Note: This report is a part of the FlyCast Lite reporting program and is updated seasonally or in the event of substantial changes that alter fly fishing tactics. FlyCast Lite reports are intended to give anglers a high level overview on seasonal conditions and general fishing tactics.
South Boulder Creek, below Gross Reservoir, fishes well this time of year when flows are at or above 25 cfs and while the lower stretches are prone to ice, the water nearest the dam is generally a safe bet. When flows are below 25 cfs, the fishing becomes far more technical as trout are prone to be skittish and selective. Hatch activity has been fairly consistent with midges making a regular appearance in the late morning and afternoon. The mornings have been and will continue to be slow given winter weather and sluggish trout. As such, it is in your best interest to fish the warmest hours of the day. In general, a dry dropper or hopper dropper is our go to mode of fishing, regardless of the time of year. While you might not see much action on your stimulator dry fly, the entire set up will be more stealthy and spook fewer trout. Otherwise, a heavy nymph rig with a yarn indicator is a good fall back option. Regardless, you'll want to focus on getting your nymphs into the deepest water column while targeting the deep and slow pools, runs and pockets as this is where the highest concentration of trout will be. Searchers and attractor patterns like a Copper John, Flashback PT, Hare's Ear, Rainbow Warrior or San Juan Worm will make for great lead flies. Smaller midge and baetis imitations like a Tube Midge, Zebra Midge, Medallion Midge, Manhattan Midge, RS2, Darth Baetis or Stalcup's Baetis will make for great trailer flies. On warmer days, this tailwater can get crowded. Either way, you'll want to cover a lot of water and do your best to sight fish.
South Boulder Creek is one of the more beautiful places to fish within an hour of Denver. It originates in the Indian Peaks Wilderness and makes its way down to the Gross Reservoir. Below the reservoir is the tailwater, which flows through the Walker Ranch Open Space. While the creek above the reservoir presents some decent fishing and offers a number of public access points, for the sake of this report, we’ll be focused on the section below the Gross Reservoir. The tailwater is home to a variety of trout species. However, it is most known for its brown and rainbow trout. This section is one of the more popular stretches and can be fished year-round. That being said, much of the river freezes over in the winter leaving fewer fishable locations. The creek itself meanders through a beautiful canyon and is detached from the road. So if you enjoy some peace and quiet as well as a short hike, South Boulder Creek is for you.
South Boulder Creek is fairly forgiving and a viable option for anglers of all skill sets. Given that it is a creek, you can expect comparatively narrow water as well as large boulders that create some amazing pocket water. While flows in the spring, late summer and fall are fairly stable, this stretch is particularly prone to run-off from feeder creeks. That said, you can still manage to catch fish during this time. The summer and fall offer prime dry fly fishing conditions as there are a variety of hatches in the caddis, PMD, BWO, midges and terrestrial variety. You can’t go wrong with the dry dropper set-up. Elk Hair Caddis, Amy’s Ant’s and Chubby Chernobyls all make for great point flies. Otherwise, the nymph rig with searchers, attractors or imitative nymphs will treat you well all year. Regardless of how you fish, you’re going to want to focus on the banks and outer seams to start, but don’t discount the shallow riffles and runs, pools or pocket water.
To access South Boulder Creek below Gross Reservoir, take Highway 93 (north from Golden or South from Boulder) until you reach Highway 72. From here, follow the highway until you reach the Gross Reservoir turnoff (Crescent Park Drive). After about 4.5 miles you’ll make a right on Gross Dam Road to which you’ll find parking via the Walker Ranch Open Space.