DEMO Site 2: Algarve and Alentejo, Portugal
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| Rio Seco river bed infiltration ponds | NaCl tracer test at Rio Seco river bed infiltration pond |
The "Campina de Faro" aquifer system is classified as poor groundwater status in the recently finished watershed management plan of Algarve region. It also integrates the "Faro" protected area (vulnerable zone). This is an area of strong agricultural practices where rehabilitation through artificial recharge is welcome, aiming at the minimization of diffuse pollution effects caused by traditional agricultural practices.
Demonstration is carried out in two infiltration basins located in the Rio Seco river bed at the Campina de Faro DEMO site. According to studies developed during the GABARDINE EU project, in average 5.6 hm3 of water are annually available for artificial recharge, not uniformly distributed along the year but available only during about 67 days per year, in winter time. The demonstration activities include infiltration of surface flow water to monitor the long-term infiltration capacity of the basins and potential clogging effects, and the assessment of the groundwater quality improvement in the area. The final aim would be to transform the Rio Seco stream along its path over the Campina de Faro aquifer system into an infiltration stream by constructing infiltration basins all along the stream. The infiltrating water would contribute to dilute and to increase the gradient towards the sea shore of the contaminated water.
The DEMO site is equipped with two infiltration basins (each 20 m x 5 m, 5 m deep), filled with clean gravel, and three monitoring wells for groundwater quality and piezometric levels measurement. The facility also has two concrete sections where two pneumatic gauges for river water levels control were installed, upstream and downstream of the infiltration basins. Near the infiltration basins monitoring wells are located which will be used to monitor the results of the aquifer recharge process in terms of diminishing electrical conductivity and nitrate. The entire infiltration basin will be continuously monitored: (i) river discharge upstream and downstream of the infiltration basins, (ii) piezometric levels, electrical conductivity, and nitrate at the monitoring wells in order to monitor the performance of the infiltration basins.
Besides the infiltration basins, large diameter wells (locally called "nora") are available in most of the Algarve aquifers, including the Campina de Faro aquifer, and will be included in the demonstration activities. Their characteristics are exemplified by: area at the bottom of the "nora" with a diameter of 5 m = 19.625 m2; total well depth = 24 m; available storage volume at the "nora" = 373 m3. The monitoring equipment used includes multiparametric water sensors for continuous monitoring installed in the "nora" and in a nearby well for continuously recording the discharged water volume. Another experimental medium diameter well of 0.5 m diameter, located in Areal Gordo and called LNEC6, is also available for the demonstration.
The effectiveness of the artificial recharge process will also be monitored using geophysical surveys (electrical resistivity profiles), conducted by LNEC.
To enlarge the knowledge on the capability of MAR to improve the water quality in areas with agricultural diffuse pollution, other areas will also be demonstrated: Ribeiro Meirinho stream site, where infiltration/treatment basins will be used to reduce nitrate concentrations by recharging treated effluents of the WWTP of São Bartolomeu de Messines in the karstic Querença-Silves aquifer; Cerro do Bardo site near a small dam, where infiltration wells will allow the recharge of surface water into the deeper layers of the karstic Querença-Silves aquifer, thus contributing to increase the groundwater storage of the aquifer system that further downstream is pumped for public supply; finally, Melides lagoon, where infiltration/treatment basins will be used to clean highly nutrient-rich water produced in rice fields that otherwise is directly discharged into the lagoon, with correspondent disastrous environmental impact.
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MAR clogging and MAR infiltration experiments developed in Rio Seco river bed basin (Campina de Faro, Algarve, PT) case-study, by MARSOL Partners LNEC, TARH and UALG, July 1st, 2014. |
MARSOL
Demonstrating Managed
Aquifer Recharge as a
Solution to Water Scarcity
and Drought
An EU FP7 Project
Coordination & Contact:
Prof. Dr. Christoph Schüth
Darmstadt Technical University
Institute of Applied Geosciences
Schnittspahnstr. 9
64287 Darmstadt
Germany
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The MARSOL project receives funding from the European Union's Seventh Framework Programme for Research, Technological Development and Demonstration under grant agreement no 619120. This project website reflects only the authors' views and the European Union is not liable for any use that may be made of the information contained therein. |