure 3) an assessment of inputs, outputs and changes in storage, both in the lake and the surrounding rice crops 4) an analysis of the spatial distribution of water intake 5) a quantification of pollutant loads and 6) a module of the quality processes related to eutrophication.For its construction we applied the principle of superposition and we have studied separately the natural flow system (based on the model "Simpa" by Cedex) and the modified flow regime. The module related to the water balance includes five reservoirs; four of them simulate the rice fields within the park and the fifth, the lake. We have added a module of spatial distribution and a module to calculate pollutant loads based on standard concentrations for different types of inflows. The module of water quality in the lake has been built with the two-dimensional simulation software "Sobek WQ" by Deltares.Second, we used the model to generate monthly series of the main indicators of the system, including 1) total water inflow 2) number of annual renewals in its central lake 3) external loads and 4) average concentrations of organic matter, phosphorus and nitrogen in water inflows. We paid particular attention to assessing the indicators in the early seventies when the lake rose sharply to a turbid state dominated by phytoplankton. We also evaluated those indicators after the completion of major infrastructures for nutrient diversion.We started from a central hypothesis: there are substantive aspects of the development of L'Albufera trophic status that can only be explained through its relation to the water system infrastructure.The Cabhal model can be used to study the environmental flow requirements of L'Albufera de València. The main value of the model, which overcomes shortcomings of previous works, is a strong anchor in the area through a detailed process of calibration and validation. We obtained results that reasonably reproduced the reality over a long period of time in different sectors of this wetland under very different circumstances. ABREVIATURAS, SIGLAS, ACRÓNIMOS Y SIGNOS UE Unión Europea UPV Universidad Politécnica de Valencia USA-CERL US Army Corps of Engineers Construction Engineering Research Laboratory UV Universidad de Valencia& En primeras citas de varios autores, en lugar de la conjunción "y" utilizaremos este signo, tan común como superfluo en español, por una limitación del procesador de textos.

Evolución de la conductividad en la Albufera de Valencia entre 1985 y 2018

“…Y comenzaron los primeros trabajos con el fin de evaluar los niveles de contaminación existentes y su estado ecológico realizados por la Universidad Politécnica de Valencia (Primo et al, 1975) y la Universidad de Valencia (Serra et al, 1984). Con la calificación como Parque Natural en 1986, se sucedieron los trabajos para conocer en profundidad el estado del ecosistema (redacción del Plan de Saneamiento), la ejecución de las primeras infraestructuras de recogida de aguas residuales (construcción del colector oeste), la depuración de aguas en las poblaciones de la cuenca (construcción de depuradoras de aguas residuales) y la implantación de otras medidas de mejora ambiental (construcción de filtros verdes), síntesis recogida documentalmente en la Tesis Doctoral de Mondría (2010). La Generalitat Valenciana asume el seguimiento de la calidad del agua de la laguna y desde 1991 existe una toma de datos regular de las aguas de la Albufera, así como otras medidas hidrológicas de interés, en las que también participa en ocasiones el Organismo de Cuenca (Confederación Hidrográfica del Júcar).…”

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

“…In 2003-2004 another campaign was carried out with bimonthly measurement samples in all the canals in order to know the hydrological situation. In 2008 the most detailed measurement work ever carried out took place in order to make a hydraulic model of operation and future forecast in various scenarios of water use, the poor ecological state of the lagoon and water needs for its maintenance, which were set out in the Plan for Sustainable Development [28]. These works carried out weekly measurements in the main canals and monthly in all the canals during one year, using all the instruments described in the methodology.…”