Three engineering proposals differ on timing and scope for Kanosh post-fire flood work

Four engineering teams presented competing approaches to reduce near-term flood risk after the Widemouth Fire. Layne Jensen of Franson Civil Engineers said Franson’s pre-existing HEC-RAS model could be modified for a fully burned watershed “in a matter of days” and recommended activating the High Line Ditch auxiliary spillway and installing a graded swale to replace four undersized culverts. Jensen warned that the debris basin has seepage in the embankment and an undersized emergency spillway relative to current standards, meaning “even moderate storms could produce flows that overtop the embankment.”