Level of the Lake

Rivers into Lake Travis

204 cfs flowing in right now from 4 gauged rivers. Tap a river for its gauge page.

Where the water is flowing

Swipe sideways to follow the river to the lake →

48 cfs143 cfsyesterday135 cfsyesterday152 cfs0 cfs556 cfsyesterday579 cfsyesterday4 cfs852 cfsyesterdayColorado48 cfsLlano152 cfsSandy Creek0 cfsPedernales4 cfs96% fullLake BuchananBuchanan Damin 48 · out 143 cfsnet −95 cfs ≈ -188 af/dayInks LakeInks DamLake LBJWirtz Damin 287 · out 556 cfsnet −269 cfs · level held steadyLake Marble FallsStarcke Dam90% fullLake Travisin 583 · out 852 cfsnet −269 cfs ≈ -0.36 in/day on the lakeLake Austinbelow Mansfield Dam
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 4 river gauges (USGS or LCRA, whichever is newer), plus yesterday's average dam releases (LCRA). Labels are gauge readings in cfs. Line width isn’t to scale. The lake’s net is worked out from these gauges (flow in minus flow out), so it misses ungauged creeks, evaporation and withdrawals.

The rivers, gauge by gauge

204cfs combined

75% of the inflow is coming from the Llano

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 0.71 in forecast over the next 3 days, averaged across the basin, heaviest in the Lakes area basin (1.17 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 thisToday’s water budget: what came in and what went out

Up or down? Down 0.82 ft over the last 7 days (LCRA lake level).

Where the water came from and where it went, at today’s rates. Dam releases and withdrawals have no complete public feed, so they land in the leftover line, which is inferred from the other lines.

  • River inflowmeasured
    +405 af/day≈ +0.28 in/day on the lake

    LCRA gauges, at current rates

  • Evaporationmodeled
    −317 af/day≈ −0.22 in/day on the lake

    Estimate from long-term averages over 17,583 surveyed acres (TWDB)

  • Everything leaving that we can’t meter (releases, withdrawals)inferred
    −2,148 af/day≈ −1.47 in/day on the lake

    What’s left once the other rows and the storage change are counted

  • =Storage changeinferred
    −2,060 af/day≈ −1.41 in/day on the lake

    The lake's level change over the last 7 days (−0.82 ft, LCRA), as a daily average, × 17,583 surveyed acres (TWDB)

The lines above add up to the storage change: what the lake gained or lost. Inflow is current; storage is the average over the last 7 days, so the leftover also absorbs any change in pace over that time.

That leftover is about 1,083 cfs leaving the lake, mostly dam releases and withdrawals, plus whatever the upstream gauges missed.

Where it’s going

  • Colorado River below the damsmeasured

    USGS gauge at Austin

    547 af/day≈ 276 cfs
  • Evaporationmodeled

    estimate from long-term averages

    317 af/day≈ 160 cfs
  • Withdrawals and other unmetered waterinferred

    the leftover from the budget above

    1,601 af/day≈ 807 cfs

Colorado River below the dams (USGS gauge at Austin) is measured downstream of the dam and stands in for releases. 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 converts current streamflow at the gauged tributaries (LCRA) to 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 the lake’s level change (LCRA) times that surface area, averaged per day over the last day for a once-a-day feed, otherwise over the last seven days. The leftover is what it takes to make the lines add up. It lumps together dam releases, 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 →