USGS Water IV Fetch

Core Goal

• Fetch USGS Water Services iv data for one bounding box or explicit site list.
• Keep the call atomic: one request, one structured JSON payload, no follow-up site-discovery chain required.
• Return site metadata plus flattened time-series records that downstream normalization can map into hydrology observations.
• Keep runtime deterministic with retries, throttling, response-size caps, and validation summaries.

Repository Policy

• This is the canonical USGS station-hydrology skill in this repository.
• When eco-council or OpenClaw assigns a raw artifact path, write this skill's full JSON payload to that exact path with --output.
• Do not treat dry-run output as collected evidence.

Required Environment

• Configure runtime by environment variables in references/env.md.
• Start from assets/config.example.env.
• Load env values before running commands: