Deer Creek Reservoir on a July morning and Great Salt Lake in a fall wind are not the same activity. One is 2,520 acres of held water up in the mountains. The other is salt water with no outlet, 884,166 acres of it, measured at 3,578.1 square kilometers from the chart polygon itself. In between sit the lakes people actually tow to: Utah Lake at 90,663 acres with nothing on it to break an afternoon wind, Bear Lake cold and clear at 69,585, Flaming Gorge Reservoir at 38,647 down its canyon, Strawberry Reservoir at 16,136 up in the high country.
The pack carries 1,847 charted water bodies. Of those, 744 carry a name, and 82 of the named ones cover more than a square kilometer, which is roughly the size at which a crossing stops being something you eyeball from the ramp and starts being a plan. Depth on these lakes is built from state elevation surveys, and the water bodies themselves come from the National Hydrography Dataset. Every size on this page is measured off the chart polygon, not copied out of a fishing guide.
Great Salt Lake is the largest water body the pack carries, 3,578.1 square kilometers, or 884,166 acres. Sevier Lake comes next at 493.4 square kilometers, so the step down from first to second is more than seven to one. Utah Lake is third at 366.9 square kilometers, which makes the first one almost ten times the size of the third. None of that is visible on a map where every lake is the same shade of blue.
Under the big water the pack fills in with a lot of small water. 82 named lakes clear a square kilometer. The other 662 named ones are under that mark, and once you count everything the dataset holds, named or not, the total reaches 1,847. Most of them are ponds and small mountain lakes you will never launch a trailer on, and a few of them are the reason a creek arm on a big reservoir has a name at all.
| Lake | Charted surface area |
|---|---|
| Great Salt Lake | 3,578 km² (884,166 acres) |
| Sevier Lake | 493 km² (121,922 acres) |
| Utah Lake | 367 km² (90,663 acres) |
| Lake Powell | 314 km² (77,616 acres) |
| Bear Lake | 282 km² (69,585 acres) |
| Flaming Gorge Reservoir | 156 km² (38,647 acres) |
| Strawberry Reservoir | 65 km² (16,136 acres) |
| Willard Bay Reservoir | 40 km² (9,934 acres) |
| Sevier Bridge Reservoir | 37 km² (9,044 acres) |
| Kennecott Tailings Pond Number One | 20 km² (5,016 acres) |
| South Bay | 17 km² (4,225 acres) |
| Mud Lake | 14 km² (3,459 acres) |
The twelve largest named lakes the Utah pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 1,847 charted water bodies in all, 744 of them named, and 82 named lakes larger than one square kilometer.
There is no NOAA chart for a reservoir. NOAA charts the coast, the intracoastal and the navigable rivers, and a storage lake sitting up a canyon has never been on that list. So inland depth in Helm is built from state elevation surveys instead, and the outline of the water body comes from the National Hydrography Dataset.
Those two things together are the difference between a lake that is a blue shape on the screen and water you can plan a route across against your draft. With the outline and the bed elevation both in hand, the lake carries contours and a depth number on the water, the draft you entered shades what you cannot take the boat over, and the router has something to work with away from the coast. Each reading carries the date of the survey behind it, so you can see how old the measurement under you is.
A reservoir sits at whatever level the people running it have decided to hold it at this month. Flaming Gorge, Strawberry, Jordanelle, Deer Creek and Scofield are all storage first and recreation second, and the surface you launched onto in June is not the surface waiting for you in September.
What an elevation survey measures is the bottom, and the bottom does not move. The old creek channel running down the middle of the basin is in the same place at every stage the lake is held at. The flat at the mouth of a cove rises at the same point on the bed whether the lake is full or well down.
So the way to read one of these is to know the elevation it is being held at this week, which the operator publishes, and then read the contours for shape. Where does the channel run, which side of the bend is the deep one, which arm comes up first. A drawn down reservoir is when that shape is worth the most to you, because the channel is where the water still is.
Utah Lake and Lake Powell land close together in this pack, 366.9 square kilometers against 314.1, or 90,663 acres against 77,616. Utah Lake is the larger of the two by 13,047 acres. They do not fish alike and they do not feel alike, and the acreage is about the only thing they share. Bear Lake follows at 281.6 square kilometers, 69,585 acres, and then the drop to Flaming Gorge Reservoir at 156.4 and Strawberry Reservoir at 65.3 is a steep one.
The packs are cut to a box rather than to a state line, so a lake sitting on a border is carried by more than one of them. Powell runs south out of this box and Bear Lake runs north out of it. If your weekend covers the whole length of either, pull down the neighboring pack too and you keep the chart under you the entire way.
Below the headline water, the reservoirs people tow to on a Saturday sit in a tight band, close enough together that two pairs of them match to the acre.
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. No NOAA chart exists for a terminal lake with no outlet, so Helm builds the water body from the National Hydrography Dataset and the depth from state elevation surveys. The pack measures it at 3,578.1 square kilometers, 884,166 acres, the largest water body it carries.
This one carries 314.1 square kilometers of it, 77,616 acres. Because the packs are cut to a box rather than to a state line, the Arizona pack carries Powell as well. Download both before you leave if the run goes down the length of the lake, and the chart is on the device with no signal either way.
That is when they are worth the most. The elevation survey measures the bed, and the bed stays where it is no matter what level the reservoir is being held at. The creek channel and the shoulders either side of it keep their positions, so with your draft entered you can see which arm still holds water and where the flats come up. Check the elevation for the week, then read the contours for shape.
Helm Boating