hofmann, managing the drought / flood cycle
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Texas Water Conservation Association Midyear Conference
John HofmannLCRA Executive Vice President of Water
June 17, 2016
What a difference a year makes
June 2016March 2015
The Highland Lakes
A shared resourceThe Highland Lakes provide water for:
• More than a million people
• Seven power plants capable of providing power to more than 3 million homes
• Businesses and jobs
• Agriculture
• The environment
Highland Lakes watershed
Lake BuchananLake Travis
Water flowing into theHighland Lakes
0
25,000
50,000
75,000
100,000
125,000
150,000
175,000
200,000
225,000
250,000
275,000
300,000
325,000
350,000
375,000
400,000
425,000
January February March April May June July August September October NovemberDecember
Acre-feet
Average since 1942
Average of 2011-2015
2011
2015
2016
Record-low inflows into the Highland Lakes
10 Lowest Annual Inflows on Record2011 127,802 acre-feet2014* 209,023 acre-feet2013 215,138 acre-feet2008 284,462 acre-feet2006 285,229 acre-feet1963 392,589 acre-feet2012 393,163 acre-feet1983 433,312 acre-feet1999 448,162 acre-feet2009 499,732 acre-feet
*Preliminary data
Floods
Date Comment1938 22 floodgates opened at Buchanan Dam
Led to larger design for Mansfield Dam1952 Filled Lake Travis overnight
Flood of Record for LBJ and Marble Falls1957 Ended the Drought of Record
First time gates were opened at Mansfield1991 Flood of Record for Lake Buchanan
Flood of Record for Lake Travis1997 Llano River basin flood2004 Upper and lower basin flood2007 Marble Falls “Rain Bomb”
1952 floodDaily Elevations of Lake Travis
600
610
620
630
640
650
660
670
680
690
700
710
720
8/28/1952 9/27/1952 10/27/1952 11/26/1952 12/26/1952Date
Elevation (msl)
Observed daily Lake Level
681 msl Travis is considered full
619
675
Rising lake levels • In 2015:– Lake Travis rose more than 53 feet– Lake Buchanan rose more than 25 feet– Combined storage increased more than 1 million acre-feet
• Current levels compared to Jan. 1, 2016:– Lake Travis is about 7 feet higher– Lake Buchanan is about 6 feet higher– Combined storage is up about 260,000 acre-feet
Full vs. full-full
11
Two-week rainfallWhite boxes show totals of about 8-15 inches
White boxes show totals of about 8-14+ inches
Some areas received totals of 3-5 and even 7+ inches
Lake Travis elevation
Crested: 692.7 feet msl
(for water supply purposes)
Feet msl = feet above mean sea level
Hydromet system
• Provides information vital for flood management
• Includes more than 275 gauges
• Transmits data every 15 minutes
• Uses LCRA’s radio system
• Data is shared with partners and the public
River Operations Control Center
Lake Travis 1991
Buchanan DamJune 2
Our work continues …
Lake Travis won’t stay full
19
0.0
0.5
1.0
1.5
2.0
2.5
3.0
1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
Millions of acre-feet
Sept. 30, 1940, to June 15, 2016
Total combined storage in lakes Buchanan and Travis
Full storage (2.01 million acre-feet)Average storage (1.62 million acre-feet)Combined storage (million acre-feet)
Questions?
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