Properties and components of deposit which occurred inside a drainage tube

In poorly drained fields, tube drains are used to improve drainage. In some cases, however, there are fields where the effects of tube drainage have deteriorated within several years after installation. One cause of malfunction is low permeability of backfilled soils (Ishiwata et al. 1990, 1992, 1993). Another cause is clogging of tubes by deposits (Trafford et al. 1973; Dent 1986; Koutani et al. 1989; Kusaka et al. 1993; Kaneko et al. 1995).