Most of the big water in this pack is impounded river. Lake Marion and Lake Moultrie sit joined behind the Santee Cooper dams, Lake Murray backs up the Saluda, and Hartwell Lake, Richard B Russell Lake and J. Strom Thurmond Reservoir come one below the next going down the Savannah. Running water like that is a different job from running the coast. The old creek channel is still down there under the flat you are crossing, the coves shallow out at the head faster than they look like they will, and a shoreline of pine and clay bank reads about the same for a long way in either direction. What you want on the screen is the bottom.
The pack carries 2,251 charted water bodies. 975 of them are named, and 40 named lakes run over a square kilometer. The water bodies themselves come from the National Hydrography Dataset, and the depth under them is built from state elevation surveys. That is the reason a reservoir in Helm has contours and a depth number on it instead of a flat blue fill with a name across the middle.
2,251 charted water bodies is mostly small water. Only 975 of them carry a name, so the bulk of what the pack holds is the unnamed stuff: mill ponds, farm ponds, the wide places in a creek, the backwater behind a causeway. The 40 named lakes over a square kilometer are the ones people trailer to.
Surface area is concentrated hard at the top of the list. Four of them are over 40,000 acres apiece, and the first two are over 56,000. These are the largest named lakes the pack carries, measured off the chart polygon itself rather than off a published figure:
Lake Keowee and Lake Jocassee are on the list at 68.0 and 31.0 square kilometers, and the pack also carries Monticello Reservoir at 26.8, Lake Tillery at 19.5 and Parr Shoals Reservoir at 12.5.
| Lake | Charted surface area |
|---|---|
| Lake Marion | 322 km² (79,691 acres) |
| Lake Moultrie | 229 km² (56,587 acres) |
| Lake Murray | 196 km² (48,556 acres) |
| J. Strom Thurmond Reservoir | 164 km² (40,649 acres) |
| Richard B Russell Lake | 99 km² (24,488 acres) |
| Hartwell Lake | 73 km² (17,965 acres) |
| Lake Keowee | 68 km² (16,803 acres) |
| Wateree Lake | 47 km² (11,713 acres) |
| Lake Greenwood | 42 km² (10,329 acres) |
| Lake Wylie | 38 km² (9,514 acres) |
| Lake Waccamaw | 36 km² (8,797 acres) |
| Lake Jocassee | 31 km² (7,660 acres) |
The twelve largest named lakes the South Carolina pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 2,251 charted water bodies in all, 975 of them named, and 40 named lakes larger than one square kilometer.
There is no NOAA chart for a reservoir. The federal nautical charts cover the coast and the navigable rivers, which leaves the depth under Lake Greenwood or Wateree Lake to come from somewhere else entirely. In Helm it comes from state elevation surveys of the lake bed, matched to water bodies from the National Hydrography Dataset. That pairing is the whole difference between water you can plan a route across against your own draft and water that is a shape on a map.
A contour on a reservoir is a line on the bottom, not a line on the surface. The bottom is the part that stays put. The surface sits wherever it is being held, full through the spring and pulled down through a dry stretch of summer, and on working water like Monticello Reservoir and Parr Shoals Reservoir it moves on a much shorter clock than a season. So read a contour the way you would read it alongside the current lake level. The shape of the creek channel and the shoulders on either side of it is the part you can rely on. The level tells you how much water is standing on top of it that day, and with your draft entered, the shoulders are what shade.
Lake Marion at 322.5 square kilometers is larger than Lake Murray and Hartwell Lake put together. Lake Moultrie is the next one down at 229.0, and it still covers more water than J. Strom Thurmond Reservoir does at 164.5. The two of them are joined, which is why a long day on the Santee Cooper water can be two lakes without the boat leaving the piece of chart you started on.
Going up the Savannah the steps get smaller. Richard B Russell Lake at 99.1 square kilometers is about three fifths of Thurmond. Hartwell Lake at 72.7 and Lake Keowee at 68.0 land within five square kilometers of each other. Lake Jocassee at 31.0 is a little under half of Keowee, which surprises people who have run both.
The middle of the list is crowded. Wateree Lake at 47.4, Lake Greenwood at 41.8, Lake Wylie at 38.5 and Lake Waccamaw at 35.6 all sit inside twelve square kilometers of each other. If you know the scale of one of them, you know roughly what you are looking at on the other three before you pull up to the ramp.
Chart packs are rectangles, so the edge of this one does not follow the border, and near the line that works in your favor. Lake Wylie at 38.5 square kilometers is in the box, and so are Mountain Island Lake at 7.9, Lake Tillery at 19.5, Lake Waccamaw at 35.6 and Lake Burton at 10.2. None of that makes any of them a South Carolina lake, and the pack makes no such claim. It means border water is generally carried in more than one pack, and the North Carolina and Georgia packs hold the same lakes from their own side.
Once the pack is on the phone, the charts, the depth shading, the measure tool and routing all keep working without a signal. Pull it down at home on wifi, before the tow rather than in the ramp parking lot.
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.
Yes. Both are charted water bodies in the South Carolina pack, Lake Marion at 322.5 square kilometers or 79,691 acres and Lake Moultrie at 229.0 square kilometers or 56,587 acres. The outline comes from the National Hydrography Dataset and the depth under it from state elevation surveys, so you get contours and a depth reading on the water rather than a plain fill.
The contours describe the lake bed, and the bed does not move with the level. Lake Murray is 196.5 square kilometers, 48,556 acres, and the creek channels and the shoulders beside them stay where the survey found them. Check the level the lake is being held at and read the contour against it. With your draft entered, the shoulders that come into play at that level are the water Helm shades.
Yes. The packs are cut to a box rather than to the state line, so Hartwell Lake at 72.7 square kilometers, Richard B Russell Lake at 99.1 and J. Strom Thurmond Reservoir at 164.5 are all carried here. The Georgia pack carries that same Savannah water from its own side, so either one puts the whole chain on your screen.
Helm Boating