# U.S. Geological Survey Aquifer Codes API

**Canonical:** https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-aquifer-codes-api/  
**Provider:** U.S. Geological Survey — https://apis.io/providers/u-s-geological-survey/  
**Base URL:** https://earthquake.usgs.gov/fdsnws/event/1  
**Documentation:** https://www.usgs.gov/tools/asset-identifier-service-ais

U.S. Geological Survey Aquifer Codes API is one of 47 APIs that [U.S. Geological Survey](https://apis.io/providers/u-s-geological-survey/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. This API exposes 3 JSON Schema definitions. Tagged areas include aquifer-codes. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, a getting-started guide, a JSON-LD context, authentication docs, and 3 JSON Schemas.

Local aquifers in USGS data are identified by an aquifer name and geohydrologic unit code (a three-digit number related to the age of the formation, followed by a 4 or 5 character abbreviation for the geologic unit or aquifer name). For the age of formation (aquifer age), generally the smaller the number represents the younger the geohydrologic unit. Aquifer names and the definition of an aquifer can be very subjective. One rock unit may be called different aquifer names by different people. Local aquifers and layered aquifers are often grouped into larger named regional aquifers or aquifer systems. For example, the National Northern Atlantic Coastal Plain aquifer system (National aquifer) consists of five layered regional aquifers. Each regional aquifer is divided into two or more aquifers which may have a different name in each of the states in which the aquifer is found.

## Operations (8)

| Method | Path | Summary |
|---|---|---|
| GET | `/collections/aquifer-codes` | Get Aquifer codes metadata |
| GET | `/collections/aquifer-codes/items` | Get Aquifer codes items |
| OPTIONS | `/collections/aquifer-codes/items` | Options for Aquifer codes items |
| POST | `/collections/aquifer-codes/items` | Get Aquifer codes items with CQL2 |
| GET | `/collections/aquifer-codes/items/{featureId}` | Get Aquifer codes item by id |
| OPTIONS | `/collections/aquifer-codes/items/{featureId}` | Options for Aquifer codes item by id |
| GET | `/collections/aquifer-codes/queryables` | Get Aquifer codes queryables |
| GET | `/collections/aquifer-codes/schema` | Get Aquifer codes schema |

## Machine-readable artifacts (13)

- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/openapi/u-s-geological-survey-aquifer-codes-api-openapi.yml
- **Conformance** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/conformance/u-s-geological-survey-conformance.yml
- **Documentation** — https://earthquake.usgs.gov/fdsnws/event/1/
- **GettingStarted** — https://earthquake.usgs.gov/earthquakes/feed/
- **JSONSchema** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/json-schema/usgs-earthquake-api-earthquake-properties-schema.json
- **JSONLD** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/json-ld/usgs-earthquake-api-context.jsonld
- **Examples** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/examples/usgs-earthquake-api-earthquake-properties-example.json
- **Documentation** — https://api.waterdata.usgs.gov/docs/
- **Authentication** — https://api.waterdata.usgs.gov/signup/
- **JSONSchema** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/json-schema/usgs-water-data-api-monitoring-location-properties-schema.json
- **JSONSchema** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/json-schema/usgs-water-data-api-time-series-properties-schema.json
- **JSONLD** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/json-ld/usgs-water-data-api-context.jsonld
- **Examples** — https://raw.githubusercontent.com/api-evangelist/u-s-geological-survey/refs/heads/main/examples/usgs-water-data-api-monitoring-location-properties-example.json

## Other U.S. Geological Survey APIs (12)

- [USGS Water Data APIs](https://apis.io/apis/u-s-geological-survey/water-data-ogc-api/)
- [Asset Identifier Service (AIS)](https://apis.io/apis/u-s-geological-survey/asset-identifier-service-ais/)
- [Seismic Design Web Service](https://apis.io/apis/u-s-geological-survey/seismic-design-web-service/)
- [ScienceBase](https://apis.io/apis/u-s-geological-survey/sciencebase/)
- [StreamStats Web Services](https://apis.io/apis/u-s-geological-survey/streamstats-web-services/)
- [USGS Water Services (Legacy)](https://apis.io/apis/u-s-geological-survey/usgs-water-services/)
- [U.S. Geological Survey Catalog API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-catalog-api/)
- [U.S. Geological Survey Earthquakes API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-earthquakes-api/)
- [U.S. Geological Survey Monitoring Locations API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-monitoring-locations-api/)
- [U.S. Geological Survey Reference Data API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-reference-data-api/)
- [U.S. Geological Survey Time Series Data API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-time-series-data-api/)
- [U.S. Geological Survey Agency Codes API](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-agency-codes-api/)

## Tags

aquifer-codes

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/u-s-geological-survey/u-s-geological-survey-aquifer-codes-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/u-s-geological-survey/.