Overview
John Martin Reservoir is a large Arkansas River flood-control and irrigation-storage reservoir in southeastern Colorado near Las Animas, operated by the U.S. Army Corps of Engineers. Recreation on the water and adjoining lands is managed in partnership with Colorado Parks and Wildlife at John Martin Reservoir State Park. The dam was built in the 1940s to store Arkansas River flows for flood control and irrigation compact needs.
At conservation/recreation full pool near 3,852 feet the lake covers about 11,700 acres; flood pool can expand much larger. The reservoir is generally shallow (often cited average depths under 10 feet) with maximum depth near 60 feet and on the order of 20-35 miles of shoreline depending on pool. Broad, shallow flats mean wind and turbidity often dominate the fishing day when the pool is up.
Warmwater fishing, boating, and birding draw visitors under Colorado Parks and Wildlife regulations. State park ramps, campgrounds, and wildlife areas provide access on the high plains. John Martin Reservoir State Park and adjoining Corps wildlife lands support camping, birding, and hunting.
Corps operations move water between conservation and flood pools for Arkansas River compact and flood purposes. Elevations can change dramatically with upstream runoff and irrigation demand - monitor current lake levels before launching. Interstate compact accounting on the Arkansas River is a core reason elevations can change quickly.
Current Conditions
John Martin Reservoir is currently 49.82 feet below full pool and has fallen slightly over the past week.
- 7-day trendFallingLatest movement can differ from the seven-day trend.
- 7-day changeDown 0.09 ft
- 30-day changeDown 1.27 ft
- Drought conditionsModerate Drought
About This Lake
Learn how this lake is managed, what affects its water level, and where Lake Insights gets its data.
John Martin Reservoir is a 11,658-acre reservoir on the Arkansas River managed by U.S. Army Corps of Engineers; Colorado Parks and Wildlife (state park recreation).