Kevin,
I almost always start at the lowest end and work up, because if I dump more water into a lower dam/pond, that makes the water deeper, and adds to the water going over the lower dam, which means I won't be able to dig it as deep, or to the original/intended depth. If I start at the lowest dam, I'm making it shallower at all the downstream dams as I go, making cleaning out the tailpieces easier/ exposing the long sticks at the bottom of the dams. Some times I have to take the dams out in sections/ depths so I have water, to canoe into them, or back into them to finish them and get the required depth. Most often I pull my traps as I pull the dams, so I have to make sure I have enough water to float my traps/ gear back out. Sucks dragging a canoe weighted with traps through loon poop, been there, done that, got the T-shirt!! LOL
In some of these long bog lines, the ditches have huge pieces of floating bog that grow all the way across. If we just pull the dams out, the pieces of bog will just settle down to the bottom as the water recedes, and they make dams that are about two feet thick, and form, or work as filters, and slow the water down quickly. We go in canoes, cut the bog in pieces, with old log cross cut saws, and float them to the edge of the ditches and pin them to the banks where there are depressions. Occasionally, we tear out a dam upstream of an area like this, to add more water to that area, to help float the chunks of bog around.
It used to be pretty common practice around here, for loggers to fill the ditches with logs, to form bridges for skidders and slashers, to access timber tracts, during early logging operations. The DNR really frowns on that practice now, because they often had to leave the logs in the ditches, because they froze in over winter, and they had no access to retrieve them after break-up in the spring. There are still plenty of logs in these ditches for that reason, and some jerks, used to push their tops piles into the ditches, knowing they would freeze over and be out of sight when the DNR comes back to scale their logs and inspect the sale. This debris floats around for years, and eventually ends up in a beaver dam, then I get to cut it up to open the dams. Now they put in culverts, or use portable bridges to span the ditches, but there are still plenty of tops dumped or pushed into the ditches.