Big Lost HUC8 17040218
A 6,355 km² sub-basin of the Pacific Northwest region in ID. Drought coverage is from the US Drought Monitor (map of 2026-10-13); streamflow classes place each USGS gauge's latest reading against its own day-of-year record.
Health score
57
Moderate
Drought index
205
Severe
Area in D2+
42.1%
0% exceptional (D4)
Gauges below normal
60%
of 5 reporting
Median flow
82%
p23 of record
Water assets
1,868
43 springs · 1,346 wells
USGS gauges (15)
- BIG LOST RIVER NR ARCO ID131325000 cfsp10 · below normal
- NF BIG LOST RIVER AT WILD HORSE NR CHILLY ID1312000028 cfsp23 · below normal
- BIG LOST RIVER BL MACKAY RES NR MACKAY ID1312700066 cfsp23 · below normal
- BIG LOST RIVER AT HOWELL RANCH NR CHILLY ID13120500104 cfsp38 · normal
- LOWER CEDAR CREEK AB DIVS NR MACKAY ID1312890011 cfsp55 · normal
- THOUSAND SPRINGS CREEK NR CHILLY ID131220005 cfsno long-term record
- WARM SPRINGS CREEK BELOW DIVERSION NR MACKAY ID1312426543 cfsno long-term record
- BIG LOST RIVER NR LESLIE ID1313030057 cfsno long-term record
- ANTELOPE CREEK NR DARLINGTON, ID1313100032 cfsno long-term record
- BIG LOST RIVER BELOW MOORE DIV NR MOORE ID131321000 cfsno long-term record
- BIG LOST RIVER AT ARCO AT SUNSET ROAD ID131323730 cfsno long-term record
- INL DIVERSION AT HEAD NEAR ARCO ID13132513no readingno long-term record
- BIG LOST RIVER BL INL DIV NEAR ARCO ID13132520no readingno long-term record
- BIG LOST R AT LINCOLN BLVD BRIDGE NR ATOMIC CITY13132535no readingno long-term record
- BIG LOST RIVER AB BIG LOST RIVER SINKS NR HOWE ID13132565no readingno long-term record
Recent conditions
| Date | DSCI | D2+ % | Gauges low | Flow pct |
|---|---|---|---|---|
| 2026-10-22 | 205 | 42.1 | 3/5 | p23 |
| 2026-10-21 | 205 | 42.1 | 3/5 | p23 |
| 2026-10-20 | 205 | 42.1 | 2/5 | p27 |
| 2026-10-19 | 205 | 42.1 | 2/5 | p34 |
| 2026-10-18 | 205 | 42.1 | 2/5 | p34 |
| 2026-10-17 | 205 | 42.1 | 2/5 | p36 |
| 2026-10-16 | 205 | 42.1 | 2/5 | p38 |
| 2026-10-15 | 241 | 50.84 | 1/5 | p39 |
| 2026-10-14 | 241 | 50.84 | 1/5 | p41 |
| 2026-10-13 | 241 | 50.84 | 1/5 | p41 |
| 2026-10-12 | 241 | 50.84 | 1/5 | p40 |
| 2026-10-11 | 241 | 50.84 | 2/5 | p28 |
| 2026-10-10 | 241 | 50.84 | 3/5 | p24 |
| 2026-10-09 | 241 | 50.84 | 3/5 | p25 |
Top water assets
- 69Warm Springs Creek Below Diversion Nr Mackay Idriver
- 69Big Lost River At Howell Ranch Nr Chilly Idriver
- 69Big Lost River Nr Leslie Idriver
- 69Antelope Creek Nr Darlington, Idriver
- 69Lower Cedar Creek Ab Divs Nr Mackay Idriver
- 69Nf Big Lost River At Wild Horse Nr Chilly Idriver
- 69Thousand Springs Creek Nr Chilly Idriver
- 69Big Lost River Bl Mackay Res Nr Mackay Idriver
- 69Kane Creekriver
- 69Rock Creekriver