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Tile Drain Research and Development Gains Momentum in the Industry and at Stone

Feb 15, 2017

Since the early 19th century, growers in the United States have employed tile drainage to improve field productivity, bringing many acres into cultivation that otherwise would be unsuitable. In certain areas of the U.S., up to 85% of cropped areas are tile drained. The presence of tile drainage systems can also provide pathways for nutrients and other compounds to move from farm fields to surface waters.

Stone is proud to be at the forefront of scientific study in the assessment of tile drainage systems. In the past year, our team has led four projects, described below, that are contributing to a better understanding of how tile drainage affects nutrient loading, and implementing innovative practices to mitigate this nutrient loading.

Assess the Impact of Tile Drainage Systems on Surface Water Quality with Respect to Nutrient Loads

In progress for the Lake Champlain Basin Program
Phase 1 of this project entailed a review of published literature and other quality resources documenting reported contributions of agricultural tile drainage to nutrient loading to surface waters. Phase 2 is in progress and involves constructing 12 end-of-tile monitoring systems to track discharge (continuous) and nutrient concentrations for a period of 12 months. The monitoring phase is expected to be complete by March 2018.

Develop the Best Methodology for Identifying and Mapping the Existence of Tile Drains to Support Better Management Over Time

Completed for the Vermont DEC Clean Water Initiative Program
Stone reviewed the use of GIS-based modeling, remotely sensed data acquisition and interpretation, and field-based approaches that could be employed to identify or predict locations of tile-drained fields. Based on the findings, recommendations were submitted to the State of Vermont about best practices for quantifying the location and extent of tile drainage systems. Copies of the report can be made available upon request.

Research and Develop Effective Media Filters to Minimize Phosphorus Contributions from Tile Drains 

In progress for Friends of Northern Lake Champlain
This project involves designing and constructing two packed bed media filters for treating dissolved phosphorus in tile drainage water and monitoring the phosphorus removal efficiency of the filters over a 12-month period. Based on a thorough review of available materials with properties that could make them suitable as a treatment media, two types of media were selected for evaluation (a ground limestone from Swanton, Vermont and drinking water treatment residuals from the Champlain Water District in South Burlington, Vermont). Both media show promise for removal of phosphorus from tile drainage water. The final report is expected to be complete in March.

Develop and Apply New Modeling Approaches to Simulate Nutrient and Chemical Losses through Tile Drains

Stone's modeling team has been developing and applying new modeling approaches to estimating the losses of phosphorus and pesticides through tile drained fields. The simulation of phosphorus losses through tile drains has become a component of Stone's web-based APEX model ( for farm-scale nutrient management planning and analysis. The modeling approach accounts for field specific soil conditions, local weather, and agronomic practices in estimating the amount of field-level phosphorous losses through tiles and via surface runoff and erosion. Stone's analysis of pesticide losses through tiles has focused on the watershed scale, and has sought to evaluate whether pesticide residues found in streams are due to transport via the subsurface or primarily through surface transport processes. In this analysis, Stone has made custom enhancements to the SWAT model ( to enable the prediction of tile drain pesticide fluxes. The modeling of both nutrient and pesticide movement through tile drains will ultimately provide farmers and planners with better information for determining appropriate actions to reduce these non-point source pollutants from reaching sensitive water bodies.

Learn more about this topic and stone's exciting work

Download Stone's Literature Review for our Resource Library here.

Download the Vermont Agencies of Agriculture and Natural Resources Recent Report to the Legislature on Tile Drainage here

Discover how our tile drain research and studies might support your work. Contact us today