In April, caddis will kick off the summer hatches. They'll explode below Glenwood Springs and move rapidly upstream with warming waters. Along the Middle Park section of the river, the hatch is more likely to flourish in May yielding very dense hatches until runoff strikes. Heavy caddis hatches will likely continue throughout the summer into fall. The spring caddis can be matched with standard patterns such as the LaFontaine series, Prince Nymph, dark olive Stimulators, Elk-Hair Caddis and Goddard Caddis in No. 14 to 18.

As runoff hits, change to a heavier rod and tie on some large willowfly-stonefly imitations and hold on. No. 4-8 20-Incher, Halfback or Prince nymphs with lots of weight or Sofa Pillows, Turk's Tarantulas, and Orange Stimulators attached to a 4X tippet can attract some big Colorado River trout from Middle Park down to Gore Canyon.

Fish the dry flies right along the edges and dredge the very bottom with nymphs if the trout ignore the dry patterns.

Middle Park stoneflies may begin to move as early as late April and compete with the caddis for the trout's attention, but generally they seem to arrive with runoff in late May.

There is plenty of access and excellent fishing in the moderate Colorado River flows from around Granby west to Troublesome Creek just east of Kremmling. Riffles, runs and pools highlight this section largely paralleled by Highway 40. West from Kremmling, the river has more heavy water with some thrashing white water. At this time of the year, heavy water and reduced clarity combine with large, hungry trout to produce a less selective quarry -- a perfect combination for spring anglers.

Animas River
Many thousands of acres of the pristine San Juan Range yield the watery lifeblood of the Animas, sustaining a healthy population of trout and creating a Gold Medal stretch of river within the city limits. Prime fishing water on the Animas flows right through the middle of Durango.

In the spring, the Animas may be difficult to wade. This is a big, powerful river. But large browns make it a worthwhile venture when the spring caddis burst forth, normally in mid to late May.

Caddis may arrive with runoff. This very dense caddis hatch can be fished successfully by concentrating casts along the river edges. In heavy snow years, water may run high and roily into late June or early July. By mid-June, the caddis will still be coming off heavily.

Thomas Chacon of Duranglers favors No. 16-18 light brown or light gray patterns like the Goddard Caddis. He and Dennis Lum, also from Duranglers, recommended a lime-green dropper, like a Chartreuse Copper John dropper, to imitate the cased caddis in the river here.

Lum said the seven-mile, sidewalk-paralleled section through town is the best part of the river.

Downstream, a $40 fee will gain entrance to the river within the Ute Indian Reservation. This section is loaded with 12- to 15-inch fish. You can avoid summer's "rubber hatch" by fishing the reservation.

Gunnison River
Spring brings a strong caddis hatch along the upper Gunnison River and lower Taylor River above its confluence with the Gunnison. Unfortunately, a sparse mid-May hatch often kicks off coincidentally with runoff and doesn't peak until around mid-June.

John Bocchino from Willowfly Anglers in Almont recommends Elk-Hair or Mathews X-Caddis patterns -- olive or tan in No. 14-16, as well as a smaller black or yellow No. 18. Bocchino said they almost exclusively fish dry caddis after runoff because the fish feed on the surface. These fish are not picky, so you don't have to closely match the spring caddis. In the evening, skating or twitching dry caddis patterns will usually bring fish to the surface.