Flood protection
The Saale flows through Jena from south to north. The river drains a total catchment area of 24,167 km².
Since the 1930s, the water discharge of the Saale has been regulated by the Upper Saale dam system. Below the dams, other larger watercourses flow into the Saale, such as the Loquitz, Schwarza, Orla and Roda.
The construction of the dams has significantly reduced both the frequency and the extent of flood events in Jena. Nevertheless, the risk of flooding has not been completely eliminated.
The most recent large-scale flooding occurred in June 2013 after prolonged rainfall in the catchment area.
Building in the floodplain
The Saale still has some well-preserved floodplain areas in the city of Jena. Some are used for agriculture or are home to large sports facilities. Others are protected under nature conservation law.
These floodplain areas perform important functions as retention areas during flood events. They are therefore designated by ordinance as so-called floodplains.
The boundaries of the floodplains on the Saale and Roda rivers can be viewed at the lower water authority. Here you can also obtain information on any risk of flooding to your property.
Only uses that are compatible with the function as a drainage and retention area are permitted in floodplains.
Changes of use in the floodplain that are relevant to flood protection require approval from the lower water authority.
This includes, for example, the construction or extension of buildings, embankments, excavations or the conversion of grassland into arable land. Further details are regulated by the Water Resources Act.
For detailed information, please refer to the city's service portal: Floodplain - Permit.
Flood forecast
The state of Thuringia maintains an extensive network of flood warning gauges. The nearest gauge on the Saale above Jena is in Rothenstein.
The current flow rates and water levels can be viewed at the flood information center for the state of Thuringia
If a danger situation becomes apparent, the flood information center will issue corresponding flood reports and messages as well as alert levels.
In the event of flooding, depending on the situation, additional information is available on the city of Jena's website and in other media such as the press and radio.
Measures in the event of flooding
If the water levels in the upper reaches of the Saale indicate an imminent flood event in Jena, measures are taken to avert danger.
The necessary protective measures are set out in the fire department's alarm and deployment plans and in the emergency plans of the supply and disposal companies.
The type and scope depend on the predicted extent of the flooding. In addition to technical protective measures by the fire and water services, the population is also provided with extensive information via sirens and the relevant media.
Technical flood protection concept for the city of Jena
In the event of flooding, the personnel and technical capacities of the emergency services are often not sufficient to protect endangered areas on a large scale with mobile elements (e.g. sandbags).
Mobile systems can therefore not replace stationary flood protection facilities.
As part of a technical flood protection concept for the Saale in the city of Jena, it was investigated which areas at risk of flooding are suitable for the construction of stationary flood protection facilities. These are recommended in particular for the Zwätzen and Göschwitz areas.
The Free State of Thuringia is responsible for implementing and financing the measures. The measures planned throughout the state are prioritized here.
The flood protection concept can be viewed at the lower water authority of the city of Jena.
Self-preparedness for floods and heavy rain
If a property is located in an area at risk of flooding, buildings must be protected against the ingress of water into the structure and against the water pressure and buoyancy in the event of flooding.
In addition, adequate protection against groundwater ingress and backwater from the sewer system is required.
Technical equipment and electrical installations must be located in flood-proof rooms. Damage caused by flooding can also be reduced by choosing water-resistant building materials.
Detailed information on property protection and building precautions in flood-prone areas can be found in the "Flood Protection Guide" published by the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety under Downloads.
The increasing number and intensity of heavy rainfall events requires similar precautionary measures as in the case of flood risk.
In contrast to flood events, heavy rainfall usually occurs briefly and locally. They are difficult to predict. How homeowners and planners can nevertheless arm themselves against them is compiled in the "Guidelines for heavy rainfall prevention" published by the JenaWasser Association under Downloads.