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Newsletter and Technical Publications

<Sourcebook of Alternative Technologies for Freshwater Augumentation
in Small Island Developing States>


PART C - CASE STUDIES

5.1 Augmenting Freshwater Resources in Kiribati

Introduction

Kiribati consists of three main island groups scattered over 3 million km2 of the Central Pacific, between latitudes 4° N and 3° S, and longitudes 172° E and 157° W. The total land area is 810.8 km2, comprising 33 low-lying coral islands, 10 of which are coral atolls (Figure 36). The Gilbert Island group consists of 17 islands (including Banaba, or Ocean Island) with a total land area of 285.7 km2. Tarawa Atoll, in the Gilbert group and the location of the capital, consists of more than 20 named islets, the southern six of which are linked by causeways. The distance between Tarawa and outer islands in the Gilbert group ranges between 51 km and 600 km. The Phoenix Island group consists of 8 largely uninhabited islands with a total land area of just 28.6 km2 located some 1 750 km east of Tarawa. The only inhabited island of the Phoenix group is Kanton (Canton) Island with the land area of 9 km2. The Line Island group consists of 8 islands with a total land area of 496.5 km2, extending over a north-south distance of 2 100 km, located at a distance of between 3 280 and 4 210 km east of Tarawa, and some 800 km south of Hawaii. This group includes the largest island in Kiribati, Christmas Island (Kiritimati), having an area of 388.4 km2. Most of the islands are not more than 2 km wide, or more than 6 m above sea level, except Banaba in the Gilbert group which rises about 87 m above mean sea level. The depth of water wells in most cases varies from 0.5 m to 3.0 m.

Figure 36

Figure 36. Map of Kiribati.

Climate: The climate of Kiribati is dominated by that of the dry equatorial zone, which extends as a narrow belt over the central Pacific, and by an inter-tropical front in the zone of convergence of the north-easterly tradewinds, which remain fairly constant between 5°N and 8° N. Rainfall varies considerably, not only between islands, but also from year to year. In an average year, annual rainfall in the Gilbert group ranges from 1 000 mm in the vicinity of the equator, to 2 000 mm on Tarawa, to 3 000 mm in those islands furthest to the north. In the Phoenix Islands, annual rainfall is 1 000 mm and in the Line Islands annual rainfall ranges from about 700 mm on Kiritimati to about 4 000 mm at Teraina Island about 400 km to the northeast of Kiritimati. The central and southern Gilbert group, Phoenix Islands and Kiritimati are subject to severe droughts lasting many months. At such times, as little as 200 mm of rain may fall in a year.

Types of Technologies Used: In Kiribati, there are several types of technologies used to augment and maximise the use of freshwater resources for domestic purposes (i.e., drinking, cooking and sanitary uses only). The use of water for agriculture, industry and others is not considered as top priority, and no attempt has been made to consider using potable water for agricultural use due to the very limited potable water resources on the low lying atoll islands. The types of technologies used in the outer islands (rural areas) are solar powered pumps, windmill pumps, hand operated diaphragm pumps, and piston hand pumps (locally known as Tamana pumps). In the urban areas electric pumps are used in piped reticulation systems. Groundwater is the main water source for drinking, cooking and other uses. Rainwater is also widely used, but only as a supplementary water source.

Technical Description

Open, hand-dug wells are the traditional method used by I-Kiribati to obtain freshwater for their basic needs. As the depth from the surface to the groundwater table is generally just a few metres, and the soil is fairly easy to excavate by hand, open wells or pits, 1 m to 2 m in diameter, are excavated to a depth of 30 cm to 50 cm below groundwater table. The walls are usually supported by stones and the well is left uncovered for everyone to scoop up water as needed. However, under the guidance of the Ministry of Health and Family Planning (MHFP), and, earlier on, of experts from various aid-donor agencies, certain improvements have been introduced into the construction of these dug wells. Concrete rings were introduced as support walls. These are placed up to about one-half metre above ground level, and surrounded by a concrete apron cast around the well to impede the seepage of mud, debris, and other contaminants into the water. A concrete cover is placed over the well, with an opening for drawing water out with a bucket.

Mainly on Kiritimati (Christmas) Island there are several infiltration galleries, consisting of open trenches, each some 150 m long and approximately 3 m wide, dug to about 50 cm below the water table, from which groundwater is pumped by diesel-operated horizontal pumps. The sides of the trenches are supported usually by slabs of coral stone, and, sometimes, by sheet metal or timber. Boards cover the trench. There is no treatment of the water. A more advanced design, introduced in recent years and adopted by an on-going UNDP/UNCDF Project, includes, in addition to a hand-dug well, a 100 mm diameter, slotted polyethylene pipe, extending between 20 and 60 m on either side of the well. The pipe is laid at a depth of 30 cm to 50 cm below water level, and the trench is refilled with gravel. The well and the pipework "gallery" is located a few hundred meters away from the village, primarily to remove the source of water from sources of pollution in the village, but also to extract the water from the freshwater lens at a location where its thickness is greatest (and this usually occurs some distance inland from the village). The freshwater is thus skimmed from the uppermost layer of the lens, and from a larger water-table area, compared to a well alone, thereby reducing the risk of upconing of the underlying seawater. Extraction of groundwater from the well is by either hand-operated diaphragm pumps, solar pumps, or windmill pumps.

Hand pumps are installed at convenient supply points in the village and draw water from the well through a 32 mm to 50 mm diameter polyethylene transmission pipe of up to 750 m in length. The pumps are of a plain diaphragm type, suitable for the conditions typical of usual coral islands (i.e., low, near-flat topography and shallow depths to the water table, resulting in low suction heads). A system of this type usually consists of up to three pumps drawing from the same transmission main, with each pump designed to supply three families at an assumed per capita consumption rate of 30 l/day. Several dug and covered wells have been equipped with a hand pump, mounted on top of a concrete cover. The pump used in these applications is either a semi-rotary, diaphragm type suction pump, or a portable Tamana pump. The Tamana pump is an innovation developed by a man from the island of Tamana in the southern Gilbert group of islands. The basic components of the Tamana pump are 25 mm PVC pipe, usually up to 30 m long; a 50 mm PVC pipe, 1.0 m long; a 25 mm to 50 mm, 45° PVC reducer bend; a 25 mm elbow; a 25 mm PVC male adaptor; a foot valve; and, a piston made of wood. A new design of piston, made of one-half inch PVC piping, has proven to be more durable than the wooden piston and is now widely used throughout Kiribati for extracting water for bathing and other sanitary uses.

Where the distance from the well and galleries to the village exceeds 750 m, an horizontal electric pump is installed near the well and draws water into a 50 mm to 63 mm polyethylene transmission main which discharges into 2 or 3 storage tanks. Water flows from the storage tanks through 32 mm to 50 mm distribution pipes feeding a number of stand-pipes in the village (up to 20 standpipes may be served). The volume of each tank is 9 m3 and each tank is intended to supply up to 60 households. Electricity for the pump is generated by a set of photovoltaic panels, without battery storage, designed to pump water for a rather conservatively-calculated 6 hours of sunshine per day. The storage tanks can be of ferrocement or concrete blocks, constructed on top of 1.5 m to 1.8 m high stands made of concrete blocks and reinforced concrete.

There are several types of solar pumps used in the country. The earliest types are the Southern Cross and BP CR2-30 solar pumps. At present the Public Works Division is using a newer type of solar pump designed by Mono Pumps Australia. The technical specification of these solar pumps are given in Table 6.

TABLE 6. Technical Specifications of Solar Pumps.

Pump Brand Pump type Motor Size Number of
solar panels
Typical Flow
rate at 20 m head
Southern Cross Positive Displacement 24 Volt DC 1/3 hp 8-10 0.6 1/s
BP Pump CR2-30 Centrifugal 24 Volt DC 1/3 hp 8-10 0.6 1/s
Mono Pump Possitive Displacement 180 Volt DC 1 hp 10 0.6 1/s

Windmill pump systems are essentially the same as solar pump systems, but rarely used. The problem with windmill pumps is that they are very difficult to maintain and operate. Erecting the windmill tower requires a special skill which is not often available locally. Also, the windmill gear box is located at the top of the tower. Further, the wind itself as a source of energy is found to be unreliable due to its intermittent nature.

Level of Involvement

Water consumption rates, determined by the Water Unit for planning purposes only, range from 30 l per capita per day in rural areas to 50 l per capita per day in urban areas, based upon consumption rates for cooking and drinking water supply only. People are encouraged to use alternate sources of water (rainwater and groundwater in the vicinity of the village) for sanitary and other purposes.

Prior to the on-going UNDP/UNCDF Project, eleven villages had been provided with solar powered water supply systems; namely, two villages on Tabiteuea North Island were provided with a solar powered water supply system using funds provided by the Norwegian Government, seven villages on Nikunau Island were provided with a solar powered water supply system using funds provided in part (for solar pumps only) by the South Pacific Commission, one village on Arorae Island was provided with a solar powered water supply system using funds provided by the Save the Children Foundation, and one village on Tamana Island was provided with a solar powered water supply system using funds provided by the United Nations Development Programme (UNDP). Of these, the seven villages on Nikunau Island had previously been supplied with pumped water using a windmill-powered system installed in the 1960s using funds provided by the World Health Organization (WHO). The windmill pumps were subsequently replaced or supplemented with solar-powered systems installed using funds provided by the South Pacific Commission (SPC). Two other windmill systems remain operational; namely, one windmill in a village on Arorae Island, and one in a village on Tabiteuea South (installed originally by WHO and later rehabilitated by the Public Works Division using funds provided by the Government of Australia). The windmill pumps last about twenty years with proper maintenance, and, hence, most are near the end of their useful life. Few windmill pumps installed in the late 1960s are working today, and most are being replaced with solar pump systems, installed during the UNDP/UNCDF project, which perform as well as, or better than, the wind-powered systems. The only problem that is very often encountered with the solar systems is that of a broken belt, but this can be fixed by the Island Council plumber.

South Tarawa

On South Tarawa, the New Zealand Government, and, later, the Australian Government, installed a basic water supply system serving South Tarawa in the 1970s (Figure 37). This system provided water primarily through public standpipes. However, an increasing population on South Tarawa and a cholera outbreak in 1977, resulted in the Government of Australia-funded, Tarawa Water Supply Project. This Project provides reticulated water to all the population of South Tarawa and to Buota in North Tarawa. Construction work for the project was carried out between 1983 and 1987 by the Australian Department of Housing and Construction. The system was later improved and extended in 1989 by the Snowy Mountains Engineering Corporation (SMEC), with funding again provided by the Australian Government. Total capital investment by the Government of Australia to date to this project amounts to approximately $6.4 million. Under this scheme, water is pumped from collection galleries installed in two freshwater lenses. There are 17 galleries on Bonriki, and 6 galleries on Buota. Each gallery has a concrete- or fibreglass-lined well and each well is equipped with an electric, horizontal helical rotor-type pump (a Mono-type pump). The discharge pipes of all the wells are connected to a collection pipe, into which chlorine is injected at the point where the 30 km long, 155 mm to 225 mm diameter rising main begins. The rising main extends along the South Tarawa chain of islets, connected by causeways, to the reticulated consumer areas where it is stored in elevated tanks, 4 m above ground level (except the Betio tank which is at 13 m above ground level). These tanks are filled from the rising main either directly or by pumping from ground-level reservoirs connected to the main.

Figure 37

Figure 37. Map of Tarawa.

Based on extensive hydrogeological investigations, the sustainable yield of the Buota and Bonriki lenses was estimated as 1 300 m3/day. At present, some 1 250 m3/day are extracted. This amount is supplied to a population of some 26 000, the Betio port, and several other large consumers. Actual demand for water is far higher than 1 250 m3/day, and the Public Utilities Board (PUB) restricts the supply to daylight hours normally and to 6 to 7 hours a day approximately one-third of the time, in order to enable water to reach all part of the system during these hours. Pumping from the lenses, however, is maintained at a constant rate all the time.

In the three most-populated areas (namely Betio, Bairiki, and Bikenibeu), seawater reticulation systems have been constructed, since the early 1980s, for flushing toilets and waste disposal through ocean outfalls. This reserves the groundwater for other domestic use. No treatment, other than the grinding of solids in the pumps, is provided for wastewater before the sewage is discharged through the ocean outfalls.

The increasing population of South Tarawa is placing a great deal of strain on the limited water resources available. In addition, the issue of squatters living on the Water Reserves has not been resolved, and there are already indications that the freshwater lenses are being polluted by such development. Most of the suitable freshwater lenses in the vicinity of South Tarawa have been utilised and any major expansion of the water supply would involve either the development of lenses on North Tarawa, such as on Abatao and Tabiteuea Islands, or other solutions, which would increase water production costs. The current water tariff of $0.80/m3 is not sufficient to cover the operation and maintenance costs of $1.44/m3 incurred by PUB, even with some Government subsidy, and revenue collection is incomplete and slow. There is a high percentage of unaccounted-for water, estimated at 50%, of which perhaps 15% is due to physical losses while the rest is due to unread water meters and illegal connections. Notwithstanding, there is under-utilisation of rainwater at present, as many houses and buildings do not have rainwater collection facilities; many of those government and private houses that do have rain catchment facilities have broken or blocked gutters and downpipes which render then inoperable.

The performance of the South Tarawa water supply system is a fine example of a fully-developed freshwater lens. During the 10 months drought (1988-1989) and 1995, the lens suffered only marginal thinning effects. The total land area of the Buota and Bonriki groundwater lenses is only a little over 1 square kilometres (km2) and it is supplying over 1250 m3/day. The conductivity reading of the water supplied towards the end of the drought never went above 600 FS/cm which is within the WHO water-quality guidelines.

Kiritimati

On Kiritimati Island (Figure 38), water is supplied from a combination of groundwater extraction, collection, and distribution schemes; rainwater collection schemes using a variety of storage tanks; and, privately-owned or communal shallow dug wells. The estimated population of the island in 1995 was 3 095, but the island, which is the largest in Kiribati, features high among that country=s priorities for development. A sustainable water supply is critical for the potential future development of the island, mainly as a tourist destination. Water supply systems exist at Decca (supplying Ronton and the public buildings of Tabakea); Banana (supplying the Main Camp, Banana, and the Fisheries building near Kiritimati Airfield); the Captain Cook Hotel at Main Camp; and, Boran (Poland).

Figure 38

Figure 38. Map of Kiritimati Island.

The Ronton water supply system is in a poor state. The pipeline from the galleries in Decca to the settlement at Ronton (which had a 1995 population of about 1 234) is leaking, with recent tests indicated a 20% loss rate, and the quality of the abstracted water is not suitable for drinking. Faecal coliform bacteria are present in the water and conductivity exceeds 3 000 mS/cm. The overhead tank which feeds the Ronton reticulation system is also leaking resulting in low water pressures in the system. As a consequence, water is imported into Ronton by the water tanker truck which transports water from the Banana and Decca water reservoirs. However, only those people living in houses with a storage tank enjoy the full advantage of the water tanker service. Very few houses in Ronton have rainwater tanks. Tabakea (which had a 1995 population of about 796) has no public water supply system, and freshwater is obtained from shallow wells and a few rainwater tanks. This village is also served by the water tanker truck, which most benefits those properties having water storage tanks. Banana (which had a 1995 population of about 857) has a water supply system, based on pumping from a gallery and a well north of the village which was constructed during the late 1980s by the Ministry of Line and Phoenix Development (MLPD), although, apparently, not in accordance with the design proposed in a 1983 study. The system does not provide a 24-hour supply, and, while the quality of the water has an acceptable salinity level, the water is highly contaminated. The water supply system is currently not operating very well and water is also imported into this community by the water tanker truck. Boran (which had a 1995 population of about 208) has an old reticulation system, but new galleries have been constructed close to the village by the MLPD. However, the galleries are overpumped and the quality of the water is excessively saline and bacteriologically contaminated.

Operation and Maintenance

Most of the technical problems encountered in the operation of the small diaphragm pumps used for water abstraction from dug wells have been caused by air entering the transmission mains through poorly-jointed pipes or pipe damage. The handpump, itself, can last for more than five years if it is properly maintained; the life span of the Southern Cross handpump (used for infiltration gallery systems) can be ten years with proper maintenance. Table 7 lists the parts of the handpump that need frequent replacement. The Southern Cross handpumps are simple to maintain, and, given available spare parts, breakdowns are minimal. At present, the country relies on overseas supplies for spare parts, but there are plans to set up a local industry to fabricate simple parts such as the plunger rod and handle assemblies. The rubber diaphragm can be replaced with rubber salvaged from tractor truck inner tubes. Based on experience, the rubber diaphragms provided by pump manufacturers last for only three weeks to three months, depending on the pump usage. Diaphragms made from tractor truck inner tubes can last over six months.

The problems that can occur with solar pumps are breakage of the drive belt that connects the motor pulley to the pump pulley (which can be fixed with a new belt); malfunction of the maximum power point tracker (MPPT) (the Mono pump can still work without it); wear on the rotor/stator; and, failure of the pump cannot start on its own (usually due to tight spots on the rotor/stator caused by the expansion of the rubber stator). Based on field experience, these problems commonly occur after five years of operation, although the drive belt can break after over two years. Repair of the drive belt is very simple and can be done by the Island Council Plumber (if a spare belt is available). The MPPT and the rotor/stator failures cannot be fixed by the Island Council Plumber, although, if a spare MPPT is available on the island, it can be replaced by the Island Council Mechanic. With appropriate training, tools and spare parts, the Island Council Plumber could also be enabled to replace the rotor/stator.

TABLE 7. Components of Handpump Requiring Frequent Replacement.

Pump Part Description Frequency of Replacement Unit Cost of Part
Diaphragm Rubber Three weeks - three months $ 0.05
Bolts and Nuts for Hundle One year $ 0.30
Handle Assembly One year $12.00
Bolts and Nuts for Pump Body Two years $ 5.00
Plunger Rod Three years $ 8.00
Top Half Three years $52.00

Level of Involvement

The technologies adopted are generally accepted by the communities. Given the health-associated benefits of clean water, people are willing to participate in the implementation of a project, and, with the completion of water supply systems in some villages, people living in neighbouring villages or islands can be motivated to request water supply systems or work voluntarily to speed up the work. The water systems in the outer islands are operated and maintained by the village people, and the Island Council Plumber or Sanitary Aide, with readily available spare parts. Only the case of solar pump breakdowns is technical assistance required from the Public Works Division. Such problems, however, are rare within the first five years of operation.

Costs

The capital, operation and maintenance cost of village water systems are tabulated in Table 8 below.

TABLE 8. Capital, and Operation and Maintenance Cost of Village Water Systems.

System Type Capital Cost2 Per Capita Capita Cost Operation
Cost
Maintenance Cost
Hand-Operated
Diaphragm Pump
$1 800 $32 Negligible $0.06/m3
Solar-Powered Pump $20 000 $40 Negligible $0.04/m3
Tamana-Type Hand Pump $160 $26 Negligible Negligible

aCapital cost includes the costs of all system components (i.e., pipes, tanks, solar panels, pumps, etc.). For the hand-operated diaphragm pumps, the capital cost was derived using the typical three handpumps installation per transmission line.

It is clear that from Table 7 that the cheapest pumping option is the Tamana-type handpump. However, the Tamana pump cannot be used in reticulated potable water systems as it is only capable of drawing water from wells within a 30 m radius of the house. The second cheapest option is the solar pump system, but the capital cost is high. However, should the (outer island) communities become involved at the grassroots level in local fundraising, acquisition of such systems to improve community water supply systems may be possible, and, in such situations, government assistance in purchasing an appropriate type of system and adequate quantities and selections of spare parts is available. Because of the local sense of ownership that results from community funding, such systems are usually very well maintained.

The availability of spare parts can be a problem, as many have to be imported. The government presently assists with ordering spare parts from overseas suppliers and resells them at a reasonable price to respective island councils. However, in consultation with pump manufacturers in Australia, the possibility of setting up a local industry to manufacture simple spares for handpumps under license is being investigated as a means of reducing the cost of spare parts. Until then, the government has set up a revolving fund to finance maintenance of water supply systems in the outer islands. The initial fund of $8 000 was established in 1995 to purchase the most-needed spare parts for handpumps and solar pumps installed during 1985. Also, the idea of setting up village water committees to operate and maintain village water systems, and to collect affordable water fees from the consumers, is being pursued to ensure the sustainability of village water systems. Water fees would be collected from village water consumers for maintenance, operation, and replacement of water supply infrastructure at a proposed rate of $1.00 per household per month for handpump users and $2.50 per household per month for solar pump users. In urban areas, the water tariff is $0.80/m3.

Effectiveness of the Technology

The Southern Cross solar pumps were difficult to start when the pumps were first installed in 1985. The pumps would not start automatically in the morning before 0800, or in the afternoon after 1500 hours until sunset, or during cloudy periods of the day. This was resolved by installing a power maximiser (controller) to boost the current from solar panels to start the motor during these periods, and by placing a spacer gasket at both ends of the rotor/stator to eliminate tight spots. Such problems cannot occur with the Mono pumps as the Mono Solar pumps use a larger horse power motor (i.e., 1 hp versus 1/3 hp, as shown in Table 6). The Mono pumps also can work without controllers, but they have approximately 30% less pump output.

Suitability

The Tamana pump may prove to be the best, most affordable and maintainable means of pumping water from shallow hand-dug wells even though the Tamana pump can only draw water efficiently from a distance of not more than 30 m. While the use of the pumps reduces the risk of transmitting diseases in comparison to the traditional method of dipping a bucket into the well, the problem of contamination of hand-dug wells from pit latrines located in close proximity to the wells remains. This problem can be minimised to a degree by using community-based infiltration galleries, which can be located at some distance from the village centre, and which draw water from the surface of a freshwater lens. However, there is a need for low cost, low discharge handpumps, distributed over fragile freshwater lenses, which are environmentally preferable to having many wells used at low intensities spread over the lens, to effectively skim the aquifer, drawing off the highest quality water and minimising saline water up-coning.

From operational experience, the best pumping systems for use in Kiribati are the Mono-type solar pump and Southern Cross type hand-operated diaphragm pump. The Tamana-type hand pump should be used for sanitary purposes only. The Southern Cross handpumps draw small volumes of water from distances of up to 750 m over a 7 m lift head. Where the good water sources are located more than 750 m away from habitations, or where a greater head exists, solar pumps should be selected. These pumps are used to pump water from infiltration galleries into elevated storage tanks or reservoirs. These pumps typically have a minimum design flow of 0.8 l/s when operated on a 6 to 8 hour pumping day over a total head of 20 m maximum. The pedestal horizontal type helical rotor pump is the most suitable type of this pump.

Advantages

Infiltration gallery systems reduce the risk of up-coning of the underlying seawater. However, these systems require the use of pumps. Present experiences with the small diaphragm pumps indicate that such pumps are reliable and relatively easy to maintain: the diaphragm, made of plain rubber, can readily be replaced by the village plumber by unscrewing four bolts on the pump body. However, because of their limited pumping range, solar pumps are often used. Solar pumps have no fuel costs and limited operation and maintenance requirements.

Disadvantages

Open, hand-dug wells have the obvious drawback of being a potential health hazard, as the well water is exposed to contamination. In addition, the villagers tend to dig these wells close to their dwellings, where pigs and other domestic animals move about and could potentially foul the exposed water. Moreover, the proximity of pit latrines (first introduced in the 1970s) to the hand-dug wells is causing many wells to become unsafe for drinking. In high-density housing areas, such as South Tarawa, the remaining, old, open dug wells are now a severe health hazard, and even though covered dug wells are well protected, recent tests on the water quality of these protected wells have proven positive for the presence of faecal coliform bacteria. Open galleries or collection trenches also are open to contamination in the same manner as the dug wells.

Cultural Acceptability

In Kiribati, water collection is not the sole responsibility of women as it is in other countries in Asia and Africa, and some countries in Latin America. The people in Kiribati tend to live in places where good groundwater exists and water collection from distant wells is done collectively by the members of the community and households who can walk long distances. The traditional method of obtaining drinking water is simply to bail water out of an open, hand dug well using any type of container that could be tied at the end of a string (rope). Similarly the traditional method of defecating is to use the beach or the bush. The introduction of piped water supply systems, and water-sealed latrines or flush toilets especially in the outer islands, are imported ideas which are not well received by the people. Nevertheless, the problem with the use of the traditional methods of obtaining water is that open hand-dug wells are often located dangerously close to pit latrines and other sources of contamination in the village. An high incidence of water-related diseases (mainly diarrhoea) in recent years can be attributed to the fact that many people still use shallow, open, hand-dug wells contaminated by nearby leaking toilets, pipes, and fixtures, or nearby soak-away pits. With the problem of high incidence of water-related diseases, the people are now beginning to appreciate the health-associated benefits of piped water supply and proper sanitation.

Notwithstanding, the implementation of water projects in the outer islands of Kiribati require much patient and time-consuming groundwork before successful implementation is achieved. This is because community consensus and participation are not easy to achieve, despite the fact that water projects are often initiated by the community. The main reason for community reluctance to participate is due to the facts that they are expected to provide free labour as their contribution to the project, and that they are very busy with the routine chores everyday. Land disputes over the siting of wells, galleries, or tanks can also cause delays in the implementation of a project. Land in Kiribati is traditionally owned by individuals and the landowner consent is required before the land is utilised for the benefit of the community. If the landowner does not agree to surrender the land for use by the community, then government can exercise power under the Land Acquisition Act to acquire the piece of land for public use, but such powers can only be used after all diplomatic means of negotiation fail. Lands acquired by the government under the Land Acquisition Act may be subject to vandalism, and the former landowners may continue to occupy the water reserve areas. Nevertheless, there have been cases where people living on water reserve areas in Kiribati were removed by force.

In addition, problems between upstream and downstream water consumers is universal and Kiribati, with its low-lying islands, is no exception. However, this problem only occurs with solar-powered pumping systems. People living at the upstream end of the rising main tend to misuse the water by keeping their taps on, resulting in low water pressures or no water at the downstream taps. This problem can result in downstream water consumers ransacking the water system.

Further Development of the Technology

Due to the pressing problem of land scarcity, the government is keen to explore alternative water sources to meet water demands on South Tarawa, the capital of Kiribati. Alternative water sources being considered include desalination, reclamation of depressed areas for water harvesting, and establishment of rainwater catchments. There are several types of desalination plants available on the market and Kiribati has to choose the most appropriate type. In contrast, water harvesting by reclaiming low-depression areas on Tarawa, of about 350 ha in areal extent, so as to form a freshwater lens, could yield approximately 2 600 m3/d, while the use of rainwater by individuals and institutions to alleviate the water shortages is to be promoted. Currently, the use of rainwater systems is not widespread, and, in spite of existing regulations, many existing roof collection installations are inoperable or under-utilised. There is a need to design rainwater catchment systems for particular roof areas of adequate size to sustain a long drought. This is an expensive option as it will involve constructing huge-volume tanks. The costs of these three alternatives has been estimated to be in the range of $1.6 million to $24 million, based on preliminary costings. However, it must be noted that there can be no life without water.

The experience gained by Kiribati in augmenting and maximising fresh groundwater resources is unique to a low-lying coral islands situation. The technologies used so far have been tested for quite a number of years and have been proved to be working well. The best type of pump for use in the country is the positive displacement pump, as the pumping rate can be optimised to minimise salt water intrusion. For centralised water supply systems with distribution tanks and communal taps, the best type of pump is the Mono pump. For handpump systems, the best pump is the Southern Cross hand-operated diaphragm pump, although another type of pump that should be promoted for sanitary purposes, especially in the outer islands and peri-urban areas, is the Tamana pump. The performance of the Tarawa Water Supply scheme, which at present is serving more than 26 000 people, is an exemplary case of a fully-developed groundwater lens. The use of properly-constructed infiltration galleries and the use of positive displacement pumps is an effective groundwater extraction method with minimal thinning effect on the freshwater lens. The lens area is just over 1 km2 with a total water production rate of 1 250 m3/d. The conductivity reading of the water never exceeded 600 FS/cm, even during a 10 month long drought. A significant factor in the success of this project was the recognition and inclusion of social and cultural consideration at the inception stage and during the implementation stage of the project.

Despite these successes, there is a need to improve the design of the Southern Cross handpump so that it has a longer useful life. There is also a need to try other types of pumps available on the market to determine their suitability for use on low-lying coral islands. It is also important to promote public awareness of the health-associated benefits of clean water, water conservation, and well location within the community. This could be done using radio advertisements, posters displayed in public places, inclusion of appropriate teaching materials in the primary schools curriculum, and through meetings and workshops held in the village maneaba (traditional meeting hall). The public awareness campaign should be an on-going activity. Further, in order to fully utilise rainwater, all buildings with permanent roofing should have a rainwater catchment system. This should be done to an appropriate engineering design, promoted through the public awareness campaign, and included in enforceable legislation. It is very important that the design of the rainwater system be adequate to sustain supply during prolonged drought periods.

Information Sources

Contacts

Taboia Metutera, Public Works Division, Government of Kiribati, South Tarawa.

Bibliography

Australian Government Department of Housing and Construction 1981. Kiribati - Tarawa Water Resources Pre-Design Study. Australian Department of Housing and Construction, Canberra.

Australian Government Department of Housing and Construction 1986. Review of Tarawa Water Supply Project. Coastal and Environmental Engineering Branch Report No. OS 236, Australian Department of Housing and Construction, Canberra.

Burke, J. 1995. Mission Report No. KIR/93/001 - Kiribati and Fiji. United Nations Department of Development Support and Management Services, United Nations Development Programme, New York.

Falkland, A.C. 1992. Review of Tarawa Freshwater Lenses. Hydrology and Water Resources Branch Report, ACT Electricity and Water, Canberra.

Falkland, A.C. 1983. Christmas Island (Kiritimati) Water Resources Study. Australian Department of Housing and Construction, Canberra.

Metutera, T., D. Hapugoda, and P. Mosley 1989. Outer Island Community Water Supply, Inception Report. United Nations Development Programme Project No. KIR/87/C02, UNDP, New York.

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