Daily Analysis

Day 38 (April 7, 2026) — Third consecutive dry day. Event 4 recession continues.

1. PRECIPITATION SUMMARY

Zero precipitation across all 37 HUC12s. This is the third consecutive dry day (Apr 5, 6, 7). The Harriet gauge recorded 0.17" but this appears to be a trace/artifact — no other gauge or QPE source shows any rain, and there's no corresponding gauge response. The 7-day antecedent remains unchanged from yesterday at 1.4–2.8" across the watershed.

2. GAUGE RESPONSES

All gauges continuing clean recession from Event 4. No new inputs.

End-of-day values and recession tracking (Apr 7):

Gauge End Apr 6 End Apr 7 Daily Change Recession Rate
Boxley 2.80 ft 2.65 ft -0.15 ft 5.4%/day (height)
Ponca 224 cfs 195 cfs -29 cfs 13%/day
Pruitt 367 cfs / 4.64 ft 299 cfs / 4.43 ft -68 cfs / -0.21 ft 19%/day
St. Joe 1,340 cfs / 5.87 ft 955 cfs / 5.28 ft -385 cfs / -0.59 ft 29%/day
Harriet 1,700 cfs / 5.61 ft 1,260 cfs / 5.15 ft -440 cfs / -0.46 ft 26%/day
Richland 2.19 ft 1.98 ft -0.21 ft 9.6%/day (height)
Bear Creek 27.8 cfs / 2.69 ft 18.6 cfs / 2.55 ft -9.2 cfs / -0.14 ft 33%/day

Key recreational status crossings today: - Ponca crossed below Optimal (200 cfs) at ~17:15-18:00 CST — readings fluctuated around 200 from 15:15 through 19:00, then firmly below at 197 by 19:15. Now in "Low but Floatable" (150-200 cfs) at 195 cfs. Event 4 total Optimal duration at Ponca: ~55 hours (from ~11:00 Apr 4 to ~18:00 Apr 7). - Pruitt remains in Optimal (>200 cfs) at 299 cfs. At current recession rate (~68 cfs/day, decelerating), Pruitt should remain above 200 cfs for approximately 1.5 more days (crossing ~Apr 9). - St. Joe remains firmly in Optimal at 955 cfs (threshold 200). Still 4.8x above the lower Optimal threshold. At current rate (~385 cfs/day, decelerating), St. Joe could remain Optimal for many more days. - Harriet remains firmly in Optimal at 1,260 cfs (threshold 200). Still 6.3x above lower Optimal.

3. RAINFALL-RESPONSE PAIRS

No new rainfall. Recession analysis continues.

4. DOWNSTREAM PROPAGATION

No new propagation events.

5. MULTI-DAY EVENTS — RECESSION ANALYSIS (Day 3 of dry recession)

This is the most valuable clean recession dataset of the study so far — three consecutive dry days.

Recession deceleration confirmed across all gauges:

Gauge Apr 5→6 Rate (%/day) Apr 6→7 Rate (%/day) Deceleration
Ponca 21% 13% Strong
Pruitt 27% 19% Moderate
St. Joe 40% 29% Strong
Harriet 41% 26% Very strong
Bear Creek 50% 33% Strong

The deceleration pattern is universal and significant. Every gauge is slowing its recession rate on the third dry day compared to the second. This is the classic exponential recession curve — the rapid surface runoff component has largely drained, and what remains is increasingly sustained by slower subsurface/baseflow pathways.

St. Joe deceleration is particularly notable: From 40%/day to 29%/day. At this rate of deceleration, St. Joe will likely maintain Optimal flows (>200 cfs) for 5+ more dry days. This strongly supports the hypothesis that the 14-HUC12 sub-watershed provides substantial baseflow sustenance. Confidence upgraded from moderate to moderate-high.

Harriet shows the strongest deceleration: 41% → 26%. This makes physical sense — it has the largest drainage (2,775 km²) and the most diffuse baseflow pathways. Harriet will likely be the last gauge to drop below Optimal.

Boxley recession is remarkably slow: Only 0.15 ft/day decline on Day 3, and the height is approaching what appears to be a baseflow floor around 2.6-2.7 ft. This is consistent with local knowledge about pool-and-drop morphology retaining water.

Bear Creek recession comparison: Bear Creek has gone from 203 cfs peak → 18.6 cfs in just 3 days (91% decline). This confirms it as the flashiest gauge in the network, consistent with its small drainage area (239 km²) and steep terrain.

6. ANOMALIES OR SURPRISES

Pruitt recession anomaly on late Apr 6: On Apr 6, Pruitt CFS jumped from ~347 at 19:30 to ~374 at 20:00, then stayed elevated through end of day. Today (Apr 7), Pruitt started at 360-367 cfs, higher than the pre-jump value. This ~27 cfs bump with no QPE is puzzling. Possible explanations: (1) delayed subsurface contribution arriving at Pruitt, (2) gauge noise/rating curve artifact, (3) very localized rain not captured by MRMS. Given it persisted into Apr 7 morning before resuming decline, explanation (1) seems most likely — a late pulse of subsurface water from Cove or Hoskin Creek. However, it's small enough to be within gauge noise range. Noted but not actionable.

Harriet 0.17" gauge precip: This trace amount on an otherwise dry day with zero QPE everywhere suggests either a very localized shower below MRMS resolution or an instrument artifact. No gauge response detected, so it's below any detection threshold. Filed as noise.