Closed water cycle and natural prerequisites

The natural cycle of water movement operates according to strictly established rules that have been in place since the beginning of the world. Water evaporates from the surface of the soil, from streams, riverbeds and the sea, forming clouds in the upper layers of the atmosphere. The cooling of water vapor creates precipitation that soaks the ground. The water then seeps through the surface permeable layers, creating underground lakes, rivers and streams. Moving over impermeable layers, through pores and cracks, the water again erupts to the surface forming springs that eventually flow back into larger water masses, thus closing the cycle.

It is common knowledge that water resources are not evenly distributed. While regions with rich springs abound, there are vast desert expanses completely devoid of vegetation. Historically, the largest human settlements were formed exclusively where the supply of drinking water was permanently fixed. In order to respond to the needs of the population in drier regions, hydrogeology was developed — a scientific branch that studies the factors of the occurrence and movement of groundwater. Dyes are often inserted into the sinkholes in order to precisely determine where the same water rises to the surface again.

Geomorphological entities and relief specificities

Experts who do dowsing in the field must have a solid geological background to know what soil profile to expect. By analyzing typical landforms, three characteristic geomorphological units can be observed that clearly illustrate different water supply conditions:

• Plain areas and river plains: They are composed mainly of clayey, sandy and gravel deposits. Due to the high water permeability, the occurrence of water is widespread, and the level of underground water directly depends on the water level of the main river courses in the area. The challenge is precisely locating living running water instead of stagnant "pools", as well as the danger of peat, which can give the resulting water an unusable smell of rot.
• Hilly areas and mountain slopes: They were built from Neogene sediments, mostly clayey and limestone marls with occasional sand. The water in these marly (impermeable) substrates is not constant and solely depends on the frequency of precipitation and the slope of the terrain, which is why such areas are considered extremely unfavorable in geology for searching for drinking streams.
• Diluvial river terraces: They rest on marly deposits and are predominantly built of clay with quartz pebbles and occasional layers of sand. The hydrogeological conditions are much more favorable here, because the clayey surface layer with sand acts as a natural reservoir of water that flows downwards by gravity, as a result of which the chances of finding a vein of underground water are much higher.

Investigations in impermeable rocks (Laporci)

Although general geology suggests that marls and similar rocks (such as sandstone and dolomite) are unfavorable, practice shows that finding water is possible, albeit extremely complex. In such substrates, water does not move through the layers themselves, but exclusively through narrow tectonic cracks and faults created by subsequent movement of the soil.

These underground streams rarely have a high yield (usually between 1 and 3 liters per minute). The biggest problem during the works is the precision of the drilling itself. If there is a water vein only 5 to 10 centimeters wide at a depth of 20 to 30 meters, even the slightest deviation of the drill leads to failure. A deviation of only one degree in the vertical means an error of 24 centimeters at a depth of 10 meters, and even 48 centimeters at a depth of 20 meters, which is why the machine easily passes right next to the water. However, excellent results have been recorded in practice; in some thermal spas, artesian water was successfully pumped under pressure to a depth of 30 meters on such terrains, while in some rural settlements a strong water jet was created, which is fully supplied by the local water supply.

Well capacity and water supply calculation

The water level in wells and boreholes is subject to constant oscillations; it rises due to heavy rainfall, and falls during dry periods. When determining the location, the estimated water flow (for example, 2 liters per minute, which is 120 liters per hour, or 2.88 cubic meters per day) must be taken with some engineering margin.

This calculation is correct only if the capacity of the well itself, from the bottom to the hydrostatic pressure line, can store that entire volume, or if the suction pipe is placed well below the hydrostatic level. The volume of the well is calculated according to the classic formula for the volume of the cylinder (base area multiplied by the height of the water column). The inner diameter of the pipe plays an absolutely crucial role in the formation of the water reserve.

Table: Volume of water per one meter of well height (1.00 m)

The following conclusion clearly follows from the above data: if the water in the well rises 3 meters from the bottom due to hydrostatic pressure, a well with a diameter of 1 meter will hold an impressive 2,355 liters of water, while a narrow pipe with a diameter of 0.30 meters will collect barely 213 liters, despite the exact same inflow from the underground vein. This explains in detail why the inhabitants of rural areas exclusively dig wide wells, in order to ensure safe and sufficient quantities of water for the entire household and livestock.

Modern installations of narrow pipes with water pumps are recommended only for spacious flat areas with a high degree of yield, while on hilly and uneven terrain this option is very often not feasible. The general recommendation of the profession is that a well for cottages should not have a diameter of less than 60 centimeters, while for large agricultural holdings that diameter must be at least one meter. Also, strict care must be taken to ensure that two wells are never dug too close to the same water body, so as not to involuntarily deplete each other's reserves.