A contour map is a set of instructions if you know what the shapes mean. Bass relate to depth changes, and almost every good spot on a reservoir is one of six shapes. Learn the six and a map you have never seen becomes a list of places to start.
| SHAPE | ON THE MAP | WHY BASS HOLD THERE |
|---|---|---|
| Point | Contours bulging out from the bank in a V | A highway between deep and shallow. Fish stage here moving either direction. |
| Ledge / drop | Contour lines bunched tight together | A vertical wall of ambush. The tighter the lines, the sharper the break. |
| Hump | Closed rings offshore, shallow in the middle | Isolated shallow surrounded by deep — a feeding station with no competition. |
| Channel swing | The old creek bed bending against a bank | Deep water against cover. The single most reliable summer and winter spot. |
| Flat | Contours far apart, wide open | Spawning and feeding ground. Worthless without an adjacent break. |
| Saddle | A shallow bridge between two humps | A pinch point fish travel through. Small, and often the whole day. |
The number on a contour matters far less than how fast it changes. Twenty feet of flat bottom holds nothing; twenty feet next to eight feet holds fish. When you look at a map, look for where the lines crowd together, then find the piece of that break with cover on it.
This is why pre-impoundment survey sheets are worth so much. Before the dam, somebody walked and mapped the ground that is now under the water — the roadbeds, foundations, fence lines and creek beds. Those are the hard, distinct pieces of structure on a bottom that is otherwise silt.
Conditions pick the shape for you. Falling water and high sun send you to the sharpest break you can find — channel swings and ledges. Rising water and cloud send you shallow onto the flats and the points leading to them. Post-frontal sends you into the thickest cover on the nearest structure.
Cold water concentrates fish on the last break before the deepest water. Pre-spawn puts them on secondary points inside the creeks rather than the main-lake ones.
A contour is drawn at a survey pool. If the lake is four feet low, every depth label on that map is four feet wrong in the direction that matters, and the ledge you meant to fish at 18 is at 14. BassHawk adjusts its depth labels to today's pool level for exactly this reason.
Find more fish. Every lake we cover publishes today's score free · the daily guide report is in the app