Phillip Owens and Eileen Kladivko. Purdue University-Agronomy Dept., Purdue Univ., 915 W. State St, West Lafayette, IN 47907
Subsurface drainage is an important water management method on poorly drained soils for agricultural practices and septic system performance. The objective of this study was to quantify the impacts on duration and water table depth due to tile drainage. The Clermont soil (Fine-silty, mixed, superactive, mesic Typic Glossaqualfs) was used for this study. This soil has a perched seasonal water table that approaches the surface during periods where rainfall exceeds evapotranspiration. Tile drains were placed in the field at 0.75 cm depths on 5-, 10 and 20-m spacings. Only the water levels from the 20-m spacing was used analyzed in this study. Piezometers and wells were placed at 0.5, 1.0, 2.5, 5 and 10 m lateral distance from the tile drain at depths of 0.6, 1, 1.5, 2 and 3 m. The wells and piezometers were equipped with pressure transducers with dataloggers to record the water depth at 1-hr time increments. The results indicate the most rapid drawdown nearest to the tile drain. Within 3 d the tile drain decreased the water table in the piezometers at the 20 m distance from the tile by 20 cm. During the drainage, the slopes of the drainage changed to reflect the drawdown of the perched seasonal water table.