The construction, improvement or repair of a culvert with an arch must meet the following conditions:(1) the work area must be dried;
(2) the length of an arch must be not more than 24 m;
(3) an arch must be installed in the natural axis of the watercourse, in a relatively straight section whose banks are well defined. The length of an arch must be greater than 80% of the length of the thalweg of the section of the watercourse that will be disrupted by the work;
(4) an arch must not have the effect of reducing the width of the watercourse, measured from the upper limit of the banks;
(5) the walls of a wooden culvert or the shoes of an arch other than wooden must be installed outside the upper limit of the bank;
(6) the parts of each shoe of an arch other than wooden must be installed so as to form a continuous shoe and be attached over the whole length of the arch. Where there are materials, in particular in millwork wood or concrete, between the foundations and the shoes of an arch other than wooden, they must be attached to the shoes and cover their whole length;
(7) the walls of a wooden culvert or the shoes of an arch other than wooden must be installed on level foundations consolidated over the whole length of the arch. The foundations must be below the thalweg. Where the banks are disturbed by the work, the foundations must be at least 300 mm under the thalweg. If rock is present before reaching that depth, the walls or shoes must be anchored to the rock. For ground with weak bearing capacity, the walls or shoes must be installed on foundations made of a granular blanket at least 400 mm thick;
(8) the walls, shoes, foundations and materials placed between the shoes and the foundations of an arch must be adequately protected with riprap that is flood resistant in order to prevent scouring. The riprap of an arch must not encroach on the bed of the reconstituted watercourse;
(9) a section of watercourse disrupted by the construction, improvement or repair work of a culvert with an arch must be reconstituted by meeting the following conditions:(a) the reconstituted section of the watercourse must have the same width as that measured from the upper limit of the banks before the work;
(b) the bed must be reconstituted with heterogeneous materials similar to that constituting the bed of the natural watercourse to which big rocks must be added;
(c) wood debris, organic matter and topsoil may not be used to reconstitute the bed. The materials that may be used must include enough fine particles to seal the reconstituted bed. Where materials from the bed excavated during the work are used to reconstitute the bed, only surface materials may be used;
(d) a canal must be laid out in the reconstituted section of the watercourse in order to concentrate the water during the low flow period;
(e) the water of the watercourse must be gradually re-circulated in the work area to allow the adjustment and imbrication of the materials of the reconstituted bed and thus ensure the imperviousness of the bed;
(f) in a salmonid watercourse, the devices used to temporarily dry the work area must be removed gradually so that 2/3 of the flow of the watercourse is re-circulated in the work area;
(g) in a salmonid watercourse, the arch, riprap, bed and banks located in the work area must be cleaned to remove fine particles deposited on the surface. The cleaning must take place before opening the cofferdam located downstream from the culvert with an arch;
(h) in a salmonid watercourse, roily water must be pumped outside the work area to vegetation areas located more than 20 m from the watercourse. The 20-m distance is measured from the limit that separates the stand from the watercourse or, in the presence of a riparian ecotone, from the limit of the ecotone farthest from the environment to be protected. The water must be clear before opening the cofferdam located downstream from the culvert with an arch and before removing all the devices used to temporarily dry the work area.