Thursday, November 21, 2013

Update on post-flood fish in the Big Thompson

Post-flood assessment of the fish in the Big Thompson

 The Colorado Division of Parks and Wildlife has completed an early assessment of the remaining fish populations in the Big Thompson River below Estes Park, with some encouraging results from the catch and release section between Watonia bridge upstream to Olympus Dam below Lake Estes.  Further down though, the river’s short-term health is pretty murky and survey work has not been completed. 

With U.S. 34 reopening, the club should be able to see for ourselves what it’s now like from Drake east to Loveland.  Expect to find some serious channelization and stream stabilization, and potential conflicts to come as decisions are made on restoration of the river, one of Colorado’s best known trout waters.

Ben Swigle, this region’s aquatic biologist, described the division’s electroshock survey results on the Big Thompson at the Nov. 20 meeting of Rocky Mountain Flycasters in Fort Collins.  Results in the stream section just below Olympus Dam, which looked dismal immediately after the July 14 flash flood, “show us that the trout population in that area is in good shape,” Ben says.  All year classes for rainbows were found in numbers comparable to previous surveys, and they even found two walleye, presumably washed out of Lake Estes.

Go downstream two miles “and it’s not pretty,” but the fishing should be okay, he says.  Even four miles downstream, division staff shocked enough fish to estimate about 4,000 trout per stream mile, comparable to surveys in 2008.

The handicap pier on the river was destroyed, though.  And go further east around Drake and the extraordinary construction efforts to restore travel on U.S. 34 make the Big Thompson has the river resembling more of an irrigation ditch that a wild river Ben reports.  In the Narrows area just west of Loveland, the once-healthy portion of the river has been temporily channelized.  Around Glade Park, where the state made major habitat improvements in 2009 to help fishing, the surveys identified a substancial decline of the brown trout population with this, section of the river suffering major damage