The reservoir is a man-made pool created to store water and prevent flooding. It is normal for water levels at Amistad Reservoir to fluctuate due to increased rainfall or ongoing drought and greater demand for water downstream along the Rio Grande.
From 1992-2002, the reservoir dropped and remained low during an extended drought. A tropical storm system in 2003-2004 brought increased rain to southwest Texas. By 2005, the lake was near the conservation pool level of 1117 feet above mean sea level.
The reservoir maintained near conservation pool levels into 2011, before beginning to decrease. Historic low lake levels were reached in 2013 due to the most recent period of drought. The International Boundary and Water Commission continues to release water from Amistad Dam to provide for municipal use and irrigation for both US and Mexican communities downstream along the Rio Grande.
Boat Ramp Status
Many boat ramps at Lake Amistad were closed as a result of the historic low lake levels in 2013. The National Park Service opens boat ramps as lake levels allow and it is safe to launch a boat from the ramp.
The lake reached its historic low on May 23, 2013, at a level of 1055.93 feet above mean sea level, which was 61.07 feet below the reservoir's conservation pool level of 1117 feet. One year later on May 23, 2014, the lake was at 1070.79 feet above mean sea level; up 14.86 feet from the historic low.
To find out which boat ramps are currently open, please visit the Boat Ramp Status chart.
Historical Data
The graph shows Amistad Reservoir’s water surface elevation from January, 2021.
Text only description of image: The graph shows Amistad Reservoir’s water surface elevation from 1968 to January, 2021. The vertical axis of the graph shows elevation from 1020 feet (311 meters) to 1150 feet (351 meters) with designations made at every 10 foot interval. The horizontal axis represents the years from 1968 to 2022 with designations made every 2 years.
Elevations demarcated on the graph include: Lowest Outlet at 283.5 meters, Spillway Crest at 1086.4 feet (331 meters), Conservation Pool Elevation at 1117 feet (340.46 meters), Bottom of Spillway Gates at Full Open at 345.64 meters, Top of Flood Control Pool at 347.59 meters, Top of Super Storage Pool at 348.78 meters, Bottom of Spillway Bridge Beams at 349.58 meters, Lowest Known Embankment Settlement Point at 350.79 meters, Bottom of Spillway Bridge at 350.95 meters.
Approximate Water Level Every Two Years:
1968 – 1020 feet
1970 – 1070 feet
1972 – 1100 feet
1974 – 1121 feet
1976 – 1118 feet
1978 – 1112 feet
1980 – 1116 feet
1982 – 1121 feet
1984 – 1115 feet
1986 – 1112 feet
1988 – 1119 feet
1990 – 1115 feet
1992 – 1124 feet
1994 – 1110 feet
1996 – 1075 feet
1998 – 1084 feet
2000 – 1081 feet
2002 – 1067 feet
2004 – 1086 feet
2006 – 1110 feet
2008 – 1109 feet
2010 – 1115 feet
2012 – 1108 feet
2014 – 1082 feet
2016 – 1093 feet
2018 – 1087 feet
2020 – 1070 feet
Noted Historic Levels
September 22, 1974 – 1135.66 feet
July 6, 2010 – 1129.86 feet
May 2013, Historic Low, 1055.9 feet
Storage at Conservation (in Thousand Cubic Meters)
1964 – 1980: 4,174,100 TCM
1981 – 1992: 4,173, 900 TCM
1993 – 2004: 3,883,160 TCM
2005 – Present: 4,036,250 TCM
(Decreases in water storage capacity due to silt accumulation.)
(Increases in storage capacity, consolidation of silt during drought.)
