The main objectives in the monitoring of the physico-chemical parameters of the water both in the rivers as well as in the lakes are:

  • To detect significant medium- to long-term variations in the average water temperature, as well as the influence of these variations on the rest of the parameters (pH, dissolved oxygen, and electrical conductivity) and physico-chemical processes.
  • To detect significant variations in the natural water cycle, whether major irregularities occur in the flow, as well as a possible reduction of the quantity of water in the high-mountain rivers and streams.

Method and effort


23 sampling localities have been established, where data are taken in situ with multiparametric probes: temperature, dissolved oxygen, electrical conductivity, and pH. At the same time, water samples are collected and analysed in the laboratory using a multifunction photometer that measures: ammonium, nitrates, nitrites, total chloride, and phosphates. At some of these localities, dataloggers have been installed that measure the temperature in order to detect thermal oscillations, hourly, seasonally, and according to elevation. The calculation of the flow in one stretch of the river representative of the season is recorded according to the scheme in the next figure:


The sampling is made by the collection of an integrated water sample to analyse the different parameters (nitrates, ammonium, orthophosphates, silicates, electrical conductivity, water temperature, pH, and dissolved oxygen). For temperature and depths, dataloggers are placed for continuous measurement every three hours.


Rivers are monitored by sampling each location under study in spring, summer, and autumn, while high-mountain lakes are sampled monthly.


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Prat, N. y Munné, A. 2009. A. Caudales escasos y más temporalidad en los ríos. P.p.: 237-248. En: Agua y Cambio Climático. Diagnosis de los impactos previstos en Cataluña. Agéncia Catalana de l`Aigua. Generalitat de Catalunya.
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