November 2011, Vol. 23, No.11

Problem Solvers

Flow Measurement

Engineers Without Borders restores clean water supply to Les Anglais, Haiti

Problem: Underground blockages prevented reliable water supply.

Solution: A clamp-on ultrasonic flowmeter helped volunteers locate and clear blockages, thus restoring water service.

  

The island nation of Haiti is the poorest country in the Western Hemisphere. Even prior to the devastating 7.0-magnitude earthquake that struck in January 2010, a large portion of the population struggled to obtain the most basic resources necessary for remaining healthy. Currently, one of the most prevalent threats to health and well-being in Haiti is the absence of clean and safe water for drinking, cooking, and bathing.

Contaminated water currently is the leading cause of pediatric illness and infant mortality throughout Haiti. In fact, it is estimated that 90% of Haiti’s children suffer from waterborne gastrointestinal diseases and intestinal parasites, and that these diseases lead to more than half of all deaths in Haiti. The residents of Les Anglais, a small town in Haiti’s southwestern peninsula, experienced exactly this problem and were in need of a practical solution.

 

Contaminated water supply 

In 2008, the Portland, Ore., chapter of Engineers Without Borders (EWB) was approached by a local church group with a request to assist the community of Les Anglais in resolving their drinking water issues. The church group had determined that some of Les Anglais’ health problems were due to a contaminated water supply. Two engineers from the chapter traveled with the church group to Les Anglais.

The engineers learned that Les Anglais is served by two separate water source springs, which form when rainwater seeps into the ground and moves through soil or cracks in the rock until natural pressure forces it to the surface. The water distribution system in Les Anglais is gravity-fed, meaning that no pumps or motors are used to move water downhill from the springs to the two storage reservoirs and the distribution pipeline they feed. The system includes about 600 taps between the reservoirs and the town, and serves an estimated 12,000 people.

 

Taking on a life-saving project 

While in Les Anglais, the EWB engineers confirmed that both water springs were contaminated. They further observed that residents walked as far as several miles to reach one of the few hand-pumped wells in town or, when necessary, simply gathered water from irrigation ditches. The Les Anglais water board and mayors were supportive and very willing to work with the volunteers.

Based on findings from the exploratory trip, the Portland EWB chapter agreed to take on the Les Anglais project. They put together a team consisting of engineers with backgrounds in civil, mechanical, environmental, electrical, and agricultural engineering, as well as public health professionals with knowledge of water and sanitation policies. 

 

Called to action 

At the time of the engineers’ initial visit in the spring of 2008, the water distribution system in Les Anglais was more than 20 years old. It was operational, but had maintenance issues that reduced capacity, enabled contamination, and left the system vulnerable to future damage. Several months later, Hurricane Hanna blew through and further impaired the system. It was now barely functioning because of breaks and blockages in the main pipeline.

In January 2009, the EWB team traveled to Les Anglais with tools and materials to fix the pipeline. Dozens of local residents worked with their bare hands and the tools brought from the United States. The pipeline was repaired in just a few days, but water flow into the reservoir remained very low. It turned out that the breaks at main stream crossings were easy to see, but many blockages were still hidden somewhere in the 4.8 km (3 mi) of buried pipe.

 

Restoring the flow 

The EWB team planned another trip to Les Anglais in June 2009. This time, they knew they had to be better equipped to find the problem. After considering various options, one of the volunteers made the decision that a clamp-on ultrasonic flowmeter would be a useful troubleshooting tool. These nonintrusive meters have sensors mounted externally to the existing pipe wall, eliminating the expensive process of interrupting the flow and cutting the pipe. They also offer a high level of accuracy through the use of bidirectional wide beam technology, in which the resonant frequency of the pipe wall is utilized to achieve a strong ultrasonic signal. Wide-beam technology allows these meters to produce accurate measurements even if aeration, suspended solids, or other anomalies exist within the fluid.

 

A portable solution 

The volunteer put in a call to Portland, Ore., office of Branom Instruments (Seattle), the local representative of Siemens Industry Inc. (Alpharetta, Ga.), and was offered a portable clamp-on ultrasonic solution: the Sitrans FUP1010 flowmeter, which comes in a rolling, weatherproof case. The flowmeter was shipped from the Siemens office in Hauppauge, N.Y., to Portland, and the volunteer brought it to Haiti, where he used it to troubleshoot the water distribution system in Les Anglais.

After excavating the pipeline in seven different locations, the team identified and cleared two separate blockages. Each time they made an excavation, they used the flowmeter to determine if the blockage was upstream or downstream. With the aid of the local populace, the volunteer and his team ultimately were able to restore clean drinking water to the community. According to the volunteer, there was a great celebration when full flow finally reached the reservoir, and “there really was dancing in the streets.” 

The EWB team has continued its work in Les Anglais and recently finished adding chlorination systems to most of the distribution system. More information on the work in Les Anglais is available online at www.ewbportland.org/haiti.

 

Pat Di Visconti is a senior marketing specialist in the Hauppauge, N.Y., office of the Process Instrumentation & Analytics business unit of Siemens Industry Inc. (Alpharetta, Ga.). 

 

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