Blue River Streamflow Update Below Dillon Reservoir – October 11, 2013
October 11th, 2013
The release from Lake Dillon into the Blue River in Silverthorne, continues to run at a very healthy 260 cfs. This is the highest flow from the reservoir in over two years. The fact that this is happening so late in the year is nothing short of amazing. All of this is, of course, due to an exceptionally wet September. While those of us here on the west side of the continental divide did not see the destructive levels of rainfall that pounded the Front Range, we were fortunate to have a steady stream of Monsoon rains late in August and for the first three weeks of September. A combination of that local rainfall running into the lake, coupled with such heavy rain on the Front Range that Denver Water no longer has a current need for Dillon Reservoir water and stopped drawing water through the Roberts Tunnel to Denver, created a situation where the inflow to the reservoir far exceeded the outflow. As a result, the level of the reservoir, or “elevation”, rose. Not only did it rise, it jumped an incredible 2 and a half feet! In the words of the folks over at Denver Water this is “unprecedented”. Typically, the reservoir only gains in elevation from April through July, as snow melt runs into the lake in greater amounts than the outflow, for the elevation to be rising so late in the season, in a month that is usually one of the drier of the year, was definitely a first.
Currently the elevation of Lake Dillon is about 9,014 1/2 feet above sea level, 9,017 is full. In a conversation with Denver Water on Thursday, they said that in order to close the spillway for the winter, they needed to get that elevation down to at least 9,014, as the lake needs to be 3 feet below capacity in order to put the lid on the overflow spillway. That being the case, it looks as if the current flow should continue for at least another 2 to 3 weeks, with only a slight chance of minor adjustments up or down if necessary. This is great news for the tailwater stretch here in Silverthorne, as the Mysis Shrimp patterns have been very productive with these higher flows. Between that and the continuation of a solid Baetis emergence on most days, fish have been active throughout the day on both nymph and dry fly offerings.
While the current flow is higher than many anglers are accustomed to fishing, this is still a great level for wade fishing. Simply add a little more weight to your nymph rigs and don’t worry about having to throw as fine of tippet. Definitely make sure to have your favorite Mysis patterns in size 16-18, along with a good mix of Blue Wing imitations in both nymph and dry. RS 2, Split Case BWO Nymph, Lawson’s No Hackle Slate Gray, CDC Parachute Dun, among others, have all been productive lately. As well as the usual assortment of tailwater Midge imitations, San Juan Worm and Egg patterns that typically work here in town. The other positive to all of this, is the heavier flow will pull a considerable amount more food from the reservoir in the form of high protein Mysis Shrimp, providing a boost in calories for resident fish, allowing them to potentially bulk up a little bit before Winter.