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Cossatot River — Daily Analysis: 2026-04-18

Classification: no_prediction Confidence: Continued pattern of no predictions being generated limits calibration opportunities, but observed responses suggest coefficients still need refinement

Event Summary

Moderate rainfall (0.64 inches at gauge) produced a 0.35 ft rise with very broad hydrograph shape, but no prediction was generated to evaluate model performance.

Prediction vs Actual

Metric Predicted Actual Error
Peak height N/A 3.01 ft N/A
Total rise 0.35 ft

Band Contributions

Band Precip Predicted Rise Intensity Moisture

Analysis

This event featured moderate rainfall concentrated in the morning hours (05:12-10:12 UTC) with the gauge recording 0.64 inches total precipitation. The QPE data shows relatively uniform distribution across all bands (0.64-0.80 inches), suggesting watershed-wide coverage. The river responded with a 0.35 ft rise starting at 09:30 local time and peaking 10.8 hours later with a very broad hydrograph shape, indicating contributions from multiple lag zones.

The lack of a prediction prevents direct model evaluation, but we can assess the observed response against expected coefficients. Under WET conditions (1.5x multiplier), the total expected response would be approximately 0.64 × 2.4 × 1.5 = 2.3 ft from Band 1 alone, which severely overestimates the actual 0.35 ft rise. This suggests either the rainfall intensity was lower than moderate (reducing the multiplier) or the Band 1 coefficient remains too high despite recent reductions.

The very broad hydrograph shape and 10.8-hour duration to peak suggests significant contributions from multiple bands, which is consistent with the uniform rainfall distribution observed. However, the modest total rise indicates the current coefficients may still be overestimating watershed response, particularly for Band 1.

Coefficient Adjustments

Band Change Reason
1 -15% Expected response of ~2.3 ft vs actual 0.35 ft suggests Band 1 coefficient still too high despite recent reductions
2 -10% Broad hydrograph suggests multi-band contributions but total response indicates overestimation
3 -10% Broad hydrograph suggests multi-band contributions but total response indicates overestimation

Notes

Continued pattern of no predictions being generated limits calibration opportunities, but observed responses suggest coefficients still need refinement

← 2026-04-16  |  2026-04-24 →