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Arrowrock Reservoir water level

Reservoir, Idaho, United States

Directions

Normal for mid-October

Surface elevation

3,130.08ft Up 3.39 ft over the last 7 days

Water stored
76,505 acre‑ft
3,100 3,125 3,150

History

3,1003,1203,140ftOct 12Oct 13Oct 14Oct 15Oct 163,1003,1203,140ftOct 12Oct 14Oct 16
3,0803,1003,1203,140ftSep 19Sep 25Oct 2Oct 9Oct 163,0803,1003,1203,140ftSep 19Oct 2Oct 16
3,1003,1503,200ftOct 2025Jan 2026Apr 2026Jul 2026Oct 20263,1003,1503,200ftOct 2025Apr 2026Oct 2026
3,1003,1503,200ftOct 2016Apr 2019Oct 2021Apr 2024Oct 20263,1003,1503,200ftOct 2016Oct 2021Oct 2026
3,1003,1503,200ftJanMarMayJulSepNov20263,1003,1503,200ftJanAprJulOct2026

202120222023202420252026

Surface elevation Normal range (10–90 %)

What this means

Nothing unusual at Arrowrock Reservoir right now: the lake level of 3,130.08 ft is in the normal range for mid-October.

The median for mid-October is 3,129.26 ft, based on 36 years of readings, so the lake level is 0.82 ft above typical. On the same day last year the reading was 3,133.50 ft, a difference of −3.42 ft.

The water is rising: up 3.39 ft over the past week. Over the past 30 days it has moved between 3,125.51 ft and 3,130.99 ft.

Many reservoirs are drawn down through summer and fall; most of the refill comes later, with winter rain or spring snowmelt.

Compared with 36 years of daily readings for this time of year. How to read levels

Key numbers

Median for this date
3,129.26 ft0.82 ft above the median for this date
Normal for this date
3,093.55 ft – 3,145.21 ft8 years in 10 fall in this range (36 years of records)
Same day last year
3,133.50 ft−3.42 ft
Lowest and highest in 30 days
3,125.51 ft – 3,130.99 ft
Lowest and highest in 12 months
3,110.62 ft – 3,215.07 ft

Swimming and boating at Arrowrock Reservoir

At a normal level, ramps and marinas generally run as usual, and fishing tends to follow the season more than the water level.

If you swim, pick a spot with an easy way out, and remember that drop-offs move as the level changes.

Weather at the gauge

No rain in the last 3 days.

17 Sat 75° 49° – Wind 11 mph
18 Sun 71° 49° – Wind 7 mph
19 Mon 76° 53° – Wind 11 mph
20 Tue 73° 52° – Wind 10 mph
21 Wed 72° 54° 0.18 in, 28% Wind 14 mph
22 Thu 65° 51° 0.15 in, 55% Wind 9 mph
23 Fri 62° 47° – Wind 11 mph

Forecast: Open-Meteo

Sunrise 07:02 AM Sunset 05:57 PM Daylight 10 hr, 55 min First quarter 47%

Map

Nearby gauges

Gauge Level Compared with normal 24 hours Distance
Mores Creek above Robie Creek near Arrowrock DamRiver gauge, Mores Creek 1.86 ft Below flood stage ±0 4.9 mi
Lucky Peak LakeLake 2,945.52 ft Normal 8 mi
Boise River near Twin SpringsRiver gauge, Boise River 304 cfs Low −3.0 cfs 11 mi
Boise River at Glenwood Bridge near BoiseRiver gauge, Boise River 232 cfs Normal −7.0 cfs 18 mi
Boise River South Channel at EagleRiver gauge, Boise River South Channel 213 cfs Normal −10.0 cfs 22 mi
Eagle Drain at EagleCanal gauge, Eagle Drain 13.3 cfs Normal −1.0 cfs 23 mi
Canyon Creek at Oregon Trail Xing near Mountain HomeRiver gauge, Canyon Creek 0.0 cfs Very low ±0 26 mi
Payette River near Horseshoe BendRiver gauge, Payette River 803 cfs Low ±0 28 mi

Questions and answers

Is Arrowrock Reservoir higher than last year?

No, it is 3.42 ft lower than on the same day last year, when the reading was 3,133.50 ft.

What is a normal level for Arrowrock Reservoir in mid-October?

The median for mid-October is 3,129.26 ft. In 8 years out of 10 the reading falls between 3,093.55 ft and 3,145.21 ft, based on 36 years of records.

Is Arrowrock Reservoir really 3,130.08 ft deep?

No. 3,130.08 ft is the height of the water surface above sea level (or the agency's vertical datum), not the depth of the water.

What is the water level of Arrowrock Reservoir today?

On Oct 16, 2026, the surface elevation was 3,130.08 ft. Up 3.39 ft over the last 7 days.

Is Arrowrock Reservoir rising or falling?

Up 3.39 ft over the last 7 days.

Is the level of Arrowrock Reservoir normal?

Normal for mid-October. Compared with 36 years of daily readings for this time of year.

How often is this data updated?

The U.S. Bureau of Reclamation publishes a new reading once a day. This page refreshes within minutes of each update.

For specialists

Station codes, datum, parameters, data quality and downloads
Operator
U.S. Bureau of Reclamation
Station code
usbr:3642 (Agency page)
Coordinates
43.59520, -115.92300 (WGS84)
Update interval
once a day
Licence
Public domain. Data: U.S. Bureau of Reclamation (RISE), provisional data subject to revision

Published series

ParameterLast valueTime (UTC)Quality
Surface elevation 3,130.08 ft 2026-10-16 06:00 Provisional
Water stored 76,505 acre‑ft 2026-10-16 06:00 Provisional

Download

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How to cite

U.S. Bureau of Reclamation: Arrowrock Reservoir (usbr:3642). Accessed October 18, 2026 via Nivelmap, https://nivelmap.com/en/united-states/idaho/arrowrock-reservoir

How we check values

Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.

Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer