John,

It may be a few more years, but it should come back if you don't get more fires in the mean time. The S Platte had some major fires upstream from my local waters in Waterton Canyon back in the late 90's and early 2000's. This filled up the reservoir directly upstream from the canyon so badly that they spent most of a year dredging the reservoir in 2010. The dredging caused so much ash and silt to flow down river for so long that it pretty well killed all the fish and bugs in this stretch of the river. I didn't bother to fish it for several years. The last few years it has improved every year, to the point that this year it has been fishing as well as it every did before the fires. This past June we had two great hatches that lasted for weeks, PMDs and Golden Stoneflies. I don't ever remember seeing more that a few of these flies before in the canyon. So, the river has come back, maybe better than before, even if it seemed to have to die first.
Ted