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Please note that all necessary permits must be obtained prior to starting construction on a "beaver deceiver". For example, the construction at Peterson Pond required permits from King County (grading permit) and the Washington State Department of Fish and Wildlife (Hydraulic Project Approval).


  • Cedar posts: 10, at least 8 feet long with an average diameter of 4 1/2 to 5 inches (6 inch diameter posts were used at Peterson Pond as they were more readily available). Four posts were actually installed. Several posts were discarded due to splitting or otherwise becoming damaged during construction. To reduce possible delays in construction, this is a case where it's better to have too many on site than not enough.
  • Fencing: 5 sheets, 6" x 6" square grid, 4 gauge wire. The sheets are 7'6" by 20'. Non-galvanized concrete reinforcement steel was used at Peterson Pond, however galvanized fencing would be preferable. It may be also acceptable to use 6" x 8" grid fencing, with the 8" dimension oriented in the vertical direction.
  • Cedar stringers: one 16' and two 12' lengths. 2" x 6" is preferred, 2" x 4" is acceptable.
  • Spruce or fir braces. ten 8' lengths, four 10' lengths, and four 12' lengths. Untreated wood was used at Peterson Pond, although certain types of pressure treated wood were acceptable under the Washington State Department of Fish And Wildlife HPA permit.
  • Nails: 50 penny weight nails, galvanized, 20 lbs.
  • Staples: 1 1/2" or 1 3/4", galvanized, 20 lbs.
  • Pipe: 18" x 20', corrugated, double walled, polyethylene pipe.
  • Steel rod: 1/4" x 4' long, galvanized (5/16" non galvanized may be used.)

There are many steel fabricators who are potential suppliers for the fencing material. The following list includes only those that we found while searching for supplies for the Peterson Pond project. It is important to get the proper size grid fencing. Larger grids will allow beavers through and smaller grids may trap too much debris and cause problems with fish passage.

Possible suppliers:

Graham Steel (Seattle area, 425-823-5656 ) non-galvanized concrete reinforcement
Harvard Steel (Seattle, 206-762-6205) non-galvanized concrete reinforcement
Oklahoma Steel ( galvanized utility fencing


  • 8' stepladder
  • 12 lb. sledge hammer
  • 8 lb. sledge hammer
  • 22 - 28 oz. framing hammer
  • ¼" drill bit for wood
  • 12 volt cordless drill
  • small boats if working in deep water
  • 18" - 24" high quality bolt cutters
  • large truck or trailer to move pipe and fence
  • small sharp chainsaw
  • wire cutting snips
  • 6' level
  • chest waders
  • hearing protection, tool pouch and hammer holster