William's Fork River
The William's Fork River offers the fly fisher a chance at fat rainbows and big browns with relatively low fishing pressure in a classic mountain setting. There are some smaller trout here as well, but concentrating your efforts on the deepest runs and undercut banks should produce bigger trout. This river runs from the dam of William's Fork Reservoir for a little over two miles to a confluence with the Colorado River. Although it can be tempting to rush yourself and try both rivers, it is worth while to take your time on the 'Fork as there are plenty of fish here to keep you busy.
This river has all of the attributes of any good, high-mountain trout stream. Pocket water, deep runs, riffles, overhangs and undercut banks offer different angling presentations and plenty of hiding places. The stream rarely gets more than 15 feet wide and the angler, at times, can literally be right on top of the trout. Needless to say, stealthy approaches to the water are a must for success. Due to the size of the river, high-stick nymphing is the most productive method. Nine-foot leaders down to 4X or 5X (depending on flow) tippets will allow for 'clean' presentations. Using the correct amount of weight is as important here as anywhere. Keeping your split shot bouncing on the river bed will ensure that your fly stays close to the bottom and the feeding trout. Pay close attention to your strike indicator and be certain that your split-shot is bouncing off the rocks.
This river is especially popular in March and early April. The spawning rainbows coming up from the Colorado, some to five pounds or more, are a big attraction to the locals and front-range fisherman alike. During this period, small pheasant tails and loop winged emerger patterns work well. In late April/early May, fish can be taken on subsurface midge and caddis patterns, but continue to fish the mayfly nymphs as well. Runoff is generally over by early July when the insect population really starts to thrive. At this time, choices can include pale morning duns, terrestrials, green drakes and caddis patterns; Caddis being the most productive. I have caught a few fish on dry flies, but the majority have been taken on nymphs. If you want to try surface patterns, look for fish taking mayflies in the riffles and terrestrials along the banks. Casting to risers seems to work better than blind casting.
I prefer fishing this river in late August and September when angling pressure is down. Fishing a golden stone pattern with a caddis larva trailer will produce heavy strikes during this time. You may also fish elk-hair caddis, stimulator, and hopper patterns on the surface. One important thing to bring if you fish the Williams' Fork in the late summer and fall is insect repellent and lots of it. You'll need to apply it about every 45 minutes! The mosquitoes up here can quickly ruin a day of fishing if you aren't prepared. Continue fishing the stonefly nymphs thru September and into October, though you may want to downsize as winter approaches. The blue-winged olive hatches again in late September and stays until the cold water keeps them in the nympal state, you may come across the sporadic trico hatch as well. Because this is a tailwater, scuds of varying colors fished deep are always an option. On those fall days when nothing seems to be working, try fishing streamers in the deepest holes you can find. It is important to get these deep! Instead of loading up on split-shot, buy or tie weighted wooly burgers and muddlers. These look much more natural if the weight is in the fly as opposed to 6-8 inches up your tippet.
As with the Colorado River, Whirling disease has taken its toll on the William's Fork, however, there are still some large rainbows about. Fortunately, the disease doesn't attack the browns with the same effectiveness as it does the rainbows meaning there are plenty of nice browns (14-16 inches) to be had.
Directions
From Denver, take I-70 west to Silverthorne. Take Highway 9 north to Kremmling then head east on Highway 40. Just past Parshall turn right on dirt road that leads to William's Fork Reservoir. About a half-mile up you will see a dirt parking lot and portable toilet. From there, walking the trail to river takes about 20-25 minutes thru heavy mosquito country. You may also take highway 40 from eastbound I-70. This route takes you over Berthoud pass and thru Granby and Hot Sulphur Springs and, in my opinion , adds about 15-20 minutes to the drive.
Travel Time Approx 95 minutes.