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World Environmental & Water Resources Congress

May 21 - 25, 2017
Sacramento, CA

Christine Gingras, PE is presenting at ASCE’s 2017 EWRI World Environmental and Water Resources Congress on May 23, 2017 at 11:24 AM in Room 317. Her presentation, "Phosphorus Removal from Subsurface Drainage Water Using Media Filters," will cover Stone's work with the Friends of Northern Lake Champlain in researching and developing effective media filters to minimize phosphorus contributions from subsurface drainage water.

The theme of this year's World Environmental & Water Resources Congress is "Creative Solutions for a Changing Environment." The conference includes 13 concurrent technical sessions covering more than 20 unique tracks, plus poster sessions, technical tours, and networking events. For more information, visit


Phosphorus Removal from Subsurface Drainage Water Using Media Filters

Irrigation and Drainage Track / May 23, 2017 / 11:24 - 11:42 AM / Room 317

Co-Authors: Dave Braun, Montpelier, VT – Stone Environmental, Inc.; Christine Gingras, Montpelier, Vermont – Stone Environmental, Inc.; Denise Smith, St. Albans, Vermont – Friends of Northern Lake Champlain

Subsurface (tile) drainage is an essential water management practice on many agricultural fields, allowing timely equipment access, reduced soil compaction and increased crop yields in fields otherwise too wet to efficiently farm. The combined effects of drawing down the water table and providing rapid conveyance of subsurface water to an outlet can significantly change the hydrologic behavior of a field, reducing surface runoff by enhancing infiltration and ground water transmission. It was long believed that, despite hydrologic changes caused by implementation of tile drainage, phosphorus (P) losses from agricultural lands occurred primarily via surface runoff and that very little P was lost through subsurface drainage such that tiling a field could reasonably be expected to reduce P losses. Recent research has revealed that tile drainage systems in agricultural fields can discharge significant quantities of P under a wide range of soil characteristics and management practices. In 2014, the Vermont office of the Natural Resource Conservation Service (NRCS) issued an interim practice standard for phosphorus removal systems – systems designed and installed to intercept tile drain water and provide treatment that reduces the concentration of phosphorus prior to discharge. A prototype, filter-media system was installed on a small Vermont dairy in 2015. The filters are scheduled to remain on-line through the end of calendar year 2016; flow-paced composite samples of filter effluent are being collected weekly. This paper and presentation will review results achieved by the media filters, as well as lessons learned from this demonstration project.