High Plains aquifer · regional scaling
What would scaling to the Ogallala take?
The High Plains aquifer includes the Ogallala. USGS estimated 286.4 million acre-feet of decline in recoverable storage from predevelopment to 2019, with about 2.91 billion acre-feet remaining. That is a historical regional benchmark, not a current reading or one refillable underground tank. Check the USGS report.
Interactive comparison · scenario assumptions
No transfer vs. a phased water program
Enter an estimate of candidate floodwater per year, then choose what fraction remains legally and physically eligible after protected flows. The percentage is applied to that annual candidate volume—not to the aquifer, total rainfall, or the ocean. The example values below are invented to demonstrate the arithmetic; they are not a forecast or project estimate.
Capacity exceeds eligible supply in year 30. The modeled modules could divert 4,760,331 AF over the entered flood days, but only 100,000 AF is assumed eligible. Growth beyond the supply or receiving limit buys hardware without adding water. Reduce the maximum or growth rate before treating the spending path as a sensible build-out.
Phased project spending
Unpriced
Cumulative through year 30; year 30: Unpriced.
No-transfer economic impact proxy
Unpriced
Cumulative through year 30; user-defined $/lost AF, not a government loss estimate.
Year-by-year timeline
| Year | Modules | Eligible AF | Diverted AF | Retained AF | No transfer MAF | Project MAF | Annual spend | Cumulative spend | No-transfer impact/year | Cumulative impact |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 2 | 100,000 | 4,760 | 2,666 | 2,905 | 2,905 | Unpriced | Unpriced | Unpriced | Unpriced |
| 5 | 12 | 100,000 | 28,562 | 15,995 | 2,885 | 2,885.04 | Unpriced | Unpriced | Unpriced | Unpriced |
| 10 | 93 | 100,000 | 100,000 | 56,000 | 2,860 | 2,860.27 | Unpriced | Unpriced | Unpriced | Unpriced |
| 15 | 710 | 100,000 | 100,000 | 56,000 | 2,835 | 2,835.55 | Unpriced | Unpriced | Unpriced | Unpriced |
| 20 | 2,000 | 100,000 | 100,000 | 56,000 | 2,810 | 2,810.83 | Unpriced | Unpriced | Unpriced | Unpriced |
| 25 | 2,000 | 100,000 | 100,000 | 56,000 | 2,785 | 2,786.11 | Unpriced | Unpriced | Unpriced | Unpriced |
| 30 | 2,000 | 100,000 | 100,000 | 56,000 | 2,760 | 2,761.39 | Unpriced | Unpriced | Unpriced | Unpriced |
Method: Each year’s eligible water = candidate water × selected share. Diversion = least of eligible water, 40 cfs × modules × flood days, and the optional receiving limit adjusted for delivery. Retained addition = diversion × delivery × aquifer retention. Both paths subtract the same assumed annual net decline; only the project path adds retained water. Storage is floored at zero. Capital is charged only for newly added modules. This repeats one annual source estimate every year and does not model storms, changing withdrawals, regional groundwater flow, reservoir operations or changing climate.
The USGS 2019 storage estimate is used only as a dated starting proxy. Scenario year 1 is not asserted to be 2020 or 2026. Blank receiving capacity does not mean unlimited capacity.
Adjust the assumptions · planning arithmetic
Scale a share of the historic decline
Choose a share of the USGS 2019 regional decline and the number of years available. “Operating days” means days with eligible floodwater each year, not 365 days of guaranteed supply. Delivery and retained-recharge fractions are assumptions to test, not measured site performance.
Reality check: This does not show available river floodwater, a route from that water to the aquifer, compatible water quality, land or water rights, site acceptance rate, capital cost, pumping power, or enough flood days. Continued groundwater withdrawals would add to the required rate; stopping losses through conservation may be essential. A Satsop module is an equipment-size comparison, not an approved design for the High Plains.
Evidence required before anyone funds construction
The interactive comparison runs on declared assumptions. To produce a financeable forecast, the following must refer to the same source, route, destination and period:
- Current aquifer storage by area, withdrawals, natural recharge and a defensible no-action trend.
- Multi-year event hydrographs at proposed intakes; baseline and legally protected downstream flows.
- Flood timing and volume after rights, water quality and intake restrictions, with dry-year uncertainty.
- Mapped routes, rights of way, surveyed lift, pump curves, energy demand and transfer losses.
- Site-specific infiltration or injection tests, water-quality treatment, permitted recharge and monitored storage response.
- Engineered capital, land, mitigation, staffing, maintenance, replacement, power and financing costs with contingencies.
- Valuation of actual avoided damages and comparison with conservation, reuse and local recharge alternatives.
A single national percentage cannot establish these conditions. The data-readiness ledger tracks what is loaded and what still requires field work. EPA recharge guidance and Reclamation cost-index guidance provide context, not project prices.
What turns the calculation into a testable project?
Start with one flood source and one reachable recharge site. Measure storm-period excess after protected downstream flows, test water quality and infiltration or injection capacity, then map the route and energy. Monitor groundwater storage response and subtract ongoing withdrawals. Regional numbers cannot substitute for any of those site measurements.