Effectively zero precipitation today across the entire watershed. Only trace amounts recorded: Boxley HUC12 received 0.021", and a few Ponca-zone HUC12s received 0.002". All other HUC12s recorded 0.000". No gauge-mounted rain gauges recorded any precipitation (Pruitt 0.0", St. Joe 0.0", Harriet 0.0", Bear Creek 0.0").
This is a dry day — ideal for observing the recession limb of Event 1 (March 5) and completing the propagation analysis.
Boxley (07055646): Steady recession all day. Height declined from 2.64 ft at midnight to 2.48 ft at EOD — a drop of 0.16 ft over 24 hours. The recession rate slowed through the day: ~0.04 ft in the first 6 hours, ~0.03 ft in the last 6 hours. This is classic exponential recession from the 3/05 event peak of 2.77 ft. Total recession from peak: 0.29 ft over ~32 hours. Still 0.58 ft above pre-event baseflow (1.90 ft), indicating significant subsurface drainage continuing from yesterday's rainfall.
Ponca (07055660): Monotonic recession all day. Discharge dropped from 177 cfs at midnight to 147 cfs at EOD — a decline of 30 cfs (17%). The recession is smooth and well-behaved, confirming this is entirely runoff drainage from Event 1. Ponca is now approaching the "Low but Floatable" threshold (150 cfs) from above — it briefly touched 200 cfs equivalent yesterday.
Pruitt (07055680) — MAJOR EVENT: This is the headline of Day 6. Pruitt experienced a dramatic rise of 0.63 ft (3.52 → 4.15 ft) with zero local precipitation today.
Timeline: - 00:00-07:15: Gradual rise from 3.53 → 3.59 ft (+0.06 ft over 7 hrs) — this is the tail of yesterday's slow Pruitt rise - 07:30-08:15: Accelerating rise 3.60 → 3.63 ft - 08:15-09:30: Rapid surge 3.63 → 4.00 ft (+0.37 ft in 75 min) — peak rise rate 0.32 ft/hr at 09:30 - 09:30-11:15: Continued rise 4.00 → 4.15 ft (peak) - 11:15-23:30: Slow recession 4.15 → 4.07 ft (-0.08 ft over 12 hrs)
Discharge rose from 62.6 cfs at 00:15 to 206 cfs at 11:15-11:30 — a 230% increase. This is the first time Pruitt has crossed into the Optimal range (200+ cfs) during the study. The new rating curve (post-shift on 3/05) now reads 206 cfs at 4.15 ft height.
Attribution: This is clearly propagated flow from the Boxley/Ponca event of 3/05. The evidence: - Zero local precipitation at Pruitt today - Ponca peaked at ~179 cfs around 19:45-20:30 on 3/05 - Pruitt's rapid rise began ~08:15 on 3/06 - Lag time from Ponca peak to Pruitt rapid rise onset: ~12 hours - Lag time from Ponca peak to Pruitt peak: ~15 hours - The Pruitt peak (206 cfs) exceeds the Ponca peak (179 cfs), which makes sense because Pruitt is cumulative — it receives Ponca flow plus Cove Creek and Hoskin Creek contributions, plus the direct Pruitt-zone rainfall from 3/05 (0.43" at the Pruitt zone) is contributing delayed subsurface flow.
Recreational significance: Pruitt crossed from "Too Low" (<100 cfs) through "Low but Floatable" (100-200) into "Optimal" (200+). At 206 cfs, the Boxley-to-Pruitt reach was briefly floatable. This demonstrates that ~1" of rain in the upper watershed can produce recreational flows at Pruitt with a ~24-hour delay from rainfall onset.
St. Joe (07056000): Height range 3.38-3.46 ft — this is within the normal noise band observed during baseflow (0.08 ft range, same as 3/04). No clear trend upward. CFS fluctuated 144-169, also within baseflow noise. No detectable response yet from Event 1 at St. Joe through EOD 3/06. This is somewhat surprising — if Pruitt peaked at 206 cfs at 11:15, one might expect St. Joe to show some signal by late evening. However, St. Joe integrates 1,342 km² of tributaries, and the mainstem signal from the upper watershed may be diluted by the large St. Joe basin still at baseflow.
Harriet (07056700): Height 3.53-3.57 ft, declining slightly through the day to 3.54 ft. CFS 172-189, trending down from 185→176. This appears to be continued slow recession from the modest Event 1 response. No new signals.
Richland Creek (07055875): Declined from ~1.16 to ~1.14 ft through midday, then recovered slightly to 1.16 ft by evening. This is recession from the 3/05 event. Richland is already approaching its pre-event level (0.93 ft was baseflow, but the 3/05 event raised it to 1.18; it's now at 1.16, suggesting a new elevated baseflow plateau from soil moisture recharge).
Bear Creek (07056515): Flat at 2.32 ft / 6.58 cfs all day. Completely at baseline. No response to anything.
Critical new data point — Ponca→Pruitt propagation: - Ponca peaked at ~179 cfs around 19:45-20:30 on 3/05 - Pruitt began rapid rise at ~08:15 on 3/06 - Pruitt peaked at 206 cfs at ~11:15 on 3/06 - Propagation lag (peak to peak): ~15 hours, Ponca to Pruitt - Propagation lag (peak to onset of rapid rise): ~12 hours - Distance Ponca to Pruitt: approximately 25 river km
This is a long lag for a relatively short distance. Two factors explain this: 1. The Pruitt local zone (Cove Creek + Hoskin Creek, 123 km²) received 0.43" on 3/05, which is contributing delayed subsurface flow that overlaps with and amplifies the mainstem propagation. 2. At these low flows (the channel is carrying only ~60-80 cfs at Pruitt pre-event), water velocity is very slow — perhaps 0.3-0.5 m/s, giving a travel time of ~14-23 hours for 25 km.
Revised Event 1 magnitude assessment: - Total Boxley rise: 1.90 → 2.77 ft (+0.87 ft), from 1.038" rainfall - Total Ponca rise: 83.7 → 179 cfs (+95 cfs, +113%) - Total Pruitt rise: 3.44 → 4.15 ft (+0.71 ft); 62.3 → 206 cfs (+144 cfs, +231%) - Pruitt response was larger than anticipated yesterday, and represents the most significant gauge response in the study so far
Transfer ratio at Pruitt: The cumulative watershed above Pruitt (513 km²) received roughly weighted-average 0.6-0.7" of rain on 3/05 (Boxley 1.04", Ponca 0.59", Pruitt 0.43"). This produced a rise from ~62 to 206 cfs, or +144 cfs. Very rough: ~200 cfs per inch per 500 km² under dry antecedent conditions. This will need refinement with more events.
Full propagation chain observed for Event 1 (updated with today's data):
| Gauge | Peak Time | Peak Value | Lag from Boxley Peak |
|---|---|---|---|
| Boxley | 3/05 15:15-16:00 | 2.77 ft | 0 hours (reference) |
| Ponca | 3/05 19:45-21:30 | 179 cfs | ~4-5 hours |
| Pruitt | 3/06 11:15-11:30 | 4.15 ft / 206 cfs | ~20 hours |
| St. Joe | Not detected through 3/06 EOD | — | >32 hours (if it arrives) |
The Boxley-to-Ponca leg (~4-5 hours) is much faster than the Ponca-to-Pruitt leg (~15 hours peak-to-peak). This likely reflects: - Boxley-to-Ponca distance is shorter - Multiple tributaries (Beech, Smith, Whiteley Creeks) add flow in the Ponca zone, producing a faster composite response - The Ponca-to-Pruitt reach has fewer significant tributaries adding quick runoff
Estimated flow velocity at low-to-moderate flow: - Boxley→Ponca: ~15 km in ~4 hrs = ~1.0 m/s (reasonable for a small mountain river with some gradient) - Ponca→Pruitt: ~25 km in ~15 hrs = ~0.46 m/s (slower due to wider, shallower channel and lower gradient downstream)
Event 1 is now confirmed as a multi-day event: - Rainfall: 3/05 (concentrated 03:00-11:00 UTC, i.e., ~21:00 3/04 to 05:00 3/05 CST) - Gauge responses span 3/05 through 3/06 and are still ongoing - Pruitt is still at 4.07 ft / 183 cfs at EOD 3/06, well above its pre-event 3.44 ft / 62 cfs - Boxley still at 2.48 ft vs 1.90 pre-event - Ponca still at 147 cfs vs 83.7 pre-event
The event was sufficient to move Pruitt into recreational range briefly (>200 cfs for approximately the 11:00-13:30 window on 3/06, roughly 2.5 hours in the optimal zone). Event 1 should be upgraded from Tier 2 to Tier 2 confirmed — it produced recreational flows at Pruitt.
1. Pruitt response magnitude was much larger than expected. Yesterday's analysis described Pruitt's direct response as "barely detectable" (+0.03 ft direct, +0.06 ft evening propagation). Today revealed the full propagation pulse reaching +0.63 ft total, with Pruitt peaking at 206 cfs. This is a 3x larger response than the Ponca gauge (in percentage terms). The amplification likely comes from: (a) the Pruitt local zone's delayed contribution, (b) channel storage effects releasing water over a longer period, and (c) the subsurface pathway through karst terrain delivering water on a 12-24 hour delay.
2. The Ponca-Pruitt discharge inversion may now be assessable. With the new Pruitt rating curve, Pruitt at 4.07 ft reads 183 cfs while Ponca at 147 cfs. For the first time, Pruitt discharge exceeds Ponca discharge, which is the expected physical relationship (downstream > upstream). This suggests the new rating curve may have partially corrected the inversion. However, we need to wait until both gauges return to baseflow to make a fair comparison.
3. St. Joe non-response. Through 36+ hours after peak rainfall, St. Joe shows no detectable signal from Event 1. This is consistent with the massive basin area (1,342 km² of direct tributaries plus 513 km² upstream) diluting the upper-watershed signal. The mainstem pulse from Pruitt (peaking at 206 cfs) is propagating into a basin where baseflow tributaries contribute ~150+ cfs already. The incremental rise may be only 0.01-0.03 ft at St. Joe — below the noise floor.
4. Pruitt rating curve validation. The new rating curve (post-shift 3/05 15:00) is now being exercised across a wider range: 3.47 ft → 55 cfs to 4.15 ft → 206 cfs. The height-discharge relationship appears internally consistent (monotonically increasing, reasonable nonlinearity). The curve shift was likely a legitimate USGS update, not an artifact. Confidence in the new Pruitt curve: Moderate-High for the 3.47-4.15 ft range.
Local knowledge comparison: The propagation timing (15-20 hours from upper watershed to Pruitt for peak arrival) is consistent with what experienced paddlers would describe as "put in at Boxley when it rains, float to Pruitt the next morning when the water arrives." The "pool and drop" nature above Boxley (local knowledge) helps explain why Boxley's response was delayed until ~10:30 on 3/05 despite rainfall starting around 03:00 — a ~7-hour fill-and-spill delay.