Agricultural Runoff Chemical Dosing

Low Intensity Chemical Dosing of Agricultural Runoff in the Sacramento-San Joaquin Delta, Rio Vista, CA, 2007 – 2014.

Collaborating Organizations:

Bachand & Associates, UC Davis Department of Land Air and Water Resources, and USGS

Funding Organization:

Department of Water Resources and CALFED, Proposition 13

Project Description:

The Sacramento-San Joaquin Delta is a valuable resource, with large swaths of agricultural land surrounded by a river system that provides water to approximately 22 million Californians. However, agricultural drainage water from the Delta Islands contributes somewhere in the range of 13 – 49% of dissolved organic carbon (DOC) to the San Joaquin Sacramento river system depending upon the season. When these waters are chlorinated or ozonated for use as drinking water, carcinogenic disinfection byproducts (DBPs) are formed posing a human health concern. Furthermore, during nearly one hundred years of farming, the islands have subsided approximately 20 feet. This subsidence has created a large hydraulic head against the levees, increasing the risk of levee failure and catastrophic flooding of farmland.

Based on research conducted by Dr. Philip Bachand in the Florida Everglades, Bachand & Associates is working collaboratively with USGS and UCD to test the use of chemical dosing in combination with constructed wetlands to remove DOC from agricultural drainage water and to mitigate subsidence. This project is a combination of laboratory and field scale studies.

Dr. Bachand is the technical lead on the project and Bachand & Associates leads the construction, implementation, O&M, and data collection of the two-year constructed wetland field study. Bachand & Associates designed and is constructing an in situ field-scale pilot study, including nine 4,000 ft2 mesocosm cells, coagulant dosing systems, water delivery structures, and data collection systems. Work was done in conjunction with laboratory-based research conducted by the University of California at Davis.

Project Description on USGS


  1. Bachand, P.A.M., Bachand, S.M., Kraus, T.E.C., Stern, D., Liang, Y.L. and Horwath, W.R. (2019). Sequestration and Transformation in Chemically Enhanced Treatment Wetlands: DOC, DBPPs, and Nutrients. Publicly Available on ASCE Library , "Journal of Environmental Engineering", 145(8), 04019044, Published: 2019.

  2. Bachand, S.M., Kraus, T.E.C., Stern, D., Liang, Y.L., Horwath, W.R. and Bachand, P.A.M. (2019). Aluminum- and iron-based coagulation for in-situ removal of dissolved organic carbon, disinfection byproducts, mercury and other constituents from agricultural drain water. Publicly Available on ScienceDirect, "Ecological Engineering", 134, pp. 26-38, Published: 2019.

  3. Liang, Y.L., Kraus, T.E.C., Silva, L.C., Bachand, P.A.M., Bachand, S.M., Doane, T.A. and Horwath, W.R. (2019). Effects of ferric sulfate and polyaluminum chloride coagulation enhanced treatment wetlands on Typha growth, soil and water chemistry. Publicly Available on ScienceDirect, "Science of the Total Environment", 648, pp. 116-124.

  4. Bachand, P.A.M., Kraus, T.E.C., Stumpner, E.B., Bachand, S.M., Stern, D., Liang, Y.L. and Horwath, W.R. (2019). Mercury sequestration and transformation in chemically enhanced treatment wetlands. Publicly Available on Chemosphere, "Chemosphere", 217, pp. 496-506, Published: 2019.

  5. Stumpner, E.B., Kraus, T.E.C., Liang, Y.L., Bachand, S.M., Horwath, W.R. and Bachand, P.A.M. (2018). Sediment accretion and carbon storage in constructed wetlands receiving water treated with metal-based coagulants. Publicly Available on ScienceDirect, "Ecological Engineering", 111, pp. 176-185, Published: 2018.

  6. Stumpner, E.B., T.E.C. Kraus, J.A. Fleck, A.M. Hansen, S.M. Bachand, W.R. Horwath, J.F. DeWild, D.P. Krabbenhoft and P.A.M. Bachand. 2015. Mercury, monomethyl mercury, and dissolved organic carbon concentrations in surface water entering and exiting constructed wetlands treated with metal-based coagulants, Twitchell Island, California. Available on USGS, U.S. Geological Survey Data Series 950, 26 p, Published: 2015.

  7. Y. K. Henneberry., T.E.C. Kraus, J.A. Fleck, D.P. Krabbenhoft, P.M. Bachand and W.R. Horwath. 2011. Removal of inorganic mercury and methylmercury from surface waters following coagulation of dissolved organic matter with metal-based salts. Publicly Available on USGS, "Science of the Total Environment" 409: 631–637, Published: 2011.

Related Reports

  1. Bachand, P.A.M., C.J. Richardson and P. Vaithiyanathan. 2000. Phase II Low Intensity Chemical Dosing (LICD): Development of Management Practices. Final report submitted to Florida Department of Environmental Protection in fulfillment of Contract No. WM720. Publicly available from AquaDocs, Published: 2000.

  2. Bachand, P.A.M. and A.J. Horne. 2000. Denitrification in constructed free-water surface wetlands: I. Very high nitrate removal rates in a macrocosm study. Ecological Engineering 14(1-2):9-15. Available on ScienceDirect, “Ecological Engineering” 14(1-2):9-15, Published: September 1999.

  3. Bachand, P., J. Trejo-Gaytan, J. Darby and J. Reuter. 2006. Final Report: Small-Scale Studies on Low Intensity Chemical Dosing (LICD) for Treatment of Highway Runoff. Submitted to CALTRANS (California Department of Transportation) by University of California Davis. April 19, 2006. Available on the National Transportation Library, Published: 2006.

  4. Bachand, P., T. Kraus, W.R. Horwath, S. Bachand, Y. Hennebery, Y.L. Liang, E. Stumpner, B. Pedlar et al. 2016. Low Intensity Chemical Dosing (LICD), Opportunities to Improve Delta Water Quality and Mitigate Subsidence by Leveraging Hybrid Coagulation and Wetland Treatment Systems, Workshop. October 26, 2016, Delta Stewardship Council, Sacramento, CA.

  5. Sandra Bachand, Tamara Kraus, Jacob Fleck, Yan Liang, Nicole Stern, Elizabeth Stumpner, William Horwath, Sujoy Roy and Philip Bachand. Low Intensity Chemical Dosing (LICD), A Hybrid Coagulation-Wetland System Designed to Decrease DOC, Hg, and Nutrient Loads from Subsided Islands in the Sacramento-San Joaquin Delta. Bay Delta Conference, October 2014. Sacramento, CA.