ABSTRACT
Subsurface drainage technology changed and modernized more during the 1965-1980 period than in the previous 100 yr. The inefficient and slow installation of heavy rigid drainage conduit materials (clay and concrete draintile) gave way by the early 1970s to lightweight flexible corrugated plastic drain tubing installed with laser-beam-controlled high-speed trenchers and plow-type equipment. In fact, the developments of the modern drainage plow equipment and the laserbeam automatic grade control were a direct result of the technological developments for corrugated plastic drainage tubing, and the need for a rapid and accurate method to install the new drainage material.a
BACKGROUND
The development of a rapid and low-cost technique for subsurface drainage had challenged engineers and inventors for centuries. Many ideas emerged over time, but very few found widespread use or application. With the development of the power trenching machine in 1875, the goal of mechanized drain installation seemed to have been reached-and it lasted around 100 yr. However, the extraordinarily large amount of drainage work that was needed around the world required even less labor, more speed, and lower costs. Efforts to modify the mole drainage concept and installation methods were particularly important. The goal was to use the inherent high speed of installation of mole drainage and its elimination of relatively slow ditching and backfilling operations associated with conventional drainage methods. Because the mole drain collapsed after a short time in many soils, most of the research focused on stabilizing the mole channel with structural support, using a tube or mole-liner; this approach, although showing some promise, was not satisfactory for adoption or use.[1] This investigative
work with the mole plow did lead, however, to the eventual development of the drain-tube plow equipment for installing subsurface plastic drains that is in common use today throughout the world.
