Two kinds of water sit in this pack. The Missouri mainstem holds Lake Oahe, Lake Sharpe, Lake Francis Case and Lewis and Clark Lake, one impoundment after another, water wide enough that a crossing is a decision and the wind after noon is the thing you plan around. Oahe measures 178,731 acres off the chart polygon. Northeast of the river the lakes get smaller and sit closer together, Lake Thompson at 13,813 acres, Lake Poinsett at 9,736, Lake Kampeska at 5,041, near enough to each other that you pick one in the morning.
The pack carries 10,800 charted water bodies, which is fifth among the 48 state packs. Of those, 1,180 carry a name, and 161 of the named ones are larger than one square kilometer. The outlines come from the USGS National Hydrography Dataset, which gives each lake its shoreline and its name.
At 10,800 charted water bodies, this pack sits fifth among the 48 state packs. Four carry more. Most of that count never sees a boat. It is what the hydrography dataset holds as water inside the box the pack is cut to, from the mainstem reservoirs down to sloughs with no road to them.
Names run differently. 1,180 of those water bodies carry one, which is 29th of the 48, and the distance between fifth and 29th is the northeast quarter of the map, where the country is full of small basins holding water that nobody ever needed to name.
The third figure is the one to plan around. 161 named lakes cross a square kilometer, 14th of the 48, and that is roughly the set you would hitch a trailer for. One thing to know about how the packs are built: they are cut to a box rather than to the state line, so water near an edge shows up in a neighboring pack as well.
| Lake | Charted surface area |
|---|---|
| Lake Oahe | 723 km² (178,731 acres) |
| Lake Francis Case | 331 km² (81,767 acres) |
| Lake Sharpe | 235 km² (58,045 acres) |
| Lewis and Clark Lake | 101 km² (24,982 acres) |
| Lake Thompson | 56 km² (13,813 acres) |
| Big Stone Lake | 48 km² (11,812 acres) |
| Lake Traverse | 43 km² (10,675 acres) |
| Lake Poinsett | 39 km² (9,736 acres) |
| Bitter Lake | 32 km² (7,809 acres) |
| Dry Lake Number Two | 26 km² (6,400 acres) |
| Belle Fourche Reservoir | 24 km² (6,054 acres) |
| Waubay Lake | 22 km² (5,535 acres) |
The twelve largest named lakes the South Dakota pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 10,800 charted water bodies in all, 1,180 of them named, and 161 named lakes larger than one square kilometer.
Lake Oahe is the largest named lake the pack carries, 723.3 square kilometers, 178,731 acres, measured from the chart polygon itself. Lake Francis Case is next at 330.9 square kilometers, 81,767 acres. Then Lake Sharpe, 234.9 square kilometers and 58,045 acres, and Lewis and Clark Lake at 101.1 and 24,982 acres. Add those three together and the total is still smaller than Oahe on its own.
Water at that scale moves the work to before the launch. You are choosing which arm to run and what hour to be back at the ramp. Draw a line across a bay with the measure tool and you get the distance and the bearing.
There is no NOAA chart for a reservoir. Nautical charts are made for the water ships use, and Lake Sharpe is not part of it. The water body outlines in this pack come from the USGS National Hydrography Dataset instead.
The second thing to carry in your head is that a reservoir sits at whatever level it is being held at. The basin does not move. The surface does, so the habit worth having is to know the pool level the day you launch. The charted shoreline stays where it was drawn.
Creek channels are where this shows up first. The old channel stays open as the water comes down and the flats on either side of it do not. A rock point that is a landmark at full pool reads the same way once the level drops.
Lake Thompson is the largest of the lakes off the mainstem at 55.9 square kilometers, 13,813 acres. Big Stone Lake and Lake Traverse come next at 11,812 and 10,675 acres, both of them close enough to a pack edge that they appear in a neighboring pack too. For scale, Lake Kampeska at 5,041 acres would fit inside Lake Oahe about thirty five times.
Below that the figures bunch up. Lake Andes and Angostura Reservoir come out identical, 19.1 square kilometers and 4,720 acres each. Lake Whitewood is 4,448 acres, Swan Lake 4,300, Columbia Road Reservoir 4,201 and Shadehill Reservoir 3,781. At that size the difference between one lake and the next is the shape of the basin rather than the size of it, which is an argument for looking at the outline on the chart before you decide where to launch. Download the pack at home and the charts and the measure tool keep working at a ramp with no signal.
The state lake packs draw lake shorelines from the USGS National Hydrography Dataset, and a reservoir sits at whatever level it is being held at that week. Treat the shape as a guide, keep a lookout, and verify locally.
Helm shows Lake Oahe by name and shoreline from the USGS National Hydrography Dataset. It is the largest named lake the South Dakota pack carries, 723.3 square kilometers and 178,731 acres measured from the chart polygon. Of the state lake packs, Minnesota is the one that also adds depth contours.
The pool level. Helm draws Lake Francis Case by its shoreline, 81,767 acres at the chart polygon, and that outline stays where it was drawn while the water moves. Keep the day's pool level in mind, because the old creek channel stays open as the water comes down while the flats on either side of it do not.
It carries 10,800 charted water bodies, fifth among the 48 state packs. Of those, 1,180 are named and 161 are larger than a square kilometer, which takes in Lake Thompson at 13,813 acres, Big Stone Lake at 11,812, Lake Traverse at 10,675, Lake Poinsett at 9,736, Waubay Lake at 5,535 and Lake Kampeska at 5,041.
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