Saturday, August 20, 2016

The Electric Well

It’s been one week since we arrived in Ghana, and we were joined today by the last member of the travel team, Heather Morriss, coming to us from Germany. It already feels like so much longer, and we have been truly adopted as members of the community.

On Thursday, the drilling rig arrived in Amanfrom and drilled both wells. The rig showed up early, at 7:50 am, and began drilling the Primary School Well. The drillers were using an air rotary drill, in which compressed air blows the cuttings to the top of the borehole as the drill stem advances to greater depths. As a result, the drilling process is very dusty initially, but stops once water is encountered. The drillers provided us with a shovelful of drill cuttings representing each meter that the drill stem had advanced, so that we could make observations about the geology. The children gathered to watch the drill, and screamed in excitement when the water began shooting out once the drill reached a depth of 21 meters. Water seemed to be primarily in the deeper crystalline geologic formation (most likely fractured granite or gneiss), rather than the overlying shale formation. We continued to drill until 60 meters, which was the minimum in our designs. The well was briefly developed by shooting compressed air into the bottom of the borehole, causing the formation water to rush to the surface and create a fountain of water 10 meters into the air. “Development” in the context of well construction means removing any fine particles which may have been introduced into the subsurface by the drilling process, as these particles can clog the water-bearing fractures and the well screen. Even the adults, including the EWB team, were excited to see the geyser we had created! To keep the children away from the built well, Sammy told the kids that the drillers poured electricity into the borehole, and they must stay away so they don't get shocked. This worked at first, as no one was spotted anywhere near the well while we were relocating to the second drill site.

Drilling at the Primary School Premises 

The full array of Primary School well rock

We moved to the Borzey House to start drilling immediately after developing the first well. Drilling 11:30 am. Unlike the Primary School well, we did not find much evidence of water, as the shale formation extended the full depth, and the crystalline formation was not encountered. We drilled to our maximum designed depth – 100 meters – and the borehole still had not produced flowing water, only moist intervals which could indicate the presence of water bearing fractures which have been blocked by drill cuttings. We then had to decide if we wanted to drill deeper, hoping we could get to more water, or do hydro-fracking (which was recommended to us by the contractor). We gave the borehole 1 hour to recharge, and some water did come up. We decided to drill an additional 20 meters, at additional cost, in hopes that more fractures would be intersected by the boring.

Drilling at the Borzey House

Unfortunately, following this decision, the contractor proceeded to change the screen in our design to an open borehole without consulting us.  This caused some tension between the team and the contractor, as they decided on their own to change the design of the well. The contractor failed to communicate effectively to us the reason for the design change or how it worked.  They also were rushing to complete both wells in a single day, without adequate time for communication and consideration of options.  We believe this was because they didn't want to return with the full drilling crew the second day. Luckily our technical mentor, Joelle Freeman, is a professional hydrogeologist with well drilling experience, so we stopped the construction of the well until we were all in agreement on the design. We ended up with a approving a modification to an “open borehole” below 42 meters of unslotted PVC. The end of the pipe is “fanned” out to keep washed gravel from going down to the end of the borehole. The bedrock that is exposed from 42 meters to 120 meters should have minimal fine sediments after the well is developed, allowing the water to enter the borehole and remain clear. 

In the evening, the children who had been watching the slow progress of drilling the Borzey House well, proudly announced that they had tested to see if the Primary School Well had electricity!  They all laughed so hard and said, no one was shocked, we are not afraid! So, since we were caught trying to trick them, we told them the truth, that there is no electricity, but they must not disturb the well until it is complete. We were still working after the light had gone, so the constructor left before developing the well. The Borzey House well will be developed within the next few days, most likely using the same submersible pump that will be used to conduct the yield test. We are waiting for the yield test results to finalize the design of each well.

On Friday we also ventured out to Aburi to meet with the South Akwapim District Assembly. After a long and somewhat overwhelming Ghanaian government structure crash course, we presented our designs. The District Assembly was very interested in our designs and asked insightful questions. They ensured us that they will supervise the villagers and the Amanfrom Unit Committee to make sure the system is up and running even after we are long gone. The Assembly also was very interested in forming a partnership between Columbia University and the district for further projects.

The team in Aburi

We have also briefly visited Obodan, to monitor and study the water system that the Chapter previously constructed. We were pleasantly surprised at the condition of the water system. Three years later, all parts are functioning, and vegetation has grown back to protect the pipes from erosion. We also saw that the villagers modified the spigots so they can fill their heavy buckets with water, while it is already on their heads! This eliminates the need for a second person to assist with lifting the heavy bucket from the ground.  We were very impressed that the Obodan Water and Sanitation Committee took initiative and derived such a clever solution to the problem! Engineering for the win! We also learned that the income from the fees for water from the Obodan water system (10 pesewas per bucket) has provided a reliable source of income for the Unit Committee to use towards other projects. Particularly impressive is that the money was used to raise a 5% contribution for the construction of a new Junior High School by the Blue Skies Foundation. The new Obodan J.H.S. is now one of the nicest schools in the entire Eastern Region. We hope our water distribution project in Amanfrom will be as successful, and that the income from the system can be used for future community development projects as it has in Obodan.

Thank you for reading our update,
EWB Columbia University Ghana Travel Team 2016

P.S. Ghanaian Bars are called Drinking Spots...not that I would know.

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