Day 39 (April 8, 2026) — Continued dry recession from Event 4, Day 4 post-peak
Zero precipitation across all 37 HUC12s. This is the fourth consecutive dry day (since the end of Event 4's Pulse 3 on April 4). The 7-day antecedent precipitation remains unchanged from yesterday at 1.4-2.8" across the watershed, reflecting the Event 4 totals that will begin dropping out of the 7-day window starting tomorrow.
All gauges continuing smooth recession. No rises detected. End-of-day values:
| Gauge | End of Apr 7 | End of Apr 8 | Change | Days since peak |
|---|---|---|---|---|
| Boxley | 2.65 ft | 2.53 ft | -0.12 ft (-4.5%) | 4.4 |
| Ponca | 195 cfs | 173 cfs | -22 cfs (-11.3%) | 4.3 |
| Pruitt | 299 cfs / 4.43 ft | 254 cfs / 4.28 ft | -45 cfs (-15.1%) / -0.15 ft | 3.9 |
| St. Joe | 955 cfs / 5.28 ft | 753 cfs / 4.92 ft | -202 cfs (-21.2%) / -0.36 ft | 3.4 |
| Harriet | 1,260 cfs / 5.15 ft | 982 cfs / 4.83 ft | -278 cfs (-22.1%) / -0.32 ft | 3.2 |
| Richland | 1.98 ft | 1.81 ft | -0.17 ft (-8.6%) | 4.0 |
| Bear Creek | 18.6 cfs / 2.55 ft | 14.1 cfs / 2.46 ft | -4.5 cfs (-24.2%) / -0.09 ft | 4.3 |
Key threshold crossings today: - Ponca crossed below Low-but-Floatable (200 cfs) yesterday (~18:00 Apr 7) and continued declining through "Too Low" range. At 173 cfs end-of-day, Ponca is now firmly in "Low but Floatable" (150-200 cfs). Total Optimal duration for Event 4: ~55 hours (confirmed from yesterday's analysis). - Pruitt still in Optimal at 254 cfs, well above 200 cfs threshold. Declining ~15%/day. At this rate, Pruitt will cross below Optimal (~200 cfs) around April 10-11. - St. Joe still in Optimal at 753 cfs, well above 200 cfs. Declining ~21%/day but decelerating. Will remain Optimal for several more days. - Harriet still in Optimal at 982 cfs, well above 200 cfs. Declining ~22%/day. Will remain Optimal for several more days.
No new rainfall-response pairs. Pure recession data collection.
No propagation events. Recession continues uniformly downstream.
Event 4 recession — Day 4 update (the best recession dataset of the study, now 4 clean dry days):
Recession rates by day (% decline per day in CFS where available):
| Gauge | Day 1 (Apr 5→6) | Day 2 (Apr 6→7) | Day 3 (Apr 7→8) | Trend |
|---|---|---|---|---|
| Boxley | ~7% (ht) | ~5.4% (ht) | ~4.5% (ht) | Continued deceleration |
| Ponca | ~21% | ~13% | ~11.3% | Continued deceleration |
| Pruitt | ~27% | ~19% | ~15.1% | Continued deceleration |
| St. Joe | ~40% | ~29% | ~21.2% | Strong continued deceleration |
| Harriet | ~41% | ~26% | ~22.1% | Continued deceleration |
| Bear Creek | ~50% | ~33% | ~24.2% | Continued deceleration |
The Day 3 recession data confirms and strengthens the deceleration pattern. All gauges show continued slowing of recession rates, consistent with the transition from surface runoff to subsurface/baseflow contributions. The downstream gauges (St. Joe, Harriet) show particularly strong deceleration — St. Joe dropped from 40% to 29% to 21%, suggesting the large 14-HUC12 drainage continues to release stored water.
Pruitt height is approaching a possible baseflow floor. The height readings at Pruitt are slowing dramatically — ending at 4.28 ft with very flat readings from ~17:00 onward (4.28-4.30 ft for 7+ hours). This near-stabilization at elevated levels (pre-event was 3.45 ft) suggests significant sustained baseflow contribution, likely from karst springs in the Cove Creek and Hoskin Creek drainages.
Boxley approaching baseflow floor. At 2.53 ft with only 0.01 ft/hr changes, Boxley is very close to its dry-weather baseline. The pre-Event 4 value was 1.84 ft, so there's still 0.69 ft of residual elevation, but the decline rate is asymptotically approaching zero. This is consistent with the pool-and-drop morphology described in local knowledge — once pools are full, recession becomes very slow.
Pruitt height stabilization anomaly: Pruitt readings from ~17:00 onward show remarkable stability (4.28-4.30 ft range, essentially flat). This is earlier stabilization than expected given that Pruitt was still showing 15% CFS decline earlier in the day. This could be: 1. The river-right/river-left flow distribution noted in local knowledge — at these intermediate flows, more water may be shifting to river right away from the gauge, making the gauge "underread" the actual remaining flow. 2. A genuine baseflow equilibrium being reached in the local Pruitt drainage.
The CFS data still shows decline (254 cfs at end of day), so the rating curve is translating the flat height into declining discharge. This is worth monitoring — if height truly stabilizes while CFS continues declining, it may reflect rating curve extrapolation rather than actual conditions.
Bear Creek approaching baseline rapidly. At 14.1 cfs and 2.46 ft, Bear Creek is approaching its pre-Event 4 values (4.2 cfs, 2.27 ft). The 93% decline from peak (203 cfs) in 4.3 days confirms Bear Creek as the flashiest gauge in the network. By tomorrow it should be very close to baseline. This confirms the "early warning indicator" hypothesis — Bear Creek's return to baseline signals that the fast-response component of Event 4 is essentially exhausted watershed-wide.