# Van Genuchten–Mualem Retention, Conductivity & Moisture Capacity Evaluator

> Van Genuchten–Mualem Retention, Conductivity & Moisture Capacity Evaluator is a paid API for AI agents from detect.halowerk.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-11-04).

Computes water retention curve, hydraulic conductivity, and moisture capacity for a porous medium using the van Genuchten–Mualem model at specified pressure heads.

## Facts

- Endpoint: POST https://detect.halowerk.com/v1/F-TD2000-GEO-INDUSTRY-B008/van-genuchten-mualem-retention-conductivity-moisture-capacity?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/van-genuchten-mualem-retention-conductivity-moisture-capacity-evaluator-ceb249fe
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_l5rdX9cRCz7WlxGC-oP-s

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 van-genuchten-mualem-retention-conductivity-moisture-capacity-evaluator-ceb249fe -d '<json body>'
```

Example prompt: Evaluate the van Genuchten–Mualem retention and hydraulic conductivity for a soil with residual water content 0.034, saturated water content 0.46, alpha 0.016 cm⁻¹, n 1.37, saturated conductivity 0.0035 m/day, at pressure heads of -10, -100, -500, and -1000 cm.

## When to prefer this

Use this endpoint when you need a fast, deterministic computation of van Genuchten–Mualem soil hydraulic properties (retention, conductivity, moisture capacity) at specific pressure heads without setting up a local numerical solver. Ideal for validating soil parameterizations, populating lookup tables for simulation models, or integrating hydraulic property evaluation into agentic geotechnical or hydrological workflows.

## Known failure modes

- Invalid parameter ranges (e.g. n ≤ 1.01, alpha out of bounds) return validation errors
- Pressure head values outside [-1,000,000, 0] are rejected
- More than 32 pressure head values in array causes schema validation failure
- Missing required van Genuchten parameters returns a 400-level error
- Saturated water content below residual water content may cause computation errors

## How this service works

Evaluate retention, conductivity and moisture capacity of a specified porous medium model.

## Output

Returns computed water retention (volumetric water content), unsaturated hydraulic conductivity, and moisture capacity (derivative of water content with respect to pressure head) for each specified pressure head, based on the van Genuchten–Mualem parametric model.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "artifact": {
   "type": "object",
   "required": [
    "vanGenuchten"
   ],
   "properties": {
    "vanGenuchten": {
     "type": "object",
     "required": [
      "data",
      "claim"
     ],
     "properties": {
      "data": {
       "type": "object",
       "required": [
        "residual_water_content",
        "saturated_water_content",
        "alpha_inverse_length",
        "n",
        "saturated_conductivity",
        "pressure_heads"
       ],
       "properties": {
        "n": {
         "type": "number",
         "maximum": 10,
         "minimum": 1.01
        },
        "pressure_heads": {
         "type": "array",
         "items": {
          "type": "number",
          "maximum": 0,
          "minimum": -1000000
         },
         "maxItems": 32,
         "minItems": 1
        },
        "alpha_inverse_length": {
         "type": "number",
         "maximum": 1000,
         "minimum": 0.000001
        },
        "residual_water_content": {
         "type": "number",
         "maximum": 0.8,
         "minimum": 0
        },
        "saturated_conductivity": {
         "type": "number",
         "maximum": 10000,
         "minimum": 1e-12
        },
        "saturated_water_content": {
         "type": "number",
         "maximum": 1,
         "minimum": 0.000001
        }
       },
       "additionalProperties": false
      },
      "claim": {}
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/van-genuchten-mualem-retention-conductivity-moisture-capacity-evaluator-ceb249fe/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from detect.halowerk.com](https://www.zero.xyz/host/detect.halowerk.com/llms.txt)