March172010water

=March 17, 2010 - Meeting with water system experts in Las Delicias= I met with Chilo (current valvulero) and another person who used to be very involved in maintenance of the water supply system. The Spanish from both of these men was hard for me to follow, but sister Gloria helped with translation. We talked for about an hour and focused mostly on the water transfer lines delivering water from the well to the tanks and answering some of Russ' questions. I hope to prepare a sketch and send it soon, but here are the key points:
 * At the well/pump station, there are two active wells: (1) well with submersible pump that supplies water for Arenera (community downhill from Las Delicias that has a water storage tank next to the clinic in Las Delicias) and (2) well with submersible pump that feeds a cistern at the well/pump station and a transfer pump for supplying water to the Las Delicias storage tanks.
 * Both the Las Delicias and Arenera water systems share the same transfer pipes from the well/pump station to where the water main passes the clinic (and there is a T connection to supply water to the Arenera tank at the clinic)
 * Tubing in the wells is 4" diameter.
 * Tubing from the well/pumping station (including connection to transfer pump) up to the Pedrona (crossroads where transfer line splits to deliver water to two Las Delicias tanks) is 6"
 * The 6" supply line is galvanized iron close to the well/pump station (to resist "golpe" - water hammers? from the pumps) up to near the clinic. After that all pipes throughout the community are PVC
 * From the Pedrona a 2.5" pipe supplies water to Tank 3 and a 4" pipe supplies water to Tank 1, but the 4" line to Tank 1 reduces to 3" before it reaches Tank 1.
 * There was a lot of discussion about how the reductions in diameter of the transfer pipes causes pressure build-up leading to leaks.
 * All tubing lengths are 6 m and can be cut shorter as needed
 * The Galvanized-PVC connection is a threaded connection (I'm pretty sure I understood this correctly - a lot of hand motions were used to communicate this)
 * All pipes are 20 years old - except for the pipes that have been replaced during repairs
 * All leaks occur at the junctions between PVC pipes - sometimes between 6" pipes or 4" or 3", but 2.5" piping is much more robust.
 * The 20-year old joints were descibed using words like mantequilla or mantequa (which sister gloria interpreted as butter or grease) and empaque which apparently is teflon tape.
 * The new joints come with the sealing mechanism pre-installed and do NOT fail
 * There are a number of 45 degree elbows throughout the system (apparently they only use 45 degree elbows) and the elbows never fail
 * There are several control valves in the system (they did not know what type of valve). For every control valve there is a "cheque" which they described very clearly as check valves
 * The check valve closest to the cistern does not close completely. The reason and how long it has been a problem was confusing and unanswered. They think that someone will come to clean it soon.