I have never crappie fished water controlled by ocean tides. However I fish rivers that are controlled by dams. Most of the time the water atleast has to be moving in one direction or the other for me to catch fish. If it is at a stand still or moving too fast then I generally do not do well. If it is moving slowly or average I catch them. I usually have better luck with the water going out but on a few occasions incoming water was extremely productive. Speaking of a culvert, there is an area that use to be one of my favorite spots where they pump water into the fields for duck hunting and then late winter early spring they pump it back out into the main river. I use to limit out and catch anywhere from 30 to 100 crappie on a regular basis. However they added another culvert and filled in the area some and it is nowhere near as productive. It has also become to popular of a place now and so many people fish it that it is not worth tha hassle. Use to be a great place though.