DTU Full Year Temperature Monitoring Project on the Denver South Platte.
What we did and what we are finding.
Sensor Readout #1 – 2/2016 through 9/2016
John Davenport – Denver South Platte Temp & Habitat Monitoring Committee Chair
DTU anchored has anchored 7 dime sized temperature recording sensors in the Denver South Platte. We download data from them every six months at low water level. The purpose is to determine what kind of fishery we have and how restoration and constructions projects on, in, and near the river are affecting the temperature of the water as the fish encounter it.
There are many organizations which record the temperature in the river at locations and frequencies dictated by their our peculiar necessities, e.g. license compliance, chemical analysis, mixing assurance, baseline establishment, etc. Our focus is on the fish, aquatic creatures and the insects they depend on.
We hope these sensors address questions like:
Is this a warm or cold water fishery at a particular sensor location? Did upstream improvements raise or lower the temperature? Did storm events create stress level temperatures due to runoff? Where in the river are structures, inflows, springs, shadows, or human activities helping or hurting temperature levels best for fish? Where can fish of various species best be stocked for successful survivals? Do measured temperatures correlate with posted fish catches?
After our first set of readings for the period 2/2106 through 9/2016 which span the historical high and low Denver South Platte temperature swings, we find we have many more questions and some rock solid answers.
- The Overland sensor recorded temperatures very close to the temperatures of the well regarded trout waters of Arkansas River through Pueblo.
- Having hourly temperature measurements over 20 miles of the river is enormously helpful in understanding what is possible for this fishery.
- What appeared to be a data anomaly recorded by a sensors at Cuernavaca on 6/28/2016 as a 12 degree temperature drop was found to have coincided with a 1 inch hail storm. Tracking this temperature bubble as it traveled down stream is an undreamed of capability made possible by this wide scale deployment of temperature sensors.
- The bottom of the Denver South Platte is very unstable. The site of the 88th Avenue sensor appears to have changed in depth with the addition of a foot or two of a sand/gravel silt.
- Why does the temperature of the DSP actually drop between Carson Nature Center near Chatfield and Florida Avenue near Overland Park? Is it due to a solid rock substrate, springs, Bear Creek confluence, or water treatment plant inflows?
- What happened to the sensor at 88th Avenue? All sensors were recovered except this one which we believe is buried in silt. We added another sensor upstream about 100 yards in a site less likely to silt. Hopefully, when we do recover the silted-in sensor it will yield data to study the temperature differential of a silt buried sensor and one that is on the bottom where fish can lie.