SIERRA-FLOW // USGS Streamflow Processor

Run Statistics

Fetching USGS data...

30-Day Flow — All Stations

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Section I — Station Statistics (sorted by mean CFS)

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Section II — Alert & Percent-of-Normal Analysis

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Section III — Watershed Basin Roll-Up

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Build & Run

# Install GnuCOBOL
$ sudo apt install gnucobol            # Ubuntu / WSL
$ brew install gnucobol               # macOS

# Fetch live data + compile + run
$ python3 fetch_usgs.py               # pulls 30 days from USGS API
$ cobc -x -o sierra-flow SIERRA-FLOW.cob
$ ./sierra-flow && cat streamflow-report.txt

# GitHub Actions runs this automatically every morning at 7AM Pacific

About

What if the Western Regional Technical Service Center ran their streamflow analysis in 1987 — and the code was still running today?

SIERRA-FLOW is a COBOL program that reads live USGS discharge data, computes per-station statistics, flags threshold alerts, calculates percent-of-normal vs historical medians, determines 30-day flow trends, groups stations into watershed basins, and produces a formatted 132-column report. This page reads streamflow.csv — the same file COBOL processed — and renders everything live. Data updates every morning at 7AM Pacific via GitHub Actions. COBOL doesn't apologize.

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