Daily Analysis

PRE-ANALYSIS PROCEDURE (per-gauge facts, all timestamps CDT):

• Boxley (07055646): (a) first 4.38 ft @00:00; (b) max 4.38 ft @00:00; (c) last 3.47 ft @23:30; (d) intraday low 3.47 ft @23:30; (e) no low→peak rise — pure monotonic recession (Event-21 pool drain). Max = first reading.
• Ponca (07055660): (a) first 1280 cfs @00:00; (b) max 1280 cfs @00:00; (c) last 547 cfs @23:30; (d) low 547 @23:30; (e) none — pure recession.
• Pruitt (07055680): (a) first 8.17 ft / 2290 cfs @00:00; (b) max 8.17 ft / 2290 cfs @00:00; (c) last 5.70 ft / 792 cfs @23:30; (d) low 5.70 ft / 792 cfs @23:30; (e) none — pure recession (Event-21 flood-limb).
• St. Joe (07056000): (a) first 9.75 ft / 5420 cfs @00:00; (b) max 11.34 ft @02:45–03:00 / 7890 cfs @02:45–03:00; (c) last 7.24 ft / 2520 cfs @22:45; (d) intraday low 7.24 ft / 2520 cfs @22:45; (e) low→peak (from first): +1.59 ft / +2470 cfs, 00:00→02:45 (2.75 hr) — Event-21 propagation arrival.
• Harriet (07056700): (a) first 5.78 ft / 1880 cfs @00:00; (b) max 9.60 ft @09:15–09:30 / 6870 cfs @09:15–09:30; (c) last 7.03 ft / 3300 cfs @22:45; (d) intraday low 7.03 ft / 3300 cfs @22:45 (early dip to 5.77 @00:30); (e) low→peak: +3.83 ft / +5010 cfs, 00:30→09:22 (~8.9 hr) — Event-21 propagation surge.
• Richland (07055875): (a) first 1.84 ft @00:00; (b) max 1.84 ft @00:00; (c) last 1.56 ft; (d) low 1.56 ft @22:30–23:00; (e) none — pure recession, flat tributary (the +0.01 ft @17:15 is karst noise).
• Bear Creek (07056515): (a) first 3.16 ft / 198 cfs @00:00; (b) max 3.16 ft / 198 cfs @00:00; (c) last 2.78 ft / 96.4 cfs @23:15; (d) low 2.78 / 96.4 @22:30–23:15; (e) none — pure recession (Event-21 flashy tail).

QPE-peak timing for attribution: Today's basin-max QPE is 0.006" (Pruitt zone) — far below any detection floor; today's rain drives nothing. All movement is Event-21 (Day-114, Jun 22) propagation. Source-zone QPE peaks (Day-114, converting MRMS UTC stamps to CDT by −5 h): Boxley HUC-0201 1.3"/hr @06:02 CDT (11:02Z); Ponca Smith-Cr HUC-0203 1.478"/hr @06:02 CDT. Mainstem peak-to-peak propagation pairs computed below.

1. PRECIPITATION SUMMARY Effectively no rain: basin-max 0.006" (Pruitt zone, Cove Cr HUC-0204 0.010"). Every zone <0.01". This is a non-detection day on an active flood-limb recession — a higher-flow analog of Days 110–112. Note the antecedent has now flipped wet: Event 21 (Day 114) reloaded the 7-day totals to 1.5–3.9" (Boxley zone 3.65", Ponca Smith 3.909").

2. GAUGE RESPONSES - St. Joe and Harriet are the only movers, both Event-21 propagation peaks. St. Joe surged through the night to 11.34 ft / 7890 cfs @02:45–03:00 — a near-miss of the 8000-cfs flood threshold (98.6%) — then receded to 2520 cfs. Harriet crested 9.60 ft / 6870 cfs @09:22 (73% of its 9370 flood threshold), then fell to 3300 cfs. - Signal separation: Richland flat/receding (1.84→1.56 ft) → St. Joe surge is mainstem/upper-basin propagation, NOT Richland sub-basin. Bear Creek flat/receding (3.16→2.78 ft) → Harriet surge is mainstem propagation, NOT independent Bear forcing. Both diagnostics clean (Event-19-type). - Boxley, Ponca, Pruitt all in pure flood-limb recession from their Day-114 peaks. Boxley draining its study-record 9.06-ft pool (Day 114) at ~0.057 ft/hr early; crossed Hailstone Low-Floatable (3.7) downward ~14:00; ended 3.47 ft (still above the 3.2 Boxley–Ponca section threshold).

3. RAINFALL-RESPONSE PAIRS (Event-21 propagation; transfer vs Day-114 source QPE)

Today's direct QPE is non-causal, so I attribute via propagation and compute event-scale transfer against Day-114 contributing-zone QPE.

• St. Joe peak 7890 cfs / 11.34 ft. Event-scale rise from the Day-114 trough (598 cfs / 4.56 ft) = +7292 cfs / +6.78 ft against St. Joe own-zone 1.699" = ~4.0 ft/in (~4290 cfs/in). This is upstream-routing-dominated (Ponca delivered a study-record 8700 cfs into the trunk; own-zone dry-soil contribution ~1000 cfs by Event-11 analogy). Cross-event: the magnitude (~4 ft/in) matches wet flood-scale St. Joe transfers (Event 15 ~4 ft/in) despite a dry antecedent (own-zone 7-day ~0.1–0.3" at onset) — because the routed upper flood, not local soil state, set the peak. This is >3× the dry-antecedent own-zone transfer (Event 11 1.09 ft/in) and the deviation is fully explained by upstream integration, not a soil-physics change. Flag: do not file as an own-zone transfer.
• Harriet peak 6870 cfs / 9.60 ft. Rise from Day-114 trough (901 cfs / 4.73 ft) = +5969 cfs / +4.87 ft vs own-zone 1.479" = ~3.3 ft/in (~4035 cfs/in) — propagation-dominated, tracks St. Joe with the usual slight attenuation.

4. DOWNSTREAM PROPAGATION (mainstem chain, Event 21) Sinuosity factor assumed 1.5 throughout. - Ponca→Pruitt: 8700 cfs @10:30 (D114) → 9710 cfs @15:50 (D114) = 5.3 hr at flood flow. 19.9 km ×1.5 = 29.85 km → ~1.56 m/s. Matches the ~5.25-hr high-flow value. - Pruitt→St. Joe: 15:50 (D114) → 02:52 (D115) = ~11 hr at flood flow. 36.1 km ×1.5 = 54.15 km → ~1.37 m/s. At the fast end of the documented 11–15 hr wet/flood band. - St. Joe→Harriet: 02:52 → 09:22 = 6.5 hr at flood flow (7890→6870 cfs). 17.9 km ×1.5 = 26.85 km → ~1.15 m/s. Third confirmation of the ~6–6.5 hr flood-flow St. Joe→Harriet timing (Events 15, 20, 21). - Boxley→Ponca was NOT a cascade: Boxley 9.06 @09:30, Ponca 8700 @10:30 (~1 hr apart) — both under simultaneous direct heavy forcing (Event-11/parallel-direct mode), not routing.

5. MULTI-DAY EVENTS — Event 21 (Day 114–115) Today completes the trunk integration of the upper-basin-dominant flood that began Day 114 (Jun 22) on a dry antecedent (7-day 0.1–0.3"). Day-114 produced study-record peaks at the three upper gauges: Boxley 9.06 ft (demolishes prior 5.50), Ponca 8700 cfs (5.4× flood, study record), Pruitt 14.27 ft / 9710 cfs (4.9× flood, study record) — all from 3.4–3.9" upper-zone totals at 1.3–1.5"/hr intensity overrunning dry-soil damping. Day-115 delivered the lower-mainstem propagation: St. Joe 7890 cfs (near-flood), Harriet 6870 cfs (73% flood). Whole-system event magnitude: a high-end Tier-3 / sub-flood-at-trunk event.

6. ANOMALIES OR SURPRISES - Upper-basin-only floods do NOT always attenuate below trunk flood. Event 19 (Ponca 1920 cfs, 1.2× flood) attenuated to 36% of flood at St. Joe. Event 21 (Ponca 8700, 5.4× flood) reached 98.6% of St. Joe flood. The attenuation is large in absolute terms but a sufficiently large upper-basin flood nearly maintains flood at the trunk — fraction-of-flood at St. Joe scales strongly with source magnitude, not just source location. This refines (does not contradict) the Event-19 finding. - Dry-antecedent + extreme intensity = study-record stage. Boxley 2.09 ft/in (9.06 ft from 3.377" on dry soil) confirms the Event-7 principle that high-intensity bursts overrun pool storage; the 3.5-hr peak-to-peak lag is fast for a dry pool, again intensity-driven. Ponca's ~2763 cfs/in is a flood-regime nonlinear (out-of-bank) transfer, far above the in-bank wet range. - No rating-curve step at any gauge despite study-record Boxley/Ponca/Pruitt stages tracking smoothly height-vs-discharge — high-stage curves continue to perform.