I. P. Ovchinkin

Improving Well Water Supply

From the Department of Municipal Hygiene, Central Research Laboratory of Hygiene and Epidemiology, Ministry of Railways

The widespread use of dug wells is associated with the use of groundwater for drinking. Groundwater has several advantages over surface water: it generally requires no treatment and is well protected against contamination from the surface. However, the groundwater in wells may be of poor quality and pose an epidemiological hazard if the aquifer is contaminated by waste seeping into the soil from nearby cesspits, refuse pits, manure storage facilities, and waste dumps.

Dug wells must therefore be constructed in accordance with the sanitary and technical standards and rules set out below.

Well Construction

A dug well consists of a shaft (or pit) excavated in the ground, with its bottom extending 1.5–2 m into the water-bearing layer (aquifer). To obtain good-quality water, it is essential that the shaft be sufficiently deep—that is, that the aquifer from which water enters the well be sufficiently deep. The closer such an aquifer lies to the ground surface, the less protected it generally is from surface contamination, and the poorer the quality of its water.

The quality of so-called perched water is especially unreliable. This is water from the first aquifer, which lies close to the ground surface, usually no deeper than 3–6 m, and has no overlying protection against contaminants seeping into the soil.

A well must therefore be made deep enough to obtain cleaner water from the second or a deeper aquifer, lying beneath an impermeable layer that protects it from contaminated runoff from the ground surface. Dug wells are generally no more than 20–30 m deep, since drawing water by hand from greater depths is difficult.

A well should be located on clean, uncontaminated ground, preferably on elevated land with a clayey surface layer, at least 25–30 m from potential sources of soil and water contamination, such as dwellings, animal sheds, manure heaps, and polluted ponds.

Wells should not be constructed in places subject to flooding by rainwater, snowmelt, or spring floodwaters, or in low-lying areas and drainage channels through which surface water flows. For convenience, a well should be located no more than 100–150 m from dwellings. Well walls are most often lined with local materials—wood (larch, oak, pine, alder, elm, birch, spruce), bri—

…brick, reinforced concrete rings, and other materials. During the initial period of a well’s use, oak and pine impart a certain taste to the water.

Wells with a square cross-section are usually constructed with plan dimensions ranging from \(1 \times 1\) to \(1.4 \times 1.4\) m; those with a circular cross-section range from \(1\) to \(1.25\) m in diameter.

Fig. 1. Well construction. Diagram labels: \(100 \times 100\) timber; \(100 \times 100\) timber; \(d\,200\).

The yield of a dug well depends very little on its dimensions; it depends primarily on the thickness of the aquifer to which the bottom of the well has been sunk. On average, the yield of ordinary dug wells ranges from \(1.5\) to \(6\ \mathrm{m}^3\) per day.

The aboveground portion of the well’s log casing should rise \(70\)–\(80\) cm above the ground surface. The upper part of the well walls should be protected externally from surface water by a layer of compacted fat clay—a clay “seal”—\(50\)–\(70\) cm thick and extending to a depth of …

…of 1.5–2 m. Around the above-ground portion of the well, over the clay seal, within a radius of 1.5–2 m, a layer of sand should be laid and paved with stone or brick, sloping away from the well.

Fig. 2.
Drawing label: Plank 50 × 150.
Dimensions shown: 240, 675, 150.

Fig. 3.
Drawing labels: Timber 100 × 100; plank 50 × 100; timber 100 × 100.
Dimensions shown: 1250, 100, 450, 550, 875, 875, 2300, 1100.

Around the paved area, a drainage ditch 15–20 cm deep is made, with an outlet to carry water away from the well.

Well Equipment

Observations have shown that, in the vast majority of cases, water in dug wells is contaminated by dirt introduced into the well on individual buckets. Households should therefore be prohibited from drawing water from the well with their own buckets. Efforts should be made to install pumps (metal or wooden), a sweep-type water lift, a windlass with a permanently attached communal bucket, or a so-called sanitary water lift with a self-tipping bucket of the Galician type. The latter type of well equipment

Fig. 4

is the best from both a sanitary and a technical standpoint, since it completely eliminates the possibility of introducing contamination through the well opening. The sanitary water lift works as follows (see Figs. 1–4). The bucket of water is raised by a windlass and, upon reaching a bracket attached to the edge of a wide wooden trough positioned above the well shaft, catches on it by its upper rim and tips over the trough. The water then flows from the trough along a chute into a bucket placed beneath it by the user. Once the windlass handle is released, the bucket descends under its own weight and fills with water again.

To ensure that the bucket always catches easily on the trough hook, a guide pulley is suspended in the upper part of the shelter over the well. This ensures that the bucket moves strictly vertically near the hook. Without this pulley, the bucket would shift as the rope winds along the windlass.

To prevent the bucket from catching on the hook by its handle, two sheet-iron gussets are riveted to the handle. These turn the bucket through 90° if it approaches the hook handle-first. The gussets thus ensure that the bucket engages properly with the hook and tips over. Without them, the bucket, rotating about its axis as it is raised, might catch on the hook by its handle and fail to tip. To make the bucket tip more easily and ensure that all the water is poured into the trough, the handle is attached not at the rim, as on ordinary buckets, but 130 mm below it. This bucket design prevents water from spilling outside the trough.

The drawing of the equipment for fitting shaft wells with the sanitary water-lifting device shows all the dimensions needed for its construction, so they need not be given in the text.¹

¹ The enclosure over the well is constructed of 100 × 100 timbers and clad with 15 × 15 tongue-and-groove boards; the receiving trough and drainpipe are made of 20 mm thick boards. The dimensions of the enclosure may be altered to suit the dimensions of the wellhead. The ventilation openings are covered with fine metal mesh to keep insects out.