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.
Flows are low as of mid-April, but should begin to rise soon enough. In times of low flow, think dry droppers and short clean casts. As far as flies go, lead with a small attractor dry fly like an Elk Hair Caddis, Micro Chubby Chernobyl, Amy's Ant or Hippie Stomper. Trail any of these flies with 12 to 18 inches of tippet (or 1.5X the depth of the water) followed by one or more smaller nymphs. As far as trailer nymphs go, Guide's Choice Hare's Ears, Flashback PTs, Rainbow Warriors, red Copper Johns, Zebra Midges, Black Beauties and RS2s are all productive choices. As flows begin to rise, trout will spread out and feed at varying depths and locations across the river. In this case, nymphing will arguably be the most effective option. When nymphing, we like to lead with heavier, tungsten bead head bugs as opposed to applying our own split shot. That said, there's no harm in managing your own weight. Pat's Rubber Legs, Stonefly Nymphs, Leeches, worms and caddis larva will make for productive lead flies once we get a decent bump in flow. Otherwise, keep an eye out for surface activity. Midges are present in high numbers and the BWO hatch is picking up. If you see actively rising trout, rig up a dry or dry to an emerger and focus on the soft water where trout are looking up.
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.