It’s worth the time to drive to Arco just to see the Big Lost River doing something it has not done in decades. That is flow through town (currently 383 cfs) and beyond. Flow out of Mackay Reservoir is currently 1300 cfs and has been at least as high for weeks, so it is no wonder that Arco is experiencing the river again. This high flow below Mackay Dam makes approaching the river tough and fishing slow.
Flow out of Mackay Dam is well over 300 cfs meaning wading immediately downstream should be done with some care. Early morning trico activity and late in the day caddis activity are providing action. With flow at the current level, such as San Juan worms or small woolly buggers can bring action.
Flow out of Mackay Dam was raised a little recently, but at slightly over 400 cfs wading is a bit difficult. Western green drakes are finished, but terrestrial insects are coming on. Fishing has been somewhat slow, but nymphing with PMD patterns is a good method for some success. The same for presenting patterns simulating aquatic or washed-in worms (SJ worm, medium sized woolly buggers). Flows will drop as irrigation demands diminish and calls for storage in the reservoir increase. Such should make for better wading conditions during the trico activity later this summer..
Flow out of Mackay Dam has gone from about 130 cfs to a bit over 500 cfs in the last few days. Forget about safe wading and good BWO-midge hatches for a while.
With flow out of Mackay Dam at 54cfs, fish are concentrated in holes, and wading is easy. Midge life cycle patterns will bring action along with small nymph patterns of your choice.
The South Fork isn’t the only one having a significant drop in flow. Flow out of Mackay Dam was reduced yesterday from 150 cfs to 50 cfs today. It’s great for wading but not for fish. Midging will get you into the fish concentrated in holes and runs.
Flow out of Mackay Dam is at 200 cfs, an amount that makes wading practical. Flows out of the dam will likely go lower as storage takes over in the reservoir. Tricos are diminishing, but BWOs are coming on, and there always is plenty of midges for fish to key on.
AM Tricos bring fish up below Mackay Dam, but at 360 cfs, wading the river is a bit rough.
Tricos are coming out from the river below Mackay Dam. Fish there key on terrestrial insects later in the day.Only “fly in the ointment” is that flow out of the dam is around 400 cfs making wading a bit tough.
Flow out of Mackay Dam had been pretty constant at around 340 cfs ( very near its mean flow for this time of year) for the last several days. This AM, however, it was upped to about 430 cfs. That’s a pretty good jump for this small river, so wade carefully. Any day now tricos will be the major emergence, so be ready to try the river during the AM hours.