BWOs are beginning to show in better numbers. Try the drop-offs into deep water as well as riffles. Rubber leg and steamer patterns continue to produce. Flow has been almost constant with few minor increases around the middle of this week.
The irrigation reservoirs to our the south and east ( Chesterfield, Daniels, Treasureton, 24-mile, etc) are beginning to produce. Leech patterns, midge pupae under an indicator ( find taking depth), damsel fly wet & dry patterns, all work. It seems best to be on the water early in the day. Consider that these reservoir will be running low as demands for irrigation water increase in what looks like another hot dry summer coming up. So best fishing be from now into the next several weeks.
Trolling seems to be the best way to encounter good fishing. This suggests that fish are moving into deeper water and that the lake is warming up. Not hard to figure because of or warm weather and the lack of good snowfall last winter.
The big stonefly event is beginning to run out. The Coffee Pot area is its “last stand” and some action remains in Box Canyon. Next up will be the big may fly events of gray and green drakes beginning on the lower river with emphasis above Chester Dam. Watch for these in significance to trout any day now.
From what we have heard, opening weekend featured good fishing. Fish must be remaining in shallower water and so are easier to encounter. The lake is more than 100% full which a good condition for staying cooler longer. This suggests that good fishing should remain in the near future.
Both Chesterfield and Daniels are offering improving fishing. It is too early for significant speckled dun and damselfly activity on most still waters, but dragonfly nymphs are an early season food form that trout key on. Big and relatively numerous, they offer a great reward for the capture effort. Any big leech or rubber leg pattern presented during the early season in still waters will be effective in imitating these nymphs.
Still offering an uncrowded and tranquil alternative to the dense and somewhat hectic masses on the Henry’s Fork. Flow is slightly less than normal with clear, cold water ( 11400 cfs at Irwin, 12600 cfs at Heise, 6420 cfs at Lorenzo). Use the same patterns we have suggested for recent reports.
The big stone fly hatch is spread out along much of the river. Some remain on the lower river which up to now has been crowded with drift boats, rafts, and walk-in anglers. Look for Box Canyon to host a big portion of it, but the Riverside area on down into Cardiac Canyon will hold a lot of these bugs. Boats will be out ” en masse” in these water down to Hatchery Ford. If you want to get away from them, try the Bear Gulch area, go to Mesa Falls State Park and walk upstream, or walk downstream from the Hatchery Ford area. Include caddis fly life cycle patterns in your fly box. Afternoon caddis hatches can be dense throughout the river, and fish can key on them even though the big stone flies are out.
We have all grades of Yellowstone Park fishing permits ( Season : $75, 7-day $55, 2-day $40) and regulation booklets. These are also available on line through the park web site: www.nps.gov/yell/planyourvisit/fishing.htm. Park boating permits are available only at ranger stations.
The Firehole River will offer the best early season fishing here, so expect company. BWO life cycle, white miller, and soft hackle patterns are usually the most effective during the early season.
Below are some excerpts from Rob Vankirk’s latest report on the water situation in the Henry’s Fork drainage. If you plan on visiting the river in the near future to fish, what is given below could help in planning. One thing is certain; with a three-day weekend coming up and the stone fly event in full swing, you will have plenty of company.
Latest forecasts are calling for one more round of decent precipitation this evening through tomorrow night. Totals will range from 0.25 in the valleys to 0.75 inch in the northeastern corner of the watershed. Temperatures remain below average through Friday or Saturday, rising to average by Sunday. Warm, dry conditions are expected to return next week, putting an end to our 10-day break.
Given the higher-than-expected rainfall totals, streamflow response to the rain was higher than I expected. Natural flow reached its highest peak for the season to date yesterday at around 7,000 cfs. Although 2,000 cfs greater than the late-April peak, 7,000 cfs is still only 90% of average for the date. Total accumulated natural flow for the water year so far is 84% of average. Natural flow has been receding since early yesterday morning, and I expect recession to continue until late tonight, when it should increase again in response to rain this evening. However, lower rainfall totals forecast for the next 24-36 hours will probably keep total natural flow a little lower than it was yesterday. Diversion decreased another 6% yesterday and was 86% of average.
Island Park Reservoir and Henry’s Lake both reached full pool on Sunday, and Grassy Lake gained enough over the weekend that it will most likely fill, especially if rain favors the Fall River headwaters again today and tomorrow. Outflow from Island Park Reservoir was increased yesterday from 210 cfs to 925 cfs to match inflow, which reached a maximum of around 875 cfs on Sunday. Much of that inflow was from direct precipitation on the reservoir surface, but natural reach gain between Henry’s Lake and Island Park did increase in response to rain from around 450 cfs on Thursday to 822 cfs yesterday. Although this number will change a little with addition of more data over the next day or two, it will be close to the snowmelt-driven peak of 790 cfs back on April 29. Stream inflow to Island Park Reservoir is around 750 cfs this morning, and I expect that to drop throughout the day. Rain this evening and tomorrow will probably not produce much more streamflow response but will add another 300 ac-ft of inflow on top of stream inflow. Once rain ends tomorrow night, inflow will drop fairly rapidly. Outflow from Island Park Reservoir will be adjusted as needed to keep the reservoir full until draft is needed to meet downstream demand.
The biggest, and most critical question is: when will that happen? Based on April-1 conditions, I predicted that need for reservoir draft would begin on June 25. After the driest April in the last 33 years and a very dry start to May, it looked more like draft would be needed as soon as the Teton River reached its snowmelt-driven peak for the spring shortly after June 1. At this point, I expect natural flow to be sufficient to meet irrigation demand until at least June 10, if not even June 15. This won’t be as favorable as June 25 (or last year’s July 4), but it’s much better than June 1.
Rob Van Kirk, Ph.D.
Senior Scientist