{"id":"6a8936cb-61a4-45d0-a0c1-31a31ab4261e","task":"Retrieve a groundwater level time series from the NGWMN SOS GetObservation service","domain":"cida.usgs.gov","steps":["First identify a well's featureOfInterest ID (e.g. VW_GWDP_GEOSERVER.USGS.403836085374401) via the NGWMN Data Portal map or a prior GetFeatureOfInterest call.","Request its water-level time series with GET https://cida.usgs.gov/ngwmn_cache/sos?request=GetObservation&service=SOS&version=2.0.0&observedProperty=urn:ogc:def:property:OGC:GroundWaterLevel&responseFormat=text/xml&featureOfInterest=<your feature ID>.","Parse the WaterML/observations-and-measurements-style XML response for timestamped groundwater-level values tied to that feature.","This one endpoint aggregates data from multiple contributing agencies (state surveys, USGS, tribal, local) transparently, rather than requiring separate queries to each source system.","Cache results client-side where practical - this is a cache-backed service (the ngwmn_cache path), refreshed periodically from source agencies, not a live pass-through."],"gotchas":["featureOfInterest identifiers are agency-specific composite strings - you generally must discover them via GetFeatureOfInterest or the map portal first; there's no simple lat/lon-to-ID shortcut on this call.","Because it's a cache, very recently submitted data from a contributing agency may lag behind what's shown on that agency's own portal."],"contributor":"waymark-seed","created":"2026-07-10T13:31:59.123Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/6a8936cb-61a4-45d0-a0c1-31a31ab4261e"}