DTU’s Temperature Sensors Show the DSP as very Trout Friendly
Here is what we have been finding on your home river with our temperature sensors. It is quite exciting and explains why Ronnie has been catching trout from Chatfield to Cuernavaca over the years. One of the really intriguing mysteries is the temperature drop from USGS Englewood to Overland. Steven Reeves, Metro State student wrote a paper on it and suggested that it is due to cooling from Overland Park golf course.
DTU is measuring temperatures in the South Platte to determine what temperatures trout and other species face at various flow rates throughout the year. We know that trout survive the temperature of the Denver South Platte because we catch and photograph them. Some of these trout we believe have been in the river for years because of their size. We put our sensors close to the bottom in places where we believe trout would live.
Studies of Firehole (Yellowstone) rainbow trout indicate they stop feeding at about 77 F and if they can not escape the warm temperature 50% died at 81 F. But this study and similar studies trap fish in a tank and very slowly raise the temperature until 50% die. This method is not only Trout Unlimited antithetical but TOTALLY unlike the real world of the Denver South Platte where free movement of the trout allows them to find stratified cooler temperatures in the varied habitat both natural and restored. Ronnie and Rhys’s trout survive and thrive the short term temperature peaks precisely because they have fish passage, deep pools, shaded structures, cool water seepage, park land irrigation runoff, and the diurnal (day/night) temperature swings. Making sure that trout will have deep pools and shaded structures below the water line is precisely why Denver Trout Unlimited has invested so much time, and effort on studies, meetings, and raising funds for enhanced flows from the Chatfield Environmental Pool.
As the South Platte travels further north past I-70, there is less refuge from the daily high temperatures in June through September and fewer “Caught on the South Platte” photos of trout. There will be a great opportunity to add habitat with the design of the Denver South Platte restorations for the “National Western Center” project approved by voters in November 2015. The plan includes “1 mile of new River Park with river access and Water Resources Center.”
A cool water Temperature Project thank-you must go out to Rhys Duggan of Revesco Properties, Colorado Trout Unlimited, and all the interns, students, and volunteers which include among others, Ben Cole, Ben Johnston, Christen Luskey, Steven Reeves,Todd Fehr, Ronnie Crawford, Mike Hobbs, Todd Fehr, Reid Baker, and Kevin Dykstra.
Here is a link to all the charts: https://drive.google.com/open?id=0B1LQMO8mmEWdZVROZkRRLTU3LUk
Here is a link to all the data and our QAAP: https://drive.google.com/drive/folders/0B1LQMO8mmEWdUVlOVGdpeHlxUms?usp=sharing