Day 60 (April 29, 2026) — Event 8 Pulse 2 plays out across the watershed
Effectively zero rain watershed-wide today (max HUC12 0.012", most 0.000"). The rainfall driving today's hydrographs all fell on Day 59. This is a clean recession/propagation analysis day.
Boxley: Peaked at 4.10 ft at 00:30 CDT (~1 hr after midnight, ~1 hr after end of Day 59 pulse-2 rainfall). Total Day-59→Day-60 rise: 2.57 → 4.10 ft = +1.53 ft. Crossed Hailstone "low/floatable" 3.7 ft and "Optimal" 4.4 ft thresholds — wait, peak was 4.10, just below Optimal. So Hailstone reached "low but floatable" but not Optimal. Also crossed the Boxley→Ponca section "Optimal" 3.7 ft and is approaching "high" 5.0 ft from below. Now receding to 3.24 ft by 23:30 — back below the 3.7 ft Hailstone threshold. Time above 3.7 ft: ~04:00 Day 59 to ~17:30 Day 60 ≈ 13.5 hours, well within local "almost never more than 24 hours."
Ponca: Major rise. Peaked at 747 cfs at 02:45 (Optimal range, well into recreational territory). Day 58 baseline 173 cfs → peak 747 cfs = +574 cfs. Now receding through 463 cfs at 23:30. Above the 200 cfs "low/floatable" threshold for full day.
Pruitt: Peaked at 5.98 ft / 893 cfs at ~10:15-10:30 CDT. Largest hourly rise +0.81 ft at 09:30. Total event rise from baseline (~4.37 ft / 281 cfs Day-58) = +1.61 ft / +612 cfs. Currently 5.41 ft / 651 cfs and falling. Pruitt did NOT cross Tier-3 threshold (2000 cfs flood). Stayed deep in Optimal range.
St. Joe: Major rise still in progress. Baseline 4.81 ft / 722 cfs (early Day 60) → 6.84 ft / 2150 cfs at 22:45 = +2.03 ft / +1428 cfs and still rising. Largest hourly rise +0.63 ft at 08:00. Mid-day plateau around 6.40 ft suggested first peak from internal Day-59 rainfall, then renewed rise from upstream propagation. Solidly in Optimal range; nowhere near 8000 cfs Tier-3.
Harriet: Major rise still in progress. Baseline ~4.89 ft / 1030 cfs → 6.02 ft / 2120 cfs at 23:45 = +1.13 ft / +1090 cfs. Largest hourly rise +0.29 ft at 16:45. Still rising at end of day.
Richland Creek: Already past peak (4.89 ft Day 59 21:45). Continuous recession all of Day 60: 3.83 → 2.72 ft. Lost ~1.11 ft over 24 hr — classic Richland flashy recession. Spent <12 hr above 3.2 ft "low/floatable." Local-knowledge guidance ("rarely runnable >24 hr") confirmed.
Bear Creek: MAJOR new finding — Bear Creek finally responded. From 2.39 ft / 32.6 cfs at 01:30 → 3.88 ft / 558 cfs at 02:30 — a +1.49 ft / +525 cfs rise in 60 minutes. This is the largest single-hour rise observed at Bear Creek in the entire study. Now receding to 3.11 ft / 158 cfs.
Boxley (Day 59 QPE → Day 60 peak): - QPE: ~1.38" zone-avg (Terrapin Branch HUC12 0201), peak 1-hr at 00:02 UTC (19:02 CDT Day 59) - Peak: 4.10 ft at 00:30 Day 60 → lag ~5.5 hr from peak intensity to gauge peak - Transfer: 1.53 ft rise / 1.38" QPE = 1.11 ft/in — confirms strong wet-antecedent amplification (>2× dry-condition Boxley) - Faster lag than dry conditions (5-6 hr vs 10-11 hr) — Hailstone pools already full
Pruitt (Day 59 QPE 1.13" → Day 60 peak): - Peak intensity centered ~18:02 UTC Day 59 (13:02 CDT) - Pruitt peak 5.98 ft at 10:15 Day 60 → lag ~21 hr — exactly matches existing 21-hr propagation hypothesis - Transfer: 1.61 ft / 1.13" = 1.42 ft/in (very high, wet amplification) - 612 cfs / 1.13" / 513 km² watershed → strong runoff coefficient consistent with saturated soils
St. Joe (Day 59 QPE 1.03" → Day 60 peak ongoing): - Internal first wave already arrived Day 59 ~13:30 (the +63 cfs internal pulse seen yesterday) - Day 60 main rise: started ~05:00, sharpest at 08:00, still rising at 22:45 (2150 cfs) - This is upstream-sourced propagation (the Pruitt pulse arriving at St. Joe) - Pruitt peak 10:15 → St. Joe still rising at 22:45 = peak still 1-3 hr away. Suggests Pruitt→St.Joe lag of ~12-15 hr at this flow level - Forecast peak: ~7.0-7.2 ft / 2300-2700 cfs early Day 61. Solidly Optimal; below Tier-3.
Harriet (Day 59 QPE 1.06" → Day 60 peak ongoing): - Started rising ~12:30 Day 60, sharpest 15:30-16:45, still rising at 23:45 - St. Joe→Harriet lag should be ~6-8 hr; with St. Joe still rising, Harriet peak likely ~04:00-08:00 Day 61 in 6.3-6.5 ft / 2400-2800 cfs range
Bear Creek (Day 59 QPE 0.92" → Day 60 flash response): - Day 59 QPE peak ~01:02 UTC Day 60 (Headwaters Bear at 0403, 1.025" total) - Bear Cr peak 3.88 ft at 02:30 Day 60 → lag ~1.5 hr from peak intensity, ~26 hr from rainfall start - Transfer: 1.49 ft / 1.025" = 1.45 ft/in — Bear Creek's first true flash response observed - CRITICAL HYPOTHESIS UPDATE: The "Bear Creek karst storage threshold" idea is wrong. Bear Creek DOES respond strongly to wet-antecedent ~1" rainfall — but the lag is so long (~26 hr) that it appeared muted on Day 59 evening. The activation threshold is actually similar to other tributaries; Bear Creek is just exceptionally lagged, not exceptionally damped.
Cleanest propagation cascade observed in study so far. Boxley peak 00:30 Day 60 → Ponca peak 02:45 → Pruitt peak 10:15 → St. Joe rising through 22:45. - Boxley → Ponca: ~2.25 hr (very fast, both small headwater zones, wet conditions) - Ponca → Pruitt: ~7.5 hr - Boxley → Pruitt: ~9.75 hr — much faster than the 21-hr "rainfall-to-Pruitt" lag because we're now measuring gauge-to-gauge propagation, not rainfall-to-gauge - Pruitt → St. Joe peak: still pending, ~12-15 hr expected
This is wet-condition behavior. Channels full, less attenuation. Propagation velocity higher than during dry events.
Bear Creek behavior fundamentally re-characterized. Yesterday I hypothesized a karst storage threshold of 1.5-2" wet-antecedent. Today's +525 cfs flash on the same antecedent + roughly 1" total QPE demolishes that hypothesis. The actual answer is long lag, not high threshold. Bear Creek peak arrived 26 hours after rainfall onset on heavily saturated soils — much longer than Pruitt (21 hr) or Richland (~13 hr from QPE start). This is likely karst flow paths (subsurface storage that fills, then releases via spring/conduit flow) rather than storage that absorbs and never releases. Significant correction to hypothesis 6.
Hailstone activation was real and well-calibrated. Boxley peaked at 4.10 ft, in the low-floatable band (3.7-4.4) but not Optimal (4.4+). Time above 3.7 was ~13.5 hr — fits "almost never more than 24 hours" perfectly. This is the second confirmed Hailstone event in the study (none previously crossed 3.7 ft).
Propagation lags shorter under wet conditions. Pruitt→St.Joe peak-to-peak ~12-15 hr at high flow vs the ~12 hr Pruitt→St.Joe "rainfall propagation" inferred from earlier events. Channels are full and water moves faster.