Appendix V: Isolation of the Work Area

Table of Contents

Background

Protection of water quality within your project area is one of the primary focuses of all instream works standards and best practices. By ensuring complete and thorough isolation of your work area, you can help to protect water and habitat quality for aquatic life within adjacent and downstream waters.

Objectives

The objective of this set of best practices is to ensure that the water quality standards are met and aquatic species and habitats protected during instream works through the isolation of the work area from flow.

Note:

The following specific standards for work site isolation are provided in Subsection 44(1)(x) of the Water Act Regulations:

Temporary diversion construction around or through a work site (Subsection 44(1)(x)) is permitted for works providing that the worksite is no larger than the minimum area required, and

1. if pumps, pipes or conduits are used to divert water around or through the worksite,
    
   1. the pumps, pipes or conduits are sized to divert the 1 in 10 year maximum daily flow for the period of construction, and
       
   2. any pump or intake withdrawing water from fish bearing waters is screened in accordance with the Fish Screening Directive of the Department of Fisheries and Oceans (Canada),
       
2. if cofferdams are used to isolate successive parts of the construction at the worksite,
    
   1. the cofferdams are designed by a professional engineer and constructed in accordance with that design, and
       
   2. the natural channel remaining outside of the cofferdams is adequate to pass the 1 in 10 year maximum daily flow during the period of construction, or
       
3. if ditches are used to divert flow around the worksite,
    
   1. the flow of water diverted remains within the stream channel,
       
   2. the ditches are designed and constructed to divert the 1 in 10 year maximum daily flow around or through the worksite and are protected from any anticipated erosion during the period of construction and use of the ditch, and
       
   3. the ditches are completely backfilled and the area returned as closely as possible to the natural state on completion of the works.

Operational Best Practices

To ensure your works meet the requirements of applicable legislation:

Isolation of the Work Area

• Isolate your work area from all flowing water, but do not cut off flow to downstream portions of the stream at any time during construction.
   
• Temporarily divert, enclose or pump the water around the work site. Ensure the point of discharge to the creek is located immediately downstream of the work site to minimize disturbance to downstream populations and habitats.

Appendix IV: Concrete Works | Appendix VI: Salvage of Fish and/or Wildlife

Table of Contents