Federal figures released this week by the U.S. Bureau of Reclamation show Blue Mesa Reservoir has fallen beneath 25% of its total capacity, stripping it of its standing as Colorado's largest body of water. That distinction now belongs to Lake Granby, which is itself only 62% full.
The severe drawdown has brought the ruins of Iola — a community inundated when Blue Mesa was formed — back into view, and sections of the Gunnison River have reappeared across the exposed lakebed, roughly following the course the river ran before the reservoir was created in the 1960s. A volunteer at the Gunnison Pioneer Museum who passed by the reservoir this week described the scene: "You could absolutely see the river, and you could kind of imagine what it was like before."
Water managers had flagged a historically dry outcome as early as spring, when the window for mountain snowpack accumulation closed with the lowest total ever measured — snowpack being the primary driver of runoff into the Colorado River Basin. A water resources engineer at the Colorado River Water Conservation District characterized conditions at Blue Mesa as without precedent, noting the reservoir had never been reduced to its current level this early in the season.
The crisis reaches well beyond the reservoir's edge: water from Blue Mesa moves through the Gunnison Tunnel to irrigate tens of thousands of farmland acres in the Uncompahgre Valley, and the towns of Montrose, Delta, and Olathe rely on that same conduit for their municipal water supply. A secondary supply from the Uncompahgre River is described as "nonexistent" this year, and the water users association had already restricted member deliveries to half of normal allocations heading into the season. Large row-crop producers have responded by leaving between 30% and 60% of their valley acreage unplanted.
Without intervention by the Bureau of Reclamation and Gunnison River water rights holders, Blue Mesa might have been on course to fall past power pool — the level below which its 86.4-megawatt generating facility, sized to supply roughly 3,400 homes, can no longer produce electricity. Conditions have worsened on another front as well: the National Park Service reported this week that a bloom of toxic blue-green algae had appeared in the reservoir, a development associated with the shallow, warm water that prolonged drought produces.
Blue Mesa is not an isolated case. Rivers and reservoirs throughout the Rocky Mountain snowmelt system are broadly at extreme lows, water restrictions have spread across the region, agricultural operators around the state have cut back on crops and reduced livestock herds, and Colorado Parks and Wildlife currently has six emergency fish salvages in progress. Multi-year negotiations over Colorado River Basin management have remained deadlocked, prompting the Bureau of Reclamation to release its own management plan calling for significant water use reductions from Arizona, California, and Nevada before the existing 2007 operating guidelines lapse on October 1. An environmental advocate who monitors the basin argued the situation should function as a signal to water policymakers, saying "there will be more years like this in the future."
Whether Blue Mesa holds enough storage to carry the Uncompahgre Valley through the coming winter without additional emergency restrictions — and whether next spring's snowpack delivers any meaningful recovery — remain the questions water managers say they are most closely watching.