The State of the Colorado River
June 7, 2016
Things are looking relatively good this summer for the upper Colorado River Basin though the seemingly good news is tempered by the broader view of water levels and droughts hampering much of the American west as well as a sobering outlook at what lies ahead.
Officials from the Colorado River District, along with representatives from Denver Water, Northern Water, Grand County Water Information Network and local conservationists like Kirk Klancke, President of the Grand County Chapter of Trout Unlimited, outlined the current state of the rivers, streams and tributaries in Grand County as well as broader discussions of the overall state of the Colorado River Basin at a recent State of the River meeting held at Mountain Parks Electric in Granby.
General Manager for the Colorado River District Eric Kuhn cut right to the point during his presentation saying, "In Colorado conditions are okay to wet with full reservoirs, decent stream flows and few supply problems." The broader picture is not so rosy though. "Basin wide system storage is declining. Lower Basin states are facing shortages and Upper Basin states are planning for them."
It is a tale of two separate realities with the Upper Basin and Lower Basin experiencing significantly different conditions. According to Kuhn's presentation Colorado and the Front Range area of the State have been wet for the last two-and-a-half-years. The relatively high amounts of precipitation seen on the eastern side of the continental divide, including deluges in the fall of 2013 that caused significant road damage, have kept reservoirs and water storage sites east of the divide fairly full.
This has kept transmountain diversions of water through places like the Alva B. Adams Tunnel and Moffat Tunnel to a minimal level. The Lower Basin region however is dealing with a structural deficit and several portions of the basin are dry. Much of the structural deficit felt in the Lower Basin comes down to simple math. According to figures provided by Kuhn Lake Mead receives roughly 9-million-acre-feet each year in inflows from the Colorado River and other local tributary inflows while releasing roughly 9.6-million-acre-feet per year.
Additionally Mead loses roughly 600,000 acre-feet per year to evaporation, leaving the lower Basin with a structural deficit of about 1.2 million-acre-feet annually. In layman's terms this means that each year Lake Mead's storage level declines by about 12 feet. Looking at the math for the entire Colorado River Basin shows use levels at around 16 to 17.5 million-acre-feet annually.
The structural deficit of the Lower Basin is made additionally concerning by two factors: intense droughts that have plagued the western US and southern California especially leading to depleted ground water and diminished aquifers, and historic weather trends where significant droughts have followed behind El Nino weather systems.
El Nino is the term for a regularly occurring weather system affecting the Pacific Ocean marked by warm ocean currents and often resulting in higher than average precipitation. El Nino events typically last multiple years at a time and recur every few years. We are currently in an El Nino cycle that is expected to end this year.
In 2000 when Colorado began experiencing a significant drought that lasted several years the drought immediately followed a wet El Nino cycle in the late 1990s. Similar trends have occurred historically and officials who oversee the flow of the Colorado River are additionally concerned because of the already diminished storage levels in the River's reservoir storage system.
The Colorado River Basin can hold a total of roughly 60 million-acre-feet of water among all the large Bureau of Reclamation Reservoirs such as Mead and Powell, which together have a capacity of 50 million-acre-feet. The 60 million-acre-feet storage capacity does not take into account smaller local reservoirs such as Granby and Wolford Mountain.
During his presentation Kuhn explained how not a single drop of water from the Colorado River has reached the ocean for the last 18 years. If historic weather patterns hold and predictions come true the next few years could prove troublesome for the Colorado River Basin, and the entire western US as a whole.