Look at the Navionics webapp for Squaw, that is the latest data from Navionics. As stated above, the tighter the lines are together, the steeper the drop, which you will see on each side of the creek channel with the 1' contours. The one problem you are having too is that old of a card was not in 1' contours and does not have the sonar chart layer on it, which you can see on the webapp as well. One thing I would recommend as a cost effective way on see this, with the alternative being buying a new chartplotter and card, would be to download the either phone or tablet app. On this app you can do depth shading etc, to make those creek channels pop out a little more. Before making the purchase, check out the webapp online( http://webapp.navionics.com/#boating
) that will show you all of the latest mapping from Navionics before spending a dime, to make sure it is what you are looking for.