USGS · measured through 2019
286.4 MAF
Decline in recoverable High Plains Aquifer storage since predevelopment. The 2019 estimate of remaining water was 2.91 billion acre-feet; decline varies sharply by region.
USGS reportBeta floodwater recovery model
Protect people. Reduce flood damage. Move the most safe, eligible freshwater.
Test whether floodwater can be intercepted before it reaches saltwater and conveyed quickly to a verified reservoir, use or aquifer recharge site. This is a research and planning model; no flood-control benefit or transfer capacity has been demonstrated for a built system. Reservoir storage and power generation are potential destination benefits, subject to operating rules.
1 · Life safety
Protect people first. Never divert water in a way that raises flood risk elsewhere or impairs evacuation and emergency operations.
2 · Flood damage
Test flood peaks and timing at specific locations. Claim damage reduction only when a hydraulic model shows the diversion actually lowers exposure.
3 · Recover freshwater
Among safe options, move as much legally and physically available flood excess as practical to a receiving site that can accept it.
Some freshwater must continue downstream to sustain communities, existing water users and estuaries. The recoverable target is the verified flood excess after those needs, not every drop entering the sea.
Official reservoir readings · Bureau of Reclamation
Reservoir storage and hydropower
Water stored—
Change over 24 hours—
Reported Hoover release—
Above 950 ft minimum power pool—
Hoover powerplant generation
Report unavailableCheck Reclamation's power report for the latest reading.
How these numbers are calculated
The Bureau reports elevation in feet and storage in thousands of acre-feet (kAF). We multiply storage by 1,000. The 24-hour change is the latest elevation minus the reading at least 24 hours earlier. The power-pool margin is latest elevation minus 950 ft. Reported Hoover release is water passing the facility, not a measurement of recoverable floodwater.
Reclamation identifies 950 ft as the minimum effective Lake Mead power elevation. Actual generation also depends on water releases, head, equipment and operations. These readings cannot predict how much energy a proposed transfer would add.
Read Reclamation’s threshold definitions ↗These automated readings are provisional and may be revised by Reclamation. The page displays an unavailable state rather than retaining an old number without its timestamp.
The project priority · water moved per event
How much could reach a verified destination?
The Satsop supply design provides a documented 40 cfs equipment scale. Change the number of modules and event duration. Enter excess flow after downstream and ecological needs only if you have a defensible estimate for a specific river and event. These inputs are hypothetical, not operating permits or measured recovery.
Rated transport ceiling
80 cfs158.7 acre-feet over 24 hours at full rated flow.
Flow used in scenario
UnknownLesser of rated capacity and your eligible excess-flow input.
Illustrative delivered volume
Needs source estimateAfter the assumed delivery fraction; destination capacity remains unverified.
A reservoir can store transferred water only if a feasible route, water right and available space exist. Additional water does not by itself prove additional hydropower: generation depends on head, releases, equipment and operating rules. Scale a recharge target for the Ogallala · See the Satsop equipment example.
Compare the futures
What changes if a water-transfer program grows over time?
Choose the eligible fraction of a defined flood source, build-out rate, aquifer losses and costs. See both timelines and the evidence gaps behind the numbers.
Open the scenario comparison →What the records show
Evidence, with dates and limits
Project calculation · Harvey 2017
71.5 MAF
Gross precipitation in the connected area receiving at least five inches in the project’s NOAA Stage IV screening calculation. This is not an exact watershed total or available supply.
NOAA data source NOAA + USGS · computed Sep 2026
139 HUC12s
Harvey gross rainfall calculated over subwatersheds in five pilot basins. These are verified-source rainfall calculations, not measured runoff or recoverable supply. National 2022 totals remain pending.
Inspect the basin ledgerMAF = million acre-feet. The aquifer figure is a dated USGS benchmark; the 71.5 MAF Harvey figure is an older broad screening footprint. The new 139-row ledger covers only five identified pilot basins and must not be added to that screening figure.
New Harvey basin ledger · September 25, 2026
5 HUC8 basins · 139 HUC12 subwatersheds
Seven checksum-verified NOAA daily grids intersected with current USGS watershed polygons. See rainfall depth, gross acre-feet, coverage, exact HUC codes, method and original sources. A separate university HUC10 comparison remains available.
Explore the Harvey recordsNo hidden arithmetic
Seven gates before an acre-foot counts
Rain that hits the ground is only the beginning. Each step must be measured and independently checked before the project can claim delivered water or aquifer restoration.
Current status: Gross Harvey rainfall is calculated for five pilot HUC8 basins and 139 HUC12 units. It cannot yet be called legally and physically recoverable water.
- 1
Gross precipitation
NOAA Stage IV raster joined to official HUC8/HUC12 boundaries for five Harvey pilot basins.
139 HUC12 rows calculated - 2
Storm-attributable rain
Separate storm rain from background precipitation.
Pending - 3
Runoff and flood excess
Integrate event hydrographs. Rainfall is not river flow.
Pending - 4
Protected flow and rights
Reserve downstream, ecological and legally committed water.
Pending - 5
Capturable water
Check intake rate, debris, sediment and temporary storage.
Pending - 6
Delivered water
Subtract treatment, evaporation and conveyance losses.
Planning target only - 7
Credited benefit
Verify recharge or substitution without double counting.
Pending
Working planning tool
Size a pilot without pretending the water is available
Change the target, delivery efficiency and delivery days. The model calculates needed source storage and average flow. Its starting values come from the project’s reference case and are assumptions, not measured storm supply.
Modeled · pilot sizing only
What the pilot would need
Captured source water
312,500
acre-feet
Average delivery rate
700
cubic feet per second
At these assumptions, 62,500 acre-feet would be lost between capture and delivery. Storage must buffer the storm before steady delivery. This flow is an average after storage, not the storm-peak intake rate.
Show the math and limits
Required captured water = delivery target ÷ delivery efficiency.
Average flow (cfs) = delivered acre-feet × 43,560 ÷ (days × 86,400).
No event-water availability, protected downstream flow, water rights, intake capacity, recharge acceptance, energy use or cost has been established by this calculation. The result is a sizing exercise, not a recovery forecast.
The next defensible test
Start in Texas with historical Harvey rainfall and actual Lower Brazos and San Jacinto watershed boundaries. Test local storage and use before long-distance movement. Advance only when each gate passes.
Extend and audit the rainfall ledger
Five Harvey pilot basins are computed; check event timing and independent QA, then expand to other basins and storms.
Open evidence gateFlood-excess volume
Integrate hydrographs over time; subtract baseline and protected flows.
Open evidence gateStorage and recharge
Check intake rates, temporary storage, water quality and site-specific recharge.
Open evidence gateCost per credited acre-foot
Compare the full pilot with conservation, reuse and local alternatives.
Open evidence gateCheck the records yourself
Sources and project data
High Plains Aquifer storage reportU.S. Geological Survey · 2019 measurementsStage IV precipitation dataNOAA National Water Prediction ServiceWatershed Boundary DatasetU.S. Geological Survey · HUC12 boundariesAtlantic hurricane databaseNational Hurricane Center · storm tracksCurrent reservoir conditionsBureau of Reclamation · hourly readingsHoover powerplant generationBureau of Reclamation · accumulated MWhFreshwater flows to estuariesNOAA · downstream habitat
The Harvey ledger is a September 25 calculation from official rainfall grids and watershed boundaries. It does not establish storm runoff or recoverable supply.