State officials say climate change likely to result in more frequent and severe droughts
By Bob Berwyn
SUMMIT COUNTY — Colorado has experienced several serious droughts since the state was settled in the late 1880s. The most serious droughts came in the 1930s dustbowl era, and again in the 1950s, when another multi-year dry spell hit the state.
Adding up all the dry years, state water planners say that, simply put, there’s about a one-in-three chance of experiencing drought conditions in any given year. — and climate change is expected to increase the frequency and severity of drought events, according to state water planners.
Since those early days, residents and elected officials have been trying to figure out how to deal with the dry spells that are sure to come again. The latest effort is the 2010 drought mitigation plan, released in draft form and posted online for public comment. Get the links at the Colorado Water Conservation Board website, or check out the draft plan in the Scribd.com window at the end of this story.
The draft plan is worth a read by anyone interested in water issues in the state, especially as we enter the hottest part of summer with streamflows plummeting toward record-low levels after reaching a sudden peak in June.
Here’s an excerpt from the plan’s discussion on climate change impacts:
- “Warmer temperatures will likely result in precipitation occurring as rain rather than snow, an earlier spring melt, more intense precipitation events, and increased evapotranspiration (CWCB 2008, CWCB 2010, Knowles et al 2006, Mote 2006, Saunders 2005, Udall 2007). . Consequently, runoff will start earlier and end earlier. Reservoirs will fill earlier, and what cannot be stored in the spring and early summer will be spilled when agricultural demands are not as great as they are later in the summer. Decreased runoff in the summer will result in additional reservoir drawdown and many studies agree that higher temperatures and lower precipitation during summer months will further increase agricultural demands, thus causing even more stress on reservoir storage (CWCB 2008, CWCB 2010).”
One of the most interesting chapters in the draft plan is the history of droughts in Colorado. The dust bowl drought came in three waves: 1934, 1936 and 1939-1940. The last of those droughts saw excessive heat even into the high country, with many July all-time high temperature records in Frisco set in the summer of 1939.
The 1950s drought hit the Great Plains and the Southwest especially hard, with a string of five dry years. Part of that time, drought stretched nearly from coast to coast. By the time the dry spell ended in 1957, many counties in the hardest-hit areas had been declared federal disaster zones.
The next major drought came in 1976-1977, when two-thirds of the state’s streams set all-time record low streamflows that held until 2002. The 1970s drought also gave ski areas the impetus to start thinking about making their own snow, a move that was reinforced a few years later during the short but intense drought that started in the fall of 1980 and continued to the spring of 1981. The early 1980s drought also triggered formulation of the state’s first formal drought response plan.
The state’s worst drought on record was in 2002, when the Rio Grande nearly ceased flowing. Based on tree-ring studies, the 2002 event may have been the worst-ever dry spell in Colorado. If global warming causes recurrences of 2002 conditions, it could stretch the state’s water resources close to the breaking point — hence the need for an up-to-date response plan.
The draft plan goes on to rank counties based on their susceptibility to drought in different sectors, including agriculture, recreation and energy, as well as important aquatic habitat.
Look for more coverage of the drought mitigation and response plan in the next few days at Summit Voice.
Filed under: Environment, rivers, Summit County Colorado Tagged: | Colorado drought, Colorado drought mitigation and response plan, Colorado water, Colorado Water Conservation Board, drought, drought response, Summit County Colorado, Summit County News