Abyssinian Well

ABYSSINIAN WELL. To quickly reach the upper water-bearing soil layers and obtain water from them, a special method involving driving an iron pipe into the soil is used. This pipe subsequently forms the framework of the well, the so-called tubular well or Abyssinian well. Abyssinian wells received their name because they were first used in Abyssinia during the British campaign in that country. Another name for these wells is Norton wells, after the person who proposed them.

To construct an Abyssinian well, an iron pipe with a diameter usually of 25-75 mm is taken, holes with a diameter of 8-12 mm are drilled along its surface in a staggered pattern at a distance of 40-50 mm from each other, and a pointed driving tip is screwed onto its end.

The deepening of the pipe is produced by blows of a cast-iron ram. Much less frequently, the pipe is screwed into the soil. The usual depth of an Abyssinian well is no more than 10 m, but under favorable conditions (soft soil, experienced workers, etc.) they can reach a depth of 30 m. To suck water out of the Abyssinian well, a receiving valve is placed in the lower pipe with perforated holes, above them. The pump cylinder itself is the pipe above the suction valve. A piston with a rod is lowered into the pipe, which at the top is attached to an ordinary manual rocker. Such a pump can raise water only from a depth of no more than 8-10 m, i.e., to the height of one atmosphere. At greater depths, special pumps are used. Water from a newly constructed Abyssinian well at first contains a lot of turbidity and fine sand, but then gradually acquires its normal properties. If the Abyssinian well is in a fine-sandy soil, then to protect it from sand, the pipe with holes is soldered on the outside with a fine copper mesh-filter. The construction of the Abyssinian well, in general, is very simple, is produced quickly, and does not require great experience from the workers.

The construction of Abyssinian wells, like any other wells taking water from shallow aquifers, is permissible only where the soil water in its qualities satisfies hygienic requirements. Abyssinian wells must be located far from all kinds of pollution, especially from cesspools and garbage pits, dump sites, etc.; even with very clean, fine-grained, well-cleaning soil, Abyssinian wells must be no closer than 10-20 m from these places. If the soil is coarse-grained, gravelly, then this distance should be increased by 2-4 times and, in addition, in case of suspicion of the possibility of pollution from cesspools, an experiment with fluorescein on the permeability of the soil should be carried out. The greatest danger in the sense of soil water pollution is always represented by so-called absorbing wells (for liquid sewage), and therefore where such absorbing wells exist, one must avoid the construction of Abyssinian wells. It is desirable to have the depth of the Abyssinian well at least 4 m, because too high a water level in the well indicates a high standing of soil water and, consequently, the possibility of its pollution by dirty water seeping from the earth's surface. Compared to ordinary dug wells with a wooden log frame, Abyssinian wells have the sanitary advantage that their metal walls are impermeable to water and therefore the well is reliably protected from the penetration of surface pollution from the sides. Among the disadvantages of Abyssinian wells is the lack of such free water reserves in them as exist in shaft wells, as a result of which during rapid water extraction in fine-grained soil, its amount may turn out to be insufficient, because the inflow does not have time to cover the expenditure. Furthermore, fine sand gradually clogs the mesh and the holes in the pipe, so that periodically the entire pipe has to be removed from the ground for cleaning.

For rural water supply, Abyssinian wells are applicable where the local aquifer is rich in good-quality water and there is no fear that the well will be frequently clogged with fine sand. When choosing a place in villages for Abyssinian wells, one should avoid the close neighborhood of cattle yards and manure stores. To protect the soil near the well from being saturated by spilled water, the soil level around the well is made high enough so that a quick outflow of water is obtained from it; in addition, a good paving around the well should be made, and even better, a dense concrete platform on a thick clay base should be arranged. For central water supply, Abyssinian wells are poorly suited, since their productivity is small and to obtain the required amount of water it would be necessary to arrange a large number of them. An exception is represented only by localities where there are very large reserves of groundwater that are easily amenable to pumping, but even in such cases, it is better to give preference to more powerful and durable tubular Brooklyn wells, and, in addition, by systematic and prolonged water extraction from test wells, it is necessary to make sure beforehand that such extraction does not affect the lowering of the groundwater level and its amount will be quite sufficient even in the driest time of the year. An example of central water supply by small-diameter tubular wells can serve Frankfurt am Main.

To obtain good water in the Frankfurt City Forest, in a place protected from pollution, 280 tubular wells were arranged, capturing soil water flowing towards the valley of the Main River. The water turned out to be quite good and suitable both for drinking and for various domestic needs. The well pipes are made of copper, 50 mm in diameter, equipped with perforated strainers with copper meshes, 3-4 m long. During the construction of the wells, pipes enclosed in a casing with a diameter of 150 mm were lowered into the soil, then the casing was removed, and gravel was poured into the formed cavity. Every 10 wells constitute a separate group connected by a common pipe to the main collector. Pumping is carried out from one common pumping station. Each well yields about 30 liters of water per minute, and the entire installation yields more than 10,000 cubic meters per day. Abyssinian wells find good application for quickly obtaining drinking water for construction workers, for military units located in a temporary camp in an area where there are no other suitable sources of water supply. The water of Abyssinian wells is also often used for various technical purposes, for example, in laying brick and concrete buildings, for steam boilers, etc. Upon passing of the need, the well can be easily removed and, if necessary, installed in another place. An Abyssinian well can serve up to 20 years. The cost of constructing an Abyssinian well with a diameter of 75 mm, a depth of 4 m, with a filter mesh, excluding the pumping device, is approximately 250 rubles. At a depth of 10 m and a larger pipe diameter, the cost will increase, approximately, to 800-1,000 rubles. F. Danilov, I. Ignatov.