Friday, August 14, 2009

Scalable First Flush System for Rainwater Collection

gutter debris deflection

first flush systemHere is a simple idea for a "first flush" system for rainwater collection. It is made of pvc pipe and the first flush section is made of 4 inch pipe. For every 18.5 inches used, it will hold 1 gallon. It is scalable by adding more pipes to the left side. I could use 2 pipes at 46 inches each and get 5 gallons of first flush capability, for example. The pipes have a bottom cap and a small hole drilled in them. This way, when the rain starts falling, the first 5 gallons would go into these pipes and fill up faster than the small holes at the bottom will drain. After the pipes fill up, the water (now clean) overflows into the storage tank. This process rinses away bird droppings, leaves, dust, bugs, etc. If you have a larger roof, you may want more first flush, such as 10 gallons or more. It also helps to have a way to stop the leaves and big stuff from even getting this far. Some people use screened gutters, or a screened redirector right before it goes into the first flush section.

You guys have a good weekend.



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