Day 22 (2026-03-22) — Continued Extended Dry Period
Zero precipitation across all 37 HUC12 sub-watersheds for the third consecutive day. This marks 10 consecutive zero-precip days since the last measurable rainfall on March 14-15. The 7-day antecedent precipitation remains unchanged from Day 21 at 0.14-0.56" across the watershed — the driest conditions observed during this study.
All gauges continued declining. No significant rises detected at any gauge. End-of-day values:
| Gauge | Day 21 EOD | Day 22 EOD | Change | Day 22 Rate (%/hr) | Status |
|---|---|---|---|---|---|
| Boxley | 2.12 ft | 2.07 ft | -0.05 ft | ~0.10 ft/day | — |
| Ponca | 122 cfs | 115 cfs | -7 cfs | ~0.24%/hr | Too Low (<150) |
| Pruitt | 140 cfs / 3.91 ft | 124 cfs / 3.84 ft | -16 cfs / -0.07 ft | ~0.47%/hr | Too Low (<100 threshold not reached, but crossed below Low-but-Floatable) |
| St. Joe | 324 cfs / 3.94 ft | 298 cfs / 3.86 ft | -26 cfs / -0.08 ft | ~0.34%/hr | Optimal (>200) |
| Harriet | 385 cfs / 3.97 ft | 347 cfs / 3.90 ft | -38 cfs / -0.07 ft | ~0.44%/hr | Optimal (>200) |
| Richland | 1.18 ft | 1.13 ft | -0.05 ft | — | Noisy, approaching study low |
| Bear Creek | 9.3 cfs / 2.37 ft | 9.3 cfs / 2.37 ft | ~0 | At floor | At baseflow floor |
Key observations:
Ponca has dropped to 115 cfs by end of day — this is the lowest value observed during the entire study. The Day 21 estimate of ~115-120 cfs as baseflow floor appears to be in the right range, though Ponca is still declining (from 122 at start to 115 by evening). The decline rate (~0.24%/hr) is similar to Day 21, suggesting we have not yet reached the true floor.
Pruitt dropped sharply: from ~140 cfs (Day 21 EOD) to ~124 cfs average, with readings as low as 117 cfs. This is a notable acceleration — the Day 21 rate was ~0.38%/hr, now ~0.47%/hr. This is counterintuitive (recession should decelerate, not accelerate) and likely reflects the noisy Pruitt low-stage CFS readings noted in local knowledge (channel scouring directing flow to river right). The height data tells a cleaner story: 3.91→3.84 ft, a drop of 0.07 ft in 24 hours, consistent with slow continued recession.
Pruitt-Ponca gain has collapsed further: - Day 22: Pruitt ~124 cfs, Ponca ~115 cfs → Gain = 9 cfs (8%) - Compare Day 21: 18 cfs (15%), Day 20: 24 cfs (19%), Day 18: 61 cfs (42%)
This near-disappearance of the Pruitt-Ponca gain at low flow is significant. It could reflect: (a) Pruitt gauge reading artificially low per local knowledge, (b) actual loss of contributing flow from Cove Creek and Hoskin Creek HUC12s as those tributaries go dry, or (c) karst losses in the Ponca-Pruitt reach becoming proportionally significant at low flow. Most likely a combination of all three.
St. Joe declined from 324→298 cfs at a rate of ~0.34%/hr, slightly slower than Day 21 (~0.36%/hr). This very slow deceleration is consistent with sustained karst baseflow from the 14-HUC12 drainage area.
Harriet declined from 385→347 cfs at ~0.44%/hr — slightly faster than Day 21 (~0.42%/hr). Harriet continues to decline faster than St. Joe despite having larger drainage area. The St. Joe→Harriet gain has also been shrinking: Day 21 it was ~61 cfs (19%), Day 22 it's ~49 cfs (16%).
Bear Creek appears to have reached its baseflow floor at 2.36-2.37 ft / ~8.7-9.3 cfs. The CFS oscillation between 8.74 and 9.31 is just quantization noise. This is the first gauge in the study to demonstrably reach a baseflow floor.
Richland Creek continues to show noisy readings (1.13-1.18 ft range) but the central tendency has dropped to about 1.15 ft, down from ~1.18 on Day 21. Still showing the characteristic karst-influenced noise pattern.
None — no precipitation.
No events to track.
The extended dry recession continues to provide excellent baseflow characterization data. The 10-day zero-precip period is the longest in the study to date.
Pruitt recession acceleration is anomalous. The Pruitt CFS recession rate increased from ~0.38%/hr (Day 21) to ~0.47%/hr (Day 22), which contradicts the expected asymptotic deceleration toward baseflow. However, the Pruitt height data shows continued slow recession (3.91→3.84 ft), consistent with expectations. This confirms the local knowledge observation about the Pruitt rating curve being unreliable at low stages — the CFS values are becoming increasingly unreliable as stage drops. For Pruitt at low flow, height is the better metric. This is an important finding for the study: Pruitt CFS should be used with extreme caution below approximately 4.0 ft / 160 cfs.
Bear Creek has reached baseflow floor — the first gauge in the study to do so. At 239 km² drainage, Bear Creek (8.7-9.3 cfs) yields only ~0.037 cfs/km² (0.05 mm/day), which is extremely low. This suggests Bear Creek's watershed has very limited deep groundwater storage relative to other sub-basins.