Essentially zero new rainfall today (Apr 17). No HUC12 received more than 0.019" in 24 hours. The watershed is dry today — this is a pure propagation/recession day following Event 6 rainfall that fell primarily on Apr 16 (00:00-06:00 UTC, i.e., late evening Apr 15 through midnight Apr 16 CST).
Today reveals the Event 6 propagation wave moving through the system with no new rainfall to complicate interpretation. This is an exceptionally clean propagation signal.
Boxley: Receding all day from Event 6 peak. Started at 2.55 ft, declined smoothly to 2.43 ft (-0.12 ft). The Event 6 peak was 2.65 ft on Apr 16 ~13:00 CST. Recession rate ~0.01 ft/hr, very orderly.
Ponca: Also receding from Event 6 peak (167 cfs on Apr 16 ~17:00 CST). Declined from 159 cfs at midnight to 141 cfs by EOD. Ponca dropped below 150 cfs ("Low but Floatable" threshold) around 13:00 CST Apr 17. Ponca re-entered "Too Low" (<150 cfs) — the Event 6 bump kept Ponca above 150 for only ~27 hours (from ~10:00 Apr 16 to ~13:00 Apr 17).
Pruitt: Major rise today — Event 6 propagation wave arrives. - Started at 3.85 ft / 138 cfs at midnight - Rose steadily: 3.85→3.97→4.06→4.13 ft peak at ~07:15 CST (+0.28 ft / +75 cfs, from 138 to 213 cfs) - Pruitt crossed into Optimal (>200 cfs) at ~04:30 CST and peaked at 213 cfs at ~07:15 CST - Began slow recession, still at 4.03 ft / 185 cfs at EOD - Pruitt dropped back below 200 cfs around 13:00 CST — approximately 8.5 hours in Optimal
St. Joe: Clear rising limb — Event 6 + Richland/Cave Creek runoff arriving. - Started at 3.85 ft / 295 cfs (continuing prior recession) - Slight dip to 3.84 ft / 291 cfs around 03:00 CST, then began rising - Steady rise through the day: 3.84→3.91→3.97→4.09 ft by 22:45 CST - CFS: 291→314→335→379 cfs by EOD — a +88 cfs rise (+30%) - Rise is accelerating in the evening (0.05 ft/hr at 17:30), suggesting the wave hasn't peaked yet - St. Joe remains well within Optimal (200-8000 cfs)
Harriet: - Started at 3.99 ft / 396 cfs - Dipped to 3.96 ft / 380 cfs by ~08:00-12:00 CST (continued recession from prior days) - Began rising late afternoon/evening: 3.96→3.98→4.01 ft by EOD; 380→391→408 cfs - Rise of +0.05 ft / +28 cfs from the intra-day trough — upstream propagation beginning to arrive - Bear Creek flat at 2.21-2.24 ft / 19.8-21.6 cfs (minor +0.03 ft uptick in evening, likely from Bear Creek zone's 0.53" on Apr 16) — Signal separation: Bear Creek showing minimal independent response, confirming Harriet's evening rise is mainstem propagation from upstream, not local tributary input.
Richland Creek: Receding all day from Event 6 peak. 1.72→1.60 ft (-0.12 ft). Clean recession, no new rainfall in Richland zone today (0.0" QPE).
Bear Creek: Essentially flat at 2.21-2.24 ft. The minor +0.03 ft uptick in evening is consistent with delayed subsurface response to Apr 16's 0.53" in the Bear Creek zone, not a significant event.
Event 6 — now fully resolved for upstream gauges:
The Apr 16 rainfall (fell ~23:00 CST Apr 15 through ~01:00 CST Apr 16, peak around midnight) provides an excellent calibration dataset because: - Rain was concentrated in a ~3-hour window - No follow-up rain today (pure propagation) - Multiple gauge responses are cleanly separated
Boxley: - Rainfall: Boxley HUC12 0.38" (peak 0.177"/hr), plus 0.47" in prior 24hr = ~0.85" 2-day total - Pre-event: 2.15-2.17 ft (nearly at baseflow) - Peak: 2.65 ft at ~13:00 CST Apr 16 (+0.48 ft) - QPE centroid: ~01:00 CST Apr 16. Lag to peak: ~12 hours - Antecedent 7-day: ~0.67" (low-moderate) - Transfer ratio: 0.85" → 0.48 ft = 0.56 ft per inch (moderate antecedent) - Compare Event 1 (1.038" → 0.87 ft = 0.84 ft/inch, wet antecedent) and Event 5 (0.553" → 0.20 ft = 0.36 ft/inch, moderate antecedent). This is consistent — the 0.85" total with moderate antecedent yielding 0.56 ft/inch falls between dry and wet conditions.
Ponca: - Rainfall: Ponca zone avg 0.36" on Apr 16 (plus Boxley propagation) - Pre-event: 117-118 cfs - Peak: 167 cfs at ~17:00 CST Apr 16 (+49 cfs, +42%) - Lag from QPE centroid (~01:00 CST): ~16 hours to Ponca peak - Lag from Boxley peak (13:00 CST Apr 16) to Ponca peak (17:00 CST Apr 16): ~4 hours — consistent with Event 1 (4-5 hr) and Event 4 (1.75 hr at higher flow).
Pruitt: - Rainfall: Pruitt zone 0.30" + Cove Creek 0.33" on Apr 16, plus upstream propagation - Pre-event: 3.79 ft / 124 cfs - Peak: 4.13 ft / 213 cfs at ~07:15 CST Apr 17 (+0.34 ft / +89 cfs, +72%) - Lag from QPE centroid (~01:00 CST Apr 16): ~30 hours to Pruitt peak - Lag from Ponca peak (17:00 CST Apr 16) to Pruitt peak (07:15 CST Apr 17): ~14 hours - This Ponca→Pruitt lag is longer than Event 4's 10 hours — consistent with lower flow velocities (Ponca peaked at only 167 cfs vs 823 cfs in Event 4). At low flows, propagation slows significantly.
St. Joe: - Rising through EOD, hasn't peaked yet - QPE on Apr 16: St. Joe zone avg 0.45" (Richland zone 0.86", Cave Creek 0.69", Big Creek headwaters 0.62%) - Rise began ~05:00 CST Apr 17, accelerating in evening - Lag from QPE centroid (~01:00 CST Apr 16) to beginning of St. Joe rise: ~28 hours - Richland Creek peaked at 1.81 ft on Apr 16 ~14:30 CST, now receding at 1.60 ft. The Richland runoff should reach St. Joe gauge within ~12-24 hours of the Richland peak, consistent with the St. Joe rise beginning ~15 hours after Richland peak. - Signal separation: Richland gauge rose +0.56 ft from Event 6 → confirms significant rainfall in Richland sub-basin (0.88" in Headwaters Richland, 0.84" in Falling Water Creek). The St. Joe rise is therefore a combination of: (1) Richland sub-basin runoff, (2) Cave Creek 0.69", (3) Big Creek complex runoff (0.51-0.62"), and (4) upstream mainstem propagation.
Harriet: - Just beginning to rise at EOD (+0.05 ft from trough) - Bear Creek flat → confirms this is mainstem propagation, not local rain - Lag from Pruitt peak (07:15 CST Apr 17) to Harriet trough-to-rise inflection (~20:00 CST Apr 17): ~13 hours — but this is arrival of the leading edge, not peak
Event 6 provides the cleanest propagation signal in the study to date because of the single rainfall pulse followed by dry conditions:
| Segment | Peak/Rise Time | Lag (peak-to-peak) | Flow Conditions |
|---|---|---|---|
| Boxley peak | Apr 16 ~13:00 CST | — | Low flow |
| Ponca peak | Apr 16 ~17:00 CST | +4 hr from Boxley | 167 cfs peak |
| Pruitt peak | Apr 17 ~07:15 CST | +14 hr from Ponca | 213 cfs peak |
| St. Joe | Still rising at EOD | TBD (>14 hr from Pruitt) | 379 cfs and rising |
| Harriet | Just beginning to rise | TBD | 408 cfs at EOD |
Key finding: The Ponca→Pruitt lag at low flow (14 hours) is significantly longer than at moderate flow (10 hours in Event 4) or high flow (implied faster from Event 2). This confirms flow-dependent propagation velocity. At these low flows (~150-200 cfs), the Boxley→Pruitt total transit time is ~18 hours vs ~12 hours at moderate flows.
Event 6 (Apr 15-16 rain, Apr 16-17+ response) is now well-characterized at upper gauges and propagating through lower gauges.
Event 6 combined with Event 4 recession creates a compound flow pattern: - Pruitt re-entered Optimal (>200 cfs) briefly today (~04:30-13:00 CST, ~8.5 hours). This is the Event 6 propagation bump superimposed on the Event 4 recession tail. Without Event 4's residual baseflow elevation (Pruitt was at 124 cfs pre-Event 6 vs the ~48 cfs it started Event 4 at), Event 6's 0.3" of local rain + upstream propagation would likely NOT have pushed Pruitt to Optimal. - St. Joe: Currently at 379 cfs and rising. Event 4 had St. Joe declining toward 295 cfs; Event 6 has now reversed this and pushed it back above the Event 4 Day-12 level. Peak likely tomorrow (Apr 18). Given the spatial rainfall pattern (0.45-0.86" across St. Joe zone), I estimate St. Joe will peak at approximately 400-450 cfs. - Harriet: Beginning to rise at EOD (408 cfs). The combined Event 6 upstream propagation + modest local Harriet zone rain (0.43" on Apr 16) should produce a Harriet peak around Apr 18-19, likely in the 420-460 cfs range.
Recreational duration tracking: - Ponca: Event 6 pushed Ponca back above 150 cfs (Low but Floatable) for ~27 hours (Apr 16 ~10:00 to Apr 17 ~13:00). Now back below 150 at 141 cfs and declining. - Pruitt: Event 6 pushed Pruitt into Optimal (>200 cfs) for ~8.5 hours. Now at 185 cfs (Low but Floatable) and declining. Pruitt will likely drop below 100 cfs (Too Low) around Apr 22-24 unless further rain. - St. Joe: Has remained in Optimal (>200 cfs) continuously since Event 4 (Apr 4). Currently at 379 cfs and rising. Event 6 is extending the Optimal duration — now projecting St. Joe will remain above 200 cfs until approximately Apr 25-28. - Harriet: Has remained in Optimal (>200 cfs) continuously since Event 4. Currently at 408 cfs and rising slightly. Projecting Harriet above 200 cfs until approximately Apr 27-May 1.
The Pruitt rise magnitude is larger than expected. With only 0.30" local QPE and 0.33" in Cove Creek, plus upstream propagation from a modest Ponca peak (167 cfs), the +89 cfs rise at Pruitt (from 124 to 213 cfs, +72%) is substantial. Possible explanations: 1. The Pruitt zone HUC12s (Cove Creek, Hoskin Creek) may be more responsive than indicated by zone-average QPE — individual grid cells within these HUC12s may have received more rain 2. The antecedent 7-day precip at Cove Creek (0.86") and Hoskit Creek region suggests wet soils that amplified runoff 3. The local Pruitt gauge precip recorded 0.21" on Apr 16, confirming rain at the gauge itself
No contradictions with existing hypotheses. The flow-dependent propagation velocity finding strengthens the emerging model. The Boxley→Ponca 4-hour lag at low flow is remarkably consistent across Events 1, 5, and 6.