A comparison of plastic and tile drain pipes with differing cover materials

Abstract

A comparison was made between three types of plastic drain pipes and conventional earthen tile drains combined with cover materials of washed river sand, fibreglass, and tar paper. Rate of drawdown of a water table was measured for each combination of pipe and cover material over a period of 220 hours. Soil material that accumulated over three years in the observation pits and over four years in the pipes was measured. All combinations of pipes and cover materials provided satisfactory drainage and there were no differences of practical significance between them in terms of rate of drawdown. The river sand used in the experiment caused blockage of slot openings in corrugated plastic pipe, and one type of smooth walled plastic pipe was badly distorted by soil pressure leading to a widening of the slots, entry of soil material and breaking the fibreglass covering. Another type of plastic pipe was unsatisfactory because the perforation method left plastic material as hairs within the pipe. The fibreglass, 0.2 mm thick, was too thin to be entirely satisfactory, but was, under favourable conditions, a most effective cover material. Tar paper was quite unsatisfactory as material to prevent soil entry to pipes.