Time: 10:45AM – 3:00PM
Location: Below Gross Reservoir
South Boulder Creek 07/21/2026 Photo Album
My fly fishing adventure on Tuesday, July 21, 2026 contained some interesting developments. On Monday I experienced an average day on the South Platte River, and in spite of choosing a tailwater for my angling location, the water temperature registered 68 degrees, when I dipped my thermomenter in the river at 1:00PM. Flows of 108 CFS were not enough to buffer the bottom release water against air temperatures in the mid eighties, and it is not even August yet. What is an avid fly fisherman to do?
I regularly check the flows on South Boulder Creek, and when I reviewed the graph on Monday evening, I noted that the water was being released from the bottom of Gross Dam at 92 CFS. That was all I needed to see, as the narrow streambed and bottom releases would surely maintain temperatures conducive to coldwater fish. As I prepared to write this blog on Wednesday, I checked the DWR information again, and the flows actually dropped from 92 CFS to 77 CFS, while I was fishing in the tailwater creek.
Doing the Heavy Lifting on This Day
The temperature in the parking lot was in the upper seventies, so I was once again prepared for a hot day. On this stream my feet get numb, even when I wear my waders, so I decided to not wade wet, even though that option would have been advantageous for the inbound and outbound hikes. A little perspiration never hurt anyone. For my rod I chose my Loomis two piece five weight. I like the softer action of the Loomis for throwing dry/droppers and dry flies, and the shorter length also appeals to me among the tighter surroundings of a narrow creek.
I arrived along the stream by 10:35AM, and I was prepared to cast by 10:45AM. There were five cars in the parking lot, and as I hiked along the trail next to the creek, four or five anglers were spaced out throughout the section that I targeted. I selected that section because I was convinced that fishermen would avoid the relatively steep sided banks and opt for gentler terrain. I was wrong, so I hiked quite a bit beyond the initially chosen section.
Nice Brown Taken from Under Overhanging Branches
All aspects of fly fishing in Colorado in 2026 have been earlier than normal including stream levels, water temperatures and insect hatches. Based on this knowledge I decided to begin with a parachute western green drake. Normally green drakes hatch during the first week of August, but I was curious to see if they were present on July 21. My thought process was sound, but the green drake was totally ignored in my first fifteen minutes of fishing through some very attractive pockets and runs.
The Brown Trout Parade Continues
I decided to explore another pathway, and I substituted a size 14 yellow stimulator and size 16 light gray deer hair caddis. I prospected with this combination for an hour, before I broke for lunch at 11:45AM, and I pushed the fish count to three. One of the landed trout was a brown in the thirteen to fourteen inch range that clobbered the caddis beneath some low hanging branches. This was a highlight, as it was the longest fish of the day, and it required some pinpoint casting accuracy.
Lip of the Rock Contained a Decent Brown Trout
While eating lunch on a large boulder, I spotted two western green drakes, as they floated upward like helium balloons. Surely the trout would now tune into my green drake imitation.
I removed the double dries and tied on the parachute green drake for a second trial run. Nothing developed from the move other than a couple refusals. Maybe the trout were looking for a bushy fly that better imitated a large mayfly attempting to become airborne? I swapped the parachute green drake for a user friendly green drake. Once again the trout ignored my offering.
As I was working upstream, another angler popped into my field of vision. He was hidden behind a small bend and some trees. I attempted to talk to me, but I was unable to hear him over the sound of the rushing water, so I waded to the right bank, and he met me half way. He left the section between me and where he first appeared untouched, and he was moving downstream fishing streamers. He also informed me that he encountered a bull moose not too distant upstream. He said it was along the right bank in the shade between the creek and the trail. I filed this away, but I expected the moose to have moved on by the time I reached the position that was described.
The green drake ploy was not effective, so I abandoned it, and returned to an olive body size 14 stimulator and the light gray deer hair caddis. While I moved upstream with this combination, I observed another four or five green drakes. No matter. I persisted with the stimulator and caddis and boosted the fish count from three to seventeen. A few of these trout smacked the stimulator, but the caddis was by far the main attractor. I was rather amazed at how aggressive the trout were for the small size 16 caddis, particularly in riffles over moderate depth. Another popular position for feeding trout was the cushion in front of a large rock or at the lip of a pool, where the current accelerated.
By two o’clock the temperature was spiking, and the yellow stimulator began to induce refusals. I considered my options, and I guessed that perhaps a peacock body hippie stomper might be a more effective lead fly than the stimulator. I made the change, and sure enough, it worked. Of course, the move was accompanied by refusals, but the hippie stomper accounted for two nice trout, and the caddis registered another three to boost the fish count to twenty-two. I was rather satisfied with my day at this point, and I considered calling it quits. The heat was intense, and I suspected that the trout would turn off in response.
I was approaching a large bend in the creek, when suddenly the branches next to the stream parted, and a massive and very dark moose made an appearance. I froze. The moose was no more than ten yards away, and it towered above me. I always underestimate the height of a moose with its long legs and high antlers. The moose and I stared at each other for thirty seconds, and my heartrate skyrocketed. What was I to do? I was stuck in the middle of the small creek, with no easy exit path. I slowly grabbed my line and hooked the fly to the rod guide, and I turned my body to slowly wade to the opposite bank, where there was an opening in the bushes.
From Upstream. Keeping an Eye on Me.
When I reached the bank, I turned around to check on my fishing buddy, and the moose bent its long legs and collapsed in the shallow water of the creek. Apparently moose do not handle the heat any better than humans, although this male had the good sense to wade wet. I concluded that a moose wallowing in the cool creek was not about to charge me, so I removed my camera and snapped three photos and a video. My heart rate slowly crept downward, and once my photography duties were complete, I climbed a path to the top of the bank and circled around the relaxed moose. Now that it was over and my fear waned, I was euphoric with the sighting.
I stopped and fished for another ten minutes at another favorite section on my return hike, but after that I returned to the parking lot and called it a day. And what a day it was! I encountered green drakes, and although my flies did not produce, I consider it a positive sign that green drake action will elevate from here. I landed twenty-two wild trout, and this included a fourteen inch brown and a nice thirteen inch rainbow. I estimate that four of the landed fish were rainbows with the remainder browns. The deer hair caddis was a winning fly and accounted for most of my landed fish. If the water level remains in the 70 – 100 CFS range, South Boulder Creek will be a solid option, while the heat wave and drought take its toll. I’ll never forget the close encounter with a moose on the loose.
Fish Landed: 22

So Many Speckles
Monster for SBC
Another Decent Rainbow
Small Pool
Chunky Rainbow
Looks So Good
Mr. Moose
Inviting a Cast
Ooh. Looks Good.
Dry Fly Eater
I Love These Sluicing Runs on the South Platte
Tucked in the Net
Trough
Deep Pocket Surrounded by Structure
A Rainbow Joins the Count
Nocturnal Stonefly Imitation
Side Channel Invites Exploration
An Early Brown
Big Fish, Big Net
Foam and Riffles
Edna, the Guide Dog
Smooth Section
Hippie Stomper Batting Leadoff
Foam Pool
Nice Fish
Short Pool
Another Surprisingly Chunky Rainbow
Ready to Get Wet
Photo or Painting
Scarlet Stripe and Cheeks
Yet Another Prime Spot
Along the Ledge Rock
Nice One
Beaver Pond Fly Fishing
Fish Cleaning in Progress
The Last One
Five for Tacos
In the Pan
Hand Size
Hot Spot Where the Flow Was Entering
After the Brief Shower
Orange Belly
New Lace for My Simms Wading Boot
Early Brown Trout
Parachute Green Drake Along the Bank
Aligned
Nice Spot
Steep Gradient
Better Focus
Such a Pretty Pool
Starting Run and Pool
Stunning Rainbow Trout
Poised Torpedo
Long and Deep Pocket
Covered in Ink Spots
Home of Beast Brown
Pink Cheek
Rock Garden Ahead
Bankside Home
Early Brown Trout
Attractive Section
Decent Hole
Very Nice Pool
High Gradient
Prize of the Day
Very Promising
One of the Better Brown Trout
Prime Lie
Silvery Brook Trout
Just Above the Angled Log
Pleased with This Catch
Brown Trout Lair