rainwater catchment system construction and deconstruction

for years there has been talk of adding a rainwater catchment system to the roof of one of the building at the farm i work at.  this rooftop is very large and the system that would need to be built in order to catch the majority of the rain has been estimated at something like a 20,000 gallon cistern.  i very much look forward to the day when i have that system, but it’s connected to a much larger green building grant that has taken years to put together.  having not seen results, i had been seriously considering my options and decided that i wanted to build some sort of system, when along came a boy scout wanting to do an eagle scout project.

i discussed the matter with boy scout and his uncle, discussed various issues in regard to venting, how tall, placement etc.  the uncle seemed like he had it under control and i signed off on it, with some recommendations of folks he should talk to etc.

over the course of a couple of weeks the boy scouts (or as far as i can tell the eagle scout’s uncle) were hard at work building a rain water catchment system.  and this is what they ended up with.


the rain water catchment system

it’s pretty great, as you can see on the left side is where it connects to the gutter, there is a large elbow that can be swung up to catch water during the rainy season and down during the winter to keep it from getting water inside which would crack pipes and barrels.  the barrels are all interconnected so the bottom row has to fill up first and then the top fills up.  also important for the design is the vent, notice the line of smaller pipe that connects to the upper bunghole, and then goes up.  this is so air can be let into the system.  total volume capacity is 550 gallons, enough to help keep my water bill lower but since we are gardening on close to 3/4 of an acre not enough to supply all my needs.  it’s more than high enough to supply enough head pressure to supply drip tapes.  the only real improvement i would make would be a stale water run off pipe that water would have to enter before going into the barrel system.  this is basically a large diameter pipe that is connects just after the elbow where the system connects to the gutter.  it runs parallel to the wall, and has a hose bib at the bottom.  this has to fill up before the water enters the rest of the system, the idea being that the first flush of water is what is going to have all the dirt and roofing material in it, and that goes into his stale water flush pipe, and then the good water goes into the barrels. after each rain event i just have to go out and open the hose bib empty out the crappy water, and close it again.  pretty simple

now let’s look at this structure one more time and remember that we live in an urban city with some major issues.

roof top

another view of the rainwater catchment system

notice any problems?  any issues?  here is a hint, how far is the roof from the top of structure?

exactly, i walked out and took one look at this thing once they had put it together and said to myself, “well that’s a mighty nice ladder up on to the roof” for those not in the know the tops of roofs are great places to steal copper – found in heating and cooling units.  since this particular building has a huge – and i mean huge, big enough to play basket ball in – walk in freezer, there is plenty of nice copper up top and plenty of damage that could be done to contents of freezer.  i wasn’t sure what to do about it, the simplest solution seemed to be to cut the legs shorter.  i had made sure to tell the boy scouts not to make the structure too high, and to make sure to talk with the building’s owners before construction – but i think the may have missed this point.

then jesse, the building’s operations manager, called me – not angry, but seriously alarmed, about what damage someone could do and quickly with the structure in place.  we needed to act and right now.  i told jesse i’d take care of it.   i would have rather had more time, to carefully take everything apart, and rebuild it into a shorter more appropriate structure, but time was not on my side.  i had obligatiosn to take care of, and so deni, who so kindly helped out, and I went to the task of deconstruction.  first all the pvc piping was cut, and the barrels removed, then all the lag bolts removed and we started lowering boards down, and then we disconnected the main posts and lowered them down.  leaving us with what looked like little more than a pile of discarded junk.

pile of junk

pile of junk

i can’t help but keep thinking about what the eagle scout and his uncle will think if they drive by before i have time to rebuild it, or if he still needed to take pictures, or if he had to bring his scout leader by to see it.  no matter what there are big lessons to be learned, and a lot of work to rebuild it.


2 responses to “rainwater catchment system construction and deconstruction

  1. Found your website via Twitter feed, loving the articles, thankyou.

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