Lake levels inch up with November rain
Inflows remain far below average as drought persists
Two November weather systems brought much-needed rain to the lower Colorado River basin, but generated little runoff. As a result, levels in LCRA’s two water supply reservoirs – lakes Travis and Buchanan – remain significantly below average.
In addition, the amount of water flowing into the lakes from streams and tributaries – called inflows – has been below the monthly average since March 2012 because of the ongoing drought.
November inflows totaled just more than 23,000 acre-feet, or 34 percent of the monthly average. The year 2014 has been so dry that November’s modest inflows were the third highest monthly inflows for the year.
Low inflows have persisted throughout 2014, despite near-normal rainfall near the Highland Lakes. The sporadic timing of storms allowed the soil to dry out between rain events. For water to run off into the lakes, the rain must fall on saturated ground or the rain must be hard enough to generate substantial runoff. Very little of either occurred this year.
Inflows from January through November 2014 totaled 197,339 acre-feet – the third lowest for that 11-month period since 1942.
Inflows to the Highland Lakes have been at or near historic lows for an extended period during this drought:
- Six of the 10 lowest annual inflows in history have occurred since 2006. Average annual inflows for 1942-2013 are 1,230,284 acre-feet.
- The lowest annual inflows in history occurred in 2011 with only 127,802 acre-feet, about 10 percent of the annual average.
- The second lowest inflows in history were 215,138 acre-feet (about 17 percent of the annual average) in 2013.
- The third lowest inflows in history were 284,462 acre-feet (about 23 percent of the annual average) in 2008.
- The fourth lowest inflows in history were 285,229 acre-feet (about 23 percent of the annual average) in 2006.
- The sixth lowest inflows in history were 393,163 acre-feet (about 32 percent of the annual average) in 2012.
- The ninth lowest inflows in history were 499,732 acre-feet (about 41 percent of the annual average) in 2009.
Despite the low inflows, November rains raised lake levels slightly. The combined storage of lakes Travis and Buchanan rose from 680,863 acre-feet on Nov. 1 to 691,132 acre-feet on Dec. 1. Lake Buchanan rose several inches, while Lake Travis rose a little less than two feet.
In early December, the combined storage of lakes Travis and Buchanan stood at 34 percent of capacity. If combined storage falls to 30 percent of capacity, or 600,000 acre-feet, the LCRA Board of Directors will issue a Drought Worse Than the Drought of Record declaration. Following a state-approved plan, LCRA then would require cities, industries and other firm customers to reduce their water use by 20 percent from a baseline year and would cut off all Highland Lakes water to interruptible customers.
Without additional rain in the Highland Lakes watershed, there is a small chance the combined storage of lakes Buchanan and Travis could fall to 600,000 acre-feet as soon as March 2015.
Though lake levels are low, the Highland Lakes are doing exactly what they were designed to do – capture water when it rains to ensure the region has a reliable water supply during droughts.
Lakes Travis and Buchanan provide drinking water to more than a million people and water to industries, businesses, the environment and, when available, agriculture in the lower Colorado River basin.
LCRA has been working aggressively to conserve water and expand the water supply during the drought. With permission from the state, LCRA has cut off Highland Lakes water to most interruptible agricultural customers for three years in a row and is seeking
emergency drought relief again for 2015.
In December, LCRA is holding a groundbreaking ceremony for the first new water supply reservoir in the lower Colorado River basin in decades. The
Lane City Reservoir is the first project that will allow LCRA to capture and store significant amounts of water downstream of the Highland Lakes. The reservoir could add up to 90,000 acre-feet per year to LCRA’s firm water supply and is expected to be completed in 2017.