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Level of the Lake

Water budget · Lake Buchanan

Up or down? Up. TWDB's daily storage for Lake Buchanan rose 221 acre-feet on Nov 13.

Where the water came from and where it went on Nov 13, the latest day with every figure published. LCRA publishes the dam’s daily release and what flowed in, and TWDB the lake’s daily storage, so all three are measured. The leftover line covers water with no meter (withdrawals, seepage, ungauged creeks) and is inferred from the other lines.

The lines above add up to the storage change: what the lake gained or lost. Every measured line is a published daily figure for Nov 13; evaporation is a long-term average.

Where it’s going

The release leg is LCRA's reported average release through Buchanan Dam for Nov 13. The withdrawals line is the budget’s leftover: city intakes, ungauged runoff and estimation error. The lines can overlap, so treat the split as approximate.

River flow toward the lake now

Swipe sideways to follow the river to the lake →

224 cfs224 cfsColorado224 cfsLake BuchananColorado incl. San Saba Riv…96% fullBuchanan storage
SteadyReceding · high water draining downOn the rise · climbing right nowInbound wave · big rise upstreamFlooding · NWS, by river heightNo current readingRising or falling is judged from each gauge’s last 48 hours, scaled to its river. Dot speed follows the flow. NWS flood status comes from river height and outranks direction.

Streamflow at the river gauge (USGS or LCRA, whichever is newer). Labels are gauge readings in cfs. Line width isn’t to scale.

How this is computed

Inflow is the water that reached Lake Buchanan on Nov 13: each gauged river's daily average where it enters the lake, as LCRA River Operations Report publishes them, in acre-feet per day (1 cfs ≈ 1.9835 af/day). Evaporation uses long-term monthly averages for the region over today’s lake surface. That surface area is TWDB’s daily survey where published, otherwise estimated from storage. With no storage reading, evaporation isn’t estimated. Inches on the lake divides each volume by that same surface area, so an inch takes less water when the lake is low and narrow than when it’s full and wide. Storage change is TWDB’s daily storage, compared with the day before. The leftover is what it takes to make the lines add up. It lumps together withdrawals and ungauged runoff, which can’t be split without data the operator doesn’t publish.

All inputs are provisional. This page is an estimate, not an official accounting.