This time of year during drawdown I like exploring for old lures and such. While on these walks I always gather brush from along the waters summer pool level and make piles. No blocks or other weight is needed if you use brush that is usually under water anyhow. is already waterlogged and will staywhere you put it. Around here they pull the water down at least 5 ft, so what ever you build will be 5 ft deep come spring. I also do the same on the ice once safe enough. On ice I may wire them together to keep them together as they fall to through the ice. They can't say much if you use brush that is already in the lake.