The monitoring network within this area

Hydrionis holds 398 values from 4 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.

4
Gauges
398
Values held
1902–2025
Record spans
Gauges within the Upper Merced huc8 subbasin
4 monitoring points, positioned as the publisher records them.
Gauges within the Upper Merced huc8 subbasinMERCED R A HAPPY ISLES BRIDGE NR YOSEMITE CA, MERCED R A POHONO BRIDGE NR YOSEMITE CA, MERCED R A EXCHEQUER CA, MERCED R BL MERCED FALLS DAM NR SNELL CAMERCED R A HAPPY ISLES BRIDGE NR YOSEMITE CAMERCED R A POHONO BRIDGE NR YOSEMITE CAMERCED R A EXCHEQUER CAMERCED R BL MERCED FALLS DAM NR SNELL CA

Every gauge Hydrionis holds within this area

Gauges within the Upper Merced and what each holds
GaugeMeasuresValuesRecord
MERCED R BL MERCED FALLS DAM NR SNELL CAmean river flow1201902–2024
MERCED R A HAPPY ISLES BRIDGE NR YOSEMITE CAmean river flow1101916–2025
MERCED R A POHONO BRIDGE NR YOSEMITE CAmean river flow1091917–2025
MERCED R A EXCHEQUER CAmean river flow591902–1963

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 — 18040008. 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.

What each gauge’s link to this water rests on
GaugeEvidenceEstablished
MERCED R BL MERCED FALLS DAM NR SNELL CAStated 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/42026-08-26
MERCED R A HAPPY ISLES BRIDGE NR YOSEMITE CAStated 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/42026-08-26
MERCED R A POHONO BRIDGE NR YOSEMITE CAStated 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/42026-08-26
MERCED R A EXCHEQUER CAStated 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/42026-08-26

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.

Information-gain signals held for this water body
SignalHeldCounts
Gauges holding a real record4yes, 3 or more
Years spanned124yes, 20 or more
Values held398no
Distinct measurements1no
Publishers measuring it1no
Official identifiers1recorded, not counted

Where these figures come from

Spatially aggregatedHigh confidence2024

Source: USGSNational Water Information System, USGS site 11270900, 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.