Because bridges usually span bodies of water, quantifying and controlling non-point pollutant flux from them will take on added significance as federal regulations begin to address non-point contamination of the environment. The objectives of this study were to examine the quality and quantity of the non-point contamination coming from the Cross Lake Bridge and to examine the effectiveness of a detention pond (holding pond) in removing contaminants from the runoff. These objectives were accomplished by installing sampler/flow meters at the basin inlet and outlet to quantify the volume of runoff and mass of conventional contaminants (COD, TSS, nutrients, hydrocarbons) entering and leaving the basin. The runoff flow rate into and out of the basin was logged at periodic intervals and discrete samples were collected across flow hydrographs entering and leaving the basin. Using this data, the basin efficiency in removing pollutants from runoff could be estimated. Study results show that runoff from the bridge contains pollutant concentrations similar to those found in domestic wastewater. However, the Cross Lake holding pond removed 100 percent of total petroleum hydrocarbons, 82 percent of oil and grease, and 85 percent of the total suspended solids entering the pond. Removal percentages for other contaminants were smaller and exhibited greater variation. Analysis of pond sediments and the overlying water column showed that the majority of the metals in the runoff were concentrated in (sorbed onto) the sediments. Partitioning coefficients on the order of several thousand were measured. Holding ponds are relatively simple, low-maintenance systems that could be employed as a best management practice (BMP) at a number of DOTD facilities and be a major factor in reducing non-point contamination at existing DOTD facilities such as district offices and maintenance yards. Holding ponds appear to be a simple and relatively inexpensive way of complying with upcoming federal and state mandates regarding export of non-point contamination from DOTD facilities; however, such facilities must be cleaned on a regular basis to remain functional.

  • Record URL:
  • Summary URL:
  • Corporate Authors:

    Louisiana Tech University, Ruston

    Department of Civil Engineering, 600 W Arizona Avenue
    Ruston, LA  United States  71272

    Louisiana Transportation Research Center

    4101 Gourrier Avenue
    Baton Rouge, LA  United States  70808
  • Authors:
    • Griffin Jr, D M
    • Bhattarai, R R
    • Eslami, M
    • Shretha, S
  • Publication Date: 2003-6


  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 82 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00961956
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/LA03-346,, 32-4116-40490,, Final Report
  • Contract Numbers: State Project No. 736-99-0206
  • Files: NTL, TRIS
  • Created Date: Aug 19 2003 12:00AM