Zero precipitation across the entire watershed today. All 37 HUC12s recorded 0.00" for the 24-hour period. All gauge tipping buckets (Pruitt, St. Joe, Harriet, Bear Creek) recorded 0.00". This is the first completely dry day of the study period.
The 7-day antecedent precipitation values are still slowly increasing for eastern HUC12s due to the 3/01-3/02 rainfall remaining in the rolling window, but no new moisture was added today. Peak 7-day antecedent values: Leatherwood Creek (ungauged) 0.846", Clabber Creek (ungauged) 0.769", Boat Creek (ungauged) 0.756". Within gauged zones, the highest are: Cove Creek (Pruitt) 0.610", Water Creek (Harriet) 0.608", Cane Branch (St. Joe) 0.424".
All gauges continued baseflow recession with no rainfall-driven response. Updated end-of-day values and recession tracking:
| Gauge | EOD Value | Prior EOD (3/02) | Daily Change | Rate |
|---|---|---|---|---|
| Boxley | 1.90 ft | 1.92 ft | -0.02 ft | Steady recession |
| Ponca | 82.4 cfs | 85.1 cfs | -2.7 cfs | ~3.2%/day |
| Pruitt | 62.3 cfs / 3.43 ft | 69.4 cfs / 3.48 ft | -7.1 cfs / -0.05 ft | ~10%/day (CFS), accelerating |
| St. Joe | 165 cfs / 3.43 ft | 171 cfs / 3.45 ft | -6 cfs / -0.02 ft | ~3.5%/day |
| Harriet | 180 cfs / 3.55 ft | 189 cfs / 3.57 ft | -9 cfs / -0.02 ft | ~4.8%/day |
| Richland | 0.92 ft | 0.93 ft | -0.01 ft | Recession, reached new study low of 0.90 ft intraday |
| Bear Creek | 6.58 cfs / 2.32 ft | 7.2 cfs / 2.33 ft | -0.62 cfs / -0.01 ft | ~8.6%/day — stepped down to new quantization level |
Notable observations:
Ponca stepped down to the 83.7 cfs quantization level around 04:30 and held there most of the day, with a final step to 82.4 cfs at 23:30. The recession is orderly but continuing.
Pruitt continues its diurnal cycling pattern. Today's minimum was 59.6 cfs at both 11:15 and 13:45, a new study low. The nighttime peak was only ~69.4 cfs (down from ~73.8 yesterday night). The diurnal range today was ~10 cfs (59.6–69.4), consistent with the ~14-15% of mean pattern. The diurnal minimum timing today: 11:15 and 13:45 — notably earlier than yesterday's 16:30 and the day before's 14:45-16:00. This shift backward is unexpected and may relate to the fully dry conditions (no evapotranspiration demand from residual soil moisture?). However, there were also isolated low readings at 15:15 (59.6 cfs). The pattern may be becoming noisier as flow drops.
Pruitt recession is accelerating sharply. Nighttime values dropped from ~72-73 cfs (3/02 overnight) to ~67-68 cfs (3/03 overnight) to ~63-65 cfs (3/03 late evening). This represents an overnight-to-overnight decline of ~5-6 cfs/day (~7-8%/day). If we compare the diurnal minimums: 63.7 cfs (3/02) → 59.6 cfs (3/03), that's a decline of ~6.5% in one day for the minimum values.
St. Joe set new study lows: minimum height 3.41 ft (at 11:45 and 13:00 and 17:00), minimum discharge 158 cfs (at 11:45 and 13:00 and 17:00). The noise band remained at 0.07 ft (3.41-3.48), same as yesterday. Discharge is now firmly approaching the lower bound of "Low but Floatable" (40-200 cfs range).
Harriet continued its accelerated recession. Height dropped from 3.57 to 3.55 ft, and discharge stepped down from the 189 cfs level to solidly at 180 cfs by late afternoon. The transition from 3.56 to 3.55 ft occurred around 17:30. The recession is now very clear: 201→189→180 cfs over 3 days.
Bear Creek stepped down to the 6.58 cfs quantization level around 16:30, a new study low. Height dropped to 2.32 ft (new low). This creek is approaching extremely low flow — specific discharge now ~0.028 cfs/km².
Richland Creek showed an interesting intraday pattern. After declining to new lows (0.90 ft at 13:00-16:15), there was a brief spike to 0.95 ft at 17:45, falling back to 0.91 by 18:00. Additional smaller bumps at 18:15 (0.94), 18:45 (0.94). Given zero precipitation in the Richland zone today, this is not rainfall-driven. Possible explanations: (1) sensor noise at very low levels, (2) brief discharge from a karst spring pulse, or (3) animal/debris disturbance. The pattern is unusual — multiple elevated readings in the 17:45-19:30 window followed by settling back to 0.91-0.92. This is within the previously established ±0.05 noise range for Richland, but the clustering at a specific time is notable.
Ponca-Pruitt discharge inversion update: Using overnight values to avoid Pruitt's diurnal cycling: Ponca ~85 cfs, Pruitt nighttime max ~68-69 cfs → deficit ~16-17 cfs. The inversion continues with the deficit slightly widening as Pruitt drops faster. This is consistent with the losing reach hypothesis: as total flow decreases, the fixed karst loss represents a larger fraction.
None. Zero precipitation today across all HUC12s.
No rises to track. All gauges receding.
The light rainfall from 3/01-3/02 (0.1-0.6" in various zones) produced zero detectable response at any gauge even 24-48 hours later. This further strengthens the non-detection result. With 7-day antecedent precipitation reaching 0.6" in some eastern zones and still no response, the soil moisture deficit hypothesis is well-supported.
Pruitt diurnal minimum timing shift: The minimum appeared to shift earlier today (11:15) compared to the progressive later shift observed 2/28→3/02 (14:00→16:30). This reversal is unexpected. One explanation: the previous late-afternoon minimums may have been influenced by subtle subsurface drainage from the 3/01-3/02 rainfall that temporarily buffered the daytime decline, delaying the minimum. With a fully dry day today, the natural diurnal pattern may have reasserted earlier. Confidence: Low — only one data point of the reversal.
Richland Creek anomalous spikes (17:45-19:00): Brief height spikes to 0.94-0.95 ft from a baseline of 0.90 ft, during zero-precipitation conditions. Most likely sensor noise or brief karst discharge, but worth noting for pattern recognition.
Harriet recession continues to accelerate: Three consecutive days of faster decline (2.6%/day avg → 4.8%/day today). The baseflow "floor" hypothesis remains contradicted — no sign of stabilization.