Collecting gutter water, use a screen at an angle as it will naturally wash/filter the water to keep debris out of the barrel. Set at a 45 degree angle, the water will filter through and as well wash the screen off as debris collects on it. Very simple and easy to do, then have an overflow from top of barrel to run access water away or into a secondary barrel.
This shows the screen flat which wont self clean.... put the screen on a 45 degree angle
This shows the screen flat which wont self clean.... put the screen on a 45 degree angle