Dye tracing

A dyeing test is in hydrogeology, the deliberate introduction of a chemical substance for the purpose of determining the course of an underground drainage. For sufficiently dense arrangement of seepage points can be used to determine the catchment area of ​​a source or the location of the watersheds. Underground drainage is an essential characteristic of karst areas, so that the dyeing tests are often counted among the methods of Speleology.

Hot dyeing tests in English dye tracing; this term is used synonymously in the German literature. The introduced substance is accordingly called tracers.

Originally actual dyes were used as tracers, whose appearance can be visually perceived at a source. Nowadays but invisible substances are widely used and detected in a chemical way. This often cheaper means are safe for people and imperceptible, its occurrence can be determined automatically with electronic sensors. Nevertheless, it continues to speak from the dyeing test, even if no actual dyeing is carried out.

With the use of salts is also called Salzungsversuchen.

History

In 1877, the geologist Adolf Knop from the Technical University of Karlsruhe rejected by dyeing test according to ( uranine ), that the water of the Donauversinkung feeds the Aachtopf.

An involuntary dyeing test took place in 1901, when in a fire on the premises of the company Pernod in Pontarlier in the French Jura, the fire threatened to spread to the absinthe - stock. To avoid a fire of alcohol and the risk of explosion associated, an employee opened the barrels, followed by a million liters of high-proof absinthe flowed into the Doubs, its water was milky due to the louche effect and the typical anise smell exuded. Two days later went to the 15 km distant source of the Loue from the same milky water. Thus, must be present in the river bed of the Doubs swallow holes which derive a portion of the river water and underground power the Louequelle.

Nine years later, the cavers Édouard Alfred Martel repeated the experiment by having specified a fluorescent dye in a sip hole in the bed of the river Doubs. After 64 hours, the dye reached the source of the Loue.

Method

To determine the path of the water, the experiment must be precisely planned. It is selected a suitable tracer and all eligible re- exit points equipped with appropriate measuring devices. Then a larger amount of water is released with the diluted tracer on the percolation and monitors the measuring points. The measurement time can be very different, but is typically less than a week. A plurality of individual measurements grouped into series of measurements, in addition to the determination of the flow paths and flow rates can also determine the qualitative and quantitative Schadstoffwegsamkeit. To this end, the material must be measured in addition.

The marking is done usefully with substances that do not occur in nature, at least not in the study area. You must be basically harmless, are well spread by the groundwater flow and be detected quantitatively even at high dilution.

When tracer following materials are used:

• Fluorescent dyes: uranine, eosine, rhodamine
• Good detectable salts: sodium bromide, sodium chloride, potash, borax
• Radionuclides: 3H, 51Cr
• Special Drift Body: Lycopodium, fluorescent plastic particles

An important part of planning the necessary permits. Karst areas are usually groundwater protection areas must therefore account all such tests and / or approved. Contact the affected communities and the conservation authorities.

Credentials

• Hydrogeology
• Speleology