New storage needed in the Upper Missouri?

Across the headwaters of the United States’ largest river basin, we estimated region-wide, decadal-scale drought severity during the “turn-of-the-century drought” ca. 2000 to 2010 was potentially unprecedented over the last millennium.

That’s the headline result from a new paleo reconstruction from Justin Martin (USGS) and colleagues. The study published in PNAS yesterday, and has already caught the attention of some mainstream media outlets, such as The Washington Post.

The study adds to a long and growing list of publications documenting evidence for increased drought risk linked to warming temperatures—notably through snowpack loss.

There are clear implications for water management:

The combination of elevated air temperature and low streamflow presents a dual challenge for water managers in the UMRB where both agricultural irrigation demands and in-stream water quality for aquatic species are top management priorities. High temperatures and low flows simultaneously increase heat stress and evaporative demand on crops while reducing available water for irrigation.

…and the authors do not shy away from policy implications, notably the need for new storage:

Recent trends and projected changes suggest a future that may require the capture and storage of increasingly early snowmelt runoff, with increased risk of either severe flooding or increasingly severe drought for the portion of the Missouri basin lacking significant multiyear storage capacity. Improvements in multiyear to decadal forecasting capabilities made by incorporating temperature information in snowmelt dominated basins combined with implementing subbasin drought plans could result in enhanced infrastructure operation and water allocation during increasingly severe future drought events.