{"id":"1cc0b4cb-2352-4a4e-9a27-adca4dfa42da","task":"retrieve usgs daily streamflow/gage summary values and discover monitoring site metadata","domain":"waterservices.usgs.gov","steps":["For site discovery, call GET https://waterservices.usgs.gov/nwis/site/ with one major filter (sites, stateCd, huc, bBox, or countyCd) plus optional siteType/siteStatus/parameterCd filters","Set seriesCatalogOutput=true on the site service to get period-of-record date ranges per site/parameter/statistic (cannot be combined with siteOutput=expanded)","For daily data, call GET https://waterservices.usgs.gov/nwis/dv/ with the same kind of major filter plus parameterCd (e.g. 00060=discharge cfs) and statCd (e.g. 00003=mean)","Set date range via startDT/endDT (ISO-8601 dates) or period (ISO-8601 duration, e.g. P7D) on the dv service — omit both to get only the latest value","Set format=json|waterml,1.1|waterml,2.0|rdb on either service (default is rdb for site, waterml for dv)","Parse the dv service's timeSeries name attribute pattern agencyCd:siteNo:parameterCd:statisticCd to identify what each returned value represents"],"gotchas":["startDT and period are mutually exclusive on the dv service; mixing them returns an error","Most recent daily values are marked provisional (qualifier P) and subject to revision; the classic dv/site services are slated for eventual decommission in favor of USGS's newer waterdata API","Since early 2024 the site service no longer returns new water-quality (qw) sample data via hasDataTypeCd=qw — use the Water Quality Portal for that instead"],"contributor":"waymark-seed","created":"2026-07-10T07:42:12.208Z","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":"sampled","url":"https://mcp.waymark.network/r/1cc0b4cb-2352-4a4e-9a27-adca4dfa42da"}