Evaluación de la dinámica de calidad del agua superficial e intersticial de la zona alta del río Atillo

Abstract

This study evaluated the dynamics of surface and interstitial water quality in the upper area of the Atillo River by characterizing seven interstitial water points and five surface water points, with four monthly samplings carried out in the period of May-August 2022. Geographic Information Systems (GIS), sample collection and storage protocols (INEN 2169) and standardized methods for water analysis were applied. Descriptive statistics of the physical, chemical, and microbiological parameters of surface and interstitial water were carried out, as the percentage error of the ionic balance and an inferential analysis determining the PEARSON correlation between the study variables. The percentage of enrichment of surface water concerning interstitial water was valued to finally establish irrigation water quality indicators such as Sodium Absorption Ratio (RAS), Percentage of Soluble Sodium (PSS), Residual Sodium Carbonate (CRS) and electrical conductivity (EC). The highest percentage of enrichment was valued between sodium and calcium because they infiltrate by gravity and slope of the study area. The water quality indicators for irrigation determined that the samples taken from surface water are excellent, with RAS values <10, PSS <20, CRS <1.25, and EC <250 µS/cm. The dynamics of nutrient concentration are similar both in surface and interstitial water, maintaining heterogeneity in the values, which may be affected by the chemical interaction between cations and anions, due to the advance of the agricultural frontier and mainly to the EC registered in the High Zone of Atillo. It is recommended to carry out joint work to preserve the lake system to maintain a quality water resource.