Methodology for determining the depth of underground water courses
The precise location of an underground water body on the surface of the terrain carries the same weight as the exact determination of its vertical depth. This information is of crucial importance, because the investor or the owner of the plot must know in advance the required length of the pipe and the entire financial expenses that will be required for drilling or digging a well.
Geometry of surface signals
Determining the distance to groundwater is done using several specific techniques. It is known that seven reflective, or so-called "false" signals are formed around each active watercourse on both sides of the source. In professional literature, special attention is paid exclusively to the fourth and seventh signals, which in theory are most often called "small parallel" and "large parallel".
Projection of a right triangle
Mathematically and geometrically, the space between the surface point just above the water and the line of the fourth signal forms a right triangle which is exactly half of the square. In such a projection, the legs are completely equal. This means that the vertical depth to the ground water is absolutely equal to the horizontal distance from the center point of the flow to the fourth signal on the surface. By simply measuring that surface distance with a meter, the exact depth of the water flow is automatically obtained.
Field measurement is carried out by walking the instrument (most often forks) at right angles to the water line, until the fourth signal is detected, where the tool will react abruptly. For maximum precision and control, the same procedure must be repeated on the opposite side of the flow. The direction from which the water comes can be determined by a special grip - placing the left hand vertically above the right. The tool will then rotate and point its protruding part exactly towards the source of the flow.
Methods of measuring and deviation of angles
In practice, the so-called "bishop's rule" for determining depth is widely recognized. According to this method, from a central point above the water vessel, measurements are made in several completely arbitrary directions in a circle. All obtained horizontal lengths to the signal should be identical, and they represent the depth to the water itself.
However, field tests conducted at thermal springs and spas have shown that the theory is not always perfect. The angle of 45 degrees, formed by the horizontal on the ground and the ray towards the underground flow, often varies in practice. Measurements on deep wells have shown that this angle is regularly between 48 and 50 degrees, while certain scientific statements claim that it can reach even 60 degrees. Because of such natural deviations, determining depth solely by relying on strict geometry is not entirely accurate. The most experienced field workers always apply a specific correction, acquired over the years, before issuing the final measurements for drilling.
Potential pitfalls and precautions
When determining the depth, there may be hidden errors that are sometimes impossible to eliminate in advance. A classic example is the situation when there are two separate streams in the ground, one right under the other. In such circumstances, it happens that the instrument reads the depth of a shallow stream (which has a negligible amount of water or is only a layer of extremely wet sand), while the information about the enormous generosity and power is inadvertently drawn from the lower, much deeper and stronger stream.
- Atmospheric influences: Work carried out before the arrival of a storm, due to a drop in atmospheric pressure, or during extremely strong solar radiation regularly gives completely incorrect and distorted data.
- Ideal time to work: Field tests must be performed exclusively in the early morning or late afternoon, when the energy field is most stable.
Bearing in mind that construction works and the procurement of pipes require huge financial resources, it is strongly recommended that persons without experience do not undertake independent projects. It is necessary to spend a certain amount of time with experts with a wealth of practice, in order to prevent mistakes that could result in claims from investors for compensation. Caution, composure and multiple checking of the results are the only guarantee of a successfully executed job.
