South Boulder Creek – 09/21/2022

Time: 10:00AM – 2:30PM

Location: Below Gross Reservoir

South Boulder Creek 09/21/2022 Photo Album

Having finally recovered from an intense but enjoyable four days in the Flattops area, I once again set my sights on a day of fly fishing along the Front Range. I quickly checked on South Boulder Creek, and I noted that the flows were recently adjusted to 86 CFS. I checked other Front Range possibilities, but this action was simply an exercise in thoroughness, because 86 CFS is near my ideal range, and I was sold on a trip to the small tailwater almost immediately. Weather, however, was the one negative, as high temperatures for Pinecliffe were projected to be 55 degrees, and rain was an increasing likelihood from 2:00PM on. I decided to take the risk of another day of bad weather and departed from Denver on Wednesday morning.

Three vehicles arrived in the Kayak parking lot, while I prepared to fish. One angler dressed in shorts departed with his dog, before I was prepared to do the same. I knew that Wednesday was destined to be a chilly day, so I wore my light down coat over my quick dry undershirt and fishing shirt and stuffed a long sleeved Under Armour thermal shirt in my backpack along with my raincoat. I opted for my Loomis two piece five weight, because I enjoyed it on two days of fly fishing small streams in the Flattops. I recognized that I was at a high risk of overheating on my inbound hike, but I did not have a proper place to stow my light down coat.

A Small Amount of Color Change

My concerns were well founded, and when I perched along the creek and configured my line, I felt the clammy wetness of my undershirt. In fact, I sensed that the perspiration had soaked through to my fishing shirt. I was relatively warm from the exertion, so I knotted a peacock hippie stomper to my line and began to cast to likely spots with the hope that the atmosphere would warm, or the layers would wick away the sweat. These were both bad assumptions, and although I set a goal to last until lunch before making changes, I was forced to deal with my sweaty state by 11:30AM. High gray clouds blocked the sun throughout the morning, and when a breeze commenced, I felt very uncomfortable. I stripped down to my bare chest and attempted to sop up the perspiration on my upper body, before I snugged on my Under Armour layer. It instantly felt better. I skipped my fishing shirt and went right to the down coat as my next layer, even though it displayed signs of sweat in several locations. For my final layer I pulled on my rain shell. I was hopeful that this would seal in my body warmth and block the wind and cold and eventually rain. In addition, I unfolded the earflaps on my hat, and these moves along with my lunch placed me in a tolerable level of comfort, while I continued my efforts to hook and land some South Boulder Creek trout. I rolled up the short sleeved undershirt and fishing shirt and stuffed them in the backpack in place of the raincoat and Under Armour.

Small but Appreciated Early

As mentioned earlier, I began probing the depths of the stream with a peacock hippie stomper, but gorgeous deep pools, that I was certain harbored trout, failed to deliver, so I paused to reload with a Jake’s gulp beetle. Why the beetle? I had decent success with beetles and ants during previous September trips to South Boulder Creek. It was a great thought, but the beetle attracted zero interest, so I paused once again to reconfigure. The surface flies failed to create a refusal, so I concluded that the fish were more focused on subsurface food morsels, and this thought caused me to attach a size 8 tan pool toy hopper along with a prince nymph on a three foot dropper. Although I continued to fish very attractive spots with no results, I did hook and land three small trout on the prince. Even this success, however, did not convince me that I was presenting the desired offering, so I once again began to experiment. I replaced the prince with a salvation nymph with the hope that a pale morning dun nymph imitation might kick start some action, and similar to the prince, it generated a few small fish, but it did not seem to be a prevalent food source.

Sweet Spot

Out of the Water

By noon my fish count rested on seven, and these fish were small and hard to come by. The morning fishing experience was a huge deviation from two earlier days on South Boulder Creek, when green drakes enticed a trout to eat on nearly every cast. Between 12:15PM and 2:00PM I benefitted from my layer rearrangement, and I was at my peak level of comfort for the day, although I was not basking in a glow of satisfying warmth. What I really needed was more fly fishing action to divert my attention away from my body temperature.

Certain Trout Home

Love the Orange Shade of the Lower Body

I was dissatisfied with the dry/dropper results, so I decided to revert to a dry fly approach. Could the South Boulder Creek trout still respond to green drakes? The weather remained quite summerlike up until Wednesday, so it was worth a shot. I knotted a parachute green drake to my line, and it mostly provoked refusals, although I did net a pair of very aggressive feeders with long memories. I liked the visibility of the green drake, so I left it on my line and added a size 16 gray caddis on a one foot dropper. These two flies allowed the fish count to mushroom to double digits, but I was not convinced that I was optimizing my time on the usually productive creek.

Fish the Slick

I concluded that I could generate refusals just as easily with the more buoyant peacock hippie stomper, so I swapped out the parachute green drake, and as I was performing this transition, I noted a small stonefly and a couple small pale morning duns. A few random rises appeared, and I interpreted these as a sign to tie on a PMD comparadun. I replaced the caddis with a size 18 light gray comparadun, and my fortunes suddenly looked promising. For the remainder of my time on the water I probed slower moving pockets, riffles and slicks; and the comparadun became a favorite target of the stream residents, although the stomper nailed its share of takers particularly along faster seams, where the trout had less time to inspect my offering. At some point the comparadun wing became a sparse wisp of deer hair, so I replaced it with a size 16 gray comparadun with a full fan-shaped wing, and this fly maintained the elevated catch rate, although probably a bit slower than the smaller mayfly imitation. Toward the very end of my time on the creek I replaced the comparadun with a classic size 16 Adams, and that fly also accounted for four trout.

Lovely Ink Spots


The fish count moved steadily to twenty-eight, and as this hot action transpired, a light rain began to descend, and the temperature slid downward. I used these factors as an excuse to exit, and I hiked back to the parking lot. Jane and I had a dinner commitment at 6:30PM in south Denver, so that obligation also played into my decision to quit a bit earlier than usual. On my return hike I paused at a spectacular pool, and as I gazed across the deep, smooth water, I noticed that it was boiling with rises. I estimate that at least fifty fish were in a feeding frenzy. I lobbed ten casts with my hippie stomper and Adams, but they were totally ignored by the ravenous feeders. Clearly they were locked into something very small. I did not have time to experiment with fly changes, but I was very curious regarding the source of the surface eating feast, so I stretched my quick seine mesh over the mouth of my net and seined the water for a minute or two. I was not surprised to find a size 20 blue winged olive with perky upright wings, and this explained the scene in front of me. I filed this for future reference and hiked back to the car.

Two Trout from This Pool

Twenty-eight trout in 4.5 hours of fly fishing was appreciated by this avid angler. The size of the fish was average for the South Boulder Creek tailwater, and once I locked in on the comparadun, the catch rate was more than satisfactory. The two hour window, when I caught the most fish, coincided with an increase in insect activity, so perhaps my fly choices were not as important as the time of the day. Nevertheless, I was pleased to post a solid day after green drake season, and I look forward to more trips to South Boulder Creek before the season winds down.

Fish Landed: 28