The San Juan River tailwater below Navajo Dam in northwestern New Mexico is one of the most densely populated trout fisheries in the American West and a pilgrimage site for fly anglers seeking to test their skills against large, selective fish in gin-clear water. The dam's hypolimnetic releases maintain water temperatures between 42 and 52 degrees year-round, creating a year-round fishery of extraordinary consistency. The four-mile Quality Water section immediately below the dam — a designated trophy water with strict regulations — holds fish densities estimated at over 15,000 trout per mile, making it one of the most productive tailwaters anywhere in North America.
Rainbow trout dominate the catch in the Quality Waters, with fish averaging 16 to 18 inches and trophy specimens exceeding 24 inches a real possibility. Brown trout hold in the deeper, slower pools and under cut banks, feeding selectively on the tiny midges and micro-mayflies that form the foundation of the San Juan's aquatic food chain. The size of the fish and the clarity of the water demand technical precision from visiting anglers: fine tippets in the 6X and 7X range, small flies in the #20-26 range, and presentations that achieve dead-drift accuracy within inches of a fish's nose.
Midges are the San Juan's most important hatch and the key to consistent success year-round. The Zebra Midge, San Juan Worm (technically a pattern, not a hatch), Brassie, and myriad thread-bodied emergers account for the majority of fish caught in the Quality Waters. Blue-winged Olives provide excellent dry fly fishing in fall and spring, bringing large fish to the surface in pods that reward careful approach and precise casting. The so-called "baetis blizzard" — dense clouds of tiny olives hatching simultaneously on cold, overcast fall afternoons — is one of the great dry fly events in western fly fishing.
The river below the Quality Waters section (from Texas Hole downstream) is managed under general regulations and sees less pressure, offering more relaxed fishing opportunities with slightly less demanding fish. The Texas Hole itself, located at the boundary between Quality Waters and the general section, is the single most popular fishing spot on the river — a broad, deep pool where large rainbows congregate and where the "san juan shuffle" (shuffling your feet on the gravel bottom to dislodge invertebrates and trigger feeding fish) originated. Guide services based in Navajo Dam and Farmington provide half and full-day trips on this legendary water.