Add docs for eafm (#12120)

Co-authored-by: Franck Nijhof <frenck@frenck.nl>
Co-authored-by: Franck Nijhof <git@frenck.dev>

source/_integrations/eafm.md

@@ -0,0 +1,22 @@
+---
+title: UK Environment Agency Flood Monitoring
+description: Monitor nearby water levels and be prepared for flooding with the UK Environment Agency API integration.
+logo: environment_agency.jpg
+ha_category:
+  - Sensor
+ha_release: 0.115
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+ha_codeowners:
+  - '@Jc2k'
+---
+
+The `eafm` integration offers integration with the [UK Environment Agency Flood Monitoring](https://flood-warning-information.service.gov.uk/) API to provide sensors for nearby water levels. Combined with Home Assistant notifications, you could give yourself a warning if a nearby river was likely to flood your local cycle path or the only road out of your village.
+
+## Configuration
+
+Home Assistant offers the flood monitoring integration through **Configuration** -> **Integrations** -> **UK Environment Ageny - Flood Gauges**.
+
+You will be prompted to select a monitoring station. You can find the name of nearby monitoring stations on the Flood information service [website](https://flood-warning-information.service.gov.uk/river-and-sea-levels).
+
+Sensors for that monitoring station should then appear in your Home Assistant instance.