Way back in late August of 2008, Hebgen Dam broke. The day it happened we sat there and drank beers, watching the lake drop six inches in 24 hours. A month later, PPL Montana got the situation “under control”, but none of us thought it would take this long to complete construction. Where is the accountability? For the past seven years, the angling could be hit and miss, more so than before the failure of the intake structure. During the past two seasons, it seemed as if the trout have come around to the warmer temps and fishing was pretty darn good. However, the dry fly fishing wasn’t nearly as consistent and most guides in the float stretch relied on nymphing. I’ve written about this quite a bit over the past seven years, so have others like Mike Lum down in Ennis. We’ve been pretty hard on Northwest Energy (formally PPL Montana, this change happened in the fall of 2014) and only in the past couple of years has anyone at NWE really paid attention. I’d like to give that credit to their biologist, Brent Mabbot. Brent is a diamond in the rough and is putting in some time with regards to getting out and talking with the locals who have spent their lives on the Madison River and care for it deeply. While we don’t agree on everything, he at the very least will listen and react. Brent went to bat for the river and I personally have noticed the change. While some of us would’ve held on to more water this winter in Hebgen Lake, at least we are sitting at a higher elevation that in past years…it’s not much higher, but it is better than it could be. Trout in the Madison River are spawning and it remains to be seen how they’ll do with the recent drop in flows, which is a double edged sword. Why? Well, the lake is gonna need all the water it can to be filled by the end June and our snow pack is quite low (72% for the entire Madison Drainage, slightly lower locally). Hopefully, this drop in flows (currently 654 CFS) is early enough to catch the pre-run off snow melt that is occurring right now and also to not cause the spawning channels to become too shallow, too soon.
So, cross your fingers, cross everything really, as they are almost finished with Hebgen Dam project. On or around July 1, 2015 NWE is going to begin testing the new intake structure. This will take some time as they want to make sure everything is functioning properly. Once this is the case, they will start to remove the coffer dam.
This is when things get tricky.
You see, there is roughly 56 degree water down at the intake, which is about 10 degrees cooler than what comes off the top of the lake. In August, there are times when the top of the lake is 70 degrees. If NWE switched out the flow from the warmish water on top of the lake to the cold water beneath the thermocline, this could “shock” the fish. Mabbot would like to slowly introduce the cold water to the fish and plans on mixing the top water and bottom water for a little while to gradually change the temperature of the river. Against the coffer dam sits quite a bit of silt and nobody knows exactly how much. This silt will enter the river once the coffer dam is removed. Will it blow out the river completely? Who knows, but the river betwix the lakes will get some color. With any luck, Quake Lake will act as a filter and the river from the Slide to Ennis will be green. By August 15th, or earlier if all goes well, the Madison will once again have clean, cold water. Honestly, nobody really knows how the river will react to this change, but the one thing we all know is that cold water is better than warm water. When I talk about change, I mean go back to the way it was. Back to when one needed waders to fish betwix the lakes in August. Back to when most of us fished dry flies ramp to ramp with good success no matter how skilled the angler was in the boat. This change will take some time as the river will adjust the way all ecosystems do – at their own pace.
I boldly predict that the fish, post runoff, will enjoy the river as they normally do. However, when the river begins to warm up, like it has the past 7 years in late July, it will continue to be cold because Hebgen Dam is functioning properly from the depths of the lake. Maybe, just maybe, the larger trout in the river will still be holding in the shallow riffles and boulder strewn runs through the month of August and early September and not retreat to the deepest, darkest and coolest runs in the river. Sixteen years ago, I started guiding on one of the finest rivers in the world. Some of the best advice I got was to learn the river by floating long stretches and fishing a dry fly against the banks, around the boulders and throughout the mid-river gravel bars. Float long and fish it dry. This has not been the most productive technique since 2008, with the exception of late June and early July or the random day they decide to eat it all day on top, but I want this back more than about anything else in my angling world….and I am not alone.