A quick glance at the water-related facts that shape Idaho.
| State Water Surface Area |
880 Square Miles |
| Number Of Lakes |
More Than 2,000, Of Which 1,228 Have Been Named |
| Largest Lake -- Pend Oreille |
148 Square Miles |
| Deepest Lake -- Pend Oreille |
Sounded To A Depth Of 1,140 Feet |
| Highest Waterfall |
600 feet, Big Fiddler Creek, South Fork Boise River |
| Miles Of Streams and Rivers |
93,000 Miles |
| Number Of Named Rivers & Streams |
8,941 Plus 1,478 Named Springs |
| Longest River |
Snake River--779 Miles From Entry At The Wyoming Border To Exit At Washington
Border |
| Average Annual Precipitation |
Varies From Less than 10 to More than 60 Inches |
| Most Precipitation in 24-Hour Period |
7.7 inches of rain, Rattlesnake Creek, Idaho, 1909 |
| Annual Stream Inflow to State |
About 37 Million Acre-feet |
| Annual Stream Outflow from State |
About 75 Million Acre-feet |
| Irrigated Area of State |
3.3 Million Acres Of Which About 3.0 Million Is Irrigated From The Snake
River System |
| Highest Dam |
Dworshak, North Fork Clearwater, 717 feet |
| Active Reservoir Storage Capacity |
12,384,000 Acre-feet |
| Largest Active Storage Reservoir |
Dworshak -- 2,016,000 acre-feet |
| Snake Plain Aquifer Storage |
Top 100 Feet of Aquifer -- About 100 Million Acre-feet |
Water Management