Lake Buchanan water level history
This page shows the Texas Water Development Board record for Lake Buchanan: 30,760 rows from June 30, 1937 through October 28, 2026. The rows are not all daily. The first 86 rows, from June 30, 1937 to August 31, 1942, are mostly one row per month. Daily rows run without a break from September 30, 1942, except for 34 missing days from January 30 to March 3, 2016 and two single missing days in 2012. Statistics on this page are computed from the rows as they exist in the file. The record is plotted against the reference marks LCRA publishes for the lake, in feet msl: the elevation when full, 1,020 feet, the overflow spillway at 1,020.35 feet, the historic high of 1,021.4 feet and the historic low of 983.7 feet. Nothing on this page is a forecast.
The whole record, 1937 to 2026
Loading the record…
The last row in the file is October 28, 2026, when the lake stood at 1018.33 feet above NAVD88 +0.26 (TWDB daily value). TWDB labels the file "Estimated daily average data" and calls its values best estimates. The source file is linked at the bottom of this page.
Where the last row sits in the record
On October 28, 2026, the last row in the file, the TWDB value was 1018.33 feet (NAVD88 +0.26). 26,025 of the 30,760 rows in the file are lower (84.6 percent), with the earliest of them on June 30, 1937. From September 30, 1942, when the rows become daily, 25,954 of the 30,674 rows are lower (84.6 percent). The file has a row for October 28 in 85 years, from 1942 to 2026. Among those 85 rows, the 2026 value ranks #11 highest (10 are higher). The median of the 85 rows is 1013.33 feet, so the 2026 value is 5.00 feet above that median. The lowest October 28 row is 986.30 feet, on October 28, 2014.
To check another date or elevation, use the two tools below. Both use the same TWDB file and run in your browser.
Check any date against the record
Pick a date between 1937-06-30 and 2026-10-28.
Check any elevation against the record
Enter an elevation in feet above NAVD88 +0.26, the TWDB datum.
The extremes the file actually contains
LCRA's dams-and-lakes page states a historic high of 1,021.4 feet on December 20, 1991 and a historic low of 983.7 feet on September 9, 1952. LCRA bases its table of lowest elevations on daily readings at 8 a.m. In the TWDB daily file, the highest row is 1021.26 feet on December 21, 1991. That number is 0.14 feet lower than the LCRA high, and its date is one day later. The lowest row on or after January 1, 1939 is 983.70 feet on September 9, 1952, the same number and the same date as the LCRA low. The lowest row in the whole file is 966.90 feet on September 30, 1937, during the first fill. LCRA values are in feet msl. TWDB values are daily values in feet above NAVD88 +0.26. This page does not treat them as one measurement.
LCRA publishes a table of the six lowest Lake Buchanan elevations, based on daily readings at 8 a.m. The list below puts each LCRA value next to the TWDB daily value for the same date. For 4 of the 6 dates the two numbers are equal. For September 20, 2013 and January 1, 2007 they differ.
Does Buchanan have a season?
Counting the 83 full calendar years from 1943 to 2025 (each has at least 300 daily rows; 2026 is not complete), and asking only which month carried each year's highest and lowest reading, June carries the annual high in 19 of those years (22.9 percent) and January carries the annual low in 19, with December next at 16. If each month had the same chance, each month would carry about 7 of them. When a year's high (or low) value occurs on more than one date, the earliest of those dates counts, and the counts above follow that rule.
Where these numbers come from
How this page calculates. Rows lower = the number of rows in the TWDB file with a water level below the value of the last row; percent = rows lower divided by all rows, times 100. Daily rows lower = the same count, using only rows from September 30, 1942. Same-date rank = 1 + the number of rows on the same month and day (one per year) with a higher value. Rows with an equal value share a rank. Median for the date = the middle value of those rows (the mean of the two middle values when the count is even), including the last row. Difference from the median = the value of the last row minus that median. Date check = the same counts, for the row of the date that you pick. Elevation check = the number of rows above the entered value, divided by all rows, times 100. LCRA comparison = the LCRA value next to the TWDB row of the same date, with no conversion between the two datums. LCRA values fetched from https://www.lcra.org/water/dams-and-lakes/ on 2026-10-29.
One value on this page needs its own note: the full-pool elevation. LCRA's dams-and-lakes page gives an elevation when full of 1,020 feet msl. The TWDB reservoir page gives a conservation pool elevation of 1,020.00 ft above NAVD88 +0.26 from November 1, 2024. A TWDB note dated June 12, 2025 says that, effective January 1, 2025, LCRA no longer operates Lake Buchanan to a seasonal conservation pool. This page uses 1,020 for its full-pool line. TWDB lists earlier conservation pool elevations of 1,020.50 ft until March 8, 1990, and 1,018.00 ft from May 1 to November 1 in the years from 1990 to 2024. Because the pool changed, this page compares elevations across years, not percent full. This site's lake registry, which the Lake Buchanan page uses, still carries 1,020.5 feet. A distance from full computed against 1,020.5 is 0.5 feet larger than one computed against 1,020. The datum label TWDB attaches to the daily file is NAVD88 +0.26, and LCRA's marks are stated in feet msl. This page does not claim the two are one measurement.
The chart and every rank come from the Texas Water Development Board daily file for Lake Buchanan (buchanan.csv) (the Water Data for Texas page for Lake Buchanan), fetched on 2026-10-29 at 01:13 UTC. A second download on 2026-10-29 at 02:49 UTC had the same 30,760 rows with the same values. The page prints the date of the last row in the file (October 28, 2026) rather than claiming to be live. The four reference lines come from LCRA's dams-and-lakes page, copied as published.
This chart plots TWDB's daily file. The live reading on the Lake Buchanan page comes from USGS site 08148000, a USGS gage operated in cooperation with LCRA. That page uses its instantaneous values. The two values can differ on the same day.
The TWDB file opens on June 30, 1937 at 968.90 feet. LCRA gives 1938 as the year Buchanan Dam was completed. The first row at 1,020.50 feet, the conservation pool elevation TWDB lists for that time, is July 27, 1938. This page treats the 20 rows before January 1, 1939 as the first fill. The chart, the count of lower rows, the same-date ranks and the two tools use every row in the file, from June 30, 1937. The count of lower daily rows uses only rows from September 30, 1942, and the season counts use only the 83 calendar years from 1943 to 2025. Two figures use only rows on or after January 1, 1939: the lowest row after the first fill, and the date tool's count of lower rows on or after that date.
For the live reading, the 24-hour change and the 30-day trend, see the Lake Buchanan water level page. A chart of the TWDB record for Lake Travis is also on this site.