I recently installed a debris shield and anti-vortex plate on my 15" vertical standpipe (corrugated ABS). This lasted about a week before it got clogged with leaves and small sticks, restricting water flow and causing my pond to rise a few inches.
The pond is about 1 acre and there are tons of trees around the property so I expect this to be a continuous problem. Any thoughts on a solution?
I would not recommend running the overflow without the trash rack in place. If the floating junk plugs the overflow pipe, it will be extremely dangerous to clear the jam, if the OP can. People have been killed doing so. They don't realize how much suction the pipe has, were cleaning out the pipe from the pond side, the plug broke free and they were sucked up against the pipe.
If you ever have to clean out an overflow pipe with the water level over the top of the pipe you must clean it out from the discharge end of the overflow pipe, not the intake side.