Wells - structures that serve for the collection and extraction of underground water (water well) or delete (drain well). There are mine and tube wells. The latter are shallow (7-10 m) mercotrust printed (driven into the ground to the aquifer) and drilling (drilling the ground, covering the aquifer) - artesian wells. Mine and mercotrust wells are mainly used for local water supply, artesian - mainly for centralized.

coastal infiltration well
Fig. 1. Diagram of the device coastal infiltration wells: 1 - rock placement; 2 - gravel; 3 - sand; 4 - coal.

Much less wells are used for water intake from surface sources. They are called infiltration wells (Fig. 1).
The place for holding public wells choose a representative of the local sanitary authorities. When choosing the site are governed by the following provisions:
a) wells should be built on high levels of clean, unpolluted soil in places not flooded by rain and storm water; it is impossible to build wells in the lowlands, in the gutters and other flood-prone places;
b) the site should be well away from sources of potential pollution of soil and water: cesspools (see Rowed), landfills, livestock stables etc.
Each is well recognised: the recipient of mine (shaft), the heads of water-lifting equipment. Mine wells must be waterproof. Best satisfy this requirement walls of concrete rings in diameter of 1-1 .5 m, and a well-burnt red brick on a cement; less reliable and log houses; in addition, they are short-lived. During the digging of wells possible poisoning of workers carbon dioxide, so every time before descending into the mine should check the air quality, lowering her beam lit straw, the candle.
The most important sanitary importance device to protect wells from pollution of surface waters. It is built for all kinds of wells mainly on the following principle. At the top of the frame to a depth of 2 m from the surface in a radius of 0.5 m so-called earthen castle of fatty layer, well Prometeu, layers hammered clay, on top of which the radius of up to 2 m the area should be raised, compacted and paved with stone or brick or asphalt with a gradient from the well; for a drain of water from the slopes or drainage ditch. Around melodramatic wells stack a layer of compacted clay width of 0.65-1.0 m
The above-ground part (tip) in the mine shafts are being built in the form of deaf booths with thick walls (height of 0.75-1.0 m) and the same door, inside the booth is placed water lifting device.

tubular well
mine well
Fig. 2.(left) Tubular well: 1 - pump; 2 - pipe; 3 - filter.

Fig. 3. Mine well with a wooden frame in the pit: 1 - clay sketch; 2 - door; 3 - step; 4 - drainage wells; 5 - pump - clay lock; 7 - filter; 8 - impermeable layer; 8 - the aquifer; 10 and 11 - suction and discharge hose.

For water lift in tube wells (Fig. 2) shall apply, hand pumps, and mechanical events. Mine wells public areas (Fig. 3) very suitable for water intake also make use of pumps, individual wells apply a block, cranes, gates with attached permanent bucket; the withdrawal of water from wells their buckets prohibited.
Before putting into use of newly constructed water from the well of him pumped up full of clarification: open wells to commissioning, and after each repair) disinfected with chlorine at the rate of 100 - 150 mg/L. the Solution of lime pour into a well, water, mix thoroughly, after 4-8 hours the water pumped until the complete disappearance of the smell of chlorine.
New wells, regardless of their type allowed to use after the conclusion of the relevant health authorities; among other activities, the latter carry out sanitary-chemical and bacteriological analysis of water (see water supply). Water quality testing should be conducted periodically and in the future, particularly after each repair of wells. Cm. also Water.