Evaluation order and interpretation

hydropattern evaluates the characteristics in the order they appear in a component. A characteristic outcome describes that characteristic at one timestep; the component outcome is the final classification after the characteristics are combined.

Independent and dependent characteristics

Timing, magnitude, and rate-of-change characteristics report their own conditions independently of earlier characteristics. Duration and frequency use the conjunction of the preceding characteristics to identify qualifying timesteps. Put a duration or frequency characteristic after the conditions that define which observations qualify. A frequency characteristic must be last.

For example, the magnitude condition below is met on January 2, January 3, and January 5. The duration condition assesses each entire consecutive qualifying run and accepts runs of at least two timesteps:

Date	Flow	Magnitude diagnostic	Duration diagnostic	Component outcome
2020-01-01	0	0	0	0
2020-01-02	2	1	1	1
2020-01-03	3	1	1	1
2020-01-04	0	0	0	0
2020-01-05	4	1	0	0
2020-01-06	0	0	0	0

Expected magnitude diagnostic: [0, 1, 1, 0, 1, 0]

Expected duration diagnostic: [0, 1, 1, 0, 0, 0]

Expected component outcome: [0, 1, 1, 0, 0, 0]

The duration assessment uses the later January 3 observation to classify January 2. It is a retrospective assessment, not a forecast available on January 2.

If a preceding outcome is unknown, duration considers both possibilities: the timestep may break a run or extend it. The diagnostic stays unknown when possible run lengths disagree on whether the duration condition passes. For example, with duration >= 3, preceding outcomes [0, 1, 1, unknown, 1, 0] produce [0, unknown, unknown, unknown, unknown, 0]: the unknown can split length-2 and length-1 runs, or join a length-4 run. Definite failures still settle the result where they occur.

Combining conditions

For a success-pattern component, all configured conditions must be met for the final outcome to be success. A known unmet condition makes the combined outcome failure. The final outcome is not interchangeable with any one characteristic diagnostic.

With success_pattern = false, the characteristics define a combined failure condition and the component reports its logical complement: non-failure. Non-failure does not demonstrate a beneficial ecological response. See component configuration.

Frequency is terminal: its output already incorporates its preceding conditions, so the component outcome follows the frequency result rather than requiring those conditions to be met again at the same timestep. In nested frequency, the interannual result is terminal.

Read the result columns

The raw result includes the selected flow column, dowy, a diagnostic column for each characteristic, and the final component column. The characteristic columns help explain how a classification was reached; use the component column when interpreting the configured pattern as a whole. See result files for the output layout.

Unavailable numeric calculations, such as a rate comparison without a previous flow value, remain unknown rather than becoming a failed comparison. Missing input flow values are still rejected. Other calculations and reporting summaries have separate unknown-value rules. See unknown outcomes for their propagation, denominators, and reporting behavior.