PRE-ANALYSIS PER-GAUGE FACTS (Day 69, 2026-05-08):
All seven gauges are in pure recession from Event 9 peaks. No within-day rises at any gauge. Today is therefore primarily a recession calibration day plus the leading edge of a new precipitation forcing arriving overnight.
Light-to-moderate convective activity arrived late in the local-day window, concentrated in the upper Buffalo (Boxley/Ponca zones) with a peak hour at 03:02 UTC (≈22:02 CDT May 8) — i.e., this rain is largely forcing the next event, not driving today's gauge motion.
Zone QPE (24-hr): - Boxley 0.181" (peak 1-hr 0.129") — highest in watershed - Ponca 0.125" (peak 1-hr 0.10") - Pruitt 0.088" (peak 1-hr 0.066") - St. Joe 0.060" (peak 1-hr 0.088") - Richland 0.070" (peak 1-hr 0.045") - Bear Creek 0.028", Harriet 0.013", ungauged 0.005"
Spatial concentration: HUC12 0201 (Terrapin Branch–Buffalo, Boxley HW) at 0.181"; 0202 (Beech Cr) 0.151"; 0203 (Smith Cr) 0.140"; 0102 (Headwaters Little Buffalo) 0.112". This is a headwaters-focused convective burst, NW-quadrant biased, sub-detection-threshold for most gauges (< 0.4–0.5" dry-event threshold for Boxley). Not expected to produce a discrete rise on its own.
No gauge rose today. All seven are in pure recession from Event 9.
Recession increments (24-hr, 00:00 → ~23:00): | Gauge | Δheight | Δdischarge | Rate | |-------|---------|------------|------| | Boxley | -0.10 ft | — | -0.0042 ft/hr | | Ponca | — | -22 cfs | -0.96 cfs/hr | | Pruitt | -0.13 ft | -36 cfs | -1.5 cfs/hr | | St. Joe | -0.26 ft | -117 cfs | -4.9 cfs/hr | | Harriet | -0.21 ft | -152 cfs | -6.3 cfs/hr | | Richland | -0.10 ft | — | -0.0042 ft/hr | | Bear Cr | -0.08 ft | -6.5 cfs | -0.27 cfs/hr |
No new pairs today (no responses). However, the recession-rate data refines prior findings:
St. Joe Event-9 recession (continuing): Day 67-end → Day 68 first 24 hr was ~6.96 cfs/hr (per hypothesis). Day 68 → Day 69: 613 → 491 cfs over ~24 hr = -5.1 cfs/hr, then Day 69 alone 608 → 491 cfs over 22.75 hr = ~-5.1 cfs/hr. Recession is slowing geometrically (6.96 → 5.1), consistent with the Event-8 wet-recession decay sequence (33→16→10→6.6→5.8). Dry recession appears to have a similar fractional decay but starting from a lower magnitude.
Harriet Event-9 recession: ~917 (peak D68 08:45) → 649 cfs at D69 22:45 = -268 cfs over ~62 hr ≈ -4.3 cfs/hr average, faster than St. Joe per unit baseflow but with similar fractional decay. Day 69 alone: -6.3 cfs/hr in first 24 hr post a slower segment — consistent with Harriet's two-phase pattern observed in Event 8.
Not applicable — no rise to propagate. The propagation cascade from Event 9 is fully complete; all gauges are below their Event-9 peaks and well-distributed in the recession sequence (Boxley peaked Day 66, Harriet Day 68 — 44.5 hr cascade, confirming the hypothesis-document figure).
Event 9 status: COMPLETE on the rising/peak side; recession ongoing. All five mainstem gauges plus tributaries are now back at or below their Day 65 (pre-event dry-spring baseflow) values: - Boxley: 2.36 ft (vs Day 65 baseline 2.31 ft) — slightly elevated, likely Boxley's slow pool-drain (hypothesis #5 confirmed: 36+ hr post-peak still 0.05 ft above; today is ~83 hr post-peak Boxley, finally near baseline). - Pruitt: 4.02 ft / 183 cfs (vs Day 65 4.04 ft / 188 cfs) — at baseline. - St. Joe: 4.32 ft / 491 cfs (vs Day 65 4.41 ft / 530 cfs) — slightly below baseline already, confirming the hypothesis #15 dissipation pattern continues even within an ongoing recession. - Harriet: 4.39 ft / 649 cfs (vs Day 65 4.48 ft / 712 cfs) — below baseline. - Richland: 1.46 ft (vs Day 65 1.55 ft) — below. - Bear Cr: 2.32 ft / 27.0 cfs (vs Day 65 2.35 ft / 29 cfs) — at/just below.
Event 9 total duration (peak → return-to-baseline at the lowest gauge): Boxley peak Day 66 12:15 → St. Joe at-baseline Day 69 ~22:45 ≈ 82.5 hr from forcing peak to mainstem return-to-baseline at the bottom gauge. This refines hypothesis #22 — total event resolution under dry antecedent is ~3.5 days, considerably faster than the projected 5-6 days. Likely because zone forcing was small (0.7-1.2") and no significant interflow/groundwater pulse was added.
St. Joe and Harriet are now BELOW the Day 65 dry-spring baseflow. This is unexpected — I hypothesized that recession floors return to pre-event levels, not below. Possible explanations: (a) Day 65 was not actually true baseflow; there was still a tiny residual from earlier events that has now drained; or (b) the May dry-down trend continues independent of Event 9 (seasonal recession). Confidence: this looks like option (b) — the watershed is in a multi-week drying trajectory, and Event 9 was a small perturbation on top of it. The Day 65 "true dry baseflow" anchor in hypothesis #17 should be flagged as provisional and decreasing.
Today's overnight QPE (Boxley 0.18", peak 0.13"/hr) is below detection threshold per current Boxley dry-event hypothesis (~0.4-0.5"). Watch tomorrow to confirm — the rain peaked at 22:02 CDT, so Boxley response (if any) should arrive Day 70 ~02-08 CDT under dry conditions, and may be undetectable.
Pruitt-zone QPE (0.088") is also sub-threshold. Pruitt should remain in recession Day 70.