# Natur River Anomaly Detector

> Natur River Anomaly Detector is a paid API for AI agents from natur.halowerk.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Compares a river gauge's recent readings against its historical baseline to detect extreme water levels and unusual rates of rise that may signal flooding

## Facts

- Endpoint: POST https://natur.halowerk.com/v1/river-anomaly
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/natur-river-anomaly-detector-97ffae42
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Wt0P8PDq3wwOIXo6WKmcI

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability natur-river-anomaly-detector-97ffae42 -d '<json body>'
```

Example prompt: Check gauge station USGS-01234500 for anomalies — tell me if the current reading of 4.2 meters is in the extreme percentile of its historical record, and whether its rate of rise over the past hour is more than 3 times the station's typical hourly change.

## When to prefer this

Choose this endpoint when you need to detect hydrological anomalies that are action-worthy before a flood crest arrives — particularly the rate-of-rise signal, which leads the absolute level. It is better than a simple threshold alert because it adapts to each station's own historical behavior rather than applying a fixed global cutoff. Prefer it over raw gauge data fetching when you need a decision-ready output that separates extreme levels from rapid-rise events by cause.

## Known failure modes

- Unknown or invalid gauge station ID returns an error with no findings
- Insufficient historical data for the reference period prevents percentile calculation
- Missing or malformed current reading or rate-of-rise input causes a validation error
- Rate-of-rise factor threshold set to zero or negative value may produce unexpected results
- Station with very short history may yield unreliable percentile comparisons

## How this service works

Compares the recent record of a gauge against its own longer history and reports three kinds of finding, kept separate because their causes differ. An extreme level is a reading in the top or bottom percentile of the reference period. An unusual rate of rise is a change per hour exceeding the station own typical rate by a stated factor — this is the figure that matters in a flood and it leads the level rather than following it, so it is reported even when the absolute value is still ordinary.

## Output

Returns up to three categorized findings: (1) whether the current level falls in an extreme percentile of the station's historical reference period, (2) whether the hourly rate of rise exceeds the station's typical rate by a specified factor, and (3) any third anomaly type with its cause distinguished from the others. Each finding is reported independently so users can act on leading indicators like rate-of-rise even when absolute levels are not yet extreme.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "site_id": {
   "type": "string",
   "maxLength": 20,
   "minLength": 6
  },
  "parameter": {
   "enum": [
    "discharge",
    "gauge_height"
   ],
   "type": "string",
   "default": "gauge_height"
  },
  "sensitivity": {
   "enum": [
    "low",
    "normal",
    "high"
   ],
   "type": "string",
   "default": "normal"
  },
  "recent_hours": {
   "type": "integer",
   "default": 24,
   "maximum": 168,
   "minimum": 2
  },
  "reference_days": {
   "type": "integer",
   "default": 60,
   "maximum": 365,
   "minimum": 7
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/natur-river-anomaly-detector-97ffae42/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from natur.halowerk.com](https://www.zero.xyz/host/natur.halowerk.com/llms.txt)