Daily Analysis

PRE-ANALYSIS PROCEDURE — per-gauge facts (2026-06-09):

• Boxley (07055646, height): (a) first 4.00 ft @ 00:00; (b) max 4.00 ft @ 00:00; (c) last 3.23 ft @ 23:30; (d) intraday low 3.23 ft @ 23:15-23:30; (e) NO within-day rise — pure monotonic recession from Pulse 3 peak (5.50 ft on Day 100).
• Ponca (07055660, discharge): (a) first 1020 cfs @ 00:00; (b) max 1020 cfs @ 00:00; (c) last 447 cfs @ 23:30; (d) intraday low 447 cfs @ 23:15-23:30; (e) no within-day rise — pure recession from Day 100 peak (1920 cfs).
• Pruitt (07055680, height/discharge): (a) first 7.55 ft / 1800 cfs @ 00:00; (b) max 7.55 ft / 1800 cfs @ 00:00; (c) last 5.61 ft / 755 cfs @ 23:30; (d) intraday low 5.61 ft / 755 cfs @ 23:30; (e) no within-day rise — pure recession from Day 100 Pulse 3 peak (7.98 ft / 2130 cfs).
• St. Joe (07056000, height/discharge): (a) first 5.28 ft / 985 cfs @ 00:00; (b) max 7.63 ft @ 10:30 / 2900 cfs @ 10:30; (c) last 6.73 ft / 2050 cfs @ 22:45; (d) intraday low = first reading 5.28 ft @ 00:00; (e) low→peak rise: +2.35 ft / +1915 cfs in 10.5 hr (00:00 → 10:30). This is propagation from Day 100 upper-basin event — first within-day mainstem peak today.
• Harriet (07056700, height/discharge): (a) first 4.80 ft / 957 cfs @ 00:00; (b) max 6.67 ft @ 18:45 / 2860 cfs @ 18:45; (c) last 6.47 ft / 2630 cfs @ 22:45; (d) intraday low = first reading 4.80 ft @ 00:00; (e) low→peak rise: +1.87 ft / +1903 cfs in 18.75 hr (00:00 → 18:45). Propagation peak.
• Richland Creek (07055875, height): (a) first 1.71 ft @ 00:00; (b) max 1.71 ft @ 00:00; (c) last 1.47 ft @ 23:00; (d) intraday low 1.47 ft @ 22:15-23:00; (e) no within-day rise — pure recession from Day 100 (peak 1.75 ft Day 99 evening).
• Bear Creek (07056515, height/discharge): (a) first 2.41 ft / 42 cfs @ 00:00; (b) max 2.47 ft @ ~05:30-07:15 / 48.6 cfs @ 05:30; (c) last 2.37 ft / 38 cfs @ 23:15; (d) intraday low 2.37 ft @ 21:15-23:15; (e) low→peak rise actually inverted — peak came first: from 2.41 → 2.47 ft (+0.06 ft) over 05:30-07:15, then receded. This is a small overnight propagation/baseflow bump from the Day 100 event reaching Bear Cr drainage area indirectly (or possibly trailing residual moisture; QPE today is essentially zero).

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1. PRECIPITATION SUMMARY

Basin-wide effective dry day. Maximum HUC12 24-hr QPE = 0.007" (Falling Water Creek, 0307). All gauge-zone totals ≤ 0.005". This is meteorological noise — no detectable rainfall anywhere in the watershed. Today is a recession/propagation day.

2. GAUGE RESPONSES

Two distinct behaviors today:

Upper basin (Boxley, Ponca, Pruitt, Richland Cr) — pure recession from Day 100 Pulse 3: - Boxley: 4.00 → 3.23 ft (−0.77 ft over 23.5 hr) - Ponca: 1020 → 447 cfs (−573 cfs, −56%) - Pruitt: 7.55 → 5.61 ft (−1.94 ft) / 1800 → 755 cfs (−58%) — dropped below the 2000-cfs flood threshold immediately overnight; both flood-threshold exceedances were brief Day 100 events. - Richland Cr: 1.71 → 1.47 ft (−0.24 ft) — slow tributary drain.

Mid/lower basin (St. Joe, Harriet) — propagation peaks arriving today: - St. Joe rose from 5.28 ft / 985 cfs at 00:00 to 7.63 ft / 2900 cfs at 10:30 (+2.35 ft / +1915 cfs in 10.5 hr), then receded to 6.73 ft / 2050 cfs by 22:45. Peak is firmly in Optimal range (well below 8000 cfs flood threshold). - Harriet rose from 4.80 ft / 957 cfs at 00:00 to 6.67 ft / 2860 cfs at ~18:45 (+1.87 ft / +1903 cfs in 18.75 hr), still receding slowly at EOD. Solid Optimal range, far below 9370-cfs flood threshold. - Bear Cr: small +0.06 ft bump (2.41 → 2.47 ft early morning) then recession. Likely confluence backwater or trailing baseflow from Day 100 — QPE in Bear Cr zone today is 0.0".

Signal separation check at St. Joe: Richland Cr was flat/falling (1.71 → 1.47 ft) while St. Joe surged +2.35 ft. Per the separation logic, this means the St. Joe surge is NOT from the Richland sub-basin — it's mainstem propagation from upstream (Boxley/Ponca/Pruitt zones where Day 100 dumped 1.04–1.37" on top of already-wet ground).

3. RAINFALL-RESPONSE PAIRS

Today's QPE is negligible; the response signals to attribute belong to Day 100 (Event 19 Pulse 3) rainfall in the upstream zones.

Pair 1 — Day 100 upstream QPE → St. Joe Day 101 peak (7.63 ft / 2900 cfs @ 10:30 CDT) - Source area: Boxley + Ponca + Pruitt zones (1.04, 1.04, 1.25" 24-hr respectively on Day 100). Peak 1-hr QPE Day 100 ≈ 14:02 UTC = 09:02 CDT in Boxley HUC12 0201 (0.699"). - St. Joe peak: 10:30 CDT Day 101 ≈ 25.5 hr after upstream peak QPE. - Lag (peak QPE → peak St. Joe) ≈ 25–26 hr. This is longer than typical because the routing distance from Boxley/Ponca/Pruitt to St. Joe is ~80+ river-km and channel was already elevated (wet/wet antecedent). - Transfer ratio: zone-averaged QPE across Boxley+Ponca+Pruitt+St.Joe contributing area ≈ ~0.9" (weighted), St. Joe rise within-day = 2.35 ft. Ratio ≈ 2.6 ft/in. Note this is the within-day intraday rise — the full event-scale rise (from Day 99 baseline ~4.45 ft to 7.63 ft Day 101) is +3.18 ft, giving event-scale transfer ratio ~3.5 ft/in against ~0.9" zone-averaged. - Antecedent: 7-day for St. Joe zone HUC12s averaged ~1.4–2.5" before Day 100. Wet/wet. - Comparison to prior: Event 15 (Day 88–89, watershed-wide flood) drove St. Joe ~+9 ft in event with similar order-of-magnitude QPE. Today's response is smaller because Day 100 rainfall was concentrated upstream (Boxley/Pruitt) rather than directly over the 14 St. Joe HUC12s. Lag of 25–26 hr from upstream-only-forcing is a NEW data point — prior St. Joe lags were from in-zone QPE (typically 8–14 hr). Flag: this is a fundamentally different routing scenario (pure upstream propagation, not in-zone forcing). New regime: "upstream-only forced St. Joe response" → lag ≈ 24–28 hr. Confidence: medium.

Pair 2 — Day 100 upstream QPE → Harriet Day 101 peak (6.67 ft / 2860 cfs @ 18:45 CDT) - Peak QPE in upstream zones (Day 100) → Harriet peak ≈ 33–34 hr lag. - St. Joe peak (10:30) → Harriet peak (18:45) = 8.25 hr mainstem-to-mainstem propagation (St. Joe → Harriet). - Harriet within-day rise: +1.87 ft / +1903 cfs. - Transfer ratio: Harriet zone QPE Day 100 was only 0.644" (modest), and Bear Cr was 0.458" (also modest). Most of Harriet's rise is propagated mainstem flow from upstream. Ratio computed against the broader contributing area is messy; better to express as routing — Harriet got ~98% of St. Joe's discharge (2860 vs 2900 cfs) with ~8 hr lag, consistent with prior St.Joe→Harriet observations. - Antecedent for Harriet zone: 0.65–1.4" 7-day. Wet. - Comparison: St.Joe→Harriet lag of ~8 hr matches the Event 15 propagation finding from the hypothesis (8–10 hr typical at high flow). Consistent.

4. DOWNSTREAM PROPAGATION

Today's data nicely isolates the St.Joe → Harriet leg because upstream gauges (Boxley/Ponca/Pruitt) were in recession all day — the propagation wave was already past them.

St. Joe peak (10:30) → Harriet peak (18:45) = 8.25 hr. Velocity over ~60 river-km ≈ 7.3 km/hr (≈2.0 m/s). Consistent with prior high-flow propagation estimates.

Boxley → Ponca → Pruitt propagation cannot be analyzed today (all three are in recession from Day 100; their peaks were yesterday).

5. MULTI-DAY EVENTS

Event 19 is now complete through propagation. Full event picture: - Day 98: setup/Pulse 0 - Day 99: Pulse 1 (Boxley 2.97 ft) and Pulse 2 - Day 100: Pulse 3 — study record Boxley 5.50 ft, Pruitt 7.98 ft (flood), Ponca 1920 cfs (flood) - Day 101 (today): downstream propagation peaks — St. Joe 7.63 ft / 2900 cfs (Optimal), Harriet 6.67 ft / 2860 cfs (Optimal). NEITHER mainstem mid/lower gauge reached flood threshold despite upstream flood-scale forcing.

Key event-level finding: Day 100 flood-threshold crossings at Pruitt and Ponca were geographically concentrated in the upper basin. By the time the flood pulse reached St. Joe (drainage 1932 km²) and Harriet (drainage 2775 km²), it had attenuated via channel storage and dilution from non-contributing lower-zone areas to ~36% (St. Joe) and ~30% (Harriet) of the flood-threshold discharges. This contrasts with Event 15 (Day 88–89), which was watershed-wide and flood-threshold-exceeding everywhere.

6. ANOMALIES OR SURPRISES

1. Bear Creek's small overnight bump (+0.06 ft / +6.6 cfs) with zero today-QPE and only 0.46" Day 100 QPE in zone. This is most likely the trailing edge of Day 100 forcing finally producing micro-response on a delayed schedule for the saturated headwater HUC12s — or possibly a confluence backwater effect from rising Harriet just downstream. Small, ambiguous, low confidence. Not enough signal to flag as a real event.

2. St. Joe attenuation is striking. Pruitt flood was 2130 cfs / 7.98 ft (>flood threshold 2000). St. Joe routed peak was 2900 cfs / 7.63 ft — only 36% of St. Joe's flood threshold (8000 cfs). This confirms that upstream-only flood events do NOT translate to mainstem flooding downstream — the watershed has substantial routing/storage capacity. Useful general finding.

3. Pruitt 7.98 ft height = 2130 cfs Day 100 vs St. Joe 7.63 ft = 2900 cfs today. Pruitt and St. Joe heights are nearly equal but discharges differ by 36%. This is expected — different channel cross-sections and rating curves at each location — but worth noting that "St. Joe at 7.6 ft" is hydrologically much wetter than "Pruitt at 7.6 ft."