{"nature":"This API supplies data organisation and trend description only. It is not a recommendation to act; the decision is yours. Purely descriptive - no judgement, no prediction. Every record carries an official source plus a record_hash (canonical sha256, recomputable offline for self-verification; cross-check with free /gauge/verify).","note":"Free sample: this is the COMPLETE REAL RECORD that the paid /gauge returns - it includes the common ruler (normalized_index, which quantifies how deep the reading is), the statistical ruler (same-season percentile), a self-verifiable record_hash, and provenance (age computed at request time plus the freshness criterion). Source independence is labelled per record in sources[].independent (the hydrology line has only one independent source, USGS; NOAA NWPS is the official relay channel of the same sensor, which is why source_agreement_cv=null). Try before you buy","sample":{"signal_id":"hydrology.river-level","entity":"06934500","entity_name":"Missouri River at Hermann, MO","snapshot_date":"2026-08-01","observed_at":"2026-08-01T04:30:00.000Z","data_age_hours":1,"current":{"gauge_height_ft":5.96},"previous":{"gauge_height_ft":6.1},"change":{"period":"vs_24h_ago (instantaneous vs instantaneous, same basis)","gauge_height_ft":{"delta":-0.14,"direction":"falling","direction_reason":null}},"trend_7d":[5.46,5.13,4.82,4.91,6.38,6.93,5.79],"sources":[{"name":"USGS Water Services","role":"sole data source (IV real-time current value; dv daily mean supplies trend_7d)","as_of":"2026-08-01T04:30:00.000Z","value":5.96,"weight":1,"independent":true},{"name":"NOAA NWS/NWPS","role":"Flood threshold and official classification provider; its observation is the official relay channel of the same USGS sensor (NWPS self-reports usgsId=06934500), not an independent second source","as_of":"2026-08-01T03:30:00Z","value":5.88,"weight":0,"relay_of":"USGS 06934500","independent":false}],"source_agreement_cv":null,"standard_ruler":{"band":"below_action","note":null,"unit":"ft","bands":["action","minor","moderate","major"],"scale":"flood_stage","metric":"gauge_height_ft","source":"NOAA NWS/NWPS","standard":null,"thresholds":{"major":33,"minor":21,"action":19,"moderate":26},"index_basis":null,"current_value":5.96,"pct_to_action":0.314,"normalized_index":-0.686,"official_category":"no_flooding","distance_to_action":13.04},"stat_ruler":{"doy":213,"note":null,"unit":"ft","basis":null,"range":{"max":17.3,"min":3.88},"scale":"empirical_percentile_seasonal","method":null,"metric":"gauge_height_ft","n_days":152,"source":null,"n_total":1793,"percentiles":{"p05":4.56,"p10":4.848,"p25":5.81,"p50":7.8,"p75":10.365,"p90":12.019,"p95":13.546},"source_tier":"T1","window_years":5,"current_value":5.96,"frequency_label":null,"current_percentile":0.27,"season_window_days":15},"summary_zh":"Missouri River at Hermann, MO 的 gauge_height_ft 為 5.96,較前值 falling。統一尺(flood_stage,ft;官方閾值):action 19 / minor 21 / moderate 26 / major 33;深淺 pct_to_action=0.314(0~1,1=達 action)、嚴重度 normalized_index=-0.686(action=0/minor=1/moderate=2/major=3,跨站可比)、band「below_action」;現距 action 13.04 ft;NWS 官方分類「no_flooding」(官方閾值+純算術內插,非本 API 判斷/預測,深淺可量化)。統計尺(近 5 年·同季節窗 ±15 日,n=152 日;經驗百分位):現值落在同季節第 27 百分位 → 屬「經常(常態區,約半數時間如此)」;同季節區間 3.88–17.3、中位數 7.8(方法:USGS 官方日均值 day-of-year 季節窗線性內插百分位,可自算複核;純統計描述非預測)","source_ref":"https://waterdata.usgs.gov/monitoring-location/06934500/","source_tier":"T1","record_hash":"sha256:34acba0c038f2c88cee29f7a2313d85ed82fd4c2142a1bb475df30b08dcd018d","hash_core_version":3,"ots_status":"pending","lifecycle":null,"provenance":{"served_from":"GAUGE stored snapshot (SQL) - not a live upstream API call at request time","data_as_of":"2026-08-01T04:30:00.000Z","oldest_leg_as_of":"2026-08-01T04:30:00.000Z","data_age_hours":1,"age_hours_now":3.8,"freshness":"fresh","freshness_basis":"cadence=daily; fresh<=24h; recent<=192h; dead_source>1440h; age_basis=request-time(now minus observed_at)","data_lineage":[{"signal":"hydrology.river-level","independent_dimension":"hydrology-riverflow","traceable_to":"USGS / NOAA NWPS","uncertainty":"single-source-no-CI","observed_at":"2026-08-01T04:30:00.000Z","record_hash":"sha256:34acba0c038f2c88cee29f7a2313d85ed82fd4c2142a1bb475df30b08dcd018d"}],"validation_status":"not-yet-backtested (screening-level; framework Ch19 historical baseline still being built)","note":"Non-real-time decisions are served from stored data to avoid upstream API latency; use for decisions within this data cadence. Timestamps are UTC."}}}