Phosphorus Filters for Runoff and Tile Drainage

Department of Food, Agricultural, And Biological Engineering

Presenter: Jesse Blanton Co-Authors: Dr. Andy Ward, Dr. Jon Witter


  • Dissolved phosphorus (P) is a significant driver of the increasingly large, harmful algal blooms plaguing the Western Lake Erie Basin.
  • Forty to fifty percent of the dissolved P entering the lake is a product of agricultural subsurface (tile) drainage, with loading being proportional to the size of flow events.
  • New BMPs must be developed to curtail this loading.
  • Vegetated buffer strips are useful for reducing the transport of undissolved P in surface runoff.
  • Filter beds will be constructed on the banks of agricultural ditches to intercept a portion of surface and tile flow and extract P before it enters the ditches.
  • These filters will utilize substances that have a high affinity for adsorbing dissolved P and demonstrate adequate hydraulic conductivity.
  • Locally sourced and relatively inexpensive materials will receive preference when constructing the filter beds.
  • A generalized design procedure will be developed to adapt the filter beds to specific local conditions and geometry. This procedure will be worked into an Excel tool that is easy to use, and freely available to the public.

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