Boreholes and Wells

Environmental Issues In order to keep livestock in regions without notable surface water resources it is necessary to obtain water from underground sources (ground water near the surface or deep geological layers). The choice of positioning wells or boreholes is made not only according to the availability of water resources but also according to the requirements of the farming systems and the desired system of managing pasture resources. Water points have a major bearing on the distribution of cattle in pastures and rangelands. They also permit the management of pasture carrying capacity, and also enable temporary protection of certain areas from livestock. | Environmental Issues Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators References and Further Reading

Livestock that drink in streams are a direct source of nutrient and bacterial pollution of water and often cause streambank erosion where they access the stream. These forms of water quality degradation can be eliminated by providing alternate watering facilities and fencing or excluding the livestock from the stream.

The quality of the water is significantly improved when cattle are excluded from a pond that has previously served as a watering point and they are forced to obtain their water from a trough or tank. Livestock consumption of cleaner water may also result in improved animal health.

Objectives

- Exploitation of pastures and rangelands that have no or few surface water resources,
- Improvement of herd productivity,
- Reduction of conflicts between crop and livestock farmers

Techniques

Various techniques for exploiting underground water exist in livestock farming areas.

The borehole is sunk with a small diameter drill using special machines, lined inside with metal tubing or PVC; its small diameter excludes exploitation by traditional means, hence the necessity to use a pump. A borehole-well is a borehole connected to a well (generally modern); the borehole feeds the well which is used as a water reservoir and which is then exploitable by traditional means using a connection situated at the bottom of the well below the static level. As for the well-borehole, this is a borehole with a concentric well, the borehole feeds the well by natural flow. The well is not very deep (20 to 80 m) with a big diameter (1,4 to 1,8 m); it can be exploited traditionally (manual or animal drawing of water) or by using a pump powered by renewable energy (wind, solar, etc.). Wind turbines are commonly used in ranching areas due to their relative simplicity. They do, however, require winds which are sufficiently regular and this technology may therefore not be suitable in all situations. Channels and pipes from boreholes enable water to be transported long distances from the borehole. | Solar pumps can provide water for livestock in pastures that are not serviced by conventional electricity. Water can be pumped from wells and boreholes or from surface streams, ponds and wetlands

Costs

Costs of waterworks depend on the depth of the layer used and the equipment installed. For example, in the Sahel regions of Africa, approximate costs in 1988 were:

- Boreholes:

- The borehole itself - US$ 80,900 for a large one (300 metres deep) and US$ 48,500 for a small one (120 metres deep).
- Superstructure - (100 m3 water tower 15 metres high, drinking troughs, fountain surrounds, channels, etc.) were US$ 64,700 to US$ 80,900:
- Equipment for drawing the water, - US$ 24,300:
- 8 km of borehole reticulation, - US$ 64,700 to 72,800.

- Wells:

- a community well: US$ 194 per metre deep.
- a government well: US$ 566 per metre deep.

Targeted Livestock Systems

Pastoral and mixed systems

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
Y | Y | Y | Y | Y | Y | Y | Y | Y | Y

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | Y

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | N | N | N | N | N | N | N

Impact

- Positive environmental impact

- Improvement of animal pressure distribution on pastures.
- Reduction of overgrazing in traditional rangelands.
- Alleviation of animal pressure promoted by extension of grazing areas.

- Negative environmental impact

- Compacting of soils by trampling near watering point.
- Degradation of vegetation around the borehole.
- Reduction of undeveloped or protected areas where wild animals live.
- For wells and well-boreholes without pumps, pollution of water when it is drawn.

- Impact on livestock production (milk, reproduction, meat, health, food, etc.)

- Improvement of drinking conditions in the dry season leads to major development of the herd.
- Improvement of animal health: improved herd resistance to various infections, reduction of mortality following decrease in possibility of contamination with certain parasite-borne and infectious diseases.
- Improvement of living standards as a result of more settled way of life of farmers which facilitates access to social services.

On the other hand, provision of water has sometimes promoted development of certain diseases such as botulism.

Context of Application

In traditional livestock farming systems, watering the herd is done from surface water, excavation or wells which are generally not very deep. The use of mechanisation has permitted access to deeper sources of water and offers increased possibilities for use of pasture.

The scarcity of surface water resources for the herd as a result of climatic change or extension of hydro-agricultural systems (irrigated boundaries) may, in certain livestock regions, necessitate the exploitation of water resources from deep layers. These may not be sustainable in the long-term.

- Favourable factors :

- Absence of surface water in large livestock areas,
- Difficult access to surface water due to irrigation,
- Presence of major underground water layers ,
- Greater performance of borehole techniques,
- Organisation of producers into groups to take charge of managing water works,
- Sustained political will to install such infrastructures,
- Increasing mastery of operation and maintenance of water infrastructures

- Unfavourable factors:

- Very high costs of equipment
- Inadequate community management of rangelands

Monitoring: EIA, indicators

- Number of hours pumping of boreholes.
- Quality of water.
- Depth of layer.
- Number of animals frequenting the water point.
- Plant biomass.
- Amount of tree cover, and area of bare soil (at different distances from the water sources)

References and Further Reading

Burgeap, 1980. La construction des puits en Afrique tropicale. Ministère de la coopération et du développement, Paris.

Sunmotor International, Solar Pumping Specialists. http://www.sunpump.com/

BP Solar: Rural Infrastructure - Power for rural communities. http://www.bpsolarex.com/

Jade Mountain Inc. Waterpumping. http://www.jademountain.com

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