Gross Reservoir, with 440 acres of surface area, nestles among low mountains in the Front Range southwest of Boulder. The lake, owned by Denver Water, is formed by a 340-foot-high concrete dam on South Boulder Creek. It’s filled with water from western Colorado that’s pumped under the Continental Divide through the Moffat Tunnel. Gross Reservoir is a playground for Boulderites with fishing, canoeing, kayaking, standup paddling, camping, hiking, and bouldering. The lake, free and open year round, has 10.9 miles of shoreline. The lake is big enough that it’s easy to escape from other users. Four picnic areas—North Shore, South Shore, Windy Point, and Miramonte—on the east side of the reservoir have tables, restrooms, and parking. The boat put-in is at Osprey Point on the south shore.
- Gross Reservoir is a good cold water fishery with rainbow trout, brown trout, lake trout, splake, kokanee salmon, and tiger muskie. Bag limit for tiger muskie is one at least 36 inches long. The stocked trout prefer flies or lures rather than power bait or worms. Kokanee snagging is allowed from September 1 to January 1, with the fall run in October.
- Canoes, kayaks, multi-chamber inflatables, and other non-motorized watercraft can paddle around the lake from late May to the end of September. Trailer-hitched, sail, and motorized boats are not allowed. Swimming, wading, and diving are prohibited.
- Primitive camping is allowed on the west side of Gross Reservoir in Roosevelt National Forest from Memorial Day until the first snowfall. The 20 or so campsites are dispersed in the forest and marked with a number and fire ring. Camping is free and is on a first-come first-served basis.
- Good bouldering on several blocks lie on the east side of Gross Dam Road southeast of the dam. Lots of climbing problems from V0 to V7 are on the blocks. Other boulders and small cliffs on the west side of the road invited exploration in South Boulder Creek’s canyon.
Recommended season(s): Year-round.
—Stewart M. Green