Science to Assist with the 2020-2026 Colorado River Interim Guidelines Renegotiations
Abstract
Science to Assist with the 2020-2026 Colorado River Interim Guidelines Renegotiations
Since 2000 the Colorado River, which supplies water for 40m Americans, has been in a record-setting drought. Over the last 19 years, flows have averaged only about 80% of their 20thcentury average and the reservoirs have lost about 55% of their contents. In 2007, after seeing reservoirs drop precipitously and enduring the worst 7-year drought on record, the Basin states agreed on an interim plan to manage the river's reservoirs and to allocate shortages. As the drought continued in the 2010s, it became apparent that additional measures would be needed to allocate larger shortages and keep reservoirs functional. In 2014, a process to create a Lower Basin Drought Contingency Plan was begun. By late 2017, It was foundering due to political infighting. After very low runoff in 2018 (< 50%), dire reservoir forecasts, and political pressure, the Lower Basin states have recently redoubled their efforts to complete the plan. However, these efforts even if successful in the short term, will need to be revisited in the next two years. The 2007 guidelines expire in 2026 and renegotiations are set to begin in 2020. Recent science has suggested that warming has caused significant loss of flow (Xiao, Udall, Lettenmaier, in revision) and that future warming could reduce flows by 20% in 2050 and by 35% in 2100 (Udall and Overpeck, 2017). The Drought Contingency Plan, as currently envisioned, will not provide the tools to manage shortages and reservoir volumes under additional flow loss. Scientists have struggled to provide informative medium-range forecasts for management. The river is exhibiting clear signs of non-stationarity making probability predictions difficult. 'Stress-Test' hydrology using approximately the last 25 years has been tried, and paleo-climate flow reconstructions have also been used. Some have suggested that scenarios may be helpful, too, to allow decision makers to meaningfully contemplate undesirable outcomes and proactive management strategies. How might scientists create these and other products and engage with decision makers so that the 2026 shortage and reservoir management plan can handle a wide-range of future climates?- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H52F..08U
- Keywords:
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- 1873 Uncertainty assessment;
- HYDROLOGYDE: 1880 Water management;
- HYDROLOGYDE: 4328 Risk;
- NATURAL HAZARDSDE: 6309 Decision making under uncertainty;
- POLICY SCIENCES