PRE-ANALYSIS (per-gauge facts, Day 103, 2026-06-11):
| Gauge | (a) first | (b) max | (c) last | (d) intraday low | (e) low→peak rise |
|---|---|---|---|---|---|
| Boxley | 2.86 ft @00:00 | 2.86 ft @00:00 | 2.65 ft @23:30 | 2.65 ft @23:30 | none — monotonic fall; only +0.01 ft micro-blip 08:30 (noise) |
| Ponca | 280 cfs @00:00 | 280 cfs @00:00 | 209 cfs @23:30 | 209 cfs @23:30 | none — monotonic recession |
| Pruitt | 4.94 ft / 503 cfs @00:00 | 4.94 ft / 503 cfs @00:00 | 4.56 ft / 364 cfs @23:30 | 4.55 ft @23:15 | none — +0.01 ft @08:30 (noise) |
| St. Joe | 5.69 ft / 1250 cfs @00:00 | 5.69 ft / 1250 cfs @00:00 | 5.17 ft / 920 cfs @22:45 | 5.17 ft / 920 cfs @22:45 | none — monotonic recession |
| Harriet | 5.55 ft / 1640 cfs @00:00 | 5.55 ft / 1640 cfs @00:00 | 5.08 ft / 1200 cfs @22:45 | 5.08 ft / 1200 cfs @22:45 | none — monotonic recession |
| Richland | 1.31 ft @00:00 | 1.31 ft @00:00 | 1.22 ft @23:00 | 1.22 ft @21:00 | none — flashy recession continues |
| Bear Cr | 2.26 ft / 28.5 cfs @00:00 | 2.26 ft / 28.5 cfs @00:00 | 2.20 ft / 24.2 cfs @23:15 | 2.19 ft / 23.5 cfs @23:00 | none — +0.01 ft micro-blip 07:45 (noise) |
(f) QPE-peak timing for attribution: Not applicable. Basin-max 24-hr QPE today = 0.000" (every HUC12, every zone). D-1 = 0.000". No rainfall-response pairs exist to attribute. No lag or transfer computation possible.
Every gauge's max equals its first reading — all seven gauges are in pure recession from the Event 19 peaks (Day 100–101). This is the third consecutive recession-only day (Days 102–103, with the watershed dry since Day 101).
1. PRECIPITATION SUMMARY: No rain anywhere in the basin. All 37 HUC12s report 0.000" 24-hr total, 0.000" peak 1-hr. Third straight dry day. 7-day antecedent totals are now frozen/declining (e.g., Boxley zone 3.558", St. Joe sub-zones 1.2–2.5") — these are residual from Event 19 and will roll off over coming days. Nothing to report.
2. GAUGE RESPONSES: No rises. All gauges falling. This is a clean Day ~2–3 post-peak recession day for the lower mainstem (St. Joe peak was Day 101 10:30). Recreational status remains favorable basin-wide — Event 19's elevated-baseflow tail is still delivering a multi-day Optimal window: - St. Joe 920 cfs (mid-Optimal, well above 200 floor) - Harriet 1200 cfs (Optimal) - Pruitt 364–503 cfs / 4.55–4.94 ft (Optimal) - Ponca 209–280 cfs (Optimal, but approaching the 200-cfs Low-Floatable boundary by day's end — worth watching) - Boxley 2.65 ft (normal flow, below Hailstone/Boxley-Ponca recreational thresholds)
3. RAINFALL-RESPONSE PAIRS: None. Zero QPE — no pairs to compute. Per role guidance, I will not invent patterns in noise; the ±0.01 ft/±0.7 cfs blips at Boxley/Pruitt/Bear Cr are sensor quantization, not signal.
4. DOWNSTREAM PROPAGATION: No propagating pulse. The mainstem is draining the Event 19 pipeline. I can, however, extend the high-flow recession-rate curve (Open Question #11) with today's Day-2/3 rates:
Cross-day comparison (mandatory): Day 102 recorded St. Joe ~32 cfs/hr and Harriet ~37 cfs/hr at ~1300–2500 cfs. Today (Day 103) both have roughly halved to 14.5 / 19.3 cfs/hr at ~900–1600 cfs — a fractional decay ratio of ~0.45–0.52 per 24-hr window, squarely within the documented geometric-decay range (0.5–0.9) and tracking the St. Joe canonical Event-8 fast-interflow sequence (33→16→10…). The two gauges have diverged slightly in absolute rate (Harriet now ~33% faster than St. Joe) where they were near-identical on Day 102 — expected, since Harriet still sits ~280–390 cfs higher on its recession limb (steeper part of its dQ/dt-vs-Q relationship). Convergence holds qualitatively; the small offset is a flow-level effect, not a contradiction.
5. MULTI-DAY EVENTS: Today is Day 5 of the Event 19 recession (peaks Day 100–101). The lower mainstem remaining mid-Optimal on Day 5 confirms and extends the Event-19 corollary: an upstream-only flood still produces a multi-day, basin-wide Optimal recreation tail. Event 19's Optimal window at St. Joe/Harriet is now confirmed ≥5 days and counting. Boxley has nearly completed its ~4-day pool drain from the Day-100 5.50 ft study-record peak (now 2.65 ft, into slow-seepage phase).
6. ANOMALIES OR SURPRISES: None. A textbook recession-only day. The only minor note is Ponca approaching its 200-cfs Low-Floatable threshold (209 cfs at 23:30) — if the dry spell continues another 1–2 days Ponca will be first of the mainstem chain to drop out of Optimal, consistent with its small drainage area and the fact that it has no sustaining upstream reservoir of routed flow the way St. Joe/Harriet do.