The flow characteristics of plastic drainage pipe available in New Zealand

Abstract

In recent years different types of plastic drainage pipe, intended primarily for use in agricultural underdrainage systems, have become commercially available in New Zealand. No flow resistance data has been supplied by the manufacturers, and, as all these pipes are perforated, and in some cases corrugated, the flow resistance cannot be predicted using existing data. Designers of drainage systems therefore have had no information on which to base calculations of flow in these pipes when laid on various gradients. This report presents the results of experiments carried out to determine the flow characteristics of those plastic drainage pipes available in New Zealand. Table 1 gives some details of these pipes which are illustrated at Fig. 1 . A full description appears in the Appendix. The results have been incorporated in a Plastic Drain Pipe Design Chart which is based on the Ohio Drainage Guide (5) Tile Drain Design Chart. This chart appears at Fig. 6. Test procedures developed at the N. Z. A. E. I. for determining the mechanical strength and water intake ability of plastic drainage pipes have already been described by Heiler (1).