Froschgrundsee

Froschgrundsee
	View from the dam 2009, in the background the valley bridge Froschgrundsee
Location:	District of Coburg
Tributaries:	Itz , Effelder
Larger places nearby:	Roedental
	Bavaria , Germany
Coordinates	50 ° 21 '0 " N , 11 ° 1' 42" E Coordinates: 50 ° 21 '0 " N , 11 ° 1' 42" E
	Data on the structure
Construction time:	1982-1986
Height above valley floor:	340.7 m
Height above foundation level :	18 m
Height of the structure crown:	359.0 m
Building volume:	420,000 m³
Crown length:	350 m
Crown width:	9 m
Slope slope on the air side :	1: 2.0
Slope slope on the water side :	1: 2.7
	Data on the reservoir
Altitude (at congestion destination )	344.5 m
Water surface	94 ha
Storage space	6.6 million m³
Total storage space :	6.9 million m³
Catchment area	110.84 km²
Design flood :	97 m³ / s

The Froschgrundsee , also called Schönstädtspeicher , is a flood retention basin to protect the city of Coburg in Bavaria from the floods of Itz , Effelder and Grümpen . It is located in the area of the former municipality of Froschgrund in Upper Franconia , which was incorporated into Rödental in 1978 , and when flooding occurs, one third protrudes into the Sonneberg district in Thuringia , i.e. into the GDR area before the fall of the Wall . The planning therefore required agreements with the GDR and was viewed as an "intra-German model project". The Froschgrundsee was put into operation in 1986 after four years of construction and at a cost of 43 million DM.

location

The closest villages on the lake are two parts of the Rödental municipality: Schönstädt is just 500 meters south of the dam ; northwest of the Weißenbrunn vorm Wald lake, also about half a kilometer away, adjoining the Itztal and Effeldertal nature reserve near Weißenbrunn vorm Wald . State road 2206 runs west around the lake. A few meters east of this road, near the mouth of the Effelder , begins the area of the Thuringian village Rückerswind in the community of Frankenblick .

use

The Itz, which flows through the old town of Coburg, regularly caused considerable damage there, especially during winter floods. Since full protection could only be achieved through supra- local measures, the construction of a flood retention basin above the Schönstädt district of the city of Rödental began. This basin is able to reduce the flood runoff to such an extent that Coburg is largely protected from the floods of the Itz. The Froschgrundsee is included in the overall flood protection concept for Coburg and the Itzgrund . Since 2011, this has included networking with the Goldbergsee and the Rottenbach retention basin (under construction).

The Froschgrundsee is managed by the Kronach Water Management Authority. It is partially dammed all year round, with the Grundsee having an area of 20 hectares. The total storage space is almost seven million cubic meters , the lake covers an area of 94 hectares.

An area in the valley of the Itz and Effelder flowing towards the lake has become a biotope in which endangered animal and plant species have also settled. In 1997 it was declared a nature reserve Itztal and Effeldertal near Weißenbrunn vorm Wald .

leisure

In summer the reservoir is used as a bathing lake and for water sports, in winter for ice skating . There is a circular route around the Froschgrundsee for hiking and cycling.

Fishing is also allowed. The leaseholder of the Froschgrundsee is the fishing association (AFV) Rödental. The lake is an excellent carp and predatory fish water, in which zander, catfish, tench, perch and whitefish also feel comfortable.

The water management office in Hof operates a webcam with pictures of the lake.

dam

The dam is an earth dam 18 meters high and 350 meters long.

bridge

At its end, the lake for the high-speed line Nuremberg – Erfurt is spanned by the almost 800 meter long Froschgrundsee viaduct with a 270 meter wide arch, which was built between 2006 and 2011.