Gunpowder River “Spillover” Questions Answered

Hi Theaux –
Happy Holidays! You’ve mentioned “spillover” a couple of times recently, but not offered any comments about how this is likely to affect the river or the fishing. How about letting us know what we might expect if and when water starts coming over the top of the dam?

Thanks – Bill

Thanks Bill, yours’ is an important question and I’d like to answer with a few definitions and a bit of self reference using the archives.

The term “spillover” is commonly used to indicate that Pretty Boy Reservoir is chock full and its’ waters will, if we get enough rain in the next few weeks, “spillover” into the Gunpowder River, as it reaches a level just over capacity.

The reservoir drains a watershed area of roughly 80 square miles, so even a bit of rain along I-83 will eventually trickle into the system. Because the Gunpowder is a tailwater fishery, that is, most of its’ flow is dam controlled, when “spillover” occurs during the winter months, the warmer surface waters of the reservoir can signifigantly influence, insect hatches, trout behavior and river water levels.

During the past few spillover events, higher flows, warmer water and more insect and fish activity has been noted, so we can look into the future by referencing the archives.I’m hoping to see stoneflies and black flies in the next few weeks en masse.

—give the archives a look. Find the search window, just up the sidebar, underneath the shop logo and to the right of this stream report, type in spillover and you’ll find several truncated historical reports that I hope will be helpful.
To read a full report just select the title and click over it to open the full report.