Water Harvesting and Storage

Environmental Issues For grazing, water is as necessary for animals as forage. Surface water enables the animals to drink by themselves and enables the farmer to avoid effort or expense in providing artificial water sources (e.g. Boreholes & Wells). Seasonal variation in the availability of surface water results in movement of livestock between wet and dry season grazing areas, irrespective of the availability of forage in dry season areas. | Environmental Issues Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators Further reading

| Natural ponds and rivers and artificial water containers constrain the distribution of animals relative to the forage resources. An insufficient number of water points is likely to result in localised overgrazing. The installation of additional surface water points is an important technology that enables optimum distribution of grazing pressure on pastures and natural rangeland areas.

Objectives

- Increased period of pond utilisation by livestock farmers.
- Creation of water points in areas unsuitable for boreholes and wells.
- Watering animals as long as possible during the rainy season using stored water.
- Reduction of farmer’s constraints (labour) to draw up water.

Techniques

- Creation of infrastructure: this consists of either improving existing water storage by increasing the depth and volume retained, or of constructing a small dam downstream from a storage pond.

- Work to improve utilisation of water and reduce water loss. To avoid degradation by animals, measures for protection of water storage and transport to drinking troughs are often useful.

- The judicious choice of areas to provide infrastructure requires knowledge of the importance of the watershed and the nature of the soils, which must be as impermeable as possible.

- Pond excavation is done using an excavation machine and sand transport. Natural ponds should be chosen for preference. The construction of storage tanks requires materials such as compacted earth, piles of stones or reinforced concrete.

- Reduction of water loss by infiltration can be done by using impermeable materials, e.g. clay. There are also certain measures to reduce loss through evaporation, which is very substantial in hot countries. But anti-evaporation covers (plastic film, neutral oil) have been found to be expensive and difficult to maintain.

Costs

In Sub-Saharan Africa, excavating a pond 8,000 m3 in volume was estimated at US$ 27,000 (1985 prices).

Targeted Livestock System

Pastoral systems on common rangeland or ranching, mixed systems
.
Grazing Systems

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

Impacts

- Positive environmental impact

- Reduction of overgrazing in forage areas
- Maintenance of wild animals
- For dikes, refilling of underground water layers.

- Negative environmental impact

- Development of water-borne diseases (trematodoses, etc.)
- Breeding of biting insects
- Pollution of water by livestock

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

- Increasing available surface water contributes to improvement of herd productivity, provided problems linked to parasitoses and pollution are limited.

Context of Application

This kind of installation, which is an alternative or a complement to exploitation of deep underground layers, is widely used in all livestock farming areas, in different forms depending on the region.

- Favourable factors:

- Impossibility of accessing the deep layers.
- Convenient relief and nature of soil.
- Cost of drawn up water.
- Accessibility of such water points.
- Existence of abundant untapped surface water resources (BUT dependant on rainfall and runoff).
- Unused pasture resources (BUT increased water availability for livestock will have no effect if the equivalent increase in forage is not available).

- Unfavourable factors:

- High costs of work.
- Lack of funds.
- Insufficient maintenance skills and equipment.

Monitoring: EIA, Indicators

- Number of animals watered.
- Volume of water stored.
- Period the pond holds water.
- Monitoring of livestock parasite infection.

Further Reading

Water Transport

International Centre for Integrated Mountain Development - Annual Report 1997: Widening the Choices -
Appropriate Technologies. http://www.icimod.org.sg/ann_reports/arep97/widen.htm (Despite the fact that the Hindu Kush-Himalayas (HKH) are the largest storehouse of fresh water, for many of their inhabitants getting sufficient water all year round is a problem).

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