Centennial flood 2013

Eggenfelden, 10.06.2013

Level probes for monitoring

After the flood of the century in 2013, the great clearing up dominated the daily routine of the people in the flood areas for weeks and months. Some victims are still struggling with the consequences. According to the German Weather Service, 23 trillion liters of rain fell on Germany in just a few days. In the case of material damage alone, of which the first estimates are around 11 billion. Euros, this flood will probably go down in history as one of the most expensive catastrophes in Germany.

As a ray of hope in this catastrophe, however, the enormous solidarity of the people with one another and the tireless efforts of the helpers on site must be recognized.

Measurement technology can contribute something to support the flood areas. For example, level probes with SMS transmission were used in the crisis areas around Passau and Deggendorf shortly before the flood in order to be able to monitor the current water levels there. These hydrolog probes reliably send the current water levels to the respective water management authorities via SMS. But also many other measuring points that were in service long before the flood were able to prove their usefulness in this crisis situation and, among other things, send SMS flood alarms. This worked flawlessly and was able to avert some damage.

Not only Passau and Deggendorf but also Arnstorf were affected. Level sensors from ACS-Control-System GmbH have been in use on the local stream for 3 years. According to Mr. Lechner from the Arnstorf market, they work very reliably. The probes are responsible for alerting when the stream rises for a short time, e.g. to have passages and roads blocked by the construction yard. The probes also gave reliable alarms in the event of a specific flood.

Highest requirements in level measurement

Since there is no power supply at most of the level measuring points, great attention must be paid to power management. Here the level measuring system Hydrolog from ACS-Control-System GmbH works exclusively with lithium batteries, as these offer the greatest temperature resistance and minimal self-discharge. As a result, battery life of up to 10 years can be achieved. Additional solar panels should be avoided in order to be able to make the measuring points as “inconspicuous” as possible and thus largely exclude vandalism. A high level of operational safety of the entire system will be guaranteed, which is achieved by status messages from the measuring point and early battery warning messages via SMS dispatch. Especially in the case of measuring points with remote data transmission modules, it must be possible to change the battery on site easily and without tools. However, if a battery should run out prematurely, no data is lost, as these are stored in a non-volatile memory and can then be read out again after the battery has been replaced. The quality of the Hydrolog measuring points was able to prove itself precisely during this flood, in which the levels were sometimes up to several meters under water. Therefore, only high-quality materials are deliberately used for the mechanical parts of the probe. This begins with the fact that the entire probe body and reading head of the probe are made of stainless steel V4A and a steel cable has been integrated into the suspension cable as strain relief in order to be able to absorb the highest mechanical forces. Including the remote data transmission module, all components are designed in such a way that they can withstand floods of up to several meters without damage.

The heart of every level measurement is of course the sensor itself, which must determine the water level with the highest possible accuracy and long-term stability. Here, capacitive ceramic measuring cells with their excellent accuracy, very high mechanical resilience and, last but not least, high long-term stability are increasingly displacing the classic polysilicon cells with metal membranes.

In order to keep the maintenance effort for such a measuring point as low as possible, the reference air flow should, among other things, be optimized so that, for example, no desiccants are required, which then have to be replaced cyclically.

The hydrolog system is structured in two stages. This means that a level probe with a data memory works as the basic unit, with which the recorded measured values can be read out cyclically via laptop, handheld PC or modern smartphones. This probe can be equipped with a remote data transmission module at any time – even at a later date. Several paths are open as communication paths.

Remote data transmission

Above all, alarms such as flood warnings, main alarms, deep water alarms, battery limit values, but also status messages with current water levels and battery levels are transmitted via SMS.

The classic dial-up connection is mainly used for the transmission of the collected measured values and the setting parameters of the probe and the GSM module. It is important that the data can be transmitted using both push and pull methods.

The third path is the data transfer of the measured values via GPRS directly to the Internet, e.g. to an ftp server. This modern method offers a variety of advantages over the dial-up connection. Above all, the energy-saving short transmission time should be mentioned here, since the collected data is sent “packed”, but also the possibility that any number of probes can access the server simultaneously. This eliminates the time-consuming time slot procedure in which the probes have to be called up one after the other. Because the measured values are stored on an Internet server, the user has the option of calling up the data from any location with any computer that has Internet access. By assigning a password on the server, it is possible to authorize the people who are allowed to access data.

Operability and processing of measured values

Since data collectors always require software for parameterization and also for evaluation of the collected data, great importance must be attached to easy use and preparation of the measured values for further processing. The operating concept of the Hydrolog-System from ACS-Control-System provides the parameterization of the measuring point via PC or laptop, as well as via Windows Mobile-based devices such as handheld PC or smartphone. In addition, all setting parameters can also be controlled via an SMS command. This means changes to the setting can be sent to the measuring point as SMS, which will then automatically adopt the settings the next time it goes online.

Another important point is the documentation of all events and actions that happened at the measuring point or were carried out by it. It is advisable to keep two logs separate from each other. The probe’s logbook records when and by whom data was retrieved, who made which changes to the settings, and logs any device malfunctions that may occur.

The logbook of the remote data transmission module also offers the possibility to see when and to whom, for example, alarms were sent or data transfers took place, but also which problems may have occurred with the network provider.

 

Planning, commissioning and data integration

When selecting battery-operated level measurements and remote data transmission modules, great attention should be paid to the manufacturer and its support services.

From planning to integrating the measurement data into existing systems, a few things have to be taken into account and, under certain circumstances, adjusted.

As a solution partner in the field of level and gauge measurement such as ACS-Control-System GmbH, the provider should accompany the customer from planning the measuring point to commissioning and integrating data.

Well-engineered and tried-and-tested sensors that have proven themselves in tough use over the years are recommended.

Because even in the hopefully long times when there is no flood, the level measurements should provide excellent service by reliably recording the water levels and then forwarding them to the responsible authorities either by “manual reading” or by remote data transmission. This is future-oriented and investment-safe level measurement.

Further information on flood early-warning-systems and level-measurement

Level-measurement coupled with IoT. Read everything about data storage, remote transmission and alarms:

Reports about the flood disaster 2016 in Simbach:

Installation of the flood early-warning-system in Geretsham:

All information about level-measurement paired with IoT can be found here: