The project is located within the Adour-Garonne basin. The numerous water tables that are present in this area are very permeable and being fed by rainfall which infiltrates the soil, but also by the rivers they lead to the alluvial plains.
The improvement of water resource protection is clearly one of the objectives of the national road 10 transformation into the A63 highway.
As part of the A63 transformation into a 2×3 lanes highway, a water police file has been drawn up in accordance with article R.214-6 of the Code of the Environment.
47 multi-purpose structures involved in stormwater treatment have been completed and deemed to compliant due to their design. The monitoring and maintenance of the devices have been the subject of the establishment of procedures, specific to each type of structure being implemented by the operator.
19 structures ensuring hydraulic transparency, (that is to say : the passage of water when the road intersects a watercourse), were carried out and verified. All the structures were sized for an 100 years of rain under the A63 occurrence.
The 3 derivative rivers (the Mariné stream, one of its tributaries, and the Maroutine stream) have intermittent flow. Plantations on each bank on the Maroutine stream were carried out in December 2014, making it easier for wildlife to get the use of these reworked lands.
The use by the operator of salts and phytosanitary products is controlled and carried out in satisfactory proportions. All optimizations by reducing the quantities of products are constantly sought.
Ecological monitoring of watercourse is regularly realized and has not shown any negative impact linked to the infrastructure yet.