{
  "id": "bonnet-carre-salinity-2019-v1",
  "version": "1.0.0",
  "designDate": "2026-10-21",
  "selection": "First of the two documented 2019 Bonnet Carre openings; bounded post-closure window ends before second opening. Selected from official operations record and two USGS project monitoring sites, before salinity outcome summaries. Availability/metadata inspected first; no selection for large changes.",
  "question": "Did salinity at two documented Louisiana coastal monitoring locations show the same before/during/after pattern around this freshwater-pulse window? Descriptive association, not isolated spillway causation.",
  "sites": [{"id":"301001089442600","label":"Rigolets","reason":"Documented connecting pass in USGS spillway monitoring project."},{"id":"300722089150100","label":"Grand Pass","reason":"Documented western Mississippi Sound coastal station in the same USGS project, farther east; Louisiana location. Not an unexposed control."}],
  "parameter": "00480",
  "units": "ppth",
  "sourceValueType": "Derived Value",
  "timeZone": "America/Chicago",
  "start": "2019-02-01",
  "endExclusive": "2019-05-10",
  "intervalMinutes": 30,
  "periods": [{"id":"before","label":"Before opening","start":"2019-02-01","endExclusive":"2019-02-27"},{"id":"operation","label":"Operation window","start":"2019-02-27","endExclusive":"2019-04-12"},{"id":"after","label":"After closure, before reopening","start":"2019-04-12","endExclusive":"2019-05-10"}],
  "eventBoundary": "USACE dates: opened Feb27, final bays closed Apr11; second opening May10. Operation window includes closure date Apr11, not 44 days of constant positive discharge. Daily operation boundaries are local dates; no exact gate-opening hour assumed.",
  "quality": "Correct station/parameter/unit and one series/block per station; exact 30-minute grid, parse offset-bearing timestamps to UTC; finite nonnegative values not equal to noDataValue; require qualifiers exactly [A] approved, exclude all others. Reject duplicate, off-grid and outside-study timestamps. No interpolation or gap filling.",
  "comparison": "Pair exact instants where BOTH stations qualify. Daily means use identical paired instants. Include a local day only if paired count >=ceil(0.80*expected slots); expect46 slots on March10 DST day and48 otherwise. Period means give equal weight to admitted daily means and compare only identical days. Record native valid coverage separately from paired coverage.",
  "sensitivity": "Repeat period means at90% and100% daily completeness; report admitted days and changes. Do not choose threshold based on stronger findings.",
  "timing": "Descriptive minimum seven-consecutive-calendar-day mean within study: require all7 admitted daily means. Report interval, not a causal transport lag or return-to-baseline date. No fish salinity threshold chosen.",
  "uncertainty": "Report observed between-day ranges and completeness sensitivity. One event/two stations are not independent treatment replicates; no causal confidence interval or p-value, no proven recovery inferred from gate closure.",
  "limits": "No unexposed control or adjustment for rainfall, Pearl River flow, wind, tide or seasonal change. Historical sensor depths/maintenance not established; station point measurements are not comparable depth profiles or interior-marsh salinity. No MLLW/NAVD88 level comparison, catch/effort, fish movement, seafood safety or route-depth inference. Independent scientific review pending."
}