The flush is on at the Reef and the rainbows are in.

Biggest fish of the day.

BLM started the Spring flush below the Gray Reef dam on March 22nd.  At midnight they start increasing the flow to 5000 CFS and by 3 AM they start dropping it back down to 500 CFS. By 10AM, about the time we arrived yesterday, everything appears to be completely normal.  This release schedule ends today, March 31st. The flush is a great thing for the trout habitat - and this is why they do it - to flush out fine sediment that builds up in gravelly spawning beds.  If there is not free flow of water through the gravel the eggs do not survive. Before the dams were in place, runoff flowed free in June and performed a natural flush, clearing out accumulated slit. The management of dam flows strictly to satisfy downstream water users is a quick way to ruin a river.    This is how the once great fishery on the Henry's Fork of the Snake was destroyed - or nearly so if you read the Island Park flyshop pages.  On the Henry's Fork, flow from the dams was dictated by downstream irrigation needs. Winter/spring flushes to simulate the natural flush of runoff were perceived as a waste of good water.  This nearly killed the Henry's Fork.  Annual flushing flows were started on the North Platte in 1995 and since then, trout populations have grown from 400 to 3500 per mile.  Before the flush this year they drained the Gray Reef holding reservoir so they could inspect the gates on the dam.  That dumped a lot of sediment into the river, and along with it, a lot of aquatic worms and midge larvae.

Rock Worms - tied on a DaiRiki 135 #16 with Danville 70 denier red thread wrapped over two strands of  UTC micro orange stretch tubing, and coated with Sally Hansen Hard as Nails..

From a macro point of view, the flushing flows keep the river healthy from year to year and increases trout populations. From a micro point of view, fishing during the flush is a different game than it is at other times.  In mid-February, and throughout much of the regular fishing year, even when the flows are high, midges are hot.   A Mercury Midge (or some variant of it) is my goto fly.  The flush is churning up the rich sediment that was dumped into the river.  I started yesterday with a Rock Worm and a midge on the point and
I did not get one hit on a midge - neither did Jeff.  As I've never seen it before red was the fly color of the day.  If I was a better naturalist I would have thought to pump the stomach on one of the fish I caught to see what they were feeding on. I'd bet money they were stuffed with annelids - or were they stuffed with midge larvae?  Most of the fish, including my biggest fish of the day, took a smaller worm pattern  which was tied on a size 16 Dai Riki 135 hook.  By the way, the biggest fish I caught  22" and it was the largest one I've managed to catch for some time at Gray Reef.  The flush and the pending spawn are bringing bigger fish up to the dam.

I have often been resistant to fishing worm patterns, but yesterday, to match the hatch, a worm was de riguer.  It's pretty much the only thing I could get any fish to look at though I did hook two on a green leech. The red "rock worm" is a standard pattern at Gray Reef and it produces fish on a regular basis.  Some guys fish almost nothing else.  During the spawn, a worm is often teamed with an egg - this rig is commonly referred to "Bacon and Eggs."  The standard Gray Reef Rock Worm pattern is usually tied in a larger size than the ones shown above.  Yesterday, with the fish so keyed in on red, I eventually rigged up with with a larger rock worm above the smaller one on the point.

On the web you can find the Rock Worm pattern referred to as a San Juan Worm; this just shows an unfortunate ignorance (or indifference) to fly pattern history and nomenclature.  Unfortunately this usage seems to be taking hold - I talked to someone yesterday at the Reef who had a Rock Worm tied on and told me he was fishing a San Juan Worm.   For those who may not know, a San Juan Worm is a fly pattern developed on the San Juan river in NM.  It is a bit of ultra-chenille tied on a hook. It looks nothing like the N. Platte Rock Worm.  Personally, if I ordered half a dozen San Juan Worms and a package of Rock Worms showed up instead (or vice versa) I'd be miffed.  Not all worm patterns are San Juan Worms.

I've always been a bit puzzled as to why the Rock Worm is such a popular pattern at the Reef.  Sure it brings in some good fish throughout the year - but so will a Gold Ribbed Hares Ear nymph. I caught my largest trout ever (measured at 27") on a GRHE drifted deep on the south side of the Gray Reef dam. I suspect it was taken for a crane fly larva. A day like yesterday is not enough to convince me that a Rock Worm is always the way to go at the reef - but I could see how some people might get that idea.  It seems to be common knowledge that the flush is a good time to fish and so it was as crowded yesterday as I've seen it in a long time.  That means a lot of people got the rock worm message.