ASSOCIATION PATTERNS BETWEEN RAINFALL AND TURBIDITY IN A MEDITERRANEAN RIVER: THE CASE OF THE LLOBREGAT RIVER (BARCELONA, SPAIN)

The variation in rainfall in the Llobregat River basin (Barcelona, Spain) and its cyclicality has been studied previously, but not the influence of rain on turbidity. For the first time, the potential correlation between the two variables was evaluated, using a long time series of over 200,000 records from 1995 to 2020. On most days the turbidity was less than 100 NTU, surpassing 500 NTU only on very few days (approx. 5%). The significant linear correlation between rain and turbidity indicates a relationship between both variables, although of low magnitude. Turbidity oscillations were also observed according to the season and year. The time series analysis of data from 39 meteorological stations in the river basin revealed that turbidity can be explained by the rainfall of the previous 1-4 days (1 day maximum).