Because your planned gravel spawning areas are relatively small, consider first putting down landscape fabric or weed block material under the gravel. This can help keep the gravel from working its way over time into the clay bottom, and 2. It should allow you to use a littler thinner layer of gravel in the spawning beds because the gravel will tend to not blend into the clay bottom.
Another thing I would do is outline at least one outer perimeter of the bed as a test area with cement blocks or similar retention border to keep the gravel edges from blending or moving into areas of the outer adjacent sediment. Over time expect the gravel areas of each spawning area to become infused with organic sediment. It is how aquatic nature works. An annual raking of these gravel areas helps keep the organic better decayed and cleaner. Nest building activities of fish also help keep subsurface spawning areas in better oxygenated condition with less organic buildup.
Perfect! I have about 40 feet of 8' wide geo road base fabric that has been in my way for a while, so I will lay that down as a barrier first. I was going to use some 3/4" thick HDPE plastic strips as containment walls (drop material from my work), but the cinder blocks sound like a better option to help hold down the fabric, and create the barrier, so I will pick up some of those. Thanks Bill!
I would move the middle bed location to the far end of the pond. Water flow (silting) on top of beds is a large negative. Plus it gives you more diversity in locations (wind and wave action).
See this thread link for BG beds - pics.
Mixed size gravel works best.
Thanks Ed! I was wondering about the locations as well, for that same reason. although the watershed adds very little since the pond is spring fed, I will plan on moving the middle one to the far side. Appreciate the link. I remember seeing it a few months ago, but for the life of me, could not find it, haha! I will also see if my rock yard will do a mixed sized load of pea gravel.
