U.S. Bureau of Reclamation
Reservoir storage and operations for federal projects in the Snake and Boise river basins.
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Idaho reservoir storage
Daily storage, read on the newest day every reservoir reports and on 30 September each year, and active (usable) storage capacity, for the Bureau of Reclamation reservoirs on the Snake, Boise, Payette, Weiser, and Clearwater systems that serve Idaho irrigation, plus Jackson Lake and Grassy Lake in Wyoming, which are administered as upstream Snake River System storage for Idaho delivery.
- Organization
- U.S. Bureau of Reclamation
- Dataset
- Pacific Northwest Hydromet, reservoir storage
- Geography
- Idaho (statewide; two of the 21 reservoirs, Jackson Lake and Grassy Lake, are physically sited in Wyoming)
- Time coverage
- 1910-2026 (30 September storage, varies by station); the newest daily reading and the same day a year earlier (latest storage); 2013 (capacity)
- Update frequency
- Daily at the publisher (latest storage, refreshed here every two weeks or sooner); annual (30 September storage); irregular (capacity, revised only after events such as a sedimentation survey)
- Original file
- https://www.usbr.gov/pn-bin/daily.pl
- Methodology
- https://www.usbr.gov/pn/hydromet/station.js
- License
- Public domain. U.S. federal government work.
- Our copy
- Pacific Northwest Hydromet, reservoir storage
Caveats
- Storage is read on 30 September, the approximate close of Idaho's irrigation season, and is provisional Hydromet data subject to revision.
- The latest storage is as current as this site's last refresh of the data, not a live reading; the page names the day it is from. The average for that date is computed by Understand Idaho from the 1991-2020 daily readings, for the reservoirs that reported all 30 years, and is not a figure Reclamation publishes in this form.
- Active capacity figures come from Reclamation's May 2013 Monthly Reservoir Status Report, the only edition still served; capacity changes only rarely.
- Active capacity has no figure for four of the 21 reservoirs: Black Canyon, Henrys Lake, Payette Lake and Lake Waha.
- Jackson Lake and Grassy Lake sit in Wyoming but are included as upstream Snake River System storage released for delivery to Idaho irrigators.
- Magic Reservoir is grouped with these systems in general reporting but is a State of Idaho project, not Reclamation's, and is not included.
- Hydromet publishes some storage readings below zero, meaning the water stood below the level Reclamation counts contents from; they are carried as published. Anderson Ranch (1946 to 1949) and Lake Cascade (1948 and 1949) read negative while the reservoirs first filled, and Mann Creek read -224 acre-feet on 30 September 2013, after a dry summer drew it down from about 3,000 acre-feet in early August.
- Storage is stored to one decimal acre-foot as published; capacity is converted from the report's thousand-acre-foot column to acre-feet.
Measures
- Reservoir storage (acre feet): Reservoir contents on 30 September each year, from Reclamation's Hydromet daily archive.
- Latest reservoir storage (acre feet): Reservoir contents on the newest day every reservoir has reported, and on the same calendar day a year earlier, from Reclamation's Hydromet daily archive.
- Average storage for the date, 1991-2020 (acre feet): The mean of a reservoir's 1991-2020 daily readings on the same calendar day as the latest storage, for reservoirs that reported all 30 years. Computed by Understand Idaho from Reclamation's Hydromet daily archive.
- Reservoir active capacity (acre feet): Active (usable) storage capacity, from Reclamation Pacific Northwest Region's Monthly Reservoir Status Report.
This page was last updated .