The National Park has a gauging station at the Peñalara Vale (La Hoya de Peñalara) exit with the objective of measuring the water flows circulating at the Peñalara Lagoon stream. Those data are fundamental to know the hydrologic behavior of a high mountain small basin, representative to a large extent of the behaviors of the Sierra de Guadarrama different streams basins. Therefore it is possible to know with high accuracy about phenomena such as the thaw, the water retention at the basin, the summer low water, the storms effects, etc. The station is working uninterruptedly since December 2001.
Additionally the available data indicate the Peñalara Lake limnology behavior depends to a large extent on the renovation rate, which means, on the hydrologic characteristics of that small high mountain basin. That is why the gauging station generates a data series related to flows and very reduced temporary scales temperatures, very useful for the hydrologic modeling and simulations. That facility is complemented with the GuMNet rainfall data, and as well with the snow thickness data collected manually.
The gauging station was made modifying an old water intake diversion dam of the dismantled Alpine ski station. Its design facilitates not only the summer period very small flows measurements, but as well the large flows of hundreds of liters during the thaw or strong storms.
As examples of the gathered data, maximum punctual flows of over 1.000 liters/second have been reached, and nearly every year there are days with averages over 200 l/s. Those maximum rises take usually place at the thaw, whose intensity depends of the meteorology of every particular year (cumulated snow amount and spring temperature). By the contrary, in the dryer years it allows the water circulation maintaining the stream as a small ponds series.