Rock Check Dam Spacing

Spacing between rock check dams in a channel or swale, where the toe of each upper dam sits at the crest of the next: spacing = dam height / channel slope, dams = ceil(reach / spacing). A 2 ft dam in a 4% channel spaces at 50 ft (6 dams over 300 ft); on an 8% grade the spacing halves and the count doubles. Small channels only; the AHJ governs.

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Formula and source

spacing_ft = dam_height_ft / (channel_slope_pct / 100); dams = ceil(reach_length_ft / spacing_ft).

Crest-to-toe check-dam spacing identity by name (the toe of each upper dam at the crest of the next); first-principles geometry.

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