I've also read that years ago. Our visibility here on Lake Nimrod is about 2 feet and I believe that they spawn each year around 5 feet deep. Our lake was built for flood control in 1942 and although we have some shallow buckbrush in 1 to 2 feet of water the lake level can go up or down a few feet rapidly. I think that the crappie know that and avoid spawning in such areas.
We have been catching staging females in shallow 8 to 10 feet brushpiles for the last few weeks but the fishing has really fell off this last week.
We are going to stop jigging brushpiles for a while and start spiderrigging shallow flats this morning. Hope it pays off.