Tackling Environmental Threats on Pacific Atolls
Total Page：16
File Type：pdf, Size：1020Kb
PACIFIC ECONOMIC BULLETIN Tackling environmental threats on Pacific atolls Colin Hunt Increasing population density on the main islands of both Tuvalu Colin Hunt lectures in and Kiribati is generating waste loadings that exceed the assimila- Environmental Management tive capacity of the natural systems. The resulting pollution is and Development at the lowering the quality of life and causing ill health. The renewable National Centre for resources of the atolls are being degraded and their ability to provide Development Studies at the Australian National a continuous stream of future benefits is in jeopardy. Development University. proposals pose additional environmental threats. This article (based on fieldwork conducted in Kiribati and Tuvalu in September 1995) examines the management of natural resources on these two Pacific atolls, and some of the institutional and financial implications of addressing the consequential development imperatives. Kiribati and Tuvalu lie near the equator in Sources of fresh water the central Pacific and are both made up of groups of atolls. Kiribati is comprised of A characteristic of many atolls, including the Gilbert group, including the heavily- those that make up Tuvalu and Kiribati, is populated island and administrative the presence on larger islands of a fresh- centre of Tarawa, plus the Phoenix group water lens just below ground level. The and the distant Line Islands, which lenses are recharged by rainfall. Given the include the relatively large island of absence of rivers or freshwater lakes, the Kirimitati. Tuvalu is a smaller group of only other source of fresh water to sustain atolls, south of Kiribati, whose population human populations is collected rainwater. and administrative centre is Fongafale, on The average density of the population Funafuti atoll. The key issues for these throughout the islands of Tuvalu is four times atoll countries include fresh water supply higher than the average for Kiribati —347 and contamination, and sewage and solid persons per square kilometre compared waste pollution and disposal. with 85 per square kilometre (Tuvalu 1991; 58 TACKLING ENVIRONMENTAL THREATS ON PACIFIC ATOLLS AusAID 1995:41). However, the density in water on South Tarawa for half of the South Tarawa (on the main island of households lies in wells that directly tap Kiribati) is high: 1600 per square kilometre, the lenses, while rainwater tanks are a main compared with 1137 per square kilometre source for a third of households. on Funafuti, the main island of Tuvalu. The rate of extraction of fresh water Moreover, in the suburb of Betio, South from lenses is unsustainable. The draw- Tarawa, the density rises to 5,400 per square down at Betio and Bairiki on South Tarawa kilometre, great even by world standards. of 1,250 cubic metres per day exceeds the While the Kiribati government can estimated sustainable yield of 1,000 cubic declare any area a water reserve, in practice metres per day (Kiribati 1995:15). Salt the lenses constitute common property water intrusion is thus a possibility. resources subject to open access through Moreover, the supply of reticulated water wells. As the density of the human from lenses in Buota and Teaoraereke on population above a lens increases, the South Tarawa has already been supply of potable water can be jeopardised discontinued because it is subject to by drawing down water at a rate faster uncontrolled use and pollution by squatters. than it is replenished and by pollution The Kiribati Public Utilities Board is through the very permeable overlying responsible for the operation and manage- soils. There are severe penalties for ment of the reticulated water supply. While pollution of the water supply but they are there is a charge of A$1.00 per square not enforced (Gangaiya 1994). metre, orderly supply of reticulated water Rainfall is relatively high and more and cost recovery is hampered by a failure reliable in Tuvalu, and in contrast to to read meters, meter tampering and Kiribati, the majority of households have illegal connections. Moreover, leakages been fitted with rainwater tanks, metal reduce supply by between 10 and 20 per roofing, plastic guttering and downpipes cent (Kiribati 1995). While the cost under a UNDP project. Substitution of recovery of reticulated water supply is, in rainwater for polluted ground-water theory, advisable through pro rata charges, supplies is one of the keys to the the charges should not be such as to prevention of water-borne disease and encourage the continued use of ‘free’ well other health threats posed by lens water. Gangaiya (1994) suggests that the contamination by bacteria, viruses, and high frequency of well use is a function of dissolved nitrogen. the charge on reticulated water. The supply of fresh water to the If sustainable potable water supply to increasing population of South Tarawa, the population of Kiribati is to be the goal, and to islands with growing populations, open access to lenses must be phased out, such as Kirimitati, is a major development drawdowns from safe lenses must be constraint. While untapped lenses can be managed and a plan for rainwater utilised, supply is limited. The freshwater collection developed. It appears that heavier lenses at Betio and Bairiki on South Tarawa supplementation by collected rainwater will presently provide an extraction rate of be necessary even though the collection of 1,250 cubic metres per day to some 3,500 rainwater is an expensive option on South connections (out of about 4,000 households Tarawa, given the atoll’s relatively low and in total) but the supply is only available erratic rainfall. Individual strategies for the for 1 to 2 hours for three periods of the development of sustainable water supplies day (Kiribati 1995:14). The main source of will be required on the outer islands of 59 PACIFIC ECONOMIC BULLETIN Kiribati; strategies will vary depending on construction of causeways has limited tidal island size, rainfall, and on actual and flushing of the lagoon and exacerbated projected population density and health risks posed by the contamination. A distribution. build-up of nutrient loads in the poorly- flushed parts of the lagoon poses a potential threat of eutrophication and Pollution algal blooms. The risk is acute during ‘doldrum’ periods or neap tides, when One of the most valuable natural resources natural flushing of the lagoon is minimal. of both Kiribati and Tuvalu are the lagoons Sewage systems that produce a solid and inshore waters. However, like the compost, rather than a liquid effluent that freshwater lenses, these resources are must be disposed of into the ocean, are subject to open access. Their safety and worthy of investigation. However, there productivity, as with freshwater lenses, is may be significant cultural restraints on dependent on prevention of contamination using compost derived from human faeces by sewage and other land-based pollutants. —such an option would need to be On South Tarawa, Kiribati, a reticulated accompanied by an education program. sewerage system was constructed in 1993 While cost recovery of an improved and to serve 9,000 people, via connections to universal sewage system should be the permanent housing, government buildings ultimate goal, it must be recognised that and to community toilet blocks in Betio, sewage charges will, in the meantime, tend Bairiki, and Bikenibeau. While householders to encourage traditional beach disposal of use the reticulated system to some extent, faeces (without cost to the individual, but a large proportion of the South Tarawa at a cost to the community). population still deposits faecal waste on Where population densities are ocean and lagoon beaches. This situation increasing on the outer islands, appropriate may, to a certain extent, be a function of the management options must be considered poor state of repair of the sewage system; for the prevention of pollution of the frequent mainline blockages are freshwater lenses and lagoons. Options for accompanied by vandalisation and the sewage treatment and disposal have been disrepair of community toilets. Management trialed by the Australian Government on problems are exacerbated by the failure of Kirimitati (AusAID 1994). local councils to accept responsibility for public toilets, or oversee the siting of pit In Funafuti, septic tanks are now latrines and septic toilets. Waste water is mandatory for each residence under Island Council by-law, and in the main population also a pollutant, but regulations governing concentration at Fongafale the containment its disposal are not enforced (Kiribati 1995). of sewage by septic tanks and pit latrines Recent studies of the Tarawa Lagoon seems to be complete enough at this stage have confirmed that coliform contamination to prevent pollution of the lagoon. The of both water and shellfish is greater than lens would undoubtedly be polluted by acceptable standards (Biosystems 1995). A the tanks and pits but rainwater collection South Tarawa study of lagoon pollution has, to date, obviated the necessity to draw emanating from land suggests that nutrient upon lenses. Lagoon and water-lens loadings amount to about 80,000 kg of management is jeopardised on both atolls nitrogen and 10,000 kg of phosphorous by the common practice of penning pigs per annum (Conrad 1993:109). The on lagoon shores. 60 TACKLING ENVIRONMENTAL THREATS ON PACIFIC ATOLLS Solid waste still the second most important constituent of solid waste (Tulega 1992). Composting The high density of population in South would reduce the waste burden and prevent Tawara and Fongafale has exacerbated the loss of plant nutrients but it is not solid waste disposal problems. Households practised in the urbanised areas. And the are the main source of solid wastes in the separation and recycling of much of the form of garden leaves and non-biodegradable remainder of the waste stream poses a packaging of imported foods and drinks. problem because of the inherent lack of On Fongafale there is a build-up of solid economic incentives.