Building Foundations in Nicaragua: Lessons We Learned

After reading the blog entries from Rob, Amy and John I am confident that you have gained a true representation of what you would have seen had you been with us. I would like to address some of the foundational things…beneath the surface. 

Now that we “Canadians” have departed what is the impact in Pedro Arauz?   

As far as impacts/changes that you could see from outer space, there are only three small red plates close to the community center’s well structure. As with all good foundations, there is no evidence of the time/effort/cost invested in the excavation, the construction of the structural and reinforcing elements, and the careful adjustments to ensure the plates are all at exactly the level and in exactly the position required by the design team.

As far as impacts/changes within the “community” I believe these are also substantial but like the red plates, there is minimal evidence of the how members have expanded their sense of community. Rob, Amy and John provided their observations and thoughts on how the community welcomed our return and provided enthusiastic endorsement of the Winds of Change project.

For me, indications of the developing sense of community included suggestions and concerns at a community level rather than a personal level during our gatherings. As an example, concern about the potential that more water might be pumped than the aquifer can maintain during the dry period (the season of greatest water use). “Is there enough water under the community to handle all the water pumping including that from the community well once the windmill is operating” (whenever the winds are blowing)? Then we were asked about the potential impact of massive volumes pumped for huge rice farms some distance from Pedro Arauz.  

The design team had already anticipated the need to avoid excessive withdrawal by the windmill and planned to return extra water to the well rather than run it to waste as is done in other windmill wells we viewed. They also include equipment and procedures for shutting the windmill down when the community did not want it to be operating. The community was reassured with this information.

To address concerns about taking too much water from all wells the community is interested in documenting current aquifer performance and capacity.

During its fall 2014 visit the design team gathered information on depths and water levels of some of the existing wells. We committed to design a log for reporting this information and send it to Pedro Arauz along with an approach for gathering community-wide information and interpreting what’s happening with their shared water.

An important goal of this trip was to solicit input from the community to be factored into the design. We were pleased with the suggestions:

What we were taught

1)   Someone often suggests a better way – After reviewing details of the foundation steel, community experts suggested bending the steel rod into the desired shapes rather than cutting and welding straight pieces. Once we expressed our enthusiasm, a bending tool was created, pieces of the steel rod were fabricated into super nails that were hammered into an old piece of wood to make a jig to ensure the six square and twelve “U” pieces were of the correct size and shape. Next the three pieces of each level of reinforcement (our grid) were “woven” together into a rigid shape that was then welded.  The resulting grid was then welded to the support post. These grids require fewer cuts, are stronger and require fewer welds. This will result in a decrease in the time and cost of making grids for future foundations.

2)   Local experience should be considered – We brought our ratio of cement/sand and gravel for mixing concrete but accepted the community proposal for a ratio that works there. Local mix ratios contend with existing temperatures (extreme for us) and local soil conditions. They do not have to deal with our freezing!

Several residents had concerns that design documents appeared to show exposed foundation concrete. They felt it would be ravaged by the weather. Fortunately the design did call for the hole to be backfilled. As we discussed this, community experts proposed backfilling with local sand and compacting the sand to produce a solid cover for the foundation. In Ontario we do not experience soils where during dry periods surface cracks form, which may extend ½ meter down. This local knowledge further improved foundation integrity.  

3)   Local tools and techniques usually work best – Short-handled shovels and pick axes were arranged for digging foundation holes. But local tools were more productive and easier to use. We quickly adopted the “earth chisel” for cutting through the hard layers of the soil but for soil removal at a depth of about 3/4 of a meter we were obstructed when removing the loose material from the tiny hole (½  meter by ½ meter). Diggers replaced the short-handled shovels with a small plastic cereal bowl then climbed into the hole to remove loose bits. This was a slow process and required quite the distortions. When the last hole needed deepening, a community member went into tool storage and returned with their long-handled shovel. He used it to clear out the chunks much faster and with less effort than every prior chunk digger! Perhaps if we had started by asking for a demonstration of the local tools and methods…

4)   Improvements in design must always be tested against the extremes - Many who reviewed the posters with the design features shared concerns about elements that had not worked in another location. While most of these matters had been carefully and thoroughly considered by the time we shared the design, all concerns were documented and will be considered again in the next phase of design and testing. Usually we were able to explain to the community member how the design team addressed the concern (e.g. why only six blades are proposed). In all cases we undertook to have the design team ensure the local information was being addressed.

The student team and Amy invested enormous brain power and time optimizing existing windmill and pumping theory to produce this the Winds of Change design that meets the requirements (much cheaper, permitting manufacture/erection/operation/maintenance within the community using available skill set and equipment, with the potential of commercial opportunity for the community). The design will be offered to all at no cost.  

Thanks to the community of Pedro Arauz, Winds of Change, and Seeds of Learning for permitting me this fantastic opportunity to learn! 

Wayne