Blaue Quelle

Useful Information

Location:	Mühlgraben 52, 6343 Erl. In Erl, Tirol. 300 m south of the Erler Passionsspielhaus. (47.670139, 12.186659)
Open:	no restrictions. [2023]
Fee:	free. [2023]
Classification:	Karst spring Blue Spring
Light:	no light.
Dimension:	T=8.1 °C, Yavg=750 l/s, Ymin=290 l/s, Ymax=2,132 l/s, A=471 m asl.
Guided tours:	self guided
Photography:	allowed
Accessibility:	no
Bibliography:
Address:	Blaue Quelle, Mühlgraben 52, 6343 Erl.
As far as we know this information was accurate when it was published (see years in brackets), but may have changed since then. Please check rates and details directly with the companies in question if you need more recent info.

History

1926	declared a Naturdenkmal (Natural Monument), the firt in Tirol.
1992	Quellmessstelle Nummer 395434 of the Hydrographischer Dienst Tirol installed.

Description

The Blaue Quelle (Blue Spring) is the biggest drinking water spring of Tirol. It is located only 200 m south of the Erler Festspielhaus, which is famous for its Passion Play Festival. Right beneath the spring is a former mill which is now a Hotel and restaurant of the same name. The Mühlgrabenbach flows parallel to the Inn river, after 800 m it meets the Trockenbach, which then meets the Inn after 200 m more.

This is a typical seasonal karst spring, but it never dries completely. It responds quite fast to heavy rains or snow melt, but only in flow. The low fluctuation of the water temperature by only 0.2 °C independent of the flow is quite exceptional. The conductivity also varies very moderate between 516 and 596 μS/cm with a mean value of 581 μS/cm. The low fluctuation in temperature and conductivity indicates a high proportion of deep karst water. In other words, the pressure rises when water flows into the karst aquifer, and the flow of the spring rises also. But the aquifer is quite big and first the older water flows out, and it takes quite some time to replace it. This is actually a good thing, as the quality of the water for drinking is much better.

The easiest way to visit the spring is by parking on the parking lot of the hotel or of the Festspielhaus. In both cases its about 100 to 150 m, 5 minutes walk to the spring. The pond is surrounded by a grove of horse chestnut, beech, oak, ash, lime and birch trees. The sandy bottom of the spring is covered with stoneworts.