Addressing Water Security with Solar Power

Thanks to funding from the New Zealand Aid Program, Rotary Pacific Water for Life has developed new groundwater distribution systems in three rural settlements. These Water for Life projects provide safe drinking water to 300 people in Bua.
02
Aug

Improving water security with solar power

Yes, even in Fiji where annual rainfall can reach up to 6000mm per year, communities exist without access to clean drinking water. This was a reality for families living in Cobue, Wailele and Sasake settlements. Until now, they were relying on shallow wells to meet their water demands.

Through droughts of recent years, these settlers saw the yield of their wells drop, and had no other option but to ration their water consumption. In 2014, representatives from the three communities approached Rotary Pacific Water for Life with requests to develop a permanent solution to their water problems.

In 2015, under the framework of an ongoing partnership with Rotary New Zealand Community Services, the works commenced. The projects consisted of:

• field surveys and system engineering
• drilling and equipping the boreholes
• construction of the distribution system
• awareness on water, sanitation, hygiene
• operation and maintenance training

Field surveys and system engineering
During the first phase of each project, necessary field studies were carried out to assess potential water sources in the area and determine the water demands of the communities. Once the choice for groundwater was made, potential borehole locations were identified by a hydro-geologist, in consultation with the community. Next, a full topographic survey along the proposed mainline and branches was performed using an Abney hand level. Finally, all the resulting data was fed into the design process, comprising of hydraulic pressure analysis, CAD-drawings of the infrastructure and GIS mapping of the different system elements.

Drilling and equipping the boreholes
Once design work was completed, a contractor was brought on site to drill the boreholes. The water bearing rock in this region is covered with a thick clay layer, requiring slow mud rotary drilling to drill the bore. The boreholes were completed with an 8” outer bore and 4” inner casing. Gravel packs and bentonite seals were installed to prevent polluted water from seeping in.

The key challenge of these projects was to obtain a high enough yield to meet the daily demand of each community. Since there is no grid power, the project opted for solar systems to pump the water. This effectively reduces available pumping time in a day and increases the required pump rate. Therefore, extra care was taken during the drilling to ensure that borehole yields would be sufficient. Upon completion of the boreholes, pumping tests and drawdown analysis was performed to allow an optimal design of the solar system. In Cobue, the largest settlement, fourteen 2100W solar panels were needed to yield the required pump rate of 1.3 litres per second.

Construction of the distribution system
Since there was no existing water system in place for these communities, a completely new distribution system was built. This included the main lines and service connections, pump house, valves for system operation and water storage tanks. Water storage is critical in solar systems, and must be large enough to provide for cloudy weather, when pump rates drop.

Great support was received from the communities, who assisted with labour and contracting of digging equipment. With their help and under supervision of skilled staff and engineers, the systems were built in three months.

Operation and maintenance training
This phase of the project cycle is integral to the longevity of the system. The community water committees received the necessary technical training to optimally run amaintain their water system. Particular attention was placed on monitoring the borehole performance since this is the heart of the system. Operations and maintenance training is facilitated by our technical officers. Such activities promote dialogue, inclusive participation and active learning about tailored water conservation strategies to reduce water losses.

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