ON-SITE SEDIMENT FILTRATION USING GRASS STRIPS

The use of grassed area as a sediment filter is proposed in this article for urban construction sites. The characteristics of flow of shallow water depths were studied analytically based on the momentum balance principle and experimentally using artifical grasses. The new technique developed in this study of fabricating the simulated grasses by imbedding plastic strips of various stiffness in molten paraphin in a random pattern is proven to be a very useful one. When the right flexibility of the plastic blades is chosen, a close simulation of a given type real grass property appear to be possible. The flow resistance(n vs VR) model proposed by Ree and Palmer was first used in the presentation of the experimental results of this study and found to be unsatisfactory when flow depth is shallow. A new mathematical model is proposed to relate the resistance factor to the blade Reynolds number. The experimental results also predicted high sediment filtration efficiency of grass filters. To solve the problems of sediment inundation and killing of the vegetation a new filter arrangement pattern which alternates the grass strips with bare ground strips is proposed. The preliminary tests results conducted on the use of this pattern indicated that when the appropriate width ratio of the grass to bare ground strips is selected the filter remains operating with high trapping efficiency and all the trapped sediments were retained in the bare ground regions.

Media Info

  • Features: Figures; Photos; References; Tables;
  • Pagination: p. 73-82

Subject/Index Terms

Filing Info

  • Accession Number: 00135881
  • Record Type: Publication
  • Report/Paper Numbers: UKY BU109
  • Files: TRIS
  • Created Date: Oct 26 1976 12:00AM