Hi Pat,
From your first post I understood that you wanted some sort of automatic water adjustment, that compares track points across multiple tracks. I think this is troublesome because the risk of bad or different depths (for reasons other than a change in overall water level) is too high.
Better to use the water level adjustment feature in each individual track. Open up the track edit pane, and expand the "Tide" section. For your situation, where the water level might be different for each track, but does not vary during the lifetime of the track, it is enough to enter a single depth level.
- Select "Manual" mode.
- Add a depth using the depth point edit section at the bottom of the tide editor. If you enter a single depth, then all depths within the track will be adjusted by subtracting this depth. i.e. a depth of 5m will become a depth of 2m if you enter an offset of 3m. If you enter multiple depths, then RM will interpolate values between the points, and apply them to each track point, depending on the time (this option is more useful for varying tide levels).
Note that you can apply a negative depth offset, which will increase the depths within the track by the offset amount. This could be useful if you pick, say, the first of your tracks as the baseline and adjust subsequent tracks up or down to match. You could always find the approximate difference in track levels by hand, by examining depth points that are near to each other - although this method would be far from fool proof. If the water you are mapping has a depth gauge, then this would be the best source of level data.
Matt