Newsletter and Technical Publications
of Alternative Technologies for Freshwater Augumentation
America and The Caribbean>
PART B. TECHNOLOGY PROFILES
1.8 Water Conveyance by Pipelines, Aqueducts, and Water Tankers
In some countries, water is routinely transported from regions where it
is plentiful to regions where it is scarce. Several water conveyance and
distribution techniques are available, and are actively used in many
countries of Latin America and the Caribbean.
Among the most common water conveyance methods are tanker trucks, rural
aqueducts, and pipelines. In some cases, this involves the transfer of
water from one portion of a river basin to another, or between river
basins. Each of these methods is described below.
Tanker trucks are fitted with a cistern or storage tank to transport and
distribute water from a point of supply to the point of use, particularly
to suburban and rural areas not served by a piped supply. If water is not
supplied from a central treatment facility, it is usually extracted from
the closest natural source (rivers, canals, reservoirs, or groundwater
sources) and transported by the trucks to the point of use. Water thus
transported may be pumped into a storage cistern, dispensed directly into
household or other containers, or discharged into a small-scale treatment
facility for centralized distribution. The tanks on the trucks are usually
manufactured locally, and some trucks are equipped to carry portable pumps
to extract the water from its source.
Water may conveyed through pipelines by gravity flow or by pumping. The
latter system will be significantly more expensive to construct, operate
and maintain than similar gravity-flow systems. Large-diameter pipelines
can be used to convey water over large distances, while smaller-diameter
pipelines can be used to provide bulk or individual supplies at the point
Aqueducts are canals used to bring water from a river or reservoir to a
water distribution center. The main factors to be considered in the design
of an aqueduct are the demand to be met, the source of the water, the
topography in the area in which the aqueduct is to be built, the size and
nature of the storage facilities, and the size and location of the
distribution network. Aqueducts are best suited to meeting large-scale
demands in areas with a fairly flat or gently sloping landscape suitable
for conveying water to the point of use by gravity.
Extent of Use
Tanker trucks are used in most rural and urban areas of Latin American
countries and in some Caribbean islands. Most trucks are privately owned;
in some cases government sells the water to truck owners who then resell
it to users.
Rural aqueducts have been built throughout the region and have been used
to supply water for agriculture and domestic use in rural areas.
Interbasin transfers using pipelines are common throughout the Latin
Operation and Maintenance
Pipelines and aqueducts, whether operated by gravity or by a
pumping system, need regular maintenance and repair of the pumps, pipes,
and canals, and periodic upgrading of the facilities. Problems with water
leaks, pumps, and storage facilities require immediate attention in order
to avoid interruption of services.
Maintenance of the distribution system includes servicing the pumps and
other treatment plant components, inspecting the diversion systems and
pipelines, repairing leaks, and replacing electrical motors and other
moving parts. A number of problems were encountered in the operation and
maintenance of a distribution system in Jamaica.
The level of skill needed to operate these systems is medium to high,
and involves some technical training of the operators.
Level of Involvement
In Jamaica, water distribution projects using pipelines have had
a high level of government participation. The projects were conceived and
designed by the government, funded by an international agency, and
constructed by a group of engineering consultants, with overall project
coordination provided by government. Easements to permit the pipelines to
traverse private property were purchased by the government.
The costs of these conveyance systems vary depending on their capacity
and complexity, as a function of the terrain, the availability of labor,
and the demand to be met. For example, in Panama, a small aqueduct system
designed to serve a few families cost $500. In Jamaica, the cost of
gravity and pumped-source pipeline conveyance system is shown in Table 4.
TABLE 4. Cost of a Pipeline Water Transfer System.
|Length of Pipeline
|| Diameter of Pipeline
|| 45 400 m3/day
|| 76.0 cm
|| $30 million
|| 104 000 m3/day
|| 96.5 cm
Operation and maintenance costs are a function of the specific problems
that can affect each project, such as clogging of intake pipes, or high
turbidity and/or high values of coliform bacterial in the source water
that requires treatment prior to use.
Effectiveness of the Technology
This group of technologies spans a number of scales of application.
Tanker trucks are an extremely effective means of distributing potable
water to urban and rural populations, especially as an emergency measure.
Their use on a day-to-day basis is more costly in the long term than
providing a piped supply, but, again, the method provides an effective
short-term solution to a water supply problem. On a larger scale, use of
aqueducts and pipelines can provide bulk water to users at a competitive
cost. While these latter technologies are limited by the cost of operation
to less-steep terrain, they are widespread throughout Latin America and
the Caribbean. By varying the diameter of the pipes (and, to a lesser
extent, the geometry of the channels), these technologies can span the
range of requirements from large-scale source-to-treatment-works
applications to individual user delivery applications.
This technology is suitable for use in areas where piped water service
is not available or has been interrupted. The use of aqueducts is
well-suited to transporting large volumes of water over great distances.
They are usually associated with impoundments, and are most often used in
arid and semi-arid areas.
- Transporting water obviates the need for more complex water supply
- The technology can efficiently provide water in small quantities to
less accessible areas.
Pipeline and aqueduct systems:
- Large quantities of water can be transported without degradation in
quality or evaporative losses.
- Electricity can be generated along the pipeline route if there is
significant head and flow.
- Industrial and agro-industrial enterprises can be situated where
water is otherwise unavailable if economic factors are favorable.
- The technology has a low operation and maintenance cost.
- Agricultural production can be improved and increased by transporting
water to irrigate crops.
- Compared to open channel methods, transportation of water by
pipeline reduces water loss from evaporation, seepage, and theft.
- Water prices are increased because of the expense of transporting
relatively small quantities by road.
- There is a lack of quality control.
- Water distribution is costly and slow.
- Adequate roads are required to transport water from one region to
Pipeline and aqueduct systems:
- The capital cost is high; it usually requires borrowing, thus adding
to the country's national debt.
- The skilled personnel needed to operate and maintain the project are
not always locally available.
- If the water transported is of poor quality, it will contaminate the
water resources of another basin where the necessary treatment to
rectify the problem may not be available or affordable.
- River diversion projects can create environmental problems
downstream for aquatic life and water users, and can result in the
transfer of nuisance species from one basin to another, exacerbating
water quality problems throughout a country.
- Transporting large quantities of water can deplete the resources
available within the supplying basin.
- Vandalism of the pipeline and appurtenances can occur unless the
communities through which the pipeline passes are served by the water
- Environmental impacts, such as threats to endangered species, must be
carefully considered and actions taken to minimize negative impacts.
Tanker vehicles, pipelines, and aqueducts are centuries-old
technologies for transporting water and are well accepted by all
Further Development of the Technology
Development of improved, more durable, and less costly piping materials
will improve community access to this technology, and increase the use of
this method of water conveyance. Training and development of skills among
local users is needed to facilitate the construction, operation, and
maintenance of future projects. Better methods for water quality control
need to be implemented in all water conveyance systems.
Satney Martin, Senior Agricultural Engineer,
Agriculturual Engineering Services Divison, Ministry of Agriculture,
Lands, Fisheries and Forestry, Castries, Saint Lucia.
Gerd Dercon, Profesor Universitario en la Cátedra
de Riego, Universidad de la Cuenca, Laboratorio de Hidráulica,
Quito, Ecuador. Tel. (593-7)831-688 ext. 236. Fax (593-7)832-183.
Basil P. Fernandez, Hydrogeologist and Managing
Director, Water Resources Authority, Hope Gardens, Post Office Box 91,
Kingston 7, Jamaica. Tel. (809)927-1878. Fax (809)977-0179.
Jorge Faustino Manco, Líder, Proyecto
RENARM/Cuencas, Centro Agronómico Tropical de Investigación
y Enseñanza (CATIE), Apartado 7170, Turrialba, Costa Rica. Tel
(506)556-6279/556-7830. Fax (506)556-1576/556-1533. E-mail:
Icela Ibeth Márquez Solano de Rojas, Profesora
Regular Titular en la Universidad Tecnológica de Panamá,
Calle 64 Norte, Penonomé, Provincia de Coclé, República
de Panamá. Tel. (507)997-9371. Fax (507)997-9182. E-mail:
William Murillo Montero, Ingeniero Civil, Director de
Ingeniería, Servicio Nacional de Aguas Subterráneas, Riego y
Avenamiento (SENARA), Calles 18-20, Av. 12 Transversal, Apartado 5262, San
José, Costa Rica. Tel (506)257-9733. Fax (506)222-8785.
Cox, William E. 1989. Water and Development:
Managing the Relationship. Paris, UNESCO.
Cumbrera, Jorgito, and Ricardo Núñez. 1993. Rediseño
del Acueducto Rural de Turega-Churuquita Grande. Ciudad de Panamá,
Universidad Tecnológica de Panamá. (Tesis) González,
G. 1993. "Informe Determina Porcentaje Tratamiento Potabilización
de Agua," Listín Diario (Santo Domingo), 10 de marzo, p. 10.
Government of Jamaica. Underground Water Authority. 1990. The Water
Resources Master Plan of Jamaica: Final Report. Kingston.
Kinkead, Roger A., and Hector G. Sands. 1977. Proyecto de
Abastecimiento de Agua, Comunidad E1 Llano, Provincia de Panamá.
Ciudad de Panamá, Universidad Santa María La Antigua.
Loucks, Peter. 1994. Water Resouces Management: Focussing on
Sustainability. Paris, UNESCO. (IHP-IV Project M-4-3)
Márquez Solano, Icela Ibeth. 1978. Diseño y Construcción
de una Galería de Infiltración en la Comunidad de Río
Gatún. Ciudad de Panamá, Universidad de Panamá.
Ministry of Finance, Statistics and Negotiating. 1993. St. Lucia
Economic and Social Review. Castries.
OAS. 1986. St. Lucia Natural Resources and Agricultural Development
Project: Studies and Proposals for the Implementation of a Land
Registration Programme. Washington, D.C.
Stark, J., et al. 1966. Soil and Land Use Surveys, No. 20: St.
Lucia. St. Augustine, Trinidad and Tobago, University of the West Indies,
Regional Research Centre.
World Bank. 1994. Water Resources Management. Washington, D.C.
(World Bank Policy Paper)