Costilla Reservoir
Costilla Reservoir held 1,680 acre-feet on Nov 4, 2026. It has no capacity figure we can check, so we show acre-feet only.
A storage reservoir: it holds water for later release. On Rio Costilla. Rio Grande basin.
For these reservoirs the only capacity figure is the owner's own estimate of normal storage, which has not been corrected for sediment and was not checked against the operator's measurements. We show how much water they hold, in acre-feet, and no percent.
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 | 308 | 3,660 | 2,040 | 677 | Owner-reported normal storage |
| 2025 | 365 | 6,135 | 3,409 | 1,303 | Owner-reported normal storage |
| 2024 | 366 | 6,829 | 4,279 | 1,442 | Owner-reported normal storage |
| 2023 | 365 | 12,010 | 6,852 | 3,199 | Owner-reported normal storage |
| 2022 | 365 | 6,214 | 4,541 | 2,874 | Owner-reported normal storage |
| 2021 | 365 | 6,788 | 3,931 | 2,424 | Owner-reported normal storage |
| 2020 | 366 | 9,186 | 4,867 | 1,329 | Owner-reported normal storage |
| 2019 | 365 | 11,240 | 6,094 | 2,791 | Owner-reported normal storage |
| 2018 | 365 | 12,770 | 7,032 | 1,813 | Owner-reported normal storage |
| 2017 | 365 | 14,200 | 9,341 | 5,311 | Owner-reported normal storage |
| 2016 | 366 | 12,430 | 8,568 | 4,234 | Owner-reported normal storage |
| 2015 | 365 | 12,670 | 7,760 | 3,260 | Owner-reported normal storage |
| 2014 | 365 | 5,949 | 3,667 | 2,017 | Owner-reported normal storage |
| 2013 | 365 | 4,282 | 2,740 | 1,458 | Owner-reported normal storage |
| 2012 | 366 | 5,474 | 2,753 | 1,328 | Owner-reported normal storage |
| 2011 | 365 | 9,916 | 5,402 | 1,329 | Owner-reported normal storage |
| 2010 | 365 | 15,690 | 9,237 | 6,426 | Owner-reported normal storage |
| 2009 | 365 | 15,520 | 9,617 | 5,457 | Owner-reported normal storage |
| 2008 | 366 | 15,180 | 10,343 | 7,369 | Owner-reported normal storage |
| 2007 | 365 | 15,950 | 9,559 | 5,712 | Owner-reported normal storage |
| 2006 | 365 | 12,320 | 7,719 | 3,568 | Owner-reported normal storage |
| 2005 | 365 | 16,240 | 8,745 | 3,768 | Owner-reported normal storage |
| 2004 | 366 | 10,490 | 5,370 | 2,245 | Owner-reported normal storage |
| 2003 | 365 | 5,361 | 3,620 | 2,215 | Owner-reported normal storage |
| 2002 | 365 | 6,110 | 3,062 | 535 | Owner-reported normal storage |
| 2001 | 365 | 11,400 | 5,800 | 2,900 | Owner-reported normal storage |
| 2000 | 366 | 16,000 | 9,509 | 2,630 | Owner-reported normal storage |
| 1999 | 365 | 16,100 | 11,328 | 5,400 | Owner-reported normal storage |
| 1998 | 365 | 11,000 | 6,724 | 3,200 | Owner-reported normal storage |
| 1997 | 365 | 11,500 | 5,840 | 2,500 | Owner-reported normal storage |
| 1996 | 366 | 13,300 | 6,846 | 1,020 | Owner-reported normal storage |
| 1995 | 365 | 16,500 | 10,294 | 6,360 | Owner-reported normal storage |
| 1994 | 365 | 16,500 | 8,215 | 4,210 | Owner-reported normal storage |
| 1993 | 365 | 10,600 | 5,169 | 2,530 | Owner-reported normal storage |
| 1992 | 366 | 9,020 | 5,074 | 1,580 | Owner-reported normal storage |
| 1991 | 275 | 8,230 | 5,365 | 3,400 | Owner-reported normal storage |
About this reservoir
A privately owned irrigation reservoir in the Sangre de Cristo high country, built in 1920 and operated by the Rio Costilla Cooperative Livestock Association. Its water is shared with Colorado under the Costilla Creek Compact.
How to use these numbers
- High-elevation snowpack. Spring fill tracks snowmelt from some of the state's highest terrain.
Read before quoting a number
- Storage only, and percentages use the owner-reported normal storage, which observed storage exceeds in wet years.
The dam
| Dam | Costilla Dam |
|---|---|
| Owner | Rio Costilla Cooperative Livestock Association (Private) |
| Type | Earth |
| Purposes, per the dam registry | Irrigation |
| Completed | 1920 |
| Height | 138 feet |
| Hazard class | High |
| Registry capacity | 30,499 acre-feet at most, 15,830 normal. Owner-reported and not corrected for sediment. |
National Inventory of Dams, U.S. Army Corps of Engineers.
How capacity is known
The only capacity figure is the owner-reported normal storage, 15,830 acre-feet. National Inventory of Dams normal storage (owner-reported, not sediment-corrected) Because it is not an operator's measured table, we show water held in acre-feet and no percent.
Rivers
Data and sources
Record from 1991 (36 years with readings), through Nov 4, 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: 13,002 days
Year by year (CSV) ยท Last 365 days (CSV)
Credit: 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.