Improving Runoff Water Quality on Construction Sites: Issues and Opportunities

Current erosion and sediment control practices on construction sites have been demonstrated to provide a range of water quality improvements in stormwater discharges, but considerable turbidity still remains. Reducing erosion and turbidity from slopes by applying polyacryalmide (PAM) has been well demonstrated over the last 10 years. In addition, a number of recent and current studies are cited which provide some insight to the possibilities of using passive treatment systems (PTS) to introduce flocculants to address the turbidity problem. The introduction of these systems can produce dramatic reductions in turbidity to levels <50-100 nephelometric turbidity units (NTU), as demonstrated for numerous storm events on many sites. On these active construction sites, no turbidity limit was being enforced so the function of a PTS was often compromised by construction activities. However, it is possible to quickly mitigate needed construction disturbances if the skill and motivation are in place. Overall, successful PTS requires sufficient training of construction site staff, primarily the grading crew, in PTS functions and problems to avoid. It is likely a person trained in PTS will be needed on staff, or as a contractor. In most cases, the key factor in successful PTS use is routing all water from disturbed areas into the water conveyance with PTS installed. Bypass flows of untreated runoff is often the cause of turbidity spikes. The area immediately around sediment basins needs to stabilized at all times to prevent the contribution of untreated, turbid runoff into the basin. A great deal of diligence will be required to avoid spikes above any target turbidity level.

Language

  • English

Media Info

  • Media Type: DVD
  • Features: Figures; References; Tables;
  • Pagination: 14p
  • Monograph Title: TRB 89th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

Filing Info

  • Accession Number: 01152727
  • Record Type: Publication
  • Report/Paper Numbers: 10-3127
  • Files: BTRIS, TRIS, TRB
  • Created Date: Jan 25 2010 11:32AM