I’m looking at twelve mile lake in Iowa and am not seeing a creek channel don’t most lakes have creek channels?

can some one help explain what a ridge is? I googled it but didn’t find anything that helped. 

If its a flooded stream then yes , it would have a channel  . A ridge is a long high spot under water just like a ridge above water . I have never found a ridge like that to fish . 

A lot of lakes have creek channels, but some don't. A ridge is continued elevated contour as you might find on one side of a larger creek channel or other protrusion. Don't focus on the semantics, get a good chart of the lake, or look at the FF and find "something" that the fish are relating to. This time of year, on a lake that size, fish are going to be in or near deeper water, but may wander shallower. I like to work backwards from spawning areas, and identify where fish will most likely be or stage depending on the time of year, water temp, and conditions. Unlike other fish, bass won't usually travel long distances if not required. If there is food and comfort a couple of hundred yards away, that's where they'll most likely be. 

During this time of year in cold water bass like to move more vertically than horizontally. They want to be somewhere near a drop where they can rise up to the top of the ridge or flat to feed and drop straight down into deeper water when hunkering down to be inactive. They DO NOT want to have to swim up a long slow slope in order to go from deep water to a feeding zone. They want to have to swim as little as possible while using up as little as energy as possible. 

The google map shot of that lake attached shows a channel that runs through the middle of the pic like a snake.  I have no clue about the lake but depending on the age, a lot of old lakes have siltation that sets in and fills in some of the channels if there is not a lot of current to clear them out.  That may make it a bit tougher to find hard breaks of channels with electronics once on the lake.  

Bass anglers tend to make up terms that can't be defined in a dictionary. However the terms channel and ridge we can agree on. Look at the terrain surrounding your lake,it's the same as what is underwater. Twelve Mile lake is a man made reservoir with a dam holding back water that covers the terrian before the dam was built.

Ridge is the crest of the hills that create points and continue under water down to the stream or River bed before the lake was flooded.

Channel is the stream or River bed before the lake was flooded.

Streams and river follow the terrian and meander like a snake through the valley floor, the flatter the terrian the more the channel meanders. 

This lake is fairly old and shallow that is subject to siltation filling in your channel with silt and if the lake is drawn down water tends to erode more soil.

Looking at a map of this lake there appears to be a lot of detail structure elements you should be able to see on your sonar unit.

Tom

 

Looks like you have a few great answers to your questions from the replies above.  I agree that all lakes will not have a defined creek channel.  Remember also that a ledge or steep contour change is shown by having a goop map in paper, plotter, and /or App. which I find to be very helpful.  Within the contour lines you will see reference depths that will show you the depth of a contour line.  Where the contour lines are the closest together the steeper the depth change.  depending on the location sometimes a 2 ft change may be enough to hold fish.  in others it may be 10 or 20 ft.  I live in VA so in our lakes it doesn't usually take much of a change.  But looking at your lake I see a flat with a descent drop off which I have attached a picture of using my Navionics App.. It also looks like someone has marked a couple hot spots right on top of the flat by the drop off.  hope this example helps with a place to get started.  #EscapeTheOrdinary  #1ftContours