Gravity Rocks

In the States I never thought much about where my water came from – pumped from a well at my house, or part of a huge city wide treated system in Baltimore or Worcester or Boston. In training last fall, we learned about the basics of gravity fed water flow. Many NGOs and good-hearted engineers around the world have had a habit of including fancy electric/gas/solar-powered pumps in water systems in developing countries, and the problem is that pumps are complicated and break easily.

Luckily, in the mountains and hills of Panama pumps can be easily avoided thanks to gravity. I have been working with a community-elected Water Committee to bring water to the majority of the houses in the community –nothing fancy, just a tap stand outside of each house.

I’m going to give a run-down of my experiences during the past month with the construction of a gravity fed water system (the only power source is gravity) for those of you who are interested.

1. Fix the road that is necessary to get materials in on a truck. Use several pick axes to chip away at a rock that is blocking a road.
2. Spring Water Catchment Box: Locate a spring source (where the water leaves the earth to start a stream) which is usually in the hills above the community. Carry the sand and rocks and cement up there in sacks on shoulder or head or horse. Build a box around the spring source out of cinder block, rebar, and concrete mixture. This box has an opening at the top so that if there is too much water to fit in the tube, it will exit.
3. Tube: The tube size is based on the flow rate of the spring source. The problem in Panama is that the flow rate fluctuates usually 5x between the dry season and the wet season. Community members pried large rocks and dug an 18’’ ditch to bury the 1 ½’’tubes.
4. Storage Tank: A tank is designed to be large enough to provide 30 Gallons per person per day in the community, plus allowing for population growth in the next 20 years. The tank needs to be located close to the community, but above all of the houses. The 4,000 Gallon tank is made of cinder block with a reinforced concrete floor and top. Ideally the spring catchment is built first so that water is readily available to make the cement mix, but in my case the Latinos paid a guy to haul water from the river in buckets.
5. Lay down the mother line tube down the major path through the community. Then make cuts in this big tube and put in a T, connecting it to a ½’’ tube that goes from the main path to near the house. At the house there will be a tap stand with a little cement pad.

I was more useful for theoretical knowledge such as water catchment and tank location, since my construction background is minimal. I wished I knew more about construction so I could have been more critical with quality control on the contractor’s rushed work. I did quite a bit of manual labor such as digging ditches and hauling sand and rocks on a bag hanging off my head.

This is the stage we are at now. Work remains – encouraging community members to organize and finish burying the main tube, and get the water group to start charging users 50 cents per month per family for use. We are also soliciting funds from the local government representative to use part ($,3000) of his annual “Community Fund” to buy enough tubing to reach the 9 houses that are left.

Thanks to gravity, my neighbors and I don't have to haul dirty laundry down to the river or drinking water up from the river anymore...at least, until the dry season.