South Boulder Creek – 08/16/2023

Time: 10:30AM – 3:30PM

Location: Below Gross Reservoir

South Boulder Creek 08/16/2023 Photo Album

I consider my home waters to be South Boulder Creek, but quite a bit of time elapsed since my last visit. I frequently complain about the variability of the flows on this small tailwater, but that nuisance is now complicated by the construction to expand Gross Reservoir. Twice last year I was forced to abort a trip to South Boulder Creek, when I encountered digital signs announcing the closure of Gross Dam Road. Up until recently the flows remained too high to attempt a trip, but upon my return from Carbondale, I noticed the graph depicted several days of 155 CFS. I fished at 180 CFS in August in previous years with some success especially during the green drake emergence, so I got serious about making the trip.

I visited the web site and reviewed the map that tracked road closures and interruptions. My normal route to South Boulder Creek is via Coal Creek Canyon and then down Gross Dam Road, but that route was displayed in red, and the web site informed visitors that the road was closed until 2027. Yikes. I’ll be 76 by then and probably unable to fish anymore! Upon further review, however, I determined that I could access the creek from the north by traveling through Boulder and then following Flagstaff Road. I called the Denver Water customer service number and spoke with a friendly young lady named Bernice, and she confirmed my conclusion that the Walker Ranch Loop Trailhead was open and accessible without interference from the Gross Dam project. My maps application indicated that the northern route extended my drive by fifteen minutes, and consultation with my friend, Nate, suggested that the hike to the middle creek section was comparable to that from the fishermen parking lot near the dam. I was sold on a day of fishing in South Boulder Creek.

155 CFS

I arrived at the Walker Ranch Loop Trailhead parking lot, and the temperature was already in the low eighties. Eight other vehicles occupied spaces, but I was unable to determine whether the occupants were fishermen, hikers or bikers. I assembled my Loomis two piece five weight and departed down the dirt trail at the south end of the parking lot. I chose the Loomis, because I like the slow action and the way it casts dry flies and dry/droppers, and I assumed those approaches would dominate on Wednesday.

Nice Deep Run

As I hiked along the creek, I was surprised to discover two other anglers, and they were positioned in the middle of the stretch I targeted. Initially I was inclined to reverse direction and move upstream, but then I concluded that I planned to hike a significant distance below them, and by the time I fished upstream to their current spot, I was fairly certain that they would be gone. When I arrived at my chosen starting point, I realized that the flows were indeed 155 CFS, but the creek was very clear. I quickly determined that I was unlikely to cross due to the swift currents in the center of the creek; and, in fact, I did spend my entire day casting along the right bank.

Buttery Brown

Another Fine Brown Trout

To start my search for hungry trout I armed my line with a peacock hippie stomper and a Jake’s gulp beetle. The combination quickly generated four trout, with two nice brown trout chomping on the beetle. After the initial burst of action, however, the takes slowed to zero, and refusals began to dominate my morning. I removed the beetle, and not wishing to miss out on green drake feeding, I replaced the foam terrestrial with a size 14 parachute green drake. The change paid dividends, and I built the fish count to nine by the time I broke for lunch. Roughly half the eaters favored the hippie stomper with the others chowing down on the green drake.

Another Promising Slick

After lunch I resumed my upstream progression, and the stomper and drake combination spurred the fish count to seventeen. This took place over a couple hours, so the action was steady but not hot. A decent number of refusals and looks were interspersed with the eaters, and I was forced to move frequently to find takers after the solitary fish in a pocket refused my offering. Refusals seemed to prevail more often in the slower moving pools; whereas, takes were prevalent at the tail or along seams. I only spotted two natural green drakes during my entire time on the water, and I was surprised by this. The temperature probably spiked to the low eighties, and the heat may have been a factor in the lack of natural green drakes.

A Better View of the Parachute Green Drake

Hippie Stomper

When I reached seventeen, the fish became ultra fussy, and I suffered a long fish landing drought. I concluded it was time to change. The green drake was generating looks, but no eats, so I replaced it with a green drake comparadun. I loved the look of this fly with a large fan shaped deer hair wing and long moose mane tails, and initially two above average sized trout loved it as well. However after the initial burst of action, the comparadun failed to interest additional trout, so I implemented a radical shift to a dry/dropper featuring a tan size 10 pool toy hopper, beadhead hares ear nymph, and a salvation nymph. The hopper was ignored, but the hares ear and salvation produced one fish each. In order to land these two fish I covered some prime water with no success, so I pondered yet another change. I reverted to the foam beetle as the first fly and then added a Harrop hair wing green drake as the second dry. This combination was a dud, but as I was slinging the pair, I spotted a couple pale morning duns. I snipped off the hair wing and replaced it with a size 16 cinnamon comparadun.

Vivid Black Spots on This Rainbow

Rainbow Was Tight to the Rock

By now I reached a narrow fast section that in the past signaled my exit point, so I followed tradition and scaled the rocky bank to the path. On my return hike I paused at two typically productive pools, and I added two more fish to the count to bring the total to twenty-three. Both of the late eaters sipped the trailing cinnamon comparadun.

Love the Orange Spots

The worst part of my day was still ahead of me, however. My new hiking trail to the Walker Ranch Loop Trailhead necessitated a one mile ascent from the creek to the parking lot. I executed small steps, drank water and paused many times, before I arrived at the parking lot. Needless to say, I was drenched in perspiration, and this condition developed in spite of some large black clouds obscuring the sun for much of my climb. Hopefully the difficulty of the one mile hike will fade from my memory banks, before I consider another visit to South Boulder Creek.


Twenty-three fish certainly represented a successful day in the South Boulder Creek canyon. Three brown trout and one rainbow extended to a foot with the remainder falling in the six to eleven inch range. The trout never locked into the green drakes in a manner comparable to previous August visits, when I logged ridiculous fish counts. Was it the heat, the higher flows, or the presence of a pair of anglers ahead of me? I will never know the answer to that puzzle, but I intend to return as soon as I can forget the strenuous climb at the end of the day.

Fish Landed: 23

2 thoughts on “South Boulder Creek – 08/16/2023

  1. George

    I had to chuckle when I read “Yikes. I’ll be 76 by then and probably unable to fish anymore!”. I will be 76 in October and perhaps fortunate in that I’m fly fishing and playing pickleball better than ever. May your heath let you continue for many more years.

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