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.
Since August, flows on South Boulder Creek, below Gross reservoir, have come down quite a bit and are sitting well below the historical average for this time of year. As it stands, there is minimal water for trout to spread out so you'll want to focus on the deep and slow pools, runs and pockets for the best results. The dry dropper or a dry fly rig will be the way to go. When fishing dry droppers, lead with a buoyant stimulator like an Elk Hair Caddis or Amy's Ant followed by one or more smaller searchers/attractors like a Copper John, Rainbow Warrior, Frenchie or Hare's Ear. Otherwise, smaller midge or baetis imitations have been producing as well. Target the banks and slack water in the early hours and as the day goes on hit the deeper water. Keep in mind that trout are spooky with low flows so keep a low profile when moving about the water and do your best to perform a clean presentation. Surface action has been hit or miss, but you can expect to see some midge and BWO activity. If you see actively rising trout, don't hesitate to rig up some dries.
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.