One hundred and twenty million gallons of pure water a day — enough to meet the water needs of a million people — surge out of the ground here. A short distance from the glassy pool is a bridge. Toss bread crumbs into the water from it, and you’ll see that constant flow (at a year-round temperature of 52 degrees) and the clean gravel bottom make for perfect trout habitat. Big Springs’ trout get BIG. Leave your fishing pole in the car, though: No fishing is allowed until below the outlet to Henry’s Lake, several miles away. The spring supports enormous rainbow trout which are protected from fishing. A .5 mile handicap accessible trail offers wildlife viewing of osprey, bald eagles, waterfowl and the occasional moose, white-tailed deer, and muskrat. Wildlife can be seen year-round although winter access is restricted by snow.