Two Rivers Reservoir (Diamond A Dam)
Two Rivers Reservoir (Diamond A Dam) held 0 acre-feet on Oct 16, 2026: it is empty, as a dry dam normally is.
A dry flood-control dam: no permanent pool, and water only while a flood is held back. On Rio Hondo. Pecos basin.
The latest reading for this reservoir is from Oct 16, 2026, older than most others.
These dams are empty by design. They store water only while holding back a flood and release it afterwards, so zero is normal and the news is when they are not zero.
Last 365 days
Water held, in acre-feet.
Show the data as a table
Year by year
The most, average and least water held in each calendar year, in acre-feet. The latest year is partial.
- Most
- Average
- Least
Show the data as a table
Readings are what the operating agencies report; we have not audited the latest values. Reclamation labels its data "provisional and subject to revision unless otherwise noted."
Year-by-year table, with how well capacity is known
| Year | Days | Most (acre-feet) | Average | Least | Capacity figure |
|---|---|---|---|---|---|
| 2026 | 289 | 1,010 | 32 | 0 | The operator's current table fits the record |
| 2025 | 365 | 437 | 8 | 0 | The operator's current table fits the record |
| 2024 | 366 | 445 | 6 | 0 | The operator's current table fits the record |
| 2023 | 365 | 8 | 0 | 0 | The operator's current table fits the record |
| 2022 | 365 | 1,415 | 26 | 0 | The operator's current table fits the record |
| 2021 | 365 | 1,111 | 53 | 0 | The operator's current table fits the record |
| 2020 | 366 | 0 | 0 | 0 | The operator's current table fits the record |
| 2019 | 365 | 32 | 0 | 0 | The operator's current table fits the record |
| 2018 | 365 | 0 | 0 | 0 | The operator's current table fits the record |
| 2017 | 59 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2016 | 366 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2015 | 365 | 204 | 2 | 0 | Before elevation records began; capacity extrapolated |
| 2014 | 365 | 1,200 | 26 | 0 | Before elevation records began; capacity extrapolated |
| 2013 | 365 | 1,370 | 28 | 0 | Before elevation records began; capacity extrapolated |
| 2012 | 366 | 104 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2011 | 365 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2010 | 365 | 629 | 7 | 0 | Before elevation records began; capacity extrapolated |
| 2009 | 365 | 227 | 1 | 0 | Before elevation records began; capacity extrapolated |
| 2008 | 366 | 1,328 | 10 | 0 | Before elevation records began; capacity extrapolated |
| 2007 | 365 | 6 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2006 | 365 | 1,278 | 103 | 0 | Before elevation records began; capacity extrapolated |
| 2005 | 365 | 248 | 1 | 0 | Before elevation records began; capacity extrapolated |
| 2004 | 92 | 49 | 1 | 0 | Before elevation records began; capacity extrapolated |
| 2003 | 273 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2002 | 365 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 2001 | 92 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 1999 | 273 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 1998 | 365 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 1997 | 365 | 651 | 3 | 0 | Before elevation records began; capacity extrapolated |
| 1996 | 366 | 1,600 | 23 | 0 | Before elevation records began; capacity extrapolated |
| 1995 | 92 | 0 | 0 | 0 | Before elevation records began; capacity extrapolated |
| 1991 | 273 | 1,150 | 67 | 0 | Before elevation records began; capacity extrapolated |
| 1990 | 92 | 407 | 45 | 0 | Before elevation records began; capacity extrapolated |
About this reservoir
One of the two dry flood control dams of the Army Corps' Two Rivers project west of Roswell, completed in 1963, protecting the city from Rio Hondo floods. It holds water only during storms.
How to use these numbers
- Rio Hondo flood events. Peak storage and days impounding record floods off the Sacramento Mountains' east slope.
Read before quoting a number
- Percent full is not meaningful for a dry dam.
- The Corps' combined Two Rivers series carries a constant offset against its own table, so Diamond A and Rocky are reported separately.
The dam
| Dam | Diamond A Dam, Two Rivers project |
|---|---|
| Owner | USACE - Albuquerque District (Federal) |
| Operated with | US Army Corps of Engineers |
| Type | Earth |
| Purposes, per the dam registry | Flood Risk Reduction, Other |
| Completed | 1963 |
| Height | 118 feet |
| Hazard class | High |
| Registry capacity | 264,400 acre-feet at most, 168,000 normal. Owner-reported and not corrected for sediment. |
National Inventory of Dams, U.S. Army Corps of Engineers.
How capacity is known
Capacity comes from the operator's elevation-to-storage table (USACE, effective 2023-01-01), checked against the storage the operator reports. Since the table took effect, it reproduces reported storage from reported elevation to within 0 acre-feet in the median (0.00% of storage), across 1,385 days. Where an older table was in force, we recover its capacity from the record and say how well supported it is.
| Pool | Elevation (ft) | Capacity now (acre-feet) | Where it comes from |
|---|---|---|---|
| Top of conservation pool | 3,965 | 0 | CWMS level Diamond A.Elev.Inst.0.Top of Conservation dated 2025-03-03 |
| Top of flood poolused as 100% | 4,032 | 29,505 | CWMS level Diamond A.Elev.Inst.0.Top of Flood dated 1900-01-01 |
| Top of dam | 4,054 | 70,542 | CWMS level Diamond A.Elev.Inst.0.Top of Dam dated 1900-01-01 |
Rivers
Data and sources
Record from 1990 (33 years with readings), through Oct 16, 2026. Where several agencies report the same reservoir, we take each day's value from the first in this list that has one:
- U.S. Geological Survey NWIS: 7,090 days
- U.S. Army Corps of Engineers CWMS: 3,211 days
Year by year (CSV) ยท Last 365 days (CSV)
Credit: U.S. Army Corps of Engineers CWMS; U.S. Geological Survey NWIS; National Inventory of Dams (U.S. Army Corps of Engineers). Capacity analysis by New Mexico Water. Data accessed November 4, 2026.