A recent case before the Agriculture, Food and Rural Affairs Appeal Tribunal dealt with a municipal drain affected by three Enbridge pipelines that cross it. Both the main drain and Branch "A" tiles from the drain cross three Enbridge pipelines (Line 7, Line 8 and Line 9) through manholes that function as siphons. Siphons are often the only solution (sometimes effective and sometimes not) for the installation and maintenance of tile drains when a pipeline company decides to build through the drainage area.
The drainage engineer in this situation noted that the siphon reduced capacity in the tiles across the pipelines. New tiles were to be installed as part of the project under review by the Tribunal; the engineer found that crossing the pipelines at the existing locations would not be feasible without siphons, but that it would be possible to cross underneath the pipelines in higher ground at the "centre location".
The appeal before the Tribunal dealt with the assessment costs to various landowners. The engineer had applied a modified "Todgham Method" to calculate the assessments. He calculated the assessments on the basis of a "natural route" which would have been the assessments if the drains did not have to cross the Enbridge ROW. He then did a second assessment for the "revised route" based on the presence of the Enbridge ROW and the additional cost to traverse it. The "natural route" assessment was then modified in conjunction with the "revised route" assessment.
The Tribunal accepted the appeal of one landowner and reduced that landowner's assessment. The Tribunal found that, in determining the benefit derived by the proposed drainage works to that landowner, it would have been more appropriate for the engineer simply to have made new calculations for the "revised route" rather than modifying the "natural route" calculations (which would not apply because the "revised route" was being used).
Read the decision at: Re Wakem-Weir Drain.