• Time in-water work requiring the use of explosives to prevent disruption of vulnerable fish life stages, including eggs and larvae, by adhering to appropriate fisheries timing windows.

• Isolate the work site to exclude fish from within the blast area by using bubble/air curtains (i.e., a column of bubbled water extending from the substrate to the water surface as generated by forcing large volumes of air through a perforated pipe/hose), cofferdams or aquadams.

• Remove any fish trapped within the isolated area and release unharmed beyond the blast area prior to initiating blasting

• Minimize blast charge weights used and subdivide each charge into a series of smaller charges in blast holes (i.e., decking) with a minimum 25 millisecond (1/1000 seconds) delay between charge detonations (see Figure 1).

• Back-fill blast holes (stemmed) with sand or gravel to grade or to streambed/water interface to confine the blast.

• Place blasting mats over top of holes to minimize scattering of blast debris around the area.

• Do not use ammonium nitrate based explosives in or near water due to the production of toxic by-products.

• Remove all blasting debris and other associated equipment/products from the blast area.

Figure 1: Sample Blasting Arrangement

Per Fig. 1: 20 kg total weight of charge; 25 msecs delay between charges and blast holes; and decking of charges within holes.

• Ensure that machinery arrives on site in a clean condition and is maintained free of fluid leaks, invasive species and noxious weeds.