Prosser C Reservoir water level — California
Prosser C Reservoir in California was last measured at 5,723.51 ft (datum NGVD29), as of Aug 31, 2026, 1:00 AM (UTC-07:00) (USGS Water Services). Over its recent trend window the level has been falling (−4.5 ft). This reading is provisional and subject to revision.
- % of conservation pool full
- Not reported
- Storage
- 18,460 acre-ft
- Recent trend
- ↓Falling
−4.5 ft over the trend window
Recent trend
Readings this station published between Jun 2, 2026 and Aug 31, 2026 — a 89-day window — downsampled for display.
Data: USGS Water Services (waterservices.usgs.gov) and USACE CWMS Data (cwms-data.usace.army.mil), retrieved 2026-08-31. Both public domain (a work of the U.S. Government, 17 U.S.C. §105).
Source: USGS site 10340300 · USACE SPK/Prosser, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for this lake →
About this gauge's record
This site's drainage basin covers approximately 50 sq mi of contributing watershed. USACE's continuous storage record for this project begins in 2006 (2 tracked series for this project).
The dam behind Prosser C Reservoir
Prosser C Reservoir is held back by Prosser Creek Dam (also recorded as Prosser Creek Reservoir) , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 166 ft high and running 1,830 ft along its crest , built across PROSSER CREEK in Nevada County . It was completed in 1962 and modified in 2005H;2005S , and is owned by BUREAU OF RECLAMATION (a federal owner) , to a design credited to BUREAU OF RECLAMATION.
Its recorded primary purpose is water supply — delivering water to its customers comes first, so drawdown here follows demand as much as it follows rainfall .
Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. The spillway opening is 15 ft wide.
NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in.
At its normal pool the reservoir covers about 980 acres. NID records a maximum storage of 41,220 acre-ft against a normal storage of 29,840 acre-ft. Its maximum discharge capacity is 6,130 cubic feet per second.
Dam facts: National Inventory of Dams record CA10179 , filed by Bureau of Reclamation — U.S. Army Corps of Engineers, public domain. Water levels above come from USGS Water Services and are a separate source. (How this dam was matched to this gauge →)
How Prosser C Reservoir compares nearby
All 6 nearby lakes with a current trend are also falling, suggesting a regional pattern rather than an operation specific to this dam.
Nearby lakes
The six nearest published lakes by centroid distance (great-circle) — cross-state neighbors included.
| Lake | State | Level | Distance |
|---|---|---|---|
| Boca Reservoir | CA | 5,593.97 ft | 4 km |
| Martis Creek-Pool | CA | 5,781.49 ft | 6 km |
| Stampede Reservoir | CA | 5,922.31 ft | 11 km |
| Donner Lake | CA | 5,933.71 ft | 14 km |
| Independence Lake | CA | 6,947.30 ft | 15 km |
| Lake Tahoe | CA | 6,227.55 ft | 22 km |
Frequently asked questions
- What is the current water level of Prosser C Reservoir?
- As of Aug 31, 2026, 1:00 AM (UTC-07:00), the pool elevation was 5,723.51 ft (datum NGVD29), provisional and subject to revision. See the trend chart above for the recent direction.
- Is Prosser C Reservoir full right now?
- Its managing agency does not publish a %-of-conservation-pool-full figure for this lake, so we show the bare level rather than estimate one.
- Where does this data come from?
- From USGS site 10340300 · USACE SPK/Prosser, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00).
More in California
See every lake tracked in California, or read the methodology behind these figures.