Bighorn River Flows

Over the years I have observed that tailwater fisheries (that's what we call river sections that flow "below" or after a dam) can be absolute fish factories.  The combination of (relatively) consistent water flows (so we generally avoid things like droughts and floods) and year round cool water conspire to create aquatic environments that are everything trout need to flourish.  The result can be a superb fishery-often presenting an angler with year round fishing opportunities.  Many times a tailwater creates a very viable trout habitat out of what would otherwise be a marginal/seasonal trout fishery (suited to "put and take" trout management) or more likely, a warm water fishery (with apologies to my bass fishing brethren).  And so many devoted trout fishermen flock to tailwaters because of the consistently high quality fly fishing that they offer.


The Bighorn River in Montana is just such a place.  In fact, many say that the Bighorn River is THE top tailwater in the US (with apologies to the Missouri, the San Juan, the Green River, etc.).  There is little room for any disagreement though that is is one of the best in the country.

In the picture above, you can see the mid morning 2003 Memorial Day drift boat flotilla beginning its procession down the Bighorn River...just below the Yellowtail Dam and the Afterbay.  Fact is, the Bighorn River is not a very well kept secret....at all.

Unlike a freestone river (in which the water flows can vary widely and are generally are a "force majeure"...a function of rain fall, snow packs, temperatures..all out of the control of man) the water flow in a tailwater is a precisely controlled, man made event...often left to the judgement of some sort of "water minister" who is in control of the dam's outflow.  And so the needs of the ecosystem below the dam (trout, aquatic plant life, insects, birds, crustaceans, etc... and oh by the way, the trout fisherman) are forced to compete with the needs of flood control, irrigation, power generation, and the boaters, home owners and fishermen on the reservoir that sits above the dam, etc.  Often times what is good for one stakeholder is not so good for another.  Whew!  Pity the guy controlling the flows...he's not likely to please all of these competing stakeholders.  However, it often seems that the needs of the tailwater ecosystem (and the trout fisherman) come in dead last.  At least that's the way it seems to me.

So, it was with great interest and fearful trepidation that back in May I began consulting the USGS website to see what kind of water flows were coming out of the dam above the Bighorn River.  As it turns out, there were, from a historical perspective,  monster flows coming out...nearly 10,000 CFS (cubic feet per second).  To put this in perspective, the river's "normal" flows (when I say "normal", I am referring to what I have personally experienced on this river over the 10-15 years that I have been visiting it) range between 1500-3000cfs.  So for the past 6 weeks the river has had 3-6 times the normal amount of water in it as (what I consider to be) normal.  Think of it this way....what was an easy-to-wade, knee deep run at 2,000 cfs was a raging, chest deep torrent at 10,000 cfs....powerful enough to knock you off your feet and carry you down stream.

Flows of this magnitude on the Bighorn mean that much of the "wade fishing" was impossible (because the added flows create a river that is much deeper than usual and often too dangerous to wade) and most of the fishing would have to take place from a boat.  While many anglers enjoy boat fishing, it is not something I particularly enjoy.  The fly fishing style I enjoy most is sight casting to fish...either to rising fish with dry flies or casting very small nymphs to fish that I have spotted feeding in shallow runs.  And I may just prefer sight casting with nymphs over dry fly fishing.  I know...it's heresy!

Noted Bighorn River guide Dennis Fisher (that's him above/ left) introduced me to this nymphing technique several years ago and I fell in love with it.  We would simply use his drift boat as a means of transportation...taking us from run to run.  Once out of the boat, he and I would slowly walk along a shallow run, carefully searching for a fish and once spotted, I would target that fish with a weighted nymph.  No need for strike indicators...just watch the fish turn its head, ingest my fly and "fish on"!!!   Land that one and go find another.  What a blast.  And this is the experience that I wanted Jon to have.

So, you can imagine my concern with these water flows of 10,000 cfs.  It meant that my favorite form of fly fishing on my favorite river was, in large measure, off the menu.  In all fairness, big flows like this are a good thing for a river if done for a limited time...the flows can flush out silt, debris and excess vegetation, clensing the river and actually improving the habitat.  It's just that this not how I'd like to see the river when it's my turn to fish it.  Yeah, I know....it's all about ME.

Well, I am delighted to report that this week the water ministers dropped the flows to a rather acceptable 5,200 cfs and the Bighorn Fly Shop (where we'll stay) expects that those flows will be further reduced by the time we get there.  Boo-yah!!!!