Rivers into Lake Buchanan

224 cfs flowing in right now from the gauged river. Tap a river for its gauge page.

Where the water is flowing

Swipe sideways to follow the river to the lake →

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. LCRA’s daily storage for the lake changed +221 af ≈ +0.12 in on Nov 13.

The rivers, gauge by gauge

224cfs combined

Colorado River near San Saba
224 cfsLCRA · 5:40 PM CST

Gauged rivers only. Runoff below these gauges and ungauged arms aren’t counted. Streamflow: USGS or LCRA Hydromet, whichever reported last for each gauge (provisional). Flood status: NOAA/NWS, from river height at each gauge rather than flow.

Rain outlook

modeled

About 1.22 in forecast over the next 3 days, averaged across the basin, heaviest in the Lake area basin (1.74 in).

Open-Meteo model forecast for each basin that drains to the lake.

Last 24 hours at the rain gauges →Radar map →River inflow forecast →

How we know thisThe water budget: what came in and what went out

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.

River inflowmeasured
+326 af/day≈ +0.18 in/day on the lake
LCRA River Operations Report, daily averages for Nov 13: Colorado 165 cfs
Evaporationmodeled
−215 af/day≈ −0.12 in/day on the lake
Estimate from long-term averages over 22,127 surveyed acres (TWDB)
Dam releasemeasured
0 af/day≈ 0.00 in/day on the lake
LCRA River Operations Report: Buchanan Dam, daily average for Nov 13
Everything arriving that we can’t meter (ungauged creeks, springs)inferred
+110 af/day≈ +0.06 in/day on the lake
What’s left once the other rows and the storage change are counted

=Storage changemeasured
+221 af/day≈ +0.12 in/day on the lake
TWDB Water Data for Texas daily storage, Nov 13 vs. the day before

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

Evaporationmodeled
estimate from long-term averages
215 af/day≈ 108 cfs

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.

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.

The water budget on its own page →