Levelling, fractionation and density of structures of water bodies in Loire-Bretagne

Calculation of the staging rate which is the ratio of the sum of the heights of fall of obstacles to flow (ROE) on the natural elevation of the main drains of water body (pruned from their Strahler rank 1). The fractionation rate results from the same treatment of the sum of the drop heights, this time divided by the length of the section. Density is the sum of the works divided by the length of the main drains of water body.