Why did I build a cistern? Well, it's a long story...but
here's the short version.
(If you just want the technical stuff, go
(If you just want to see the photo gallery, go here.)
I learned from Bill (my neighbor) that a previous
owner of my house decided to put the fence in the backyard; up until
that time, there were no major rain water drainage issues. As
part of installing the fence, this guy decided that a raised mound
running along the fence line would be an awesome addition. It
wasn't. Basically this guy created a retaining wall for the
runoff...and a temporary pond for me!
Complicating matters is the size and drainage pattern of my roof; my
entire back roof and part of the guest area drains to the back yard
- it appears to be planned that way. All that I can think is
that prior to the addition of the moat-maker a.k.a 'raised mound
under the fence', the yard drained
pretty well. In fact, Bill said that prior to the addition of the
fence, he had never noticed any major drainage problems in what
would become my yard.
When I first conceived of this project, I envisioned a series of
small catch basins and a trenched pipe heading out past the fence.
However, I quickly became aware of just how much water was going to be coming
off the roof. During a series of storms in the early part
of 2007, I found my yard flooded with hundreds of gallons of water.
Bill (to the rescue) offered me his submersible pump, with the
equivalent of a fire hose for an outlet, and that took care of
business - I was basically dry in a few hours...to put this into
perspective for you - the pump was moving water at a rate of ~200
gallons per hour....and it took a few hours! After seeing
this, I accepted that a few $35 catch basins from Lowes were not
going to solve my problems.
What emerged was the cistern and the irrigation system that it
feeds. The cistern itself has a capacity of ~750 gallons and
is constructed in a baffle-weir style. It has a passive
overflow to take any 'excess' water well beyond the fence line and a
pump to distribute water to the garden and the rest of the greenery.
By using the rainwater to water everything outside, I'm saving ~$10
per month on the water bills during the summer - in addition to gaining a DRY backyard.
If you'd like to see all of the technical details or if you'd
like to build your own without repeating my mistakes, please visit the
section of my site. Otherwise, feel free to look at a few of
the photos that I took during construction.