Principal Finding
It Is As Dry As It Has Ever Been
The 17-year period 2009–2025 is, in terms of native Rio Grande basin water yield, essentially as dry as the driest 17-year period ever recorded since annual Rio Grande Compact water delivery accounting began. Native basin flows at Otowi averaged 716 KAF/yr recently versus 703 KAF/yr then, a difference of only 1.8%. Both periods produced native flows above 1 MAF in exactly 3 of 17 years. The apparent difference in total Otowi flow disappears almost entirely once San Juan-Chama Project imports are subtracted. Strip those out, and the two eras are hydrologically indistinguishable.
Principal Conclusion
Water Demands and the Effective Water Supply Stress Are Now Far Greater
Groundwater pumping from aquifers hydraulically connected to the Rio Grande exerts a persistent depletive effect on surface flows that was much lower during the 1948–1964 drought — making the effective water-supply stress today far greater than the raw Otowi flow numbers suggest. During 1948–1964, the Middle Rio Grande corridor had far fewer people and cities were much smaller: Albuquerque's population in 1950 was roughly 97,000; today the metropolitan area exceeds 900,000. Municipal, industrial, agricultural, and riparian water demand is dramatically greater today. Decades of heavy withdrawals from both the alluvial aquifer and the underlying Santa Fe Group aquifer have drawn down water tables throughout the Middle Rio Grande Valley.
Context
The San Juan-Chama Project Contributed Very Reliably Until Recent Years — Then Didn't
The San Juan-Chama Project (SJCP), a U.S. Bureau of Reclamation transmountain diversion first delivering water in 1971, imports Colorado River basin water through the Azotea Tunnel under the Continental Divide into Heron Reservoir, thence down the Rio Chama to the Rio Grande. Over 2009–2025, SJCP water recorded at the Otowi gage totaled approximately 1,206,000 AF — nearly 1.2 MAF — a very significant supplement during this dry era.
The Bureau of Reclamation originally contracted with New Mexico water users based on a stated "firm yield" of 96,200 AF/yr — the quantity it projected the project could deliver with reasonable certainty each year. Heron Reservoir's 400,000 AF capacity was designed to sustain deliveries through dry years by drawing on surplus stored during wet ones. Heron remained full or nearly full through much of the 1980s and 1990s. Under sustained drought, new inflows from the San Juan headwaters have fallen far short of contractor entitlements, and the reservoir buffer has been unable to compensate. The firm-yield promise has been superseded by climate change.
In 2025, total SJCP water at Otowi — including both current-year Heron releases and ABCWUA withdrawals of previously banked SJCP allocations from Abiquiu Reservoir — was only 40,000 AF.
SJCP Contractor Entitlements · Annual AF
Who Holds the Water
| Contractor |
AF/yr |
Share |
| — Municipal & Industrial — |
| Albuquerque Bernalillo County WUA | 48,200 | |
| Jicarilla Apache Nation | 6,500 | |
| City & County of Santa Fe | 5,605 | |
| Taos Pueblo | 2,215 | |
| Ohkay Owingeh | 2,000 | |
| County of Los Alamos | 1,200 | |
| City of Española | 1,000 | |
| Village of Taos | 575 | |
| Town of Belen | 500 | |
| Town of Bernalillo | 400 | |
| Village of Los Lunas | 400 | |
| Town of Red River | 60 | |
| El Prado Water & Sanitation Dist. | 40 | |
| Taos Ski Valley | 15 | |
| — Irrigation — |
| Middle Rio Grande Conservancy Dist. | 20,900 | |
| Pojoaque Valley Irrigation District | 1,030 | |
| Stated firm yield | 96,200 | |
| Source: NM OSE / USBR; minor allocations may vary by source. |