Middle Saale Valley
 
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Expansion of the Middle Saale Valley in Germany |
The middle Saale valley comprises the middle section of the Saale river over a length of around 70 km from around Saalfeld to Naumburg .
The area of the middle Saale begins at Kaulsdorf -Weischwitz south of Saalfeld with the exit of the river from the Thuringian Slate Mountains and entry into the Triassic plateau and hill country and extends to the mouth of the Unstrut . The distance between the beginning of the middle reaches and the Unstrut estuary is 68 km as the crow flies, the run length about 115 km and the drop height 118 m. The surrounding plateaus are geologically dominated by the layers of the Triassic. The red sandstone emerges east of the river and there are gentle, rounded surfaces. In contrast, the red sandstone west of the Saale is covered by the shell limestone , which causes a rugged and angular terrain. The average height of the Ilm-Saale slab and the Saale-Elster sandstone slab is 400 m above sea level.
The Saaletal than Kerbsohlental formed km with Auenbreiten to more than 1 and up to 250 m cut into the plateau. In the southern sections, the valley is usually only a few hundred meters wide. On the steep slopes of the Saale, such as at Orlamünde and the Trumpeter Rock near Rothenstein on the left or the Eichberg near Maua on the right bank, the sandstone layers stand in steep, almost vertically sloping walls. Between Jena and Dornburg, the floodplain widens up to 1400 m, only to come closer together again afterwards, with the valley slopes often reaching right up to the river. Several tributaries such as Schwarza , Orla , Roda , Gleise and Ilm flow on both sides of the Saale in z. T. also wide and deep valleys. In addition, there are numerous small, occasionally drying up brooks with narrow and short side valleys, such as the Pennickenbach and Gemdenbach on the right and the Ammerbach, Mühltalleutra and Steinbach on the left bank of the Saale in the Jena city area. The valley slopes, which are strongly structured by the side and side valleys and sloping steeply towards the floodplain in the upper parts, appear to the east of Jena as independent, steeply rising and in places bare, light mountains. In addition to the Johannisberg near Jena-Lobeda, they include the Hausberg , the Jenzig and the Gleisberg , all of which have prehistoric or medieval fortifications. In contrast, in the urban area of Jena, the shell limestone on the western bank of the river forms a relatively closed front, which is less suitable for the construction of fortifications.
In the area of the valley widening between Jena and Dornburg, which reaches a height of around 150 m above sea level, the Saale valley was originally a wide meadow landscape with numerous islands, such as at the lawn mill, near Wöllnitz and near Kunitz, crossed by numerous river bends as well as old and secondary arms. Extensive gravel banks and sandy banks formed the " bright beaches " , which are mostly only known in literature today . A map of Jena and the surrounding area from 1846 no longer shows the original course of the Saale; Johann Wolfgang von Goethe had the first straightening and piercing of river bends carried out after a flood in January 1783 above the lawn mill weir and in the area of the Camsdorfer bridge . Such activities continued to increase in the 19th and 20th centuries. In 1920 a loop of the Saale running directly below the Jenzig was removed and a 600 m long flood dam was built on the straightened course. The transition from one side of the river to the other was made possible by numerous fords at suitable points, mostly alluvial fans of tributaries and streams or flat gravel banks as in Jena in the area north of the Camsdorfer Bridge, in Burgau, Maua, Kahla and Camburg.
The middle Saale valley is one of the climatically particularly favored areas in Germany. The strong reflection of the sun's rays on the steep valley slopes and especially the heat storage of the shell limestone create an early and mild spring, hot summer, long and warm autumn and mild winter. With an average annual temperature of 9.3 ° C, Jena is one of the warmest places in Central Germany. On the plateaus 200 to 250 m higher and the areas bordering them in the east and south, the annual mean temperature is already 1 to 1.5 ° C lower. In addition, the location is sheltered from the wind, because the course of the valley means that the winds are mostly deflected and weakened in a north-south direction. The low mountain ranges surrounding the Thuringian Basin shield the precipitation. The annual rainfall is only 570 to 680 liters per square meter, most of it falls in the summer months.
