Exact still has limits.
A reviewed station can be a clean match for the report water while one reading still fails to represent every upstream or downstream reach.
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National source audit · Method v1 · August 10, 2026
The trout-stream monitoring gap.
We inventoried every BlueStreamFly river report to show what is measured, what is only nearby context, and what still needs reach review.
134of 459 report routes returned a USGS water-temperature observation no more than 24 hours old at the frozen audit time.
Pine Creek is one audited river—not a picture of national coverage.
This is a census of BlueStreamFly's 459 report routes in 38 states—not every trout stream or every state, tribal, university, watershed, or local sensor. The library includes trout, mixed, steelhead, salmon, and warmwater reports; 275 currently have a reviewed trout fishery profile.
What it means before you fish
A gauge is not the same as an answer.
The useful question is not simply “is there a number?” It is whether the number belongs to the water you plan to fish—and whether the signal you need exists today.
Surrogate means context.
A nearby, basin, or downstream gauge can show direction without proving clarity, wading safety, or temperature at your access point.
Flow is not temperature.
Current discharge can support a useful trend while water temperature remains unverified—especially important during summer heat.
Principal findings
The gap is signal coverage and reviewed reach fit.
402 routes point to 400 distinct configured USGS stations. Only 45 routes have a documented exact-control or surrogate relationship in this first release.
Current discharge
Route rows with a recent official discharge observation at the frozen audit time.
Current water temperature
The most important missing live signal for many summer trout decisions.
Current turbidity
Useful clarity-related context is uncommon and units cannot be combined casually.
RiverReports-only routes
Their observations stay out of this download until publication rights are documented.
Check a river
See what the report can actually measure.
Gauge fit and signal availability are separate. A clean discharge station can still have no current water-temperature reading.
459 rows · loaded only when you ask
The summary and state table are already on this page. Load the detailed audit to search individual rivers without adding a database request.
National distribution
How the 459 routes are classified.
Relationship describes gauge fit. It does not describe whether discharge, temperature, stage, or turbidity is current.
Reviewed exact controls
A documented control review matches the configured official station to the report water.
Reviewed surrogates
Useful basin, downstream, or nearby context—but not a precise read for every report reach.
Mapping review pending
An attached source exists, but its reach relationship has not earned a reviewed label.
No attached USGS gauge
No machine-readable USGS station is attached in BlueStreamFly; other monitoring may still exist.
Relationship unknown
No structured station relationship has been established, so the route is not labeled exact, surrogate, or ungauged.
State comparison
Temperature coverage varies sharply.
The table is the numeric equivalent of the comparison bars and remains useful without JavaScript.
| State | Reports | Exact controls | Surrogates | Pending / no gauge | Current discharge | Current temperature | Open reports |
|---|---|---|---|---|---|---|---|
| Maryland | 5 | 1 | 0 | 4 | 5 | 5 of 5 | State reports |
| Oklahoma | 1 | 0 | 1 | 0 | 1 | 1 of 1 | State reports |
| Oregon | 17 | 1 | 0 | 16 | 17 | 13 of 17 | State reports |
| Alaska | 9 | 1 | 0 | 8 | 8 | 6 of 9 | State reports |
| South Carolina | 6 | 1 | 0 | 5 | 6 | 4 of 6 | State reports |
| Connecticut | 2 | 1 | 0 | 1 | 2 | 1 of 2 | State reports |
| Georgia | 2 | 1 | 0 | 1 | 2 | 1 of 2 | State reports |
| Indiana | 2 | 1 | 0 | 1 | 1 | 1 of 2 | State reports |
| Montana | 26 | 1 | 0 | 25 | 25 | 13 of 26 | State reports |
| West Virginia | 10 | 1 | 0 | 9 | 7 | 5 of 10 | State reports |
| Wyoming | 12 | 1 | 2 | 9 | 11 | 6 of 12 | State reports |
| New York | 17 | 1 | 0 | 16 | 15 | 8 of 17 | State reports |
| North Carolina | 10 | 1 | 0 | 9 | 10 | 4 of 10 | State reports |
| Ohio | 5 | 1 | 0 | 4 | 5 | 2 of 5 | State reports |
| Arizona | 8 | 1 | 0 | 7 | 6 | 3 of 8 | State reports |
| Pennsylvania | 22 | 1 | 0 | 21 | 19 | 7 of 22 | State reports |
| Washington | 22 | 1 | 0 | 21 | 21 | 7 of 22 | State reports |
| Colorado | 58 | 1 | 1 | 56 | 41 | 15 of 58 | State reports |
| California | 48 | 1 | 1 | 46 | 40 | 12 of 48 | State reports |
| Michigan | 16 | 1 | 0 | 15 | 13 | 4 of 16 | State reports |
| Minnesota | 5 | 1 | 1 | 3 | 3 | 1 of 5 | State reports |
| New Jersey | 5 | 1 | 0 | 4 | 5 | 1 of 5 | State reports |
| Virginia | 16 | 1 | 0 | 15 | 14 | 3 of 16 | State reports |
| Wisconsin | 13 | 1 | 0 | 12 | 11 | 2 of 13 | State reports |
| Arkansas | 7 | 1 | 0 | 6 | 6 | 1 of 7 | State reports |
| New Hampshire | 7 | 1 | 0 | 6 | 6 | 1 of 7 | State reports |
| New Mexico | 8 | 1 | 0 | 7 | 8 | 1 of 8 | State reports |
| Idaho | 33 | 1 | 0 | 32 | 32 | 4 of 33 | State reports |
| Utah | 9 | 1 | 2 | 6 | 9 | 1 of 9 | State reports |
| Tennessee | 10 | 1 | 0 | 9 | 7 | 1 of 10 | State reports |
| Kentucky | 1 | 1 | 0 | 0 | 1 | 0 of 1 | State reports |
| Maine | 9 | 1 | 0 | 8 | 4 | 0 of 9 | State reports |
| Massachusetts | 6 | 1 | 0 | 5 | 6 | 0 of 6 | State reports |
| Missouri | 3 | 1 | 0 | 2 | 3 | 0 of 3 | State reports |
| Nevada | 1 | 1 | 0 | 0 | 1 | 0 of 1 | State reports |
| South Dakota | 13 | 1 | 0 | 12 | 13 | 0 of 13 | State reports |
| Texas | 9 | 1 | 0 | 8 | 9 | 0 of 9 | State reports |
| Vermont | 6 | 1 | 0 | 5 | 4 | 0 of 6 | State reports |
Where uncertainty comes from
“Not found” is not “does not exist.”
Reach fit
A station can be on the right river but still sit below a tributary, reservoir, diversion, or the reach you plan to fish.
Signal fit
USGS may report stage without discharge, or discharge without current water temperature or turbidity.
Source fit
State, tribal, university, watershed, hydropower, and local sensors may exist outside this official USGS probe.
Provisional data
Recent USGS observations can be provisional and may change after quality review.
Method and limits
Frozen inputs. Reproducible counts. Visible caveats.
Method v1 compares the frozen canonical report registry with official USGS monitoring-location, time-series, and latest continuous records. Current means no more than 24 hours old at the audit instant.
Observation window: Aug 8, 2026, 1:33 AM UTC through Aug 10, 2026, 1:33 AM UTC. Frozen audit instant: Aug 10, 2026, 1:33 AM UTC.
Capture note: a dated official USGS capture was normalized offline to the exact 400 configured stations. No second provider request or numeric observation values were added; fields the earlier capture did not preserve remain blank instead of being inferred.
- 01
Freeze the report universe
Every canonical route appears once. The build fails if route counts, duplicates, or the frozen catalog checksum change unexpectedly.
- 02
Deduplicate stations
402 mapped routes resolve to 400 configured station IDs before coverage is counted.
- 03
Keep dimensions separate
Mapping review, source agreement, station recency, metadata revision state, reach review, and each monitored parameter remain independent.
- 04
Publish the limits
No RiverReports-only values are republished. Forecast precipitation is not measured rainfall. Station observations are not field-verified fishing outcomes.
Download, cite, correct
Use the finding. Keep the caveat.
BlueStreamFly Editorial Team. “The Trout-Stream Monitoring Gap: A 459-River Audit of U.S. Flow and Water-Temperature Data.” Method v1, August 10, 2026.
Attribute BlueStreamFly's compiled analysis separately from the underlying public-domain USGS records. Do not describe this as a census of every U.S. stream sensor.
Use it for today's decision