Head hunter,
Things may be different here in Snohomish County. I haven't heard of the concrete box culvert. All the culverts replaced around here either by the county or Adopt-A-Stream have all been corrugated steel/aluminum round pipes in 8' or 12' diameter size. These have gravel to a depth of 3' in the center. Culverts are used on small stream and the larger ones all have bridges over them because of the width. Is it WDFW that won't let you use them, the county, another state entity, the feds? What rules, regs, ordinances are they using to direct the use of this type strcture? Just curious and trying to educate myself some. I do realize the wage thing. All designed to protect union jobs and such.

Thanks much.