I knew I needed to put in a "french drain" to deal with all the water coming down the spout, I also knew that I really needed an automatic sprinkler of some kind to keep the grass going through the hot periods here in Northern Virginia. Those thoughts spun in my brain until I saw this at my local home improvement store- for half price I might add!
Step 1: The Parts
Step 2: Sprinkler Design
First, let me say that I know this is very small scale. I am blessed (or cursed as some would believe) with a very small front lawn (20' x 20'). I only need 1 zone to water the whole thing. I figured that 8 heads would cover the area.
I'm not going to explain how to install a sprinkler system. If you have ever glued PVC pipe together, you can do it. It is a matter of digging trenches, laying and gluing the PVC pipe, and connecting to a water source. You can also use flexible black pipe. Regardless, the process is the same. Here is a schematic of my system.
Step 3: What It Looks Like
THIS IS WHAT I HAVE LEARNED:
1. If you really want to go "off the grid" water-wise, you will need much larger storage! My sprinklers use about 40 gallons of water in 10 minutes- which is enough to keep the lawn going if it happens every day or other day. But that means that I need it to rain every other day to fill the cistern. N VA can go 10 days between rains, so that means that if I really wanted to be self sufficient, I would need a tank around 400 gallons big.
2. Roof water is dirty! As you can see in the pictures, fine grit from the roof eventually gets in the cistern. I put a filter in the pump and that solved the plugged sprinkler head problem.
3. Pump needs to be bigger! I was going for cheap and got a 1/6 hp pump. It works, but just. To get more pressure (and head), it should probably be a 1/3 hp pump.
BUT- OVERALL IT WORKS VERY WELL. I use house water to fill the tank when it doesn't rain. I do not have it on a timer, although that would be easy to do.
Step 4: CONCLUSIONS
I have decided to connect the sprinkler system to house water. I know, a step backward ecologically speaking, but it will permit it to be automatic and will have a constant source of water and pressure. First, you need an anti-siphon valve. This gets into local plumbing code so be careful. Do what is demanded for your area.
So, what good was the whole project if I am just going to bypass it with house water? Well there are a few ways to go here. First, I could turn the sump pump into a drip irrigation system for all the flowers and bushes my wife is busily planting. Second, I could keep the pump idea, (bigger of course) and come up with a float and control scheme that would fill the cistern with house water IF it was low, but would not be used if the tank was full due to a recent rain. Oh boy! Can you see an Arduino with relays and float sensors? I can!
One other wild idea is to do away with the sump pump and run the house water through a venturi pump that would suck up whatever water is in the cistern. One feature that immediately comes to mind is LIQUID FERTILIZER. So, you see there are many ways to go with this design and I feel it is well worth the effort.
Last but not least- MY EROSION PROBLEM IS COMPLETELY GONE!