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.
Runoff has come early for South Boulder Creek. Flows are well above the historical average for this time of year and clarity is on the lower end. While you can still have a productive time on the water, you will need to adjust your approach. With runoff getting an early start, it means that it will likely be short lived. Regardless, you can expect elevated, and potentially volatile flows, over the next few weeks. At this point, trout are stacking up along the banks and in the slack water where the current is slowest and water clarity is best. In times like these, nymphing with bigger lead flies in the stonefly, leech, worm and searcher/attractor variety followed by one or more smaller midge, baetis or caddis imitations will produce the most consistent results. Ensure plenty of weight and hit the outer seams, slack water and pockets along the banks. Otherwise, smaller streamers have been and will continue to be effective as well. As fas as surface action goes, expect minimal feeding when clarity is poor. However, as things clear up and flows settle down you can expect more attention to surface flies. Midges, BWOS and caddis are hatching sporadically throughout the day so come prepared to fish some dry flies if you see trout actively feeding on the surface. Dry droppers with bigger stimulators followed by one or more smaller nymphs will produce as well. If you go the dry or dry dropper route, target the slow water as well as the pockets.
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.