Road Deactivation and Restoration Work after Wild Fire within a Domestic Watershed

Fireguard trail rehabilitation using soil bioengineering techniques on a steep gully sideslope in a domestic watershed

Location: Hidden Creek, Arrow Forest District

Client: Ministry of Forests, Southeast Fire Centre

Objective: To ensure that all fireguard trails and roads are stabilized, natural drainage patterns are maintained and surface soil erosion is minimized.

Fireguard trails were constructed in the attempt to contain a wildfire in the Hidden Creek watershed in August 2003. Trails were constructed following a steep grade with little or no consideration for drainage control. In addition, some gullies were dammed to act as sumps used for fire fighting.

Fireguard trails cross moderately steep terrain composed of sandy till and broken or completely decomposed (saprolite) bedrock. Bedrock in the area includes granitic rock, which is susceptible to chemical weathering and often decomposes in situ to highly erodible pure sand and gravel.

Carol Wallace Consulting was retained by the Ministry of Forests, Southeast Fire Centre in August, 2003 to prepare fireguard trail rehabilitation prescriptions in the Hidden Creek watershed.

A total of 17 kilometres of trails and roads were assessed and required prescriptions. Prescriptions focused on restoring the natural surface drainage patterns where possible by using cross ditches where required. Some pull back was required where oversteepened fill was supported by standing timber, often on switchbacks and steeper terrain. Gullies that were filled in or plugged were restored. Once these structures were in place, available slash and large woody debris were placed on the trails to act as natural sediment traps. Woody debris was firmly placed to ensure that they were not undermined. Grass seeding occurred concurrently with deactivation.

The risk of sediment delivery to the stream was considered in the prescriptions, and soil bioengineering techniques were recommended in an area where the sediment delivery potential was rated as high. Straw wattles were installed where the fireguard trail follows a 65% grade down the fall line directly into the stream gully. The work was implemented by Terra Erosion Control Ltd. and will help to reduce surface erosion and the amount of sediment entering the stream.