New Zealand Agricultural Engineering Institute2024-11-062024-11-061988-05https://hdl.handle.net/10182/17808The NZAEI Guide to Subsurface Land Drainage is intended to be a readily available source of design information for farm advisors, contractors, farmers, and others involved in agricultural and horticultural drainage. The emphasis is on subsurface drainage because this is an area where the available information is often difficult to locate and can be confusing. The technical standards required in subsurface work are higher than for surface drainage, and mistakes are not only costly but also not easily rectified. This guide is not a comprehensive treatise on subsurface drainage, and for this kind of information on New Zealand conditions the reader is referred to Hudson, Hopewell, Bowler and Cross (1962), and Bowler (1980). It is presumed that the need for drainage has been established and that a suitably skilled drainage contractor is available. The information presented herein is an attempt to link these two. Drainage is by no means an exact science. Wherever possible, the physical reasons for particular recommendations are given so that the designer can make a judgement on the consequences of departing from the guidelines. In some drainage situations, local experience and practice may appear to conflict with methods presented in this guide. In such cases, proven successful practice must be allowed to reign with due regard for the physical reasons behind the apparent anomaly.71 pages© Lincoln Collegesubsurface drainageReportANZSRC::300201 Agricultural hydrology