St Vrains Creek Fly Fishing (Rocky Mountain National Park)

Overview

The St. Vrain flows out of Wild Basin, a large valley on the southeast side of Rocky Mountain National Park. It collects water from snow-covered flanks of towering peaks, not the least of which is the 14,000 foot Longs Peak, and tumbles down out of the Park, coming to rest in Button Rock Reservoir just outside Lyons.

St. Vrain Creek remains cold late well into May, with 38-40 degrees being very common. Even during the summer this stream remains cold enough that wet wading can be very uncomfortable. You’ll want to wear chest or hip waders not only due to the cold waters, but also to protect you from sticks as you wade among the beaver ponds.

May to June

In late May through mid June, runoff raises this small stream to a level where it can be dangerous to wade it. Even during this time when the water is off color, the fishing can be quite good. Baetis and caddis patterns are the rule at this time of year.

St. Vrain Creek remains cold late well into May, with 38-40 degrees being very common. Even during the summer this stream remains cold enough that wet wading can be very uncomfortable. You’ll want to wear chest or hip waders not only due to the cold waters, but also to protect you from sticks as you wade among the beaver ponds.

In late May through mid June, runoff raises this small stream to a level where it can be dangerous to wade it. Even during this time when the water is off color, the fishing can be quite good. Baetis and caddis patterns are the rule at this time of year.

Hatches

  • Caddis: May through September
  • Baetis: April / May
  • Green Drake: July / August
  • Red Quill: July / August
  • Golden Stone: July through September
  • Terrestrials: July / August

Trout here, like most other places, still take 80% of their food below the surface so a dry-dropper is your best bet for success.

A small golden stone (#14-16) with a tungsten bead can be a killer in late summer, and like the other streams discuss here, most afternoons in July and August will see some Green Drakes and Red Quills coming off.

Hatch Chart

Insect Size Begin Date End Date Best Time    
Baetis 18-24 April 1 May 30 N/A    
Caddis 10-20 May 15 September 15 N/A    
Golden Stone 6-16 June 15 August 30 N/A    
Red Quill 14-16 July 1 August 30 N/A    
Green Drake 10-12 July 1 August 30 N/A    
Terrestrials 8-20 July 15 September 30 N/A    
Baetis 18-24 September 15 October 30 N/A    

This stream has a nice population of greenback cutthroats and, lower down, some nice browns. From the small tributaries such as Coney Creek to the pools at Ouzel Falls to the main fork of the St. Vrain, trout will pounce on a dry pattern during the summer.