Even with low inflows, lake levels rise in March as drought continues
Above-normal rainfall in the Texas Hill Country helped the levels of lakes Travis and Buchanan rise slightly in March, although inflows remained far below normal as the serious drought near the Highland Lakes continued. Inflows are the estimated amount of water flowing into the Highland Lakes from rivers and tributaries based on four streamflow gauges.
March 2015 inflows were 19,136 acre-feet - about 21 percent of the March average - and were the 15th lowest inflows for that month on record. Inflows have been below average every month for 36 straight months.
The combined storage in lakes Buchanan and Travis - which store the water supply for the region - rose from 717,053 acre-feet on March 1 to 749,364 acre-feet on April 1. (An acre-foot is 325,851 gallons.)
As of early April, the lakes stood at 37 percent of capacity.
"Combined storage in lakes Buchanan and Travis has risen more than 60,000 acre-feet since Jan. 1,'' said John Hofmann, executive vice president of Water. "While that's a step in the right direction, it's not enough to put a significant dent in this historic drought."
Meteorologists are predicting near-normal to slightly above-normal spring rainfall for the region. Hofmann said that would be welcome, but it would not be enough to drive lake levels back up to average.
"That is good in terms of green yards," Hofmann said. "It's not great in terms of water supply."
The Central Texas region is in the eighth year of a severe drought. Preliminary 2014 data shows this drought is now the most severe the region has experienced since construction of the Highland Lakes began in the 1930s.
As a result of the severity of the current drought, LCRA has reduced its estimate of the amount of water it can reliably supply through a repeat of the driest conditions on record by 100,000 acre-feet, to 500,000 acre-feet. The revised inventory estimate reduces the amount of water LCRA will have available for sale in the future, but does not impact existing contracts.
Six of the 10 lowest annual inflows on record have occurred since 2008, when this drought began. Average annual inflows for 1942-2014 are 1,216,295 acre-feet.
- The lowest annual inflows occurred in 2011 with only 127,802 acre-feet, about 11 percent of the annual average.
- The second lowest inflows were 209,023 acre-feet - about 17 percent of the annual average - in 2014.
- The third lowest inflows were 215,138 acre-feet - about 18 percent of the annual average - in 2013.
- The fourth lowest inflows were 284,462 acre-feet - or about 23 percent of the annual average - in 2008.
- The seventh lowest inflows were 393,163 acre-feet - or about 32 percent of the annual average - in 2012.
- The 10th lowest inflows were 499,732 acre-feet - or about 41 percent of the annual average - in 2009.
The 10-year period ending March 2015 has the lowest cumulative inflows for any 10-year period since 1942, when Mansfield Dam was completed.
Without additional rain in the Highland Lakes watershed, there is a small chance - less than 1 percent - the combined storage of lakes Buchanan and Travis could fall to 30 percent of capacity, or 600,000 acre-feet, in the July-August 2015 time frame. That chance remains less than 4 percent through the end of 2015.
If combined storage falls to 600,000 acre-feet, specific drought response actions would be triggered under the 2010 Water Management Plan. The LCRA Board of Directors would issue a "Drought Worse Than Drought of Record" declaration that requires cities, industries and other firm customers to reduce their water use by 20 percent from a baseline year and cuts off all Highland Lakes water to all interruptible customers.
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 times of drought. Lakes Travis and Buchanan provide drinking water to more than a million people and water to industries, businesses, the environment and, when enough water is available, agriculture in the lower Colorado River basin.
In order to preserve the water supply, LCRA cut off Highland Lakes interruptible water to most agricultural customers for three years in a row with permission from the state. In March, the Texas Commission on Environmental Quality approved
emergency drought relief again for the first part of 2015. The emergency orders will be effective until June 18. LCRA could seek additional relief if the drought continues.
LCRA also is increasing the water supply available to the region by building the first significant 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 water inventory and is expected to be completed in 2017. The new reservoir will help reduce the amount of water that otherwise would be required to be released from the Highland Lakes. If the Lane City Reservoir had been in place at the first of the year, it already would be full because of the wet conditions downstream.
The rain downstream of Austin since the first of the year also has improved the water quality of the lower Colorado River and Matagorda Bay. Flow conditions in the river have been near optimal for the state-endangered blue sucker fish spawning season. Matagorda Bay has received more than 421,000 acre-feet of freshwater inflows since Jan. 1.