Water quality spatial-temporal analysis of gravel pit ponds in the southeast regional park Madrid (Spain) from 1984 to 2009.

Abstract

We used a time series of Secchi disk values retrieved from Landsat 5 images to study temporal and spatial patterns of water quality across gravel pit ponds located in Madrid, Spain from 1984 to 2009. There is a seasonal behavior in the water quality, with higher values of Secchi disks in autumn and winter (December–February) and lower values in summer (July–August), which can be explained by the relationship between Secchi disk values and temperature and solar radiation. We found that the 1994 administrative declaration of the regional park has had a positive impact on the water quality. The trophic state of the studied pit ponds has slowly improved, though the ponds have not reached the oligotrophic state.