GIS-BASED SITE SELECTION FOR AGRICULTURAL IRRIGATION WITH RECLAIMED WATER

摘要

Most of the treated wastewater produced in the Cova da Beira region (Portugal) is discharged into streams. It is believed this reclaimed water could be reused for agricultural irrigation since it is a sector with high water demand. However, it is necessary evaluating if its quality is suitable for irrigation. From flow rate data and physical-chemical analyses produced in the years 2009, 2010 and 2011, and from a supplementary monitoring campaign carried out in 2012, it was observed that the reclaimed water could be used for agricultural irrigation if the pathogenic load could be controlled. Based on 5 thematic maps and environmental and technical criteria, a Suitability Map was generated for the application of reclaimed water in 47.5 ha of corn, olive grove, orchard and vineyard, using GIS tools. This analysis involved the overlapping of exclusion and inclusion areas of thematic maps using algebraic operations (multicriteria analysis). The average volume of reclaimed water generated in the years between 2009 and 2011 would be sufficient to irrigate all the existent agricultural parcels in each year, after removing the areas with technical or environmental restrictions.