Flow out of Mackay dam is still close to 1000 cfs. That to high for safe wading. It’s an unusual situation because of run-off coming into the reservoir from above. Water is flowing even down to Arco wher years ago good fishing was possible. This high flow will end soon, and we will report such because this stream and its Copper Basin headwaters are important destinations for many fly fishers.
Other than the big stone fly event ( Bugs are now into the lower canyon), we had a serious incident on the river yesterday. Three anglers in a drift boat got too close to the big feeder gates and came nearly getting sucked through. They were luckily relieved of the situation by efforts from hard working first responders.
A long boating season is coming up on this big, powerful river, and the potential for unhappy incidents like this one, and worse, are bound to happen. We and all other businesses that serve boating, and wading fly fishers ask that we do as much as possible to remain safe. It is not because you are customers, it is because you have families and/or are part of the community to which and you contribute to in many ways. So please resolve in the hours before you arrive on the river that you will strive to be safe.
A Willow Creek Beaver Pond
This conversation is going to be general. But because so many area cutthroat spawning streams opened to fishing a few days ago there is a particular reason for fishing these, and that is because of hosted beaver ponds. Beaver ponds provide so many advantages for trout. They offer relative overhead cover, cool water this time of the season, a rich variety of food forms from damsel flies and speckled duns on down to leeches (easy protein), scuds, and even mice and snakes. You will find these pond only on low gradient sections of small streams (no way could beavers dam the South Fork!), but some can be large enough to host a flotation device (See above photo). Now is the time for best fishing on these because as summer advances they warm like all other waters.
So where does one find these ponds? Many of the best are off the beaten track. The Willow Creek drainage is a good place to start looking. Such as Cranes Creek, Hell Creek, Gray’s Lake Outlet, lower Homer Creek, Tex Creek are good candidates. All Palisades Reservoir tribs host beaver ponds and so do Salt River tribs coming out of Idaho (Crow, Jackknife, Stump, Tincup). Palisades Creek, just above the lower lake, hosts some, and so do several Henry’s Fork drainage streams. The same applies to Teton River and Big Lost River tribs. Use Google Earth and look for their presence.
Fish in these, usually brown, brook and cutthroat trout can attain surprisingly large sizes. Browns up to ten pounds use to inhabit Cranes and Willow Creek and Gray’s Lake Outlet beaver ponds. Cutthroat in Centennial Valley streams range exceed twenty inches in length. Brook trout exceeding twenty inches still inhabit Duck Creek beaver ponds.
Other streams are now worth a visit. Bitch, McCoy, Palisades and Robinson Creeks are near run-off free. Golden stones, PMDs, sallys and PM caddis are active on these. Warm River below it spring offers Brook, brown and rainbow trout (relative solitude compared to nearby Henry’s Fork) responding to the same aquatic insects. b
Big Osborn Spring at Lower Right
Fishing in the upper section of the Harriman State Park section will soon take a somewhat back seat during PMs to the lower section. March browns are mostly gone, Green Drake activity is tumbling, PMDs are getting smaller in size, but flavs remain for good PM fishing and AM spinner falls. But for brown drakes, the peak hatch peak is soon to come, and the best of their hatch will be accessed via Wood Road 16 (WR 16). For sure there will be some brown drakes throughout the entire Harriman reach (same with flavs), but there is one big reason why the best concentration is on the lower section. See the above photo? It was taken of a river section about a half mile above the WR 16 access.The US Highway bridge is at upper right. What is significant here is that water flowing from Last Chance on down to and past the bridge is warming because of water in Island Park Reservoir and inlets from Silver and other Park lakes are warming (all are shallow), and so is weather, helping to diminish dissolved oxygen in the river. However inflow from Big Osborn Spring adds a large amount of cool water to the river making better conditions for the brown drake population in the river below. Brown drakes emerge best during evenings but they are sure to peak soon. Fish are in the river “Twenty-Four Seven” and they will be gorged on these active insects just before their emergence peak. So consider being on this part of the river very soon. .
Overall, water quality continues to be excellent throughout the watershed, with the exception that afternoon high temperatures are starting to exceed optimal at some locations. Mean water temperatures yesterday were very close to average throughout the watershed, but afternoon highs exceeded 70 degrees at Buffalo River, Pinehaven, St. Anthony, and Parker. Dissolved oxygen concentrations are good in all river reaches.
Timing of aquatic insect hatches has not changed much with respect to the 2014–2022 average over the past week except at Marysville, where it has moved from 9 days later than average to 8 days later. Hatch timing in the river reach between Island Park Dam and Pinehaven is 5–6 days later than average but at or a few days ahead of that in 2022. Hatch timing at Flat Rock, Ashton Dam, and St. Anthony is still 1–4 days behind average but 1–3 days ahead of last year.
Rob Van Kirk, Ph.D.
Senior Scientist
P.O. Box 550
Ashton, ID 83420
208-881-3407 CELL
About 1000 cfs of water is coming out of Mackay Dam. This means difficult and somewhat dangerous wading in the river below. Look for flow out of the dam to remain this high until run-off from the upper drainage begins to drop.
Bechler Meadows with June High Waters
The Firehole River still offers good fishing, even though water there is warming. ShoshoneLlake still offers the best still water fishing if you follow the strategy offered in our last fishing report.
Fall River streams are rounding into shape, but water is high. Best current strategy is to fish patterns that simulate drifting earthworms (annelids) until waters drop. All meadow sections are wet and mosquitos within the timbered areas are NUMEROUS and fierce! Bring DEET to survive walks through these areas. The Ashton-Flagg Road, rough in places, is open to Grassy Lake Reservoir. It is closed just beyond at the Bridger-Teton USFS boundary
South Fork tribs below Palisades Dam with cutthroat spawning runs open to fishing tomorrow. Some of these still have large cutthroat heading down to the river. Because these currently have cooler water, top water fishing will be slower than presenting such as nymph, small leech, and streamer patterns. The Willow Creek tribs also open to fishing tomorrow. Good locations for family fishing can be around any of the crossings with with wet flies being the best way to encounter trout. Willow Creek has been stocked with rainbow trout around these, but beaver ponds, until their water warms offer better fishing, and the Willow Creek drainage has many of these. More later on best strategies for fishing beaver ponds.
Golden stone flies are still around up and down the river. Some may flies have peaked (green drakes, gray drakes, March browns) and others are yet to peak ( brown drakes and flavs on the upper river). Afternoons will be the best times for finding the brown drakes and flavs.
The other happening that will begin its season is recreational floating. Going through Box Canyon and Big Springs to Mack’s Inn will have the biggest concentrations, but they will also be common through Harriman State Park to Riverside campground. Be patient with these folks as most of them have yet to form an etiquette. Gently explain to them that you realize they have a right to the river, but we appreciate you giving anglers present enough room to enjoy what they do. To be sure, you will learn a lot about human nature through these encounters.
No change in fishing success since our last report. Looks like we need warmer water and weather. Maybe some damsel flies being active soon will help, but for now find some submerged springs and sink a midge pupa around it for a bit of action.
Elk Lake
The Madison River below Cabin Creek can be discolored from time to time, but streamer, big stonefly nymph and rubber leg patterns will produce action. Top water fishing is quite slow here. Hebgen Lake is also spotty with some action from midge pupa patterns under an indicator in shallow water. Centennial Valley streams are running high and cold because of run-off. Elk Lake offers good fishing for west slope cutthroat in shallow water through using leech and streamer patterns. No word yet on the road to the upper end being open, but fishing on the lake around Elk Lake Resort is good.