San Francisco Bay
5 monitoring stations within this area in United States, holding 284 values between 1913 and 2025. A United States federal hydrologic unit at the eight-digit subbasin level — a drainage area, not a river. Many subbasins take the name of the largest river within them, and the gauges below are anywhere inside the area, including on tributaries.
The monitoring network within this area
Hydrionis holds 284 values from 5 gauges within it. Discharge is a property of a gauge and its reach, not of this drainage area, so this page reports the network and its records rather than a single figure.
Every gauge Hydrionis holds within this area
| Gauge | Measures | Values | Record |
|---|---|---|---|
| DRY C A UNION CITY CA | mean river flow | 67 | 1917–2024 |
| ARROYO VALLE NR LIVERMORE CA | mean river flow | 56 | 1970–2025 |
| ALAMEDA C NR NILES CA | mean river flow | 56 | 1970–2025 |
| ARROYO MOCHO NR LIVERMORE CA | mean river flow | 55 | 1913–2001 |
| ARROYO DE LA LAGUNA A VERONA CA | mean river flow | 50 | 1970–2024 |
How these gauges were attached to this water
Assigned by the publisher to a numbered basin Every gauge here is assigned to this drainage area by its own publisher, which issues the area an official code — 18050004. A drainage area is not a river: it contains the tributaries as well as the main channel, and a gauge in it may be on any of them.
| Gauge | Evidence | Established |
|---|---|---|
| DRY C A UNION CITY CA | Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4 | 2026-08-26 |
| ARROYO VALLE NR LIVERMORE CA | Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4 | 2026-08-26 |
| ALAMEDA C NR NILES CA | Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4 | 2026-08-26 |
| ARROYO MOCHO NR LIVERMORE CA | Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4 | 2026-08-26 |
| ARROYO DE LA LAGUNA A VERONA CA | Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4 | 2026-08-26 |
What this record holds
Hydrionis decides which waters get a page, and which of those are offered to search, from what is actually held rather than from how the page reads. Five signals are counted; this record has 2 of them, which makes it a profile, not indexed.
| Signal | Held | Counts |
|---|---|---|
| Gauges holding a real record | 5 | yes, 3 or more |
| Years spanned | 113 | yes, 20 or more |
| Values held | 284 | no |
| Distinct measurements | 1 | no |
| Publishers measuring it | 1 | no |
| Official identifiers | 1 | recorded, not counted |
Where these figures come from
Source: USGS — National Water Information System, USGS site 11180500, parameter 00060, annual mean statistics. Licence: Open.
Method: Annual mean discharge as published by the USGS statistics service, computed by USGS from its own quality-controlled daily record. Hydrionis converts cubic feet per second to cubic metres per second and records the publisher unit alongside; it does not recompute the mean.
Data from the U.S. Geological Survey National Water Information System, a work of the United States government and therefore in the public domain.
Retrieved 24 August 2026.