Most of the boating this pack covers is reservoir boating. John H. Kerr Reservoir is 42,799 acres of open water with fingers running up every creek that feeds it, and Smith Mountain Lake, less than half that size, is all cove and shoreline instead. Lake Anna on a Saturday in July is a traffic problem before it is a navigation problem. None of these existed before somebody built a dam, which is why the deep water still follows the river channel that was there first and the shallow water is whatever the valley floor used to be.
The pack charts 2,280 separate bodies of water. Of those, 911 are named, and 61 of the named lakes cover more than a square kilometer, which is about 247 acres. The outlines come from the National Hydrography Dataset and the depth under them is built from state elevation surveys. That is what puts contours and a depth number on a reservoir instead of a flat blue fill.
Of the 2,280 water bodies, 1,369 carry no name at all. Millponds, quarry holes, the pond behind a farm road, the wide spot where a creek backs up. They are charted water the same as the big lakes are, with an outline taken from the National Hydrography Dataset.
The 61 named lakes over a square kilometer are the ones people actually launch on. A square kilometer is a rough line to draw, but it lands close to the size where a lake stops being something you walk around and starts being something you want a plan for. The twenty largest of them run from 42,799 acres at the top down to 1,161 acres at the bottom, and the remaining 41 are no larger than the bottom of that list.
| Lake | Charted surface area |
|---|---|
| John H. Kerr Reservoir | 173 km² (42,799 acres) |
| Cherokee Lake | 118 km² (29,282 acres) |
| Smith Mountain Lake | 79 km² (19,571 acres) |
| Lake Gaston | 76 km² (18,904 acres) |
| Lake Anna | 51 km² (12,602 acres) |
| South Holston Lake | 30 km² (7,438 acres) |
| Roanoke Rapids Lake | 17 km² (4,275 acres) |
| Boone Lake | 17 km² (4,201 acres) |
| Hyco Lake | 17 km² (4,151 acres) |
| Claytor Lake | 16 km² (4,053 acres) |
| Lake Drummond | 13 km² (3,237 acres) |
| Lake Chesdin | 12 km² (3,015 acres) |
The twelve largest named lakes the Virginia pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 2,280 charted water bodies in all, 911 of them named, and 61 named lakes larger than one square kilometer.
There is no NOAA chart for a reservoir. A valley that was flooded in the middle of the last century has never had a hydrographic ship over it and never will, so inland depth in Helm is built from state elevation surveys instead, laid over water bodies from the National Hydrography Dataset. That is the whole difference between a lake that is a blue shape on a screen and a lake you can plan a route across against your own draft.
A reservoir also sits at whatever level it is being held at that month. The bed does not move. A contour is the shape of the ground under the water, so when the level comes down in the fall the contour is still right and the waterline is simply somewhere else on it. In practice you read the contour and the depth number rather than the edge of the blue. On a lake that has been drawn down, the old river channel is still the deep line through the middle, and the shoulders on either side of it are where the trouble is.
John H. Kerr Reservoir is 173.2 square kilometers off the chart polygon, or 42,799 acres, and it is the largest lake the pack carries by a wide margin. Cherokee Lake is next at 29,282 acres. Put those two together and they are larger than the following five combined.
Below them the list gets tight. Smith Mountain Lake at 19,571 acres and Lake Gaston at 18,904 are within about 700 acres of each other, a difference nobody notices from a boat. Lake Gaston is half again the size of Lake Anna, which is 12,602 acres. Kerr is more than twice Smith Mountain. Lake Drummond, 3,237 acres out in the Dismal Swamp, is the odd one on the list, since it is not sitting behind a dam like the rest. At the bottom of the twenty, John W. Flannagan Reservoir and Western Branch Reservoir both measure 1,161 acres, which is as close to a tie as the chart polygons get.
Chart packs are rectangles on the map rather than tracings of a border. A lake that straddles a line does not arrive half charted, and the far bank is on the screen when you cross it. Several of the largest on this list sit near an edge of the box, Kerr Reservoir and Lake Gaston among them, and so do Cherokee Lake, South Holston Lake and Boone Lake.
The boxes overlap on purpose, which means a border lake shows up in more than one pack and either one gives you the whole thing. If the water you run sits near a corner, the packs next door are Maryland, West Virginia, Kentucky and Tennessee. Downloading both sides of an edge before you leave home is worth doing, because the ramp you are heading for often has no bars on the phone once you get there.
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.
John H. Kerr Reservoir, at 173.2 square kilometers measured off the chart polygon, or 42,799 acres. It is the only water in the pack over 40,000 acres and more than twice the size of Smith Mountain Lake, which is 19,571 acres. Cherokee Lake comes next at 29,282 acres, then Smith Mountain and Lake Gaston at 18,904.
Depth. Smith Mountain Lake covers 19,571 acres in the pack and Lake Anna 12,602, and both carry contours and a depth reading on the water itself. No reservoir has a NOAA chart, so that depth is built from state elevation surveys, and the water body outlines come from the National Hydrography Dataset. Enter your draft once and the water your boat cannot cross shades on both of them.
The contour is the shape of the ground under the water, and that shape does not change with the level. What moves is where the waterline crosses it, so you read the contour and the depth number rather than the edge of the blue. On a drawn down reservoir the old river channel is still the deep line through the middle. With your draft entered, the shoulders on either side of it shade while the channel stays open, which is the part that matters on a 42,799 acre lake full of creek arms.
Helm Boating