Hydraulic and water quality monitoring of three constructed wetlands for comprehensive management optimisation in the frame of LIFE+12 ALBUFERA project.

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Beatriz Nacher-Rodriguez, Sara Gargallo, Carmen Hernández-Crespo, Francisco J. Vallés-Morán, Eduardo Albentosa, Ignacio Andrés-Doménech, Miguel A. Eguibar, Miguel Martín

Friday 3 july 2015

14:30 - 14:45h at South America (level 0)

Themes: (T) Hydro-environment, (ST) Rehabilitation of water systems

Parallel session: 16J. Environment - Wetlands

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One of the aims of LIFE+12 ALBUFERA project is to accomplish the Water Framework Directive 2000/60/EC in three constructed wetlands (CW) surrounding Albufera de Valencia Natural Park (CW Tancat de la Pipa, CW Tancat de Milia and CW Tancat de l´Illa). In this project, monitoring both hydraulic performance and water quality of the CW is necessary, and carried out in actions B1 “Hydraulic Management” and C1 “Monitoring the impact of water quality management” The three CW have similar morphology, but different flow supply systems and flow typology in the inner sections (subsurface, surface flow or lagoon). Water quality parameters analysed are total nitrogen and its forms, total phosphorus and phosphates, silica, COD, suspended solids, chlorophyll_a, dissolved oxygen, conductivity, pH and temperature. These data, altogether with the hydraulic results, are necessary to calculate the treatment efficiency of each CW. Regarding hydraulic monitoring, besides supporting water quality monitoring, the main objective is to understand the CW performance by means of concepts such as their hydraulic residence time (HRT) and hydraulic loading rate (HLR), essential to explain the removal efficiencies obtained in these systems. These parameters are fixed at the start of the study, but in practise they can be very different and a focus of uncertainty. To achieve these goals, water samples are collected every three weeks, for two years. In each CW eight points are monitored (inlet, outlet and six intermediate singular points). At the same time, a basic water flow monitoring campaign is carried out measuring water levels and velocities with a mini current meter at those representative points. Furthermore, in CW Tancat de la Pipa, a system for continuous flow monitoring has been installed: four ultrasonic velocity sensors and three level probes. Data registered will be used to calibrate mathematical models, to simulate different scenarios, assessing their impact on the system. So far, CW have been monitored for ten months, and soon results will be available for a whole year. These results will take into account seasonal variability of income flow, as well as of the CW performance. Conclusions obtained from a detailed analysis of data collected will be used to adjust CW operation, towards management optimisation during monitoring of year 2015.