Tile Drainage in Manitoba

摘要

In 1994 a pilot project was initiated to assess the feasibility of tile drainage in Manitoba. Objectives were to determine the environmental sustainability related to water quality of tile effluent and to provide recommendations for site selection and drain spacing. The four sites studies vary in soil type but all experience water tables which fluctuate from near surface in the spring to a maximum depth of 2 metres. Data collection includes rates and volumes of discharge, precipitation, water table levels, crop management practices, and water quality of tile effluent. Electrical conductivities in the discharge water have been observed to fall between 926 and 5070 uS/cm. Nitrate-N levels were found to range from 1.8 to 73.6 ppm and are crop uptake. The application of irrigation water did not appear to affect the NO3-N concentration of the tile effluent. Except for one instance, pesticide levels have been found to be below laboratory detection levels. Water table drawdown has ranged from 5 to 30 cm/day. Discharge volumes including spring snowmelt have varied from 6.1 to 22 acre feet (2.7 to 12.6 inches over their respective drainage areas).