Welcome back to the Current Conditions postings of the National Trout Center. We are fully staffed for the 2018 season and we will post the stream conditions for the Root River watershed at least weekly for the balance of the trout season.
Streams in the Root River watershed are finally coming into PRIME CONDITION for trout fishing as we approach the Preston Trout Days weekend. Our streams this spring have been cold, dirty, and fast-flowing due to the late winter runoff and spring thunderstorms almost twice weekly in May.[pdf-embedder url=”https://nationaltroutcenter.org/wp-content/uploads/2018/05/Carimona-5-18-18.pdf” title=”Carimona 5-18-18″] The Carimona hydrograph for the past month shows the extreme variation in discharge (flow rates) caused by thunderstorm events and runoff in the basin. High flows generate turbidity by suspending sediments from the riverbed and streambanks. Added to surface runoff from agricultural lands not yet covered by new crops, the transparency of the river plummets to 0-15 cm values, causing the water to look like chocolate milk. Fortunately, all that has changed over the past two weeks in the Root River watershed.
Transparency of the South Branch of the Root River in Preston, MN, has gone from 15 cm (muddy, unfishable with artificial lures) on April 26, to 26-30 cm by May 11, and, 33-40 just Wednesday of this week. Flashy lures, spinners, and streamers begin to be effective in the 30-40 cm range. Wet flies and nymphs work at 40 cm or greater transparency. On Wednesday this week, the South Branch at Preston was at 50 cm, and yesterday, dry flies and nymphs produced excellent fishing at mid-day.
Browns and rainbows in catchable sizes are hungry and just now beginning to benefit from increased insect activity. Temperatures are beginning to rise with surface waters reaching 58-62°F in mid-afternoon. The deep cold of groundwater sources (47°F throughout the driftless area) will no longer dominate stream temperatures as area streams begin their seasonal warming. The hydrograph below shows recent changes in the stream temperatures at the Carimona stream gauge.[pdf-embedder url=”https://nationaltroutcenter.org/wp-content/uploads/2018/05/hydrograph_temps.pdf”]
The warmer temperatures this week have produced some sparse hatches of Blue Winged Olives. Sedges (caddis) are beginning to appear in black, mottled, and brown variants. Fly fishers might start their pattern search with a light-colored caddis, or an attractor such as a parachute adams. Yesterday the South Branch of the Root River in Preston produced fish on both dry flies and wet in sizes 12-16.
Check out the nice overview of the South Branch Root River trout fishery at the Perfect Fly website. If you plan to fish the Root River watershed on Preston’s signature Trout Days weekend, be sure to stop in at our local fly shops in Preston, The Driftless Fly Fishing Company, and Lanesboro, the Root River Rod Company.