Irrigation Sprinkler Uniformity

Christiansen CU and Distribution Uniformity from catch-can readings; pass/fail at 85% and 75%.

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Example

You enter

Catch volumes 100, 95, 98, 102, 105, 99, 97, 101

You get

Mean 99.625
Christiansen CU 97.6 %
Distribution Uniformity 96.4 %
Pass CU 85 Yes
Pass DU 75 Yes

Details, formula, and sources

Christiansen CU = 100 × (1 − Σ|x_i − mean| / (n × mean)). Distribution Uniformity DU = 100 × mean_lowest_quarter / mean_all. Pass / fail at CU 85 / DU 75.

Christiansen 1942 paper by name; USDA NRCS National Engineering Handbook (NEH) Part 623 (Irrigation) by name.

USDA NRCS NEH Part 623 free at nrcs.usda.gov.

Estimate. AHJ and licensed professional govern.

Field names used by the API: catch_volumes, mean, CU, DU, pass_CU_85, pass_DU_75