Water alarm
The water alarm ( French Alarme eau , Italian Allarme acqua , Rhaeto-Romanic Alarm d'aua ) is one of two alarm signals in Switzerland and is triggered by a siren . The other alert sign is called "General Alert". The water alarm is used to protect the population from a possible tidal wave in the event of an emergency in a dam.
Basics
Basically, it is the task of the operator of a dam to operate a warning network for the water alarm. The water alarm consists of a series of twelve deep, continuous tones of 20 seconds each at ten-second intervals. The general alarm warns of the water alarm. The water alarm is a request for immediate evacuation of the endangered area below a dam. The operators of dams are responsible for the timely triggering of the water alarm in the event of a risk of flooding in the so-called "near zone" below the dam. A “near zone” is defined as an area that a tidal wave below a dam can reach within two hours. The water alarm is regulated by the ordinance on the safety of dams of January 1, 1999. Article 19 of the ordinance stipulates that dams with a volume of more than 2 million m³ in the vicinity must have a water alarm system. 198 reservoirs in Switzerland must therefore operate a water alarm system. Around 600 sirens for water alarms have been installed in Switzerland. Mobile sirens are also used in remote areas.
history
For the first time, the water alarm was legally regulated by a federal decree on September 7, 1943. The occasion was the bombing of three dams in the Ruhr area during the Second World War by the Allied air forces. The first dams in Switzerland in 1945 were the Bannalp , Canton Nidwalden and the Klöntal , Canton Glarus, to be equipped with sirens. Originally, the water alarm was only intended in times of military threat. The Federal Military Department was responsible for setting up and operating warning systems. The dam ordinance of July 9, 1957 stipulated: “The Federal Military Department can prescribe additional protective measures, such as alarm devices,…. It can also oblige the plant owner to set up water alarm centers and secure observation stands in the vicinity of the facilities and to provide accommodation for security and water alarm organization ». This regulation led to considerable tensions between the military and power plant operators, as the military could demand bunkered water alarm centers and observation posts as well as permanent telephone connections from the operators. But these shied away from the costs and the dam ordinance did not define a minimum size of a dam.
A revision of the dam ordinance on February 10, 1971 made the hydraulic engineering supervision of the water alarm subordinate to the Federal Department of the Interior. The “near zone” has been increased from originally 20 minutes to 2 hours. The water alarm was no longer viewed solely as a measure in the event of military interference. It should also be able to be used for all other security threats. This development was influenced by the Vajont disaster on October 9, 1963, where a tidal wave triggered by a landslide killed 2,000 people. In addition to the military threat, 5 scenarios were defined in which the water alarm must be triggered: 1. abnormal behavior of the dam or its subsoil; 2. mass fall into the damming (rock, ice, snow); 3. flood; 4. earthquake; 5. Sabotage. An alarm had to be possible even without the “Army Warning Service” in peacetime, as the “Army Warning Service” had to be called up in peacetime. It was not until the revision of the dam ordinance of November 27, 1985 that responsibility for civil threats was established: the dam owner is responsible, the army continued to be responsible for the military threat. This changed in 2002. With the Army Reform XXI and the entry into force of the revised military law of October 4, 2002, the military water alarm detachments were dissolved on December 31, 2003. Since then, the operators have also been responsible for triggering the water alarm in the event of an armed conflict.
In February 2018 there were problems with the water alarm system during the annual siren test. According to SRF, the water alarm did not work everywhere. On February 7, 2018 at 2:15 p.m., the Federal Office for Civil Protection (BABS) triggered a water alarm across the country to test the sirens. But the central alerting by the Federal Office did not work in some cantons. An analysis showed that a software error in the BABS was the cause. The central alerting server of the BABS did not forward messages to the Polyalert / Polycom network. The test was repeated on May 23, 2018. The alarms by the barrages owner / operator were not affected. The annual siren test ran successfully in 2019. With one exception, all the water alarm sirens responded during the test.
technology
Communication technology of the Swiss Army was originally used. The SF 57 telecontrol system from Autophon AG from Solothurn was used. The system was based on cable connections, i.e. leased lines. In contrast, the sirens of the civil defense were triggered with the siren remote control SF 457, the PTT , later Swisscom . Since the SF 57 telecontrol system was no longer manufactured, the concept had to be revised. An equal working group was set up made up of representatives from the supervisory authorities and the owners. Only the framework conditions were defined, called “Water alarm 2000”. A certain product was no longer required. Since then, the dam's operator has been able to decide which switching technology to use. He can also use existing solutions such as directional radio, but must ensure redundancies. In particular, the failure of the power supply must be taken into account, and the fact that the water alarm center can also be reached in the event of an accident. For this reason, alternative, additional alarm triggering points, called “emergency posts”, have been defined, which can also trigger an alarm if the water alarm center at the dam is not manned or can no longer be reached.
The water alarm is always triggered by a person and not automatically, e.g. B. triggered by sensors. The automatic loops are no longer used to trigger a water alarm. The risk of false alarms is too great; the consequences are devastating. And since the responsibility now rests with the operators, who have to monitor the dams anyway, and no longer with the military, which would first have to be deployed in order to manned a water alarm center, an automatic alert was no longer considered sensible.
There have also been changes to the sirens: where there used to be separate sirens for the “water alarm” and the “general alarm”, today “combined sirens” are used in new installations, which are operated and maintained by the civil protection, i.e. the Federal Office for Civil Protection and the cantons . The civil defense and the operator of a dam partly share a siren. To control the sirens, the Polyalert network was prescribed, a radio network under the leadership of the Federal Office for Civil Protection based on Tetrapol . Since 2005, dams with a capacity of less than 2 million m³ have also been equipped with alarm devices for the water alarm. In contrast to the larger systems, however, they do not have to have a water alarm center or accommodation near the dam and no observation posts. Separate «combination sirens» are installed if there is a high risk. If the risk is classified as low, the sirens of the civil protection are also used by the operators. These are only able to call out a «general alarm». The Reuss dam in Bremgarten was the first to be equipped with such a system. 40 more followed.
Splash water
As flood water is Wasserablässe called the operators of dams. These water drains can occur due to operation or malfunction. Planned or unplanned water drainage may occur. Most of the water drains are secured by the operator's water rights. Areas that are affected by surge water are to be marked with warning signs. These areas may be flooded by the power plant operator without warning. In Switzerland, around 500 streams and rivers below power plants are affected by the surge water. Splashing water can lead to fatal accidents. A water alarm must not be triggered if there is a surge of water. Power plant operators also use their own sirens for warning. However, the signals must not be similar to the water alarm. Usually a penetrating tone of approx. 1000 Hertz is emitted. There are also systems where the operator makes automated announcements via loudspeaker system. Other operators use optical warning systems (flashing lights). Others only warn with signs. A surge water alarm must not be confused with the water alarm.
Alarm system for the Wägitalersee dam
Wägitalersee Bunkered observation post for the water alarm (close-up view).
Wägitalersee Bunkered observation post for the water alarm (distant view).
Wägitalersee water alarm center Note the military radio antenna (30–80 MHz)
Wägitalersee Bunker observation post for the water alarm seen from the dam wall.
Wägitalersee accommodation of the water alarm detachments directly at the dam. On the left of the picture bunkered observation post.
Individual evidence
- ↑ What is the water alarm? Federal Office for Civil Protection, accessed on July 19, 2018 .
- ↑ Two warning signs. Federal Office for Civil Protection, accessed on July 10, 2018 .
- ↑ Example of a Sihlsee water alarm evacuation zone in the city of Zurich
- ↑ History of the water alarm. Federal Office for Civil Protection, accessed on July 10, 2018 .
- ↑ Responsibilities of the dam operator: ... For systems with a water alarm system: ... Automatic triggering of the water alarm as soon as the situation is no longer controllable or an uncontrolled runoff of a large body of water is likely or has already occurred. See Guideline on the Safety of Dams, Part E: page 4.
- ↑ SRF water alarm does not work everywhere
- ↑ SRF water alarm did not work due to a technical fault
- ↑ alertswiss.ch Extraordinary siren test: general alarm and water alarm
- ↑ Aargauer Zeitung Today the sirens are being tested - you have to know that
- ^ RTR Sche l'alarm d'aua suna - Quai èsi da far Tests da sirenas senza problems
- ↑ War in the Aether Alerting and Mobilization Systems In an ordinance on dams, the federal government laid down the basis for alerting the affected population. In principle, the corresponding regions were equipped with sirens and the SF 57 water alarm remote control from Autophon by the end of 1983. Swiss Federal Institute of Technology in Zurich, accessed on July 10, 2018 .
- ↑ Siren test 2015: balance POLYALERT ... In contrast to the previous remote control system, which is based on cable connections with the switchboards ... alertswiss, accessed on July 10, 2018 .
- ↑ Siren remote control SF 457. Swiss Federal Institute of Technology in Zurich, accessed on July 10, 2018 .
- ↑ Responsibilities of the operator of dams: The operator of the dam plans and implements communication channels to trigger points and the operations center of the cantonal police / canton See: Guideline on the safety of dams on page 8
- ↑ An automatic loop or alarm loop is an electrically conductive metal band or cable that is attached to the parapet of a dam and through which an electrical current flows. If the tape or cable breaks due to a mechanical influence (dam break) then no more current can flow and an alarm is triggered. The alarm loop serves as a kind of rip cord.
- ↑ The dam breach assessed as a millennium event. Federal Office for Civil Protection, accessed on July 10, 2018 .
- ↑ "The FOCP has the following tasks: Establishing the alarm system for the population together with the cantons" Guideline on the safety of dams, page 6.
- ↑ Sirens in Switzerland now with a uniform control system. Tagblatt, accessed on July 12, 2018 .
- ↑ Splash water catalog of measures to avoid accidents. Association of Swiss Electricity Companies, accessed on July 12, 2018 .
- ↑ Splashing water Observe the warning signs on the waters. Elektrizitätswerk Zermatt AG, accessed on July 12, 2018 .
