1. PRECIPITATION SUMMARY Zero QPE across all 37 HUC12s for the 24-hour period. Watershed-wide dry day. 7-day antecedent values continue to reflect Day 66 forcing (Boxley zone 1.27", Richland 1.06", Bear Cr 0.94", St. Joe ~0.7", Pruitt 0.51", Harriet 0.32") with marginal increment from yesterday's trace.
2. GAUGE RESPONSES
Today completes Event 9 peaks at the two large mainstem gauges and shows recession everywhere else.
| Gauge | Pre (D65) | Today's peak | Time of peak | Total Event-9 rise | Status end-D68 |
|---|---|---|---|---|---|
| Boxley | 2.29 ft | (peaked D66 at 3.16) | — | +0.87 ft | 2.47 ft, recession ongoing |
| Ponca | 206 cfs | (peaked D66 at 396) | — | +190 cfs | 231 cfs, recession |
| Pruitt | 4.02 ft / 183 cfs | (peaked D67 at 4.67/377) | — | +0.65 ft / +194 cfs | 4.16 ft / 221 cfs, recession |
| St. Joe | 4.41 ft / 530 cfs | 4.91 ft / 774 cfs | ~22:30 D67 (rolled into early D68) | +0.50 ft / +244 cfs | 4.59 ft / 613 cfs, recession |
| Harriet | 4.48 ft / 712 cfs | 4.75 ft / 917 cfs | 08:45 D68 | +0.27 ft / +205 cfs | 4.62 ft / 816 cfs, recession |
| Richland | 1.53 ft | (peaked D67 at 1.86) | — | +0.33 ft | 1.57 ft, near pre-event |
| Bear Cr | 28.5 cfs / 2.34 ft | (peaked D66 at 62.8/2.66) | — | +34.3 cfs / +0.32 ft | 33.5 cfs / 2.40 ft |
St. Joe peak appears to have actually occurred late D67 (22:30 at 4.92 ft, 780 cfs) — the value just barely incremented at the day boundary. So St. Joe peak: 4.92 ft / 780 cfs at ~22:30 D67, lag ~36 hr from the 09-10 CDT D66 forcing peak.
Harriet peak: 4.75 ft / 917 cfs at 08:45 D68, lag ~47 hr from forcing peak. The gauge reached this value twice (08:45 and 09:45) before clear recession set in.
3. RAINFALL-RESPONSE PAIRS — Event 9 final closure
St. Joe (zone QPE 0.72", peak 1-hr 0.76", dry antecedent — true dry baseline): - Lag: ~36 hr (forcing peak ~10:00 D66 → gauge peak ~22:30 D67) - Rise: +0.51 ft / +250 cfs - Transfer ratio: 0.71 ft/in / ~347 cfs/in zone-avg - Comparison to prior: Wet-compound (Event 8) was ~2.1 ft/in, ~1500 cfs/in. Dry/wet damping ratio ≈ 3.0× for ft/in and ≈ 4.3× for cfs/in. This sits inside the provisional 0.7-0.9 ft/in range I forecasted Day 67. Confidence on St. Joe dry transfer is now MEDIUM-HIGH with one event. - Lag comparison: wet-compound St. Joe lag was ~14 hr from upstream Pruitt peak (full event ~26 hr from Boxley); dry lag from forcing is ~36 hr — roughly 2.5× slower under dry, consistent with my "60-80% slower" hypothesis.
Harriet (zone QPE 0.27", peak 1-hr 0.12", dry antecedent): - Lag: ~47 hr from forcing peak. - Rise: +0.27 ft / +205 cfs - The Harriet zone itself got almost no rain (0.27"). Most of the rise is propagation from upstream, not local Harriet-zone runoff. Bear Creek peaked Day 66 at 62.8 cfs (a ~34 cfs anomaly) and was already receding by the time Harriet rose — so the Harriet rise is dominantly mainstem propagation from St. Joe. - Transfer ratio is therefore not cleanly attributable to Harriet zone QPE. If forced: 0.27 ft / 0.27" zone-avg = 1.0 ft/in, but this is misleading because the source is upstream. - Better framing: St. Joe rose +0.51 ft, Harriet rose +0.27 ft. Harriet/St. Joe propagation magnitude ratio = 0.53. Under wet conditions (Event 8), this ratio was ~70%. Dry conditions show ~50% magnitude transmission St. Joe→Harriet, with extra channel storage and conveyance loss.
Pruitt→St. Joe propagation (dry): Pruitt peaked 02:00 D67, St. Joe peaked ~22:30 D67. Lag = ~20.5 hr. Earlier provisional was 22-24 hr; refining to ~20-21 hr dry. Wet-compound Pruitt→St. Joe was ~14 hr. Dry is ~46% slower, in the same direction as expected but smaller delta than estimated.
St. Joe→Harriet propagation (dry): St. Joe ~22:30 D67 → Harriet 08:45 D68 = ~10.25 hr. Wet was ~9 hr. Essentially the same — dry condition adds little to St. Joe→Harriet lag despite adding substantially upstream. Hypothesis: the channel between St. Joe and Harriet has more uniform geometry and less karst storage than upstream segments, so antecedent has minimal effect.
4. DOWNSTREAM PROPAGATION — Event 9 full mainstem cascade (DRY, COMPLETE)
| Segment | Time | Hours |
|---|---|---|
| Forcing peak (~10:00 D66) → Boxley peak (12:15 D66) | — | ~2.25 hr |
| Boxley → Ponca (15:15 D66) | — | ~3 hr |
| Ponca → Pruitt (02:00 D67) | — | ~10.75 hr |
| Pruitt → St. Joe (22:30 D67) | — | ~20.5 hr |
| St. Joe → Harriet (08:45 D68) | — | ~10.25 hr |
| Total Boxley → Harriet | ~44.5 hr | |
| Total forcing → Harriet | ~46.75 hr |
Wet-condition cascade Boxley→Harriet was ~33 hr. Dry-condition cascade is ~44.5 hr — ~35% slower end-to-end, NOT the ~80% I projected earlier. The slowdown is concentrated in the Pruitt→St. Joe segment; downstream of St. Joe the channel routes essentially the same speed wet or dry. Refining hypothesis #12.
5. MULTI-DAY EVENTS
Event 9 closure: 1.23" peak (Boxley zone, single 09-10 CDT D66 pulse) propagated through entire mainstem chain over ~46.75 hr, producing: - Boxley +0.87 ft (no recreational threshold reached) - Ponca +190 cfs (briefly Optimal at 396 cfs) - Pruitt +0.65 ft / +194 cfs (briefly Optimal at 377 cfs) - St. Joe +0.51 ft / +250 cfs (Optimal throughout — was already) - Harriet +0.27 ft / +205 cfs (Optimal throughout — was already)
Total event magnitude small but fully traceable. Recession on D68 across all gauges.
6. ANOMALIES / NOTABLE