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Newsletter and Technical Publications

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


PART C - CASE STUDIES

5.3 Solar-powered Pumping in the Federated States of Micronesia

Introduction

The State of Chuuk, Federated States of Micronesia, consists of 11 high volcanic islands and approximately 290 low lying coral islands, with a land surface area of 127 km2 (see Figure 40). About 40 of these islands are inhabited. The average annual temperature is a fairly constant 27°C. Annual rainfall averages 3 500 to 4 000 mm, with a minimum monthly rainfall of 150 mm and a maximum monthly rainfall of about 400 mm. A community water supply system on Unanu Island, Chuuk, was completed in 1987. It consists of four separate wells, each equipped with its own solar pumping system. A community water supply system on the neighbouring island of Onou was completed in 1994. The Onou Island system consisted of a single well and tank.

Figure 40

Figure 40. The State of Chuuk, Federal States of Micronesia.

Technical Description

On Unanu Island, the wells consist of a series of interlocking, ferrocement cylinders used to line the well, with the number of cylinders being determined by the depth of the well. A concrete slab was poured around the well at the ground surface and the well was covered by a concrete cover. The ferrocement cylinders were made by plastering mortar over an inner tin form. Upper and lower forms of 19 mm plywood held the inner form in place and controlled the thickness of the mortar. The lower plywood form controlled the shape of the female end of the cylinder. The mortar was held in place and reinforced by 13 mm security screen. After the mortar had cured, the upper and lower plywood forms were removed, permitting the tin inner form to fall away from the cylinder. The ferrocement cover was made using a modified version of the bottom plywood form.

Five 40-watt solar modules were mounted directly above the well to power the pump. A positive displacement (rotary vane) type of pump (Dankoff Solar Products) was used. The pump was mounted in the well (above the water table) and the well covered with the ferrocement cover. Water from the wells was pumped to two 19 m3 ferrocement storage tanks. The tanks were constructed using pieces of flat tin tied to a framework of reinforcing rods that had been perforated with a large number of holes. Mortar was then plastered over the flat tin, generally in two coats on the outside and two on the inside. Vertical reinforcing rods extending from the sides of the tank were bent to reinforce the bottom and top of the tank. In addition, circular rings of reinforcing rods were added to the top and bottom. Step by step instructions for a 5 m3 tank using this design can be found in Winter (1988a). The covers of these tanks were made of reinforced concrete. A temporary form was made by tying pieces of flat tin to the underside of the cover-reinforcing rods. The tin was then propped up with pieces of local timber to temporarily support the weight of the concrete while it cured. A manhole was cast in place in the cover. The covers were usually conical in shape, making an angle of around 10 degrees to the horizontal.

From the tanks water flowed via gravity to water-use areas at each home.

The Onou Island system consisted of a single well and tank, equipped with a centrifugal pump (A. Y. McDonald Co.) which was expected to have a longer life than the rotary vane pumps used on Unanu. The pumping rate was higher and the tank was larger (around 30 m3) than on Unanu. Larger diameter pipes were used and the tank was elevated slightly. These measures solved the low pressure problem in the distribution system. A faucet especially designed for developing countries initially appeared to solve the breakage problem, although some of the new taps may have failed due to corrosion since they were designed for use in arid areas (rather than in marine environments or where the water being pumped is slightly brackish). Power was supplied to this system from a solar array placed adjacent to an existing array used to power a solar freezer facility. This particular location was guaranteed to be shade-free for the foreseeable future.

Effectiveness of the Technology

On Unanu, the primary technical problem experienced in this project was low pressure at the water-use areas. This was because of the small-diameter pipes used in the distribution system and insufficient elevation of the storage tanks. In addition, the faucets used in the water-use areas failed prematurely, apparently because children opened coconuts by banging them on the taps. At present, this system is almost non-functional. While the Onou system was designed to minimise these problems, a few homeowners were reported to be leaving their faucets open all the time to ensure that they obtain the maximum amount of water possible. As a result, the storage tank is not kept full and homes further along on the distribution system do not receive any water.

Cultural Acceptability

When the four pumping systems were installed, the community willingly cut down coconut trees in the area to ensure that the needed sunlight would strike the solar panels. People also agreed to keep breadfruit trees in the vicinity of the wells trimmed. One family that owned a small breadfruit tree adjacent to one of the wells agreed to cut it down immediately after it produced fruit that growing season. Unfortunately, this promise was not kept and the tree continued to grow. A few years later, the family requested compensation from the island government for removal of their tree. Following this, at least two other people requested compensation for the removal of branches from their trees. As no compensation was paid and the trees continued to grow, the system became less and less effective as the arrays increasingly became shaded.

Advantages

When the project was implemented, there were no wells in the vicinity of the single village on the island. This technology made a freshwater source available.

Disadvantages

The Unanu project suffered from lacklustre community involvement. There was no local leadership of the project, and the traditional leaders on the island could not resolve the issue of the shaded array. The project never progressed to the point where it became part of the way of life on the island. Although the system was a gift, funded through a grant from the US Department of Energy, the community members, including women and children, willingly donated one month of their labour to the project. However, local municipal funds were never committed for the maintenance of the system. As a consequence, the community did not perceive that they were contributing any of their own resources to the project, and the project languished. (Labour is still regarded as free on the more traditional islands.) On Onou, the total cost of the project, including engineering assistance with the installation, etc., was almost exactly $50 000, which, as on Onanu, was provided by external funding sources. While this system has been maintained, reports of its misuse by the traditional leadership of the community likewise suggest that the lack of investment on the part of the local community has resulted in a lack of commitment to the equitable operation of the system. In both cases, there was no charge incurred for using water supplied from the solar pump systems.

In future, it would seem advisable that an initial commitment by the beneficiary community be made, perhaps in the form of a connection fee per household, as well as a longer-term commitment, perhaps in the form of a user fee. This approach would not preclude the possibility of a project being subsidized. Unfortunately, the income level of some families is so low that it would not be possible for them to underwrite the cost of their share of a project such as this.

Information Sources

Contacts

Dr Stephen J. Winter, Appropriate Technology Enterprises, Inc. Bibliography Dilaha, T.A. and W.J. Zolan 1987. An Investigation of the Quality of Rooftop Rainwater Catchment Systems in Micronesia. Water and Energy Research Institute Technical Report No. 45, University of Guam, Guam. vii + 39 pp.

Moravcik, P.S. 1989. A Further Investigation into Potential Contamination of Water Resources on Moen, Truk Islands, FSM. School of Public Health Report, University of Hawaii. 64 pp.

Stephenson, R.A. 1984. A Comparison of Freshwater Use Customs on Ulithi with Those of Selected Other Micronesian Atolls. Water and Energy Research Institute Technical Report No. 51, University of Guam, Guam. vii + 27 pp.

Stephenson, R.A. and H. Kurashina 1983. A Comparison of Water Catchment and Storage Systems in Two Micronesian Communities: Laura and Nama. Water and Energy Research Institute Technical Report No. 50, University of Guam, Guam. vii + 60 pp.

Winter, S.J. 1986. Water Supply and Sanitation Facilities for Maloelap Atoll. ATE Technical Report No. 1, United Nations Development Programme, New York. vii + 36 pp.

Winter, S.J. 1987. A Ferrocement Well for Micronesia. Waterlines, 6(2):20-22.

Winter, S.J. 1987. The Evolution of Water Supplies on the Remote Islands of Truk State: Preserving Tradition and the Environment. Journal of the Washington Academy of Sciences, 77(4):224-229.

Winter, S.J. 1988a. Construction Manual for Ferrocement Rainwater Storage Tank. United Nations Development Programme, New York. 52 pp.

Winter, S.J. 1988b. Solar Pumping of Groundwater for Atoll Island Water Supplies. ATE Technical Report No.4, United Nations Development Programme, New York. v + 23 pp.

Winter, S.J. and B.L. Campbell 1994. (Video) Water for Your Island: A Guide to Water Supply for the Remote Islands of the Federated States of Micronesia. Water and Energy Research Institute Technical Report No. 49, University of Guam, Guam.

Winter, S.J., L.D. McCleary, and R.D. Watters 1983. The WERI Well on Truk: A Solar Photovoltaic Pumping Project. Water and Energy Research Institute Technical Report No. 39, University of Guam, Guam. v + 27 pp.

Winter, S.J. and L.D. McCleary 1984. Some Improvements in the Design of the WERI Well. Water and Energy Research Institute Technical Report No. 54, University of Guam, Guam. v + 29 pp.

Winter, S.J. and R.D. Watters 1984. Solar Pumping for Village Water Supply Systems on Truk. Water and Energy Research Institute Technical Report No. 49, University of Guam, Guam. iii + 16 pp.

Winter, S.J. and L.D. McCleary 1985. Solar-powered Wells for Atoll Island Water Supplies - Part 1. Water and Energy Research Institute Technical Report No. 60, University of Guam, Guam. vi + 13 pp.

Winter, S.J. and B.L. Campbell 1995. Water Supply for Remote Tropical Islands - A High School Teaching Supplement. Water and Energy Research Institute Technical Report, University of Guam, Guam. iv + 42 pp. (includes a companion slide presentation).

Winter, S.J. and L.D. McLeary 1985. A Ram Pump Demonstration. Water and Energy Research Institute Technical Report No. 59, University of Guam, Guam.. v + 19 pp.

Winter, S.J. and R.A. Stephenson 1981. The Development of a Village Water Supply System in Truk. Water and Energy Research Institute Technical Report No. 28, University of Guam, Guam. x + 45 pp.

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