{"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":"06893000","entity_name":"Missouri River at Kansas City, MO","snapshot_date":"2026-08-19","observed_at":"2026-08-19T04:30:00.000Z","data_age_hours":1,"current":{"gauge_height_ft":11.69},"previous":{"gauge_height_ft":10.48},"change":{"period":"vs_24h_ago (instantaneous vs instantaneous, same basis)","gauge_height_ft":{"delta":1.21,"direction":"rising","direction_reason":null}},"trend_7d":[9.39,9.17,8.89,8.83,9.25,9.56,11.18],"sources":[{"name":"USGS Water Services","role":"sole data source (IV real-time current value; dv daily mean supplies trend_7d)","as_of":"2026-08-19T04:30:00.000Z","value":11.69,"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=06893000), not an independent second source","as_of":"2026-08-19T02:30:00Z","value":11.64,"weight":0,"relay_of":"USGS 06893000","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":49,"minor":32,"action":29,"moderate":35},"index_basis":null,"current_value":11.69,"pct_to_action":0.403,"normalized_index":-0.597,"official_category":"no_flooding","distance_to_action":17.31},"stat_ruler":{"doy":231,"note":"Purely descriptive statistics: where the current value falls against the same season of the last few years of official data (the seasonal window removes cyclical confounding). Not a forecast and not a risk judgement. Method and sample size are disclosed so you can recompute it yourself.","unit":"ft","basis":"day-of-year seasonal window","range":{"max":15.34,"min":7.65},"scale":"empirical_percentile_seasonal","method":"Empirical percentile over the last 5 years of official daily means, using the same-season +/-15 day window (day-of-year=231), linearly interpolated. current_percentile = the share of days in that same-season history that are not above the current value.","metric":"gauge_height_ft","n_days":153,"source":"USGS Water Services daily values (official raw data; the seasonal percentile is computed by this API)","n_total":1824,"percentiles":{"p05":8.076,"p10":8.422,"p25":8.85,"p50":9.77,"p75":10.46,"p90":12.144,"p95":12.86},"source_tier":"T1","window_years":5,"current_value":11.69,"frequency_label":"common (10-25% or 75-90% band)","current_percentile":0.889,"season_window_days":15},"summary_zh":"Missouri River at Kansas City, MO 的 gauge_height_ft 為 11.69,較前值 rising。統一尺(flood_stage,ft;官方閾值):action 29 / minor 32 / moderate 35 / major 49;深淺 pct_to_action=0.403(0~1,1=達 action)、嚴重度 normalized_index=-0.597(action=0/minor=1/moderate=2/major=3,跨站可比)、band「below_action」;現距 action 17.31 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=153 日;經驗百分位):現值落在同季節第 89 百分位 → 屬「常見(10–25% 或 75–90% 帶)」;同季節區間 7.65–15.34、中位數 9.77(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/06893000/","source_tier":"T1","record_hash":"sha256:6fe5f1196c3685b73959b57b262b72a58329256e7c2e81e347c106d57d502d03","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":"2026-08-19T04:30:00.000Z","oldest_leg_as_of":"2026-08-19T04:30:00.000Z","data_age_hours":1,"age_hours_now":2.2,"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":"2026-08-19T04:30:00.000Z","record_hash":"sha256:6fe5f1196c3685b73959b57b262b72a58329256e7c2e81e347c106d57d502d03"}],"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."}}}