Roof runoff rock rinser. Say that 10 times fast without stumbling .
My land produces rocks every time soil is moved. It's probably 10% usable rock by volume. When these rocks come out of the ground they are all the same color which is a mucky yellowy brown. They are covered in a fine silty mixture which makes it impossible to identify attractive specimens for use in building rock walls, pathways and steps. It takes two years or more for this covering to wash off naturally, often revealing a multitude of colors and textures. My land is glacial till and therefore contains many types of rock.So I've come up with a hasslefree method of washing them.
I'm building my roof on a single plane with the top of the slope facing South. So all of my runoff water will flow to the North gutter. Normally roof water is channeled into downspouts which often get clogged with the leaves of broadleaf maple and other debris. That's why I favor open ended gutters which project several feet beyond the building. During torrential rains water shoots quickly from these gutters and clogging is seldom an issue. I'll run mine up to 12 feet from the house before allowing it to splash down onto rocks which are piled for cleaning. Our rain is very seasonal and abundant so there is no need to save any of this water. It simply needs to be moved far enough from the building to prevent problems.
Before starting the rock pile, I'll excavate several feet below the surface in order to create an extremely well-drained area. The land slopes steeply toward the river not far from this splash zone so none of this water will return to the foundation. I set up a similar situation on a very small scale and the rocks were clean in a matter of weeks. My roof will run far more water and it will fall from considerably higher.
If at some point I don't need any more clean rocks, I'll still leave a good stack there since the pile would make an attractive landscaping feature on its own.
Existing rock piles on the property have become home to many small insectivorous snakes and lizards. I'll put some dry piles of rock nearby so that any creatures which choose this as a winter home will have somewhere to go when the rain starts. We don't have anything poisonous. It's nice to know that I can stick my hand into any hole on the property without that worry.
Unfortunately none of this water will be used for vehicle washing or irrigation since nature takes care of that during the wet season. I may channel some water toward the indoor aquaponics and swimming area.
During the summer we seldom get rain and any that does fall is likely to be completely absorbed by my soil covered green roof so this will be a seasonal operation.
Location: Victoria British Columbia-Canada
posted 5 years ago
When I wrote this, 2 years and 3 months ago, I hadn't contemplated watering the rocks in surges. Rather than dump the water all in one spot, this device would mix it up by regularly sending a surge of water through the gutter. A surge will travel further horizontally from the drop zone, which should make a nice splashy shower. It would be fun to send someone to check something out near the rock pile, just before a serge. You could open a window and say "no, over there a bit, another 2 feet, right by the blue rock ..." whatever you have to do to keep them there until the fateful moment.
Dale's self flushing roof gutters. --- http://www.permies.com/t/29361/rainwater/Dale-flushing-roof-gutters