Fontana Lake and Lake Jocassee are mountain water. The bank falls away from the shoreline in a hurry, an arm that reads wide on a map turns out to be a flooded creek with steep sides, and the shape of the old river channel is still the shape of the lake. Lake Norman and Lake Wylie run differently. They are piedmont reservoirs with long arms, docks most of the way down the bank and real traffic on a Saturday afternoon. Down on the coastal plain, Lake Mattamuskeet and Lake Waccamaw are open natural water, where a breeze has a long fetch and puts up a chop before there is anywhere to tuck out of it. One chart pack has to work for all of that.
The North Carolina pack carries 2,431 charted water bodies. Of those, 1,061 carry a name, and of the named ones, 111 measure more than a square kilometer of surface. The largest the pack carries is Lake Murray at 196.5 square kilometers, which is 48,556 acres. The depth under all of it is built from state elevation surveys rather than from a NOAA nautical chart, for the simple reason that no NOAA chart is drawn for a reservoir.
A charted water body here is a polygon from the National Hydrography Dataset, the federal inventory of surface water. The pack holds 2,431 of them. The ones with no name outnumber the ones that have a name, and that is the part worth knowing, because the pond above the ramp and the upper end of a creek arm are drawn on the chart even though nobody ever hung a sign on them.
Of the 1,061 named water bodies, 111 are larger than a square kilometer. That last count is the one that means something when there is a trailer behind the truck. It is the number of places in the box this pack covers that are big enough to plan a run on rather than launch and look around.
| Lake | Charted surface area |
|---|---|
| Lake Murray | 196 km² (48,556 acres) |
| John H. Kerr Reservoir | 173 km² (42,799 acres) |
| Lake Norman | 124 km² (30,641 acres) |
| Cherokee Lake | 118 km² (29,282 acres) |
| Douglas Lake | 118 km² (29,084 acres) |
| Lake Mattamuskeet | 105 km² (25,995 acres) |
| Lake Gaston | 76 km² (18,904 acres) |
| Hartwell Lake | 73 km² (17,965 acres) |
| Lake Keowee | 68 km² (16,803 acres) |
| Phelps Lake | 64 km² (15,864 acres) |
| Tellico Lake | 61 km² (15,098 acres) |
| Fort Loudoun Lake | 56 km² (13,714 acres) |
The twelve largest named lakes the North Carolina pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 2,431 charted water bodies in all, 1,061 of them named, and 111 named lakes larger than one square kilometer.
NOAA charts the coast, the intracoastal and navigable rivers. A lake held behind a dam sits outside all of that, which is why a reservoir shows up in most apps as a blue shape with a name on it and nothing underneath. Helm builds inland depth from state elevation surveys instead, and takes the water bodies themselves from the National Hydrography Dataset. One source says where the water is. The other says how far down the bottom goes. Together they turn a lake into water you can lay a route across against the draft of your own boat.
A survey of that kind measures ground, and ground does not move. What moves is the level the reservoir is being held at. Douglas Lake in November and Douglas Lake in June are the same bottom under a different amount of water, so the contour shapes keep telling the truth about a cove and about the line of the old creek channel whatever the pool is doing. Helm carries the survey date beside the reading, so you can see what you are looking at. The habit worth having at the ramp is to know the level for the day and read the chart with that in your head.
Lake Murray is the largest lake in the pack at 48,556 acres, and John H. Kerr Reservoir is close behind at 42,799. Then there is a step down. Lake Norman comes in at 30,641 acres, and Cherokee Lake and Douglas Lake land at almost the same size as each other, 29,282 acres against 29,084.
Lake Mattamuskeet covers 25,995 acres, more open water than Lake Gaston at 18,904 and well clear of B Everett Jordan Lake at 13,072. Further down the list the sizes bunch up and stop meaning much on their own. Lake Wylie at 9,514 acres and Fontana Lake at 9,439 are the same size on paper and nothing alike on the water, one of them lined with development down both banks and the other a long narrow pool between ridges. Lake Jocassee at 7,660 acres is the smallest on this list and still larger than most of the water anybody launches on.
The packs are cut to a box rather than to the state line. Water near the edge of that box is carried by this pack and by the neighboring one, so a lake you can launch on from either side comes down with whichever of the two you have on the device. The neighbors here are Virginia, Tennessee, Georgia and South Carolina.
That is a thing to sort out at the kitchen table, not at the ramp. If the tow crosses a line to get to the fishing, put the pack for the state you are driving into on the phone as well. Both sit on the device at once, and once they are downloaded the charts work with no bars, which is the usual state of a phone at the far end of a long lake.
Inland lake depth comes from state elevation surveys rather than from nautical charts, and a reservoir sits at whatever level it is being held at that week. Treat the shape and the depth as a guide, keep a lookout, and verify locally.
Real depth. Lake Norman covers 30,641 acres in this pack, and the water inside that outline carries contours and a depth number built from state elevation surveys, since NOAA does not chart reservoirs. Enter your draft once and the water your boat cannot cross shades on the chart, with the shallowest point reported on any line you draw across a cove.
Yes, because the survey measured the ground and the ground stays put when the pool drops. On Fontana Lake or Douglas Lake in the fall, the shape of a cove and the run of the old creek channel are the same lines they were in June, which is exactly what you want to steer by when the water is low. Helm shows the survey date next to the reading, and your draft keeps shading the shoulders either side of the channel.
Lake Murray, at 196.5 square kilometers or 48,556 acres, measured from the chart polygon itself. John H. Kerr Reservoir is next at 42,799 acres, then Lake Norman at 30,641. The packs are cut to a box rather than to the state line, so read that as the largest water this pack carries rather than as a ranking of one state's lakes.
Helm Boating