About This Site
Where the Data Meets the Drift
Nerd on the Fly exists because the sites I needed when I started fly fishing didn't exist. You could find gear reviews or Instagram-worthy photos — but finding a site that told you whether the river was actually fishable today, in CFS, with a real explanation of what that number meant? That was harder.
The IT Guy Who Fishes
I've been in IT and for 20 years. I think in systems. When I started fly fishing a decade ago, I immediately wanted to understand the data behind it — not just "the fish are biting" but why, and whether I could predict it from publicly available information.
Turns out, the USGS has been publishing real-time stream gauge data for free for decades. The information to make a smart decision about whether a river is fishable has always been there. It just wasn't presented in a way that was useful to someone who doesn't speak hydrology.
This site is the resource I wished I had. It translates USGS gauge readings into plain-English condition ratings, combines that with a seasonal hatch calendar, and gives you an AI assistant that knows what the river is actually doing right now — not what it was doing last week when someone posted a trip report on a forum.
What This Site Is (and Isn't)
This site is
- → A real-time stream conditions dashboard for Colorado rivers
- → A seasonal hatch calendar with specific fly patterns and sizes
- → An AI advisor that knows the current CFS when you ask it a question
- → Beginner-focused without being condescending
This site is not
- → A gear review site or affiliate marketing play
- → A fishing report forum with week-old trip reports
- → A guide service or booking platform
- → A substitute for local knowledge (talk to the fly shop)
- → A multi-species resource — this site covers trout only
- → Professionally operated — it's a one-person project
How It Works
Every river page pulls live stream data from the USGS Water Services API — the same free, public data the National Weather Service uses. CFS, gauge height, and water temperature update every 15 minutes. When a USGS gauge goes dark, the site falls back to Colorado DWR telemetry so you still get a reading.
Weather data comes from the Open-Meteo API — current conditions plus a 3-day forecast for each river's location. The site flags fishing-relevant weather: incoming cold fronts, rain or snow runoff risk, and stable barometric windows worth planning around.
Raw data is only useful if you know what it means, so the site layers context on top. Each river gets a 0–10 fishability score (flow weighted at 60%, water temperature at 40%), a comparison of today's CFS against the long-term historical median, and a 7-day flow trend sparkline so you can see whether conditions are rising, falling, or holding steady.
The AI tools run on Anthropic's Claude API (Claude Haiku). There are six of them — Hatch Advisor, Gear Check, Trip Planner, Condition Explainer, Hatch Explainer, and Fish/Bug/Fly ID. Every tool is pre-loaded with the river's live conditions, seasonal hatch data, and water temperature context. They're not generic chatbots — they know what's happening on that river right now.
The whole thing is built on Next.js and hosted on Vercel. Deliberately simple — no database, no user accounts, no tracking beyond basic analytics. Just data and the tools to make sense of it.
Stream Data
USGS API
Weather
Open-Meteo
Backup Data
Colorado DWR
AI Tools
Claude Haiku
Framework
Next.js
Hosting
Vercel
Stay Connected
I post trip reports, hatch observations, and data nerdery on Instagram. If you notice something wrong with the site — a gauge that's returning bad data, a threshold that's off, a fly pattern that's definitely not right for a specific river — hit me up. This project improves with feedback from people actually on the water.
Stream data provided by the USGS Water Services API. Data is provisional and subject to revision. Condition ratings are based on general thresholds and local knowledge — always exercise your own judgment before entering any river. This site is not affiliated with the USGS, Anthropic, or any guide service.