For several years, researchers, agricultural managers, ecologists and a variety of experts have been monitoring water usage in the west and southwest with some concern. Most of the municipal and agricultural water used between New Mexico and Colorado flows from two sources. The first is the Colorado River (including Lake Powell and Lake Mead which frame the Grand Canyon and nourish populations all the way to Southern California). And the second source--the Rio Grande--supplies water for vast agricultural and community use in southern states from California to Texas.
Increasing water requirements and agricultural demands have strained both of these two water resources for a long time, but so far, management and distribution practices have allowed the water to continue flowing throughout the summer months of highest need. Though the Rio Grande drops precipitously during these months, the water is typically replenished by the heavy snowpack that melts and flows from the Rocky Mountains every spring. It’s a cycle that repeats every two years; this year’s river water tends to represent last year’s melting snow.
In 2018, a cycle of consistently warming winters has taken a toll on the snowpack. An unusually warm, dry winter has reduced runoff from the Utah and Colorado land masses that typically direct that water into Lake Powell. Water level predictions for 2018 are among the worst in the last 54 years.
At the same time, the Rio Grande is drying with unusual speed this spring. In a typical year, the river levels drop and the mighty Rio Grande becomes unable to sustain heavy agricultural use by October. But this year, the water is already vanishing in May and will be expected to dry up by July, too early for farmers in the region who depend on the river to carry them through the full growing season. While late summer monsoons typically supplement the river and help growers finish the summer, the monsoons are notoriously unpredictable. This year, farmers may find it difficult to survive if they don’t show up.
Since the cycle of snow-to-river takes two years, not one, this year’s reduced snowpack will be felt more heavily in 2019. And as a result of heavy monsoon rains in 2016, Rio Grande reservoirs are high enough right now to partially mitigate concerns for the current year. But this year will provide a testing ground for future seasons in our current pattern of steadily rising global temperatures and shrinking water resources across the west. How we manage the summer of 2018 may help us predict and plan for potential water crises that may influence agricultural production and population fluctuations in the area during the decade ahead.