Evaluation of the water quality in the Guadarrama river at the section of Las Rozas‐Madrid, Spain

Abstract

The variation of the water quality of the Guadarrama river and its tributaries in a section of Las Rozas-Madrid, Spain, was studied during the time period between January 2003 and January 2008. The parameter water quality index (WQI) was used to determine the water quality based on the conventional parameters of pollution. It was found that the WQI was slightly affected in the section evaluated. The value of the WQI was in the range of 56-64, which corresponded to the classification of 'good quality'. It was determined that 64.3% of the organic matter present in the river was removed in the section of Las Rozas-Madrid. The river acted as a plug flow reactor and a first-order kinetics governed the ultimate biological oxygen demand (BOD 5 ) (BOD U ) decay. The value of the first-order constant demonstrated the river's high self-purification capacity. In addition, a high linear relationship was found between the WQI and the dissolved oxygen deficit (D). Therefore, a quick determination of WQI may be carried out if the values of D are known. These are easily obtainable by field measurements.Evaluation of the water quality in the Guadarrama river J. Vicente et al.Evaluation of the water quality in the Guadarrama river J. Vicente et al.

Water Quality Index of Natural Streams: A Case Study of Five Headwater Streams in Bald Eagle State Forest, Pennsylvania

“…The five selected studies are explained below and summarized in Table 2. WQI1, was used to assess a polluted stream in Las Rozas-Madrid, Spain [7]. It was calculated based on 11 parameters and the normalization factors were based on standards for surface water used for drinking water.…”

“…The correlations were used to find the best parameters to be selected for WQI calculation for these streams. Similar methods have been done to attempt to simplify the WQI calculation [5,7,17]. For instance, reference 23 used the oxygen deficit versus WQI to give an estimation since it had a linear correlation with R 2 = 0.91.…”

“…This assessment evaluates the pollution, ecosystem heath, and drinking water availability. There are many different WQI expressions used to assess the quality with each using slightly different weighs and number of parameters [5,6,7]. The weight factor is applied to parameters intended to carry dominance in the assessment of quality of water mainly for drinking water.…”

“…The number of parameters can change significantly from one study to another, depending on the nature of the stream and the objectives of the study. In certain studies, some of these parameters were even used individually in the evaluation of the water quality [7]. The ultimate result of an index is a numerical representation ranging from 0 to 100 where the higher the number, the better the quality of the water (Table 1).…”

“…Table 1. Scale values ranging from 1-100 representing the overall quality of the water reported by the WQI [7] WQI Scale Rating 91-100…”