Drainage and Water Quality in Northern United States and Eastern Canada

Abstract

Drainage has been used in the northeastern United States and Canada since colonial times. It has only been since the 1970s that substantial quantities of subsurface drains have been installed annually in Quebec. Drainage in Ontario was first installed in the early 1900s. Today there is an increasing concern that drainage is harmful to the environment. It has only been in recent years that projects have been initiated to evaluate the environmental impacts of agricultural drainage. Both nitrates and pesticides have been detected in agricultural drainage waters, sometimes at concentrations exceeding drinking-water standards. Research has identified the need for integrated management of water quality and quantity. There is a need to quantify the role of preferential flow as a mechanism of pollutant transport in surface and subsurface drainage water and to develop a modeling approach that is applicable at the field and watershed scale.