Newsletter and Technical Publications
<Sourcebook of Alternative Technologies for
in Small Island Developing States>
PART B - ALTERNATIVE TECHNOLOGIES
4. TECHNOLOGIES APPLICABLE TO SMALL ISLANDS WITH SPECIFIC PROBLEMS
4.1 Freshwater Augmentation Technologies
4.1.1 Importation Using Sea Transport/Barging
Where there is insufficient water resources on an island to meet its
demands, freshwater may have to be imported to supplement available
supplies. Barging of water and submarine pipeline have been identified as
systems of importing freshwater. Water can also be conveyed to water-poor
areas from water-rich areas by overland pipelines (inter-basin transfers).
This is common practice, well-documented in standard textbooks, and not
discussed further in this volume. A fourth option, also not discussed
further in this book, is the importation of bottled water, primarily for
Barging of water involves transportation of water from one location to
another by sea, using an ocean-going vessel or barge. The barge should
contain storage tanks of adequate size to make transportation
cost-effective. Often the barge is towed by another vessel, such as a tug
boat, but can be self-propelled. Ships have also been used to transport
water; e.g., in Nauru, the ships used to carry phosphate off-island, carry
water back to the island as return cargo. Once the vessel arrives at a
suitable port, the storage tanks must be emptied by pumping into
stationary or mobile storage tanks on land prior to distribution.
Extent of Use
Except in the Bahamas, and at some small island resorts (e.g., in Fiji),
barging is rarely used except during emergency periods. In the Bahamas,
barging is used more frequently, and facilities have been developed to
efficiently load, transport (using contract ships), and discharge
freshwater. In Fiji, water is transported by barge to the outer islands,
at various times on an "as needed" basis. During periods of
water shortage, barging of water is used extensively in SIDS.
Operation and Maintenance
Efficient operation is required to minimise the cost of barging. The
costs include suitable loading and unloading facilities as well as the
cost of a suitably-sized barge. Maintenance includes regular inspection
and cleaning of barge tanks to minimize contamination of the water. Once
unloaded, the water must be stored, reticulated, or trucked to the
consumer. Pumps are required for off-loading the water, but gravity-feed
can be used to transfer water to the barge at the loading point if the
storage tank is located at an higher elevation than the barge.
Level of Involvement
Barging requires qualified and skilled personnel to operate, load, and
unload the barges.
Barging water is a very expensive method of providing freshwater to
islands. The main component of the cost is the transportation cost. For ,
in the mid-1980s, the cost of transporting water from Dominica over
distances of 100 km to 1 000 km varied from about $1.40/m3 to $5.70/m3.
The cost of water transported over a distance of about 100 km between
Puerto Rico and St. Thomas, in the early 1980s, was $7.65/m3. This service
was provided using small tankers and barges (UNESCO, 1991). In Fiji, the
total budgeted provision for emergency water supply in 1996 was $285 000,
which included the cost of trucking emergency water to and from the
loading docks as well as barging.
Effectiveness of the Technology
To be effective, a suitably-sized barge is required to minimise shipping
costs, and proper loading and unloading facilities are necessary in the
ports of embarkation and off-loading. The expenditures required for
establishing such an extensive infrastructure can only be justified if
barging is a normal means of supplying water, as in the Bahamas.
This technology is suitable for use in most geographic areas where there
are suitable berthing facilities for the barges and infrastructure to
store the water after it is unloaded and while it is being distributed the
water to the consumers. The transport of water by barge is also acceptable
during and following emergency situations, such as during severe droughts
and following hurricanes, as a means of supplementing other water sources.
Barging can provide emergency freshwater supplies to islands during
droughts or other emergencies.
Barging incurs an high cost, and, because it depends on sea conditions,
can be very unreliable. It also depends on availability of suitable barges
or tankers, and requires efficient loading/unloading and adequate storage
facilities. The major disadvantage of this technology is the high cost of
transportation which generally precludes its use except in times of
Reliance on water from off-island sources, particularly if those sources
are from a different country, may be source of concern.
Further Development of the Technology
This technology is already well known, and there is no need for further
Bradanovic, J.Z. 1980. Overview: Certain Considerations and Criteria in
Marine Barging of Water. In: P. Hadwen (Ed.), Proceedings of the
United Nations Seminar on Small Island Water Problems, United Nations
Development Programme, New York. pp. 556-583.
Meyer, T.A. 1987. Innovative Approaches to Transportation of Water by
Tanker. In: Non-Conventional Water Resources Use in Developing
Countries, United Nations Natural Resources/Water Series No. 22,
Rogers, M. 1989. The Public Water Supply in Antigua. APUA Review,
UNDTCD [United Nations Department of Technical Cooperation and
Development] 1985. The Use of Non-conventional Water Resources in
Developing Countries. United Nations Natural Resources/Water Series
UNESCO [United Nations Education Scientific and Cultural Organization]
1991. Hydrology and Water Resources of Small Islands, A Practical
Guide. Studies and Reports on Hydrology No. 49, UNESCO, Paris.
Woodroffe, M. 1992. The General Manager Says ..... APUA Review,