The Ontario Energy Board recently granted permission to Union Gas to proceed with construction of further pipeline facilities along the Dawn-Trafalgar corridor - an area stretching from near Sarnia to Oakville.

For landowners in the corridor, this decision may cause apprehension and concern. During the course of hearings in London and Toronto, the Board heard evidence of landowners and expert witnesses appearing on their behalf with respect to the impact of pipeline construction on agricultural soils, woodlands and wetlands.

Simply put, the process of excavating the trench to lay a pipeline inevitably causes a mixing of stone and clay subsoils with topsoil. This mixing of sub and top soils decreases productivity of topsoil. Although increased use of fertilizer may alleviate this loss of productivity to some extent, it will take hundreds or thousands of years for the subsoils to be leached from the topsoil to restore the topsoil to its original productivity.

In addition, when soils are returned to the trench after the pipeline has been installed, difficulties in compacting the soils to their original levels may cause subsequent erosion. Finally, the heat that is generated by the pipeline prevents natural frost fissuring in the soils and may contribute to drainage problems.

Problems aggravated with the mixing of topsoil and clay subsoils are aggravated if construction is permitted to proceed during wet weather. Evidence presented at the hearing established that, if construction vehicles are permitted to work in weather in which a farmer would not work his fields, there is a real danger that delicate layers of topsoil will become intermixed with clay, creating a soil condition that is virtually impossible to remedy.

A number of landowners represented at the hearings requested that the Board make provision for the appointment of an independent inspector who would have control over construction procedures, including the power to shut down construction in wet weather. The Board has directed an independent environmental inspector be appointed to monitor construction. However, while acknowledging the validity of the concerns of the landowners, the Board was not prepared to infringe on Union Gas' sole authority to determine when weather may justify the termination of construction activity.

In explaining its decision, the Board stated:

"The board concurs with board staff that specific conditions related to individual Landowners are matters better left to private negotiations, rather than imposed as conditions of approval. The board notes specific conditions could result in significant costs to Union Gas and have financial impact on the landowners. In the board's opinion, such conditions might be better considered during negotiations which can deal concurrently with unique construction techniques, mitigation measures and compensation levels."

Landowners concerned about potential impact of construction on their lands should take note of the Board's direction. Union Gas has undertaken to the Board to discuss with each landowner the landowner's preferred topsoil stripping requirements. The Board did hear evidence that mixing of subsoils with topsoils and erosion might be reduced if topsoil and different layers of subsoils were removed and stored separately and if soils were restored to their original strata and compaction levels.

Particularly in view of the limitation of the powers granted to the independent environmental inspector, such landowners should include in their negotiations with Union Gas consideration of site-specific construction methods and techniques to attempt to limit long-term damage to their lands.